Agenda packet — Los Banos City Council, July 6, 2022 (part 2 of 7)

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FIGURE 24 - MONITORING SITES FOR DEPLETIONS OF INTERCONNCETED SURFACE WATER MW 92
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3.4 Undesirable Results
This section describes undesirable results for each sustainability indicator. Undesirable results occur when significant and unreasonable effects for any of the sustainability indicators are caused by groundwater conditions throughout the basin. Groundwater conditions were analyzed to determine the potential effects on beneficial uses and users of groundwater. An Undesirable Result must be defined at the Subbasin level. The SJREC worked with the other GSA’s in the Delta-Mendota Subbasin to define Undesirable Results for each sustainability indicator.

3.4.1 Chronic Lowering of Groundwater Levels
An undesirable result for chronic lowering of groundwater levels is defined as: chronic changes in groundwater levels that diminish access to groundwater, causing significant and unreasonable impacts to beneficial uses and users of groundwater.significant and unreasonable chronic change in water levels, as defined by each GSP Group, that has an impact on the beneficial users of groundwater in the Subbasin through either intra- and/or inter-basin actions.

The SJREC GSP Group does not experience and is not likely to experience a significant and unreasonable lowering of groundwater levels. Even so, sustainable management criteria have been established for this sustainability indicator. The SJREC GSP Group recharges more water than is extracted. Trigger levels have been established to recover aquifer water levels before nearing an Undesirable Result.

Significant and unreasonable impacts to beneficial uses and users of groundwater are substantially increased costs associated with higher total pumping lift, lowering pumps, drilling deeper wells or otherwise modifying wells to access groundwater, securing alternative water sources, or required mitigation of groundwater dependent ecosystems. Significant and unreasonable is quantitatively defined as exceeding the MT at more than 50% of representative monitoring sites by aquifer in a GSP area.Significant and unreasonable lowering of groundwater levels in the SJREC GSP Group occurs when water levels in all of the management areas, drop below the minimum threshold shown on Table 39 and the SJREC GSP Group has extracted more than their sustainable yield of 189 TAF/year over the most recent 10 year period; described in Section 3.1.1. In management areas not experiencing impacts on groundwater levels prior to the submittal of this plan, sustainable areas, a three year water level trend was used to extrapolate what the water level for an additional drought year beyond the historic low would be. The minimum threshold represents a 25% increase in depth to water below the trigger water level established based on an additional drought year beyond the historic low water level. This section will be periodically reviewed and updated with the best available information.

3.4.2 Reduction of Groundwater Storage
An undesirable result for reduction of groundwater storage is defined as: a chronic decrease in groundwater storage that causes a significant and unreasonable impact to the beneficial uses and users of groundwater.significant and unreasonable chronic decrease in groundwater storage, as defined by each GSP Group, that has an impact on the beneficial users of groundwater in the Subbasin through either intra- and/or inter-basin actions.

The SJREC GSP Group does not experience and is not likely to experience a significant and unreasonable reduction of groundwater storage. Even so, sustainable management criteria have been established for this sustainability indicator. The SJREC GSP Group recharges more water than is extracted. As mentioned previously, reduction in groundwater storage will be managed consistent with the 211
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sustainability indicator for chronic lowering of water levels. See Section 3.4.1 for details on what constitutes significant and unreasonable for reduced groundwater storage. This section will be periodically reviewed and updated with the best available information. A significant and unreasonable impact to beneficial uses and users of groundwater is insufficient water storage to maintain beneficial uses and natural resource areas in the Subbasin, including the conjunctive use of groundwater.

3.4.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. As defined in § 354.26. Undesirable Results: part (d) An agency that is able to demonstrate that undesirable results related to one or more sustainability indicators are not present and are not likely to occur in a basin shall not be required to establish criteria for undesirable results related to those sustainability indicators. For these reasons, the SJREC GSP Group has not established any triggers for this sustainability indicator.

3.4.4 Degraded Water Quality
An undesirable result for degraded water quality is defined as: Degradation of groundwater quality as a result of groundwater management activities that causes significant and unreasonable impacts to beneficial uses and users of groundwater. Significant and unreasonable degraded water quality is defined as impacts to beneficial uses and users of groundwater as a result of groundwater management activities are the migration of contaminant plumes or elevated concentrations of constituents of concern that reduce groundwater availability, and the degradation of surface water quality as a result of groundwater migration that substantially impair an existing beneficial use. Significant and unreasonable is quantitatively defined as exceeding the MT at more than 50% of representative monitoring sites by aquifer in a GSP area where current groundwater quality (as established in the Subbasins GSPs) does not exceed 1,000 mg/L TDS.as groundwater extractions inducing the migration of a contamination plume that makes the water unusable for beneficial use. The biggest groundwater quality concern for the SJREC is the migration of saline water from upslope drainage areas. An Undesirable Result would occur if the migration of the poor quality groundwater that exceeds the amount that can be feasibly mitigated by the SJREC. As mentioned previously, this Undesirable Result is indicative of a neighboring GSP’s inability to not impact another GSP’s ability to achieve sustainability and will serve as an indicator of enhanced monitoring and management collaboration.

3.4.5 Land Subsidence
An undesirable result for land subsidence is defined as: Changes in ground surface elevation that cause damage to critical infrastructure, including significant and unreasonable reductions of conveyance capacity, impacts to natural resource areas, or conditions that threaten public health and safetychanges in ground surface elevation that cause damage to critical infrastructure that would cause significant and unreasonable reductions of conveyance capacity, damage to personal property, impacts to natural resources or create conditions that threaten public health and safety.

An Undesirable Result for the SJREC GSP Group is highly unlikely to occur as a direct result of groundwater extractions from the lower aquifer from the GSA’s in the SJREC GSP Group. This sustainability indicator is more likely to highlight a neighboring GSP’s impact of land subsidence and their need to address the concern. Significant and unreasonable land subsidence is defined as Significant and unreasonable damage to conveyance capacity from inelastic land subsidence is structural damage that creates an unmitigated and unmanageable reduction of design capacity or 212
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freeboard. Significant and unreasonable impacts to natural resource areas from inelastic land subsidence are unmitigated decreases in the ability to flood or drain such areas by gravity. Significant and unreasonable threats to public health and safety from inelastic land subsidence are those that cause an unmitigated reduction of freeboard that causes flooding, or unmitigated damage to roads and bridgesthe reduction in conveyance capacity for water distribution and/or damage to critical infrastructure without appropriate mitigation as a result of groundwater extractions. The SJREC are committed to working with the neighboring GSA/GSP to arrest subsidence affecting infrastructure.

Refer to Section 4.0 for more details on how the SJREC are working to solve regional subsidence stemming from groundwater extractions outside the Delta-Mendota Subbasin.

3.4.6 Depletions of Interconnected Surface Water
An undesirable result of depletions of interconnected surface water is defined as: depletions of interconnected surface water as a direct result of groundwater pumping that cause significant and unreasonable impacts on natural resources or downstream beneficial uses and users.depletions of interconnected surface water, as defined by each GSP Group, that have significant and unreasonable adverse impacts on the beneficial uses of surface water.

Significant and unreasonable depletion of interconnected surface water occurs when groundwater extraction from the SJREC GSP Group decreases streamflow to a significant and unreasonable level for beneficial users in a stretch of the San Joaquin River that was historically losing (seeping from the river).

Significant and unreasonable impacts on natural resources or downstream beneficial uses and users of groundwater are a reduction in available surface water supplies for natural resource areas, and reductions in downstream water availability as a result of increased streamflow depletions along the San Joaquin River when compared to similar historic water year types.

3.5 Monitoring Network
The monitoring network shall be developed including monitoring objective, monitoring protocols, and data reporting requirements. The monitoring network shall promote the collection of data of sufficient quality, frequency, and distribution to characterize groundwater and related surface water conditions in the plan and evaluate changing conditions that occur through implementation of the plan.

3.5.1 Description of Monitoring Network
Some water level monitoring sites have continuous monitoring while most of the other sites are either measured in the field every month or quarterly. Water quality samples are taken at least annually in agriculture wells and significantly more frequently in the small community supply wells. The SJRRP conducts semi-annual land subsidence surveys. This monitoring network has proven vital for successful implementation of this plan. Long-term hydrographs (over 20 years) and water quality trends over time are reviewed each year to determine seasonal conditions, short-term hydrologic cycle conditions and long-term impacts on groundwater.

The shallow monitor wells near the San Joaquin River will be used to determine groundwater and surface water related conditions and the potential impact to interconnected water. The goal of this plan is to mitigate the potential to impact interconnected waters through well construction standards. This management is preferable to the long-term sustainability of the San Joaquin River by mitigating the risk in advance.
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The current monitoring network and associated management strategies worked through the drought of 2013-2016 to protect the local beneficial users of groundwater. The SJREC GSP Group has annually collected data necessary to prepare annual updates to the water budget including the annual change in groundwater storage.

Representative sites have been chosen for each management areamonitoring zone to determine if chronic lowering of groundwater levels or significant reduction in groundwater storage has occurred.

The wells used for these representative sites typically have water level readings each month. Seawater Intrusion is not likely to occur in the Delta-Mendota Subbasin. The Camp 13 area and FCWD have an elaborate groundwater management program to help control the migration of poor quality shallow groundwater due to upslope drainage. The management includes point source control, installation of tile drainage lines and tile interceptor lines, drainage interceptor wells, and blending of poor quality groundwater. The electrical conductivity in this area is typically not useable for agriculture without blending and the monitoring is typically to control the water levels below the effective root zone to keep the soil and crops healthy. The current monitoring network for land subsidence includes the DMC (western boundary) and the SJRRP subsidence monitoring points (eastern boundary) along with continuous monitoring sites monitored by the USGS. These sites will highlight areas of concern that warrant an in-depth investigation to mitigate inelastic land subsidence. The monitoring network for interconnected surface water will utilize the shallow monitor wells near the San Joaquin River installed as part of the USBR’s SJRRP. The quantification of potential gains and losses in the San Joaquin River is challenging since various creeks and sloughs intertwine with the San Joaquin River and provide an unmetered point source introduction of water. In order to avoid complicated and costly monitoring, the SJREC GSP Group has proposed to mitigate the risk of significantly and unreasonably depleting interconnected surface water through well construction procedures.

Each sustainability indicator has a representative site, described in section 3.5.3, with the exception of degraded groundwater quality which is actively managed through water level control as mentioned above.

The SJREC GSP Group collects data and has reported consistent with the standards prescribed in the SGMA. Refer to Appendix O for more details on the BMP for the monitoring network. For more details regarding the how the monitoring network works with the SMC and maps of the representative monitoring sites, refer to Sections 3.3 and 3.4.

3.5.2 Monitoring Protocols for Data Collection and Monitoring The SJREC updated the DWR BMP for monitoring protocols to describe the consistency of technical standards, data collection methods and other procedures to ensure comparable data and methodologies. When reviewing data the first and foremost step is to ensure that the person reviewing the data has the correct units and is using the correct reference. For more details on the SJREC BMP for monitoring protocols refer to Appendix N of this GSP.

3.5.3 Representative Monitoring
In the 1990’s, the SJRECWA developed an AB 3030 Groundwater Management Plan. One aspect of that plan was the development of groundwater management areasmonitoring zones. Those management areasmonitoring zones have proven effective managing groundwater and have carried over into this GSP. The SJREC have sentinel wells (representative monitoring) established in each management 214
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areamonitoring zone for the sustainability indicators for Chronic Lowering of Groundwater Levels, and Reduction of Groundwater Storage, and Water Quality; refer to Section 3.3 for more details and a map of the sites. Each representative site was chosen in cooperation with KDSA. Numerous hydrographs were reviewed for each management areamonitoring zone to determine the representative site. Each management areamonitoring zone has a specific yield for the upper aquifer that was defined in the USGS water supply paper 1469. Each management areamonitoring zone has a specific yield and a water level from a representative site which are used conjunctively to determine the change in groundwater storage. Therefore, groundwater elevations are used as a proxy for determining the SMC for a Reduction in Groundwater Storage.

The SJREC are using the continuous land surface monitoring sites to represent the Land Subsidence network. Additionally, the SJREC will refer to the SJRRP subsidence monitoring network and the subsidence surveys on the DMC to look at subsidence in the region. The subsidence network along the DMC will establish the western boundary conditions while the SJRRP program will establish the eastern boundary conditions. In areas of land subsidence, a detailed review of groundwater levels including drawdown are vitally important to develop a sustainable plan to stop subsidence. Since the SJREC have minimal pumping from the lower aquifer, the land subsidence representative monitoring network will be reviewed to determine 1) the amount of subsidence occurring, 2) where subsidence may be originating and 3) potential impacts to critical infrastructure. Refer to the previous sections for more details and a map of the representative land subsidence monitoring locations.

The SJREC will be reviewing shallow monitor wells near the San Joaquin River to determine impacts to interconnected surface water and groundwater. The representative monitoring network and map are detailed in the previous sections. The primary goal described in the SMC for this sustainability indicator is to use well construction procedures to mitigate the potential for undesirable results. It is anticipated that a representative monitoring network will likely not be needed in the future since the SJREC plan is to prevent the possibility of the undesirable result occurring and therefore limited the necessity for a robust monitoring network.

The representative monitoring for Degraded Groundwater Quality is further described in Section 3.3 and Appendix I. The major groundwater quality concern described in this GSP is the migration of shallow, saline groundwater from upslope lands. This saline water has mostly effected Management AreasMonitoring Zones F and I; respectively CCID Camp 13 area and FCWD. For more details refer to Section 4.2.4 of this plan. The migration of saline water is a regional problem that can cause site specific concerns. For this reason, a representative site has not been selected and the growers in this area actively manage water levels through the use of tile drainage systems to control the water level to keep the poor quality groundwater from inundating the crop root zone.

3.5.4 Assessment and Improvement of Monitoring Network
The SJREC have actively monitored and managed groundwater for decades. In the 1990’s the Exchange Contractors embarked on several groundwater investigations to determine appropriate groundwater management and to maintain a healthy aquifer for the small communities adjacent to the service area.

Through these investigations KDSA recommended to fill data gaps and improve the monitoring network in order to better understand the groundwater conditions and groundwater flows in and around the SJREC area.
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The existing monitoring network was established to monitor groundwater conditions each year through the annual groundwater reports prepared over the last two decades. The results of the groundwater report are reviewed by KDSA. If a problem starts to present itself through the annual report, the SJREC worked with KDSA to develop a more in-depth and site specific analysis to determine the appropriate course of action to mitigate the concern. One such example of the success of the monitoring network is the Red Top Area Subsidence Mitigation Project. The USBR thought that subsidence may be occurring in the Red Top Area. The SJREC had experience in recognizing and dealing with subsidence and started to do a detailed investigation. The analysis showed that there were wells perforated below the Corcoran Clay that were causing subsidence in the area. The SJREC worked with the local landowners to study the problem and work on a solution to stop subsidence near Sack Dam, the headworks of SLCC. This project is further described in Section 4.1.7.

The SJREC GSP Group does not have any data gaps that could affect the ability of the SJREC GSP to achieve sustainability. Active groundwater management for decades has afforded the SJREC GSP Group a robust groundwater monitoring system. The SJREC GSP Group is working with the other GSA’s to develop a robust network to monitor and manage interconnected surface water.

Although the SJREC GSP Group is not the cause of inelastic subsidence in the area, a more robust lower aquifer groundwater monitoring network could help the Delta-Mendota Subbasin along with the neighboring subbasins gain a better understanding of the lower aquifer. The main reason for the lack of water level data in the lower aquifer is due to the lack of wells perforated in that zone. Drilling monitor wells in the lower aquifer is an expensive task. Since the SJREC GSP Group has limited groundwater extractions from the lower aquifer, the group has historically chosen to use resources to monitor and manage in other locations. An expanded lower aquifer groundwater monitoring network will not impact the SJREC groundwater management and is therefore not considered a cost effective data gap that should be filled. Rather, the SJREC will continue to work with the neighboring GSA’s to enhance a lower aquifer groundwater monitoring network to help solve subsidence originating outside of the SJREC service area.

While the current SJREC groundwater monitoring network has proven effective in managing the local aquifers, the SJREC GSP Group is committed to reviewing the network each year and to make any necessary modifications to maintain sustainability. Furthermore, during the drought of 2013-2016, water levels in parts of the SJREC dropped below trigger levels and management actions were implemented to protect the beneficial users of groundwater in the area. 216
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4.0 PROJECTS AND MANAGEMENT ACTIONS TO ACHIEVE

SUSTAINABILITY GOAL

4.1 Projects
The SJREC GSA, working conjunctively with the San Joaquin River Exchange Contractors Water Authority, has developed a Water Resource Plan to avoid potential impacts from Critical Years under the Exchange Contract and to meet peak irrigation demand. The SJREC are sustainably managing our aquifers and these projects are not intended to mitigate Undesirable Results in this plan. Rather, these projects will provide better management of our surface water supplies, which have the additional benefit of buttressing our groundwater supply, and helps the neighboring agencies in managing their water portfolio’s. Many of these projects are done in collaboration between the SJREC and neighboring agencies to provide regional sustainability. These Projects have either been fully developed or are currently under development.

4.1.1 Los Banos Creek Diversion Facility (Complete)

4.1.2 Los Banos Creek Recharge and Recovery (Expansion Under Development)

4.1.3 Los Banos Creek Storage Project (Under Development)

4.1.4 Orestimba Creek Recharge and Recovery (Expansion Under Development)

4.1.5 BB Limited Groundwater Recharge and Recovery (Under Development)

4.1.6 Farmers Water District Groundwater Recharge and Recovery (Under Development)

4.1.7 Summary of Active Water Resource Projects 4.1.1-4.1.5

4.1.8 Red Top Area Subsidence Mitigation (Complete on-going)

4.1.1 Los Banos Creek Diversion Facility
The Los Banos Creek Diversion Facility is located southwest of the City of Los Banos where the Los Banos Creek crosses the DMC. The project participants for this facility include the San Luis Water District, Grassland Water District, and the member agencies of the SJRECWA. Construction for this project was completed in 2017. The facility has been tested and is operational. This project required close coordination with both state and federal agencies. CCID worked with the USBR to prepare a joint CEQA/NEPA environmental review resulting in a Mitigated Negative Declaration and Mitigated Finding of No Significant Impact (SCH# 2013021001). The following permits were also required prior to construction: California Department of Fish and Wildlife Section 1600 Streambed Alteration Permit, Central Valley Regional Water Quality Control Board Clean Water Act Section 401 Permit, and United States Army Corp of Engineers Clean Water Act Section 404 Permit. This project was made accessible to the public consistent with CEQA/NEPA requirements.

The Los Banos Creek Diversion Facility is located just upstream of where the DMC siphon crosses the Los Banos Creek. The project consists of a gated check structure spanning Los Banos Creek, a turnout structure on the creek, an outlet structure on the DMC, and a box culvert connecting the turnout and outlet. The operation of this facility will keep the first 50 cfs of flood flows released from the Los Banos Creek Detention Reservoir in the creek to maintain historical recharge and can divert up to 250 cfs of flood releases into the DMC. The source water for this project is from runoff in the Los Banos Creek watershed and will be put to beneficial use during times of reservoir releases. The project is designed to also deliver water from the DMC into the Los Banos Creek. This project will provide additional flood protection to the City of Los Banos, a Disadvantaged Community, and also provide wetland benefits 217
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through relieved pressure from flood flows on wetland habitat and an additional useable water supply.

The Exchange Contractors average annual yield of the project is 3,500 acre-feet/year. Yield for the project will be split, as necessary, for in-lieu groundwater recharge within the SJREC service area or sent to the Los Banos Creek Recharge and Recovery Project. The total cost of the project was about $3,100,000.

The operation of this project will reduce the net extractions from the local aquifer through in-lieu use of the water and increased recharge, thereby increasing Groundwater Storage and raising Groundwater Levels.

The SJREC GSA is working with neighboring GSA’s and Water Districts to implement this project, among others, in a sustainable manner. Successful and sustainable management of groundwater is best achieved through local collaboration with interested parties.

4.1.2 Los Banos Creek Recharge and Recovery
The Los Banos Creek Recharge and Recovery Project is along the Los Banos Creek between Pioneer Road and Sunset Avenue, southwest of the City of Los Banos. The feasibility of this project has been analyzed.

The environmental review for this project will begin in 2019. A joint CEQA/NEPA Mitigated Negative Declaration and Mitigated Finding of No Significant Impact is expected on this project. Anticipated permits for this project include: Merced County Well Construction Permit, California Department of Fish and Wildlife Section 1600 Streambed Alteration Permit, Central Valley Regional Water Quality Control Board Clean Water Act Section 401 Permit, and United States Army Corp of Engineers Clean Water Act Section 404 Permit. This project will be made accessible to the public consistent with CEQA/NEPA requirements.

This project will use an existing abandoned gravel pit and an adjacent field as a recharge facility. Flood water and/or surface water from the San Joaquin River Exchange Contractor entities, will be delivered to the site from the CCID Outside Canal and/or down the Los Banos Creek from the Los Banos Creek Diversion Facility. The approximately 60-acre site can recharge upwards of 4,500 acre-feet per year.

During a Critical Year, the entities of the San Joaquin River Exchange Contractors can extract up to 7,000 acre-feet of stored groundwater. This facility will be managed to recharge and store more water than will be extracted. The excess recharged water will help offset regional groundwater usage along Los Banos Creek. The operations of this facility will help achieve regional sustainability specifically contributing to raising groundwater levels, increasing groundwater storage and improving groundwater quality. The SJRECWA is expected to receive $3,200,00 in federal disaster relief funding through the California Office of Emergency Services to cover the total cost of the project of $4,600,000.

4.1.3 Los Banos Creek Storage Project
The Los Banos Creek Storage Project makes use of the existing Los Banos Creek Detention Reservoir (LBCDR). The feasibility of this project has been analyzed. A joint CEQA/NEPA Mitigated Negative Declaration and Mitigated Finding of No Significant Impact is expected on this project. Anticipated permits for this project include: State Water Resources Control Board Point of Rediversion and Restorage, California Department of Fish and Wildlife Section 1600 Streambed Alteration Permit, Central 218
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Valley Regional Water Quality Control Board Clean Water Act Section 401 Permit, United States Army Corp of Engineers Clean Water Act Section 404 Permit and access & use of the existing and proposed facilities within the USBR right of way. This project will be made accessible to the public consistent with CEQA/NEPA requirements.

The Los Banos Creek Detention Dam (LBCDD) and LBCDR are Federally owned and State operated facilities that were constructed jointly by the USBR and the California DWR as part of the San Luis Unit of the Central Valley Project (CVP) to provide flood control protection to the San Luis Canal. The LBCDR because of its proximity also provides flood protection to the City of Los Banos. The California Department of Parks and Recreation (DPR) operates the public recreational facilities at LBCDR. The dam and reservoir are located approximately six miles southwest of the City of Los Banos. The dam became operational in 1962 and the reservoir has a maximum storage of 34,500 acre-feet (AF). The LBCDR is currently operated near or below the United States Army Corp of Engineers (USACE) winter period conservation pool of 20,600 AF of storage, even though summer operations allow storage of 34,500 AF as authorized by the USACE guidance manual.

Currently the dam is strictly operated as a flood control facility during the late fall and winter months. A group of local agencies have proposed to operate the LBCDD in the spring to route natural Los Banos Creek flows to riparian lands downstream of the facility making space available for storage and thereby increasing the overall benefit of the Los Banos Creek Diversion Facility (See Section 4.1.1). The Project Participants consist of the San Luis Water District (SLWD), Grassland Water District (GWD), and the member agencies of the San Joaquin River Exchange Contractors Water Authority (SJRECWA or Exchange Contractors) which consists of Central California Irrigation District (CCID), San Luis Canal Company (SLCC), Firebaugh Canal Water District (FCWD) and Columbia Canal Company (CCC). The Project Participants would pump conserved water or groundwater into the available storage space in the spring and early summer and return the water to them in the summer or fall to meet peak irrigation or habitat water demands.

The purpose of the proposed Project is to more effectively manage LBCDR in order to maximize flood control and downstream benefits while maintaining recreational use of the reservoir. Project operations would be seasonal in nature and would still follow the current practice of limiting storage to the winter USACE flood control target at all times. The water pumped into the reservoir for storage by the Project Participants would be either conserved water or groundwater. During the flood control season, and potentially year-round, water in the reservoir would be allowed to accumulate and be released from the reservoir to meet Project Participant riparian demand. Starting in the spring, the project participants would pump their conserved water or groundwater into available LBCDD space for temporary storage and return to one or all participant to meet peak irrigation or wildlife water management demands.

Some of the project benefits include: improved water supply management and reliability, development of additional Incremental Level 4 refuge water supply, increased flood control protection to downstream facilities, increased access to the LBCDR recreational facilities during most flood release scenarios, increased recreational opportunities at LBCDR, along LBC and in GWD, environmental enhancements at LBCDR, along LBC and in GWD, and Disadvantaged Community (DAC) water supply and water quality improvements.

The Project includes the installation of a pipeline to deliver water from the existing SLWD Reservoir #8, located on a ridge above LBCDR, into the reservoir. The boat ramp was entirely out of the water in 2015 219
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which reduced access to the lake for recreational fishing during that time. This project proposes an extension to the existing boat ramp to ensure recreational opportunities during times of low reservoir elevation. The current access to the recreational facilities including a boat ramp, picnic area and campgrounds, is currently through a low water crossing in the Los Banos Creek below the dam. During times of releases above 50 cfs, all access to the reservoir is restricted. This project also proposes the installation of box culvert to provide access to the reservoir nearly year-round while also mitigating traffic traveling through the creek itself.

LBCDD would be operated in the October through February time period to release natural Los Banos Creek flow downstream for use by riparian lands consistent with the benefits described above and in Sections 4.1.1 and 4.1.2. The operation would also create space in the LBCDD to be used to temporarily store water. Then starting around March 15th of each year (outside flood control season) the Participants would begin temporarily storing up to 8,000 acre-feet of conserved water or groundwater in available LBCDD space. The stored water would be returned to the participating Districts during peak irrigation or wildlife water management times via the Los Banos Creek and Delta-Mendota Canal. The Dam operations would preserve and enhance but be consistent with the current flood control criteria and operation. The source of the water used to temporarily store in the reservoir is Project Participant water that is already south of the Sacramento-San Joaquin Delta and has no direct impacts to the San Joaquin River and outflow through the Delta. Furthermore, once the water is released from the reservoir it will be directly used for beneficial use for agriculture and wetland habitat. This project does not increase pumping at the Bill Jones Pumping Plant (CVP pumps in the Delta) or impact flows in the San Joaquin River out to the Delta. Rather, this project provides operational flexibility to water supply that has already moved through the Bill Jones Pumping Plant while increasing the overall beneficial use of the water.

4.1.4 Orestimba Creek Recharge and Recovery
The Orestimba Creek Recharge and Recovery Project is located west of the City of Newman on an existing farm field. The project participants for this facility include the Del Puerto Water District and the SJRECWA entities. This project consists of an existing 20-acre recharge facility that was constructed in 2018 and an additional 60-acre facility to be constructed by 20232021. The 20-acre project required close coordination with both state and federal agencies. CCID worked with the USBR to prepare a joint CEQA/NEPA environmental review resulting in a Mitigated Negative Declaration and Mitigated Finding of No Significant Impact, and it was made accessible to the public consistent with CEQA/NEPA requirements (SCH# 2017042061). The proposed 60-acre project will require CCID to work with USBR to prepare a joint CEQA/NEPA environmental review likely resulting in a Mitigated Negative Declaration and Mitigated Finding of No Significant Impact. Anticipated permits for the 60-acre site include:

Stanislaus County Well Construction Permit, California Department of Fish and Wildlife Section 1600 Streambed Alteration Permit, Central Valley Regional Water Quality Control Board Clean Water Act Section 401 Permit and United States Army Corp of Engineers Clean Water Act Section 404 Permit.

The Orestimba Creek Recharge and Recovery Project is located on existing farm land east of Eastin Road and north of Orestimba Road. Flood flows and surface water from Del Puerto Water District and/or the SJRECWA entities will be delivered to the site through an existing pipeline from the DMC. Another source of water for the recharge facility is excess flood flows from Orestimba Creek to be routed through a proposed pipeline to the project site. Diverting excess flood flows from Orestimba Creek will 220
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provide additional flood protection to the Disadvantaged Community of the City of Newman. The total 80-acre facility is expected to recharge up to 15,000 acre-feet in a given year. During a Critical Year, the member agencies of the San Joaquin River Exchange Contractors can extract up to 7,500 acre-feet of stored groundwater. This facility will be managed to recharge and store more water than will be extracted. The excess recharged water will help offset regional groundwater usage along Orestimba Creek. The operations of this facility will help achieve regional sustainability specifically contributing to raising groundwater levels, increasing groundwater storage and improving groundwater quality. The total cost to construct the existing 20-acre site was about $1,200,000. The SJRECWA is expected to received $5,900,00$6,400,000 in State grantsfederal disaster relief funding through the California Office of Emergency Services to cover the total cost of $7,900,000 for the 60-acre expansion to the project.

4.1.5 BB Limited Recharge and Recovery
The BB Limited Recharge and Recovery project is located east of the City of Mendota along the eastside of the Fresno Slough and south of the San Joaquin River. This project is on an existing 13-acre recharge site. The environmental review for this project will begin in 20192023. The project is anticipated to be fully functional in 20252020. A joint CEQA/NEPA is expected for this project resulting in a Negative Declaration and Finding of No Significant Impact. Fresno County Well Construction Permits are required for this project. This project will be made accessible to the public consistent with CEQA/NEPA requirements.

The BB Limited Recharge and Recovery project is located in an existing 13-acre site north of the existing Meyers Water Bank. Surface water from the SJREC will be delivered to the site. Additionally, excess flood water from the Kings River and/or San Joaquin Rivers will be diverted to the site. The total 13-acre facility is expected to recharge upwards of 1,500 acre-feet in a given year. During a Critical Year, the member agencies of the San Joaquin River Exchange Contractors can extract up to 4,000 acre-feet of stored groundwater. It is anticipated that the Exchange Contractors will recharge over 4,000 acre-feet over three consecutive years and ultimately extract 4,000 acre-feet in a subsequent Critical Year. This facility will be managed to recharge and store more water than will be extracted. The excess recharged water will help offset regional groundwater usage near the Mendota Pool. The operations of this facility will help achieve regional sustainability specifically contributing to raising groundwater levels, increasing groundwater storage and improving groundwater quality. The total cost of the 13-acre facility is approximately $600,000.

4.1.6 Farmers Water District Recharge and Recovery
The Farmers Water District Recharge and Recovery project is located east of the City of Mendota along the eastside of the Fresno Slough and south of the San Joaquin River in the Farmers Water District. The project participants for this facility include the Farmers Water District and the SJRECWA entities. This project consists of a proposed 90-acre recharge facility. The environmental review for this project will 221
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begin in 20192022. The project is anticipated to be fully functional in 2020.2024. A joint CEQA/NEPA is expected for this project resulting in a Mitigated Negative Declaration and a Mitigated Finding of No Significant Impact. This project will be made accessible to the public consistent with CEQA/NEPA requirements. Anticipated permits for the 90-acre site include: Fresno County Well Construction Permit, California Department of Fish and Wildlife Section 1600 Streambed Alteration Permit, Central Valley Regional Water Quality Control Board Clean Water Act Section 401 Permit and United States Army Corp of Engineers Clean Water Act Section 404 Permit.

The Farmers Water District Recharge and Recovery project is located on 90 acres of existing farm land north of the existing Meyers Water Bank and southeast of the proposed BB Limited Recharge and Recovery project. Surface water from SJRECWA entities will be delivered to the site. Additionally, excess flood water from the Kings River and/or San Joaquin River will be diverted to the site. The total 90-acre facility is expected to recharge upwards of 6,500 acre-feet in a given year. During a Critical Year, the SJRECWA entities can extract up to 4,000 acre-feet of stored groundwater. This facility will be managed to recharge and store more water than will be extracted. The excess recharged water will help offset regional groundwater usage near the Mendota Pool. The operations of this facility will help achieve regional sustainability specifically contributing to raising groundwater levels, increasing groundwater storage and improving groundwater quality. The total cost of the 90-acre facility is approximately $3,000,000.

4.1.7 Summary of Active Water Resource Projects 1-6
The San Joaquin River Exchange Contractors Active Projects 1-6 will significantly contribute to the sustainability of the Delta-Mendota Subbasin. Not only will the SJREC leave more water in the Recharge and Recovery Projects than is extracted, additional water can be recharged through the project facilities to improve groundwater conditions. The SJREC are anticipating needing dispatchable storage approximately 7% of the time through the Planning and Implementation Horizon. In these years the Exchange Contractors will recover stored groundwater to meet demand in-lieu of pumping natural groundwater. Additionally, the Exchange Contractors will recover 8,000 acre-feet of conserved water stored in the LBCDR for use during Critical Years under the Exchange Contract. This has a direct positive impact on groundwater levels and also has a benefit of 31,000 acre-feet for the regional change in groundwater storage.

4.1.8 Red Top Area Subsidence Mitigation
The Red Top Subsidence Mitigation project is located east of the San Joaquin River in the Red Top Area.

The Project Participants for this project include the SJREC and the newly formed Triangle T Water District. This existing project was constructed in 2017 and primarily consists of a pipeline under the San Joaquin River to deliver surface water from the Central California Irrigation District’s Poso Canal to the east side of the San Joaquin River. This project required close coordination with both state and federal agencies. CCID worked with the USBR to prepare a joint CEQA/NEPA environmental review resulting in a Mitigated Negative Declaration and Mitigated Finding of No Significant Impact (SCH# 2016021011). The following permits were also required prior to construction: California State Lands Commission Lease, Central Valley Flood Protection Board Permit, California Department of Fish and Wildlife Section 1600 222
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Streambed Alteration Permit, Central Valley Regional Water Quality Control Board Clean Water Act Section 401 Permit, and United States Army Corp of Engineers Clean Water Act Section 404 Permit. This project was made accessible to the public consistent with CEQA/NEPA requirements.

The Red Top Subsidence Mitigation project is in an area significantly impacted by subsidence due to extracting groundwater from the aquifer below the Corcoran Clay. The Triangle T Water District, historically solely relying on groundwater, will purchase and deliver surface water through the pipeline under the San Joaquin River. Water delivered to Triangle T Water District will either be used directly inlieu of pumping groundwater or delivered to recharge ponds. As a direct result of delivering surface water and developing a shallow groundwater recharge and recovery facility, the area will use the stored shallow groundwater and pump less water from the aquifer below the Corcoran Clay. The subsidence contribution in the Red Top Area from the Triangle T Water District will significantly reduce as a result of great collaboration between the project participants. An expert panel will review the area and determine the sustainable yield from the aquifer below the Corcoran Clay that does not cause significant or unreasonable subsidence. There is also a mandatory step-down reduction each year from 2017-2021 for groundwater extractions from below the Corcoran Clay. The annual allowable extraction from below the Corcoran Clay per acre in the Triangle T Water District is respectively; 0.90, 0.75, 0.65, 0.60 and 0.50.

The overall extraction will be limited by the lesser of the mandatory step-down reduction or recommendation from the expert panel. In addition to mitigating subsidence, this project will also contribute to regional sustainability, specifically raising groundwater levels and increasing groundwater storage. The total cost of the existing project was $1,125,000.

In addition, the Triangle T Water District is working on a proposed project to expand the acreage of recharge ponds and drill upper aquifer wells while abandoning lower aquifer wells. Pumps will be installed in the Eastside Bypass to capture flood flows and deliver to the Triangle T Water District for direct use or in-lieu use. The Triangle T Water District, through the SJRECWA, is expected to receive $9,500,00 in federal disaster relief funding through the California Office of Emergency Services, to cover the total cost of $12,600,000 for the proposed expansion to the existing project.

This project, while physically outside of the Delta-Mendota Subbasin, will have direct positive impacts on three Undesirable Results occurring outside the Subbasin. Recharging surface water into the Upper Aquifer will increase water levels and groundwater storage in the Chowchilla Subbasin. The major positive impact from this project will, and already has, reduce extractions from the Lower Aquifer resulting in mitigation of Land Subsidence. In 2015, Sack Dam, the headworks for SLCC, was subsiding at a rate of 0.5 feet/year. The subsidence rate at Sack Dam was reduced to about 0.17 feet/year after the first year of implementation of the existing project.

4.2 Management Actions
The SJREC have management actions that have been in place since the 1990’s to successfully manage groundwater in and around its service area.

4.2.1 Annual Groundwater Assessment Report
Each year the SJREC prepare an annual report (Report) of the current and historical conditions of groundwater. This report includes groundwater pumping within each member agency of the SJRECWA.

The report includes: pumping volumes, pump tests, water quality, and water levels. The report also summarizes regional groundwater pumping. This report is reviewed by our Hydrogeologist, who 223
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prepares a supplemental assessment report (Recommendation). The hydrogeologist makes a recommendation on how each management areamonitoring zone (or sub-area) within the SJREC area should be managed for the current year. The Report and Recommendation are annually reviewed and approved by the individual SJRECWA entity Board of Directors. The primary management tool is to review water levels in impacted areas. Historically, the hydrogeologist has recommended limiting the export of groundwater in those impacted areas if the groundwater elevation is below an established trigger level. This Report and Recommendation have proven essential in sustainably managing the aquifers around the districts.

4.2.2 Private Well Pumping for Credits
The member entities of the SJRECWA, allow landowners to pump private well water into the district facilities for credit. The SJREC entities have implemented a policy to regulate pumping and ensure a healthy aquifer while maintaining good service of surface water. Each year the entities work with a Hydrogeologist to prepare an annual groundwater assessment report. In the 1990’s, the entities were divided up into management areas, now termed monitoring zones. Our Hydrogeologist recommended, and the boards adopted, establishing trigger water levels to restrict the mining of groundwater in impacted areas. Groundwater cannot be exported out of an impacted area if the water level is below the trigger level. During the recent drought from 2013-2016, water levels in impacted areas dropped below the trigger. In 2017, the water levels recovered. This management action has proven effective to mitigate Chronic Lowering of Groundwater Levels and Reduction of Groundwater Storage.

All water pumped for credit must meet water quality standards. Currently, the maximum allowable Total Dissolved Solids and Boron are 1,500 TDS and 2.0 ppm, respectively. In addition, the blended water quality downstream of the well shall not exceed 700 TDS, 0.5 ppm Boron and no additional detection of Selenium. A well pumper can pump for credits every two out of three years. There is also a maximum allowable total volume that can be pumped for credit. However, the maximum allowable credit is further limited by the amount of groundwater which can be pumped without damaging other landowners or depleting groundwater storage. A groundwater consultant may be required to determine the potential impacts of pumping the well for credit. Pumping for credit must be terminated if the pumping has a detrimental impact on neighboring wells or on the groundwater table.

Since 2000, about 70% of the total pumping was subject to the curtailment of these policies and recommendation, resulting from the Hydrogeologist annual groundwater assessment report. Note that the percentage was up to about 90% during the critical water years 2014 and 2015; years of highest stress for the local aquifers. The annual groundwater assessment report, coupled with the Districts policies, have proven effective in sustainably managing groundwater even through the most recent “historic” drought.

4.2.3 Joint Groundwater Conditions Studies Between CCID and Neighboring Cities CCID nearly surrounds the following six cities: Newman, Gustine, Los Banos, Dos Palos, Firebaugh and Mendota. Three of these cities are DAC’s and the other three are Severely DAC’s. Maintaining a healthy aquifer was and is a high priority for the cities and the SJREC GSA. Starting in the early 1990’s, CCID approached the neighboring cities to embark on a joint study of the groundwater conditions surrounding the City. The cities of Newman, Gustine, Los Banos, Firebaugh and Mendota rely entirely on groundwater to meet their demand. Note that the City of Dos Palos has poor quality groundwater and has an agreement with CCID to transfer and treat surface water. These studies, updated 224
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periodically, formed a great partnership and is the basis for including each City GSA as a partner in the SJREC GSP Group. In addition, these studies form the foundation for development and implementation of sustainability criteria in and around each City. Successful implementation of the SGMA is best achieved locally through long-term partnerships.

4.2.4 Mitigation for Migration of Shallow Saline Groundwater The SJRECWA, particularly FCWD and a portion of CCID (Camp 13), have been engaged in litigation over the migration of poor quality (high electrical conductivity and high selenium) from upslope drainage areas to the south and west. Resolving this issue is of the utmost concern for FCWD and CCID for healthy soils and groundwater and also successful implementation of the SGMA. While this issue remains unresolved at the moment, FCWD and CCID have developed several management actions to help control the further migration of this poor-quality groundwater.

FCWD and Camp 13 have a perched water table, that if not controlled, would cause the overlying land to be unfarmable. Landowners in CCID and FCWD have installed buried tile lines (subsurface drainage) to control the perched groundwater table in the area and are participating in the San Joaquin River Improvement Project (SJRIP) to manage subsurface drain water produced within the region.

One successful management action for the region has been the implementation of the various components of the Westside Regional Drainage Plan; see Appendix P. Four effective strategies have been implemented to reduce drainage discharge including 1) source control, 2) groundwater management, 3) drainage reuse and 4) treatment and disposal. Source control reduces the volume of water contributing to subsurface drainage by reducing deep percolation of applied water and reducing seepage from canals and ditches. In 2002, through a joint study between the SJRECWA and the USBR, it was determined that the pumping of strategically placed wells could lower the perched water table and reduce discharge of subsurface drainage systems. As a result, 18 wells have been installed andare have successfully reduced the discharge from subsurface drainage systems. The operation of these wells have proven a vital tool for the FCWD and CCID to successfully manage groundwater and helps to control the further migration of the plume of poor-quality groundwater.

Drainage reuse is the primary function of the SJRIP. The SJRIP utilizes subsurface drain water as a source of irrigation water for salt tolerant crops. This management practice allows for the agricultural region to maintain the health of the soil with subsurface drainage lines while preventing the discharge of that drainage water to the San Joaquin River.

4.3 Implementation of Projects and Management Actions
The SJRECWA and SJREC GSA have actively managed their water resources through various Projects and Management Actions. The development of the SJREC GSP and implementation of the SGMA will work hand-in-hand with the historic practices of the member agencies of the SJRECWA. The SJREC GSA will continue to review new tools to improve management of both surface water and groundwater. One such new tool is the Soil Agricultural Groundwater Banking Index (SAGBI). Figure 25 shows the SAGBI rating for the SJREC GSP Group area.
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CHARLES TON RD W

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HALLOWELL RD

NETHERTON RD W

N RUS SELL AVE

N GALVE Z AVE

MANUCHA RD

DODDS RD
Firebaugh
Mendota
Newman
Delhi
Dos
Palos
Gustine
Hilmar-Irwin
Livingston
Los
Banos
Text
FIGURE 25 - SAGBI MAP
.
0 2.5 5 10
Miles
EXPLANATION:

SAGBI Rating:

SJREC GSP GROUP BOUNDARY

DELTA-MENDOTA SUBBASIN
Excellent
Good
Moderately Good
Moderately Poor
Poor
Very Poor
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226
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5.0 PLAN IMPLEMENTATION

5.1 Estimate of GSP Implementation Costs
Development for the SJREC GSP is anticipated to cost $700,000 which will be shared between the following GSA’s: San Joaquin River Exchange Contractors, City of Newman, City of Gustine, City of Los Banos, City of Dos Palos, City of Firebaugh, City of Mendota, Turner Island Water District – 2, County of Madera – 3, Merced County – Delta Mendota (portion), Fresno County – Management Area B (portion), further described in numerous MOU’s with the Exchange Contractors. The annual GSP cost is projected to be $50,000. During each of the five-year plan updates the projected cost is $200,000. The Exchange Contractors GSP Group has received $335,000 in funds from the Sustainable Groundwater Planning Grant Program. The Exchange Contractors have historically been actively managing groundwater and do not anticipate a significant increase in cost to monitor and report groundwater conditions. The SJREC also received Category 1 funding from the SGWP Grant to offset costs for SDAC’s.

5.2 Schedule of Implementation
The SJRECWA, and subsequent SJREC GSA, has been sustainably managing groundwater for decades.

The SJREC GSA is a net importer to groundwater. Many of the Projects and Management Actions described in Section 4.0 have already been implemented. Furthermore, the Projects and Management Actions that have yet to be implemented will only enhance the sustainability of the local aquifers and help neighboring GSA’s and GSP Groups achieve and maintain sustainability.

5.3 Annual Reporting
Consistent with Water Code Section 10728, On the April 1 following the adoption of a GSP and annually thereafter, a GSA shall submit a report to the DWR containing the following information about the basin managed in the GSP:
a) Groundwater elevation data.
b) Annual aggregated data identifying groundwater extraction for the preceding water year. c) Surface water supply used for or available for use for groundwater recharge or in-lieu use. d) Total water use.
e) Change in groundwater storage.

5.4 Periodic Evaluations
The SJREC GSA will periodically evaluate its GSP, assess changing conditions in the basin that may warrant modification of the plan or management objectives, and may adjust components in the plan. An evaluation of the plan shall focus on determining whether the actions under the plan are meeting the plan’s management objectives and whether those objectives are meeting the sustainability goal in the basin. Oftentimes, an iterative process proves most effective in managing complex plans. The SJREC GSA intends to continually update and progress groundwater management in and around its service area.
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6.0 REFERENCES AND TECHNICAL STUDIES
Below is a list of reports used for historical groundwater management in and around the San Joaquin River Exchange Contractors service area.
• Burt, C.M. and Styles, S. W., 1998. San Joaquin River Exchange Contractors Water Authority Water Use Study, Irrigation Training and Research Center, California Polytechnic State University, San Luis Obispo. Report prepared for Minasian, Spruance, Baber, Meith, Soares, and Sexton, LLP, Oroville, California.
• Burt, C.M. Freeman, B., and Howe, D., 2010. San Joaquin River Exchange Contractors Water Use Study (1997-2008), Irrigation Training and Research Center, California Polytechnic State University, San Luis Obispo. Report prepared for Minasian, Spruance, Baber, Meith, Soares, and Sexton, LLP, Oroville, California.
• Styles, Stuart W., 1998. Water Balance of the San Joaquin River Exchange Contractors Water Authority, Irrigation Training and Research Center, California Polytechnic State University, San Luis Obispo.
• Brownscombe, R. H. 1950. “Report and Recommendations on Ground Water and Land Drainage Los Banos Soil Conservation District, Merced County, California. • Central California Irrigation District, 1996-2018. Deep Well Study Summary of Central California Irrigation District Wells and Private Wells: Annual Report. • Cole, R. C., et al (1948). “Soil survey of the Newman area, California”, US Department of Agriculture, Ser. 1938, no.11, 94p.
• Cole, R. C., et al, (1952). “Soil Survey of the Los Banos Area, California”, US Department of Agriculture, Ser. 1938, no. 12, 119p.
• Croft, M. G. (1969). “Subsurface Geology of the Late Tertiary and Quaternary Water-Bearing Deposits of the Southern Part of the San Joaquin Valley, California”, US Geological Survey OpenFile Report, Menlo Park, Calif, 63p. • Davis, G. H. and J. F. Poland. (1957). Ground-Water Conditions in the Mendota- Huron Area Fresno and Kings Counties, California. USGS. Water Supply Paper No. 1360-G. • Davis, G.H., et al (1959). “Groundwater Conditions and Storage Capacity in the San Joaquin Valley, California”, US Geological Survey, Water Supply Paper 1469, 287p. • Davis, G. H., (1961). Geologic Control of Mineral Composition of Stream Waters of the Eastern Slope of the Southern Coast Ranges, California”, US Geological Survey Water-Supply Paper 1535- B 30p.
• Harradine, F. F. (1956). “Soil survey, Mendota area, California.” U.S. Department of Agriculture, Soil Conservation Service in cooperation with the University of California Agricultural Experiment Station.
• Hotchkiss, W. R., and Balding, G. O. (1971). "Geology, Hydrology, and Water Quality of the Tracy-Dos Palos Area, San Joaquin Valley, California." Open-File Report., U.S. Department of the Interior. Geological Survey. Water Resources Division.
• Ireland, R. L., Poland, J. F. and F. S. Riley, (1984). “Land Subsidence in the San Joaquin Valley, California, as of 1980”, US Geological Survey, Professional Paper 437-I, 193p. 228
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• Kenneth D. Schmidt and Associates, 1991. Groundwater Conditions in the Vicinity of the City of Los Banos, report prepared for Central California Irrigation District, Los Banos, California and City of Los Banos, Los Banos, California.
• Kenneth D. Schmidt and Associates, 1992. Groundwater Conditions in the Vicinity of the City of Gustine, California, report prepared for Central California Irrigation District, Los Banos, California and City of Gustine, Gustine, California.
• Kenneth D. Schmidt and Associates, 1992. Groundwater Conditions in the Vicinity of the City of Newman, report prepared for Central California Irrigation District, Los Banos, California and City of Newman, Newman, California.
• Kenneth D. Schmidt and Associates, 1997. AB 3030 – Groundwater Management Plan, report prepared for San Joaquin River Exchange Contractors Water Authority, Los Banos, California. • Kenneth D. Schmidt and Associates, 1997a. Groundwater Conditions in and near the Central California Irrigation District, report prepared for Central California Irrigation District, Los, Banos, California.
• Kenneth D. Schmidt and Associates, 1997b. Groundwater Flows in the San Joaquin River Exchange Contractors Service Area, report prepared for San Joaquin River Exchange Contractors Water Authority, Los Banos, California.
• Kenneth D. Schmidt and Associates, 1998. Update Groundwater Conditions in the Vicinity of the City of Los Banos, report prepared for Central California Irrigation District, Los Banos, California and City of Los Banos, Los Banos, California.
• Kenneth D. Schmidt and Associates, 1999. Groundwater Conditions in the Vicinity of the City of Mendota, report prepared for Central California Irrigation District, Los Banos, California and City of Mendota, Mendota, California.
• Kenneth D. Schmidt and Associates, 2000. Groundwater Conditions in and Near the Eastin Water District, report prepared for Central California Irrigation District, Los Banos, California and Eastin Water District.
• Kenneth D. Schmidt and Associates, 2001. Groundwater Conditions in the Vicinity of the City of Gustine, California, report prepared for Central California Irrigation District, Los Banos, California and City of Gustine, Gustine, California.
• Kenneth D. Schmidt and Associates, 2004. “Groundwater Conditions in the Firebaugh Canal Water District and CCID Camp 13 Drainage District”, prepared for SJRECWA, Los Banos, California, 50p.
• Kenneth D. Schmidt and Associates, 2007. Update on Groundwater Conditions in the San Joaquin River Exchange Contractors Service Area, report prepared for San Joaquin River Exchange Contractors, Los, Banos, California.
• Kenneth D. Schmidt and Associates, 2008. Groundwater Conditions in the Vicinity of the City of Firebaugh, in support of the Draft Environmental Impact Report for the 2030 Firebaugh General Plans, report prepared for City of Firebaugh, Firebaugh, California. • Kenneth D. Schmidt and Associates, 2008. Updated AB 3030 – Groundwater Management Plan for the San Joaquin Exchange Contractors, report prepared for San Joaquin River Exchange Contractors Water Authority, Los Banos, California.
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• Kenneth D. Schmidt and Associates, 2008-2018. Annual Report. Report on Results of Groundwater Monitoring for CCID Pumpage Program, report prepared for Central California Irrigation District, Los Banos, California.
• Kenneth D. Schmidt and Associates, 2010. Update Groundwater Conditions in the Vicinity of the City of Los Banos, report prepared for Central California Irrigation District, Los Banos, California and City of Los Banos, Los Banos, California.
• Kenneth D. Schmidt and Associates, 2013. Groundwater Conditions and Land Subsidence in the Sack Dam – Red Top Area, prepared for San Joaquin River Exchange Contractors Water Authority, Los Banos, California.
• Kenneth D. Schmidt and Associates, 2014. Updated AB 3030 Groundwater Management Plan for the San Joaquin Exchange Contractors, report prepared for San Joaquin River Exchange Contractors Water Authority, Los Banos, California.
• Kenneth D. Schmidt and Associates, 2015. Groundwater Overdraft in the Delta-Mendota Subbasin, report prepared for San Luis & Delta-Mendota Water Authority, Los Banos, California. • Luhdorff & Scalmanini, (1993). “Results of Aquifer Tests near Mendota Pool”, report prepared for US Bureau of Reclamation.
• Luhdorff and Scalmanini Consulting Engineers and Schmidt, K.D., 2001-2017. Mendota Pool Group Pumping and Monitoring Program: Annual Report. Prepared for San Joaquin River Exchange Contractors Water Authority.
• Luhdorff and Scalmanini and KDSA, (2017). “2017 Annual Report, Mendota Pool Group Pumping and Monitoring Program”, Prepared for SJRECWA, Paramount Farming Company, and MPG. • Meade, R.H., (1968). “Compaction of Sediments Underlying Areas of Land Subsidence in Central California”, US Geological Survey Professional Paper 497-D, 39p. • Miller, R.E., Green J.H., and G.H. Davis, (1971). “Geology of the Compacting Deposits in the Los Banos-Kettleman City Subsidence Area, California”, US Geological Survey Professional Paper 497-E, 46p.
• Mitten, H. T., LeBlanc, R. A., and Bertoldi, G. L. (1970). “Geology, hydrology, and quality of water in the Madera area, San Joaquin Valley, California.” U.S. Geological Survey open-file report, Menlo Park, California, 49p.
• Page, R.W. 1973. Base of Fresh Ground Water (approximately 3,000 micromhos) in the San Joaquin Valley, California. USGS. Hydrologic Investigations Atlas HA-489. • Page, R.W., (1986). “Geology of the fresh groundwater basin, Central Valley, California”, US Geological Survey Professional Paper 1401-C, 54p.
• Prokopovitch, N.P., (1969). “Land Subsidence Along Delta-Mendota Canal, California”, Rock Mechanics, 1, pp 134-144.
• Redlin, G. A., 2001. “Los Banos Area Groundwater Study”. Boyle Engineering Corporation. • Stoddard, R. (2003). “City of Los Banos Storm Drainage Master Plan Phase 1 Storm Drainage Disposal”. Stoddard & Associate Civil Engineers.
• Stromberg, L. K. (1962). “Soil Survey of Madera area, California.” U. S. Department of Agriculture, Soil Conservation Service.
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7.0 CITY OF NEWMAN GSA AREA

7.1 Background for City of Newman
The City of Newman is an expanding urban area that relies entirely on groundwater. Mutual concerns of the quantity and quality of groundwater in terms of future growth, initiated conversations between CCID and the City to investigate the long-term reliability of the surrounding aquifer. In the early 1990’s, CCID and the City jointly participated in a study of the groundwater conditions in and around the City, (KDSA 1992; Newman). Subsequent groundwater studies for the City of Newman have been completed in cooperation with CCID.

Over the years, CCID has invested in helping cities monitor, understand and manage the aquifers for the communities near the district. The relationship has resulted in a common understanding of the aquifer and a partnership which is the foundation of the SJREC GSA and the City of Newman GSA cooperating to develop this part of the GSP. Some potential impacts to the City include increased costs for the SWRCB to develop and implement a sustainable plan for the City and a standalone plan that isn’t synchronous with the lands surrounding the City. CCID recognized the potential impacts to the City of Newman, a DAC, and worked with City leaders and technical staff to understand potential opportunities and constraints of SGMA to the City. Ultimately, the City decided to form its’ own GSA with the help from the SJREC to appropriately file. The City of Newman welcomed the SJREC’s assistance in developing the required elements in a GSP. It was mutually agreed that the SJREC work with the City to develop the requirements in the GSP and to include this in a discrete Section in the SJREC GSP. This was a seamless process due to the decades of cooperation of managing groundwater for the region.

The SJREC are committed to assist this DAC to maintain sustainability through the planning and implementation horizon. The City of Newman GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix Q for a discussion on the basin setting, sustainable management criteria and projects & management actions specific to the City. Some further details are provided below.

7.2 Water Budgets for the City of Newman
Presented herein is the compilation of the historic, current and projected water budgets specific to the City of Newman GSA.

7.2.1 Historic Water Budget for the City of Newman
The City of Newman solely relies on groundwater to provide its residents drinking water. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. Groundwater pumping during this timeframe ranged from 2,100 to 2,700 AF/year with an average pumping of 2,500 AF/year. The City sends effluent to its Waste Water Treatment Facility (WWTF). They have about 160 acres of holding ponds at the WWTF. Once treated in the holding ponds, water is used to irrigate 300-400 acres of pasture, alfalfa, oats and corn. The amount of effluent used for irrigation ranged from 800 to 1,600 AF/year with an average of 1,100 AF/year. There is approximately 250 AF/year evaporation from the effluent ponds. The irrigation efficiency of the effluent 231
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water used to irrigate crops is assumed to be 70% which equates to a net crop evapotranspiration of about 550 AF/year, for a total consumptive use of about 800 AF/year.

The City water use that does not result in the production of effluent was used to water lawns, parks, etc.

The outdoor water use is the difference of pumpage and effluent and averaged about 1,400 AF/year.

Typically, a 70% irrigation efficiency is applied to urban landscape watering which results in an average annual consumptive use of about 1,000 AF/year.

The total average annual consumptive use from outdoor water use and crop demand at the WWTF is 1,800 AF/year. The City of Newman GSA covers roughly 1,250 acres. The approximate sustainable yield for the City of Newman GSA is 0.40 acre-feet/acre or about 500 acre-feet/year.

WATER YEAR

PUMPAGE
(AF)

CITY EFFLUENT
(AF)

OUTDOOR USE
(AF)

CONSUMPTIVE

USE (AF)
2003 2,100 800 1,300 1,600
2004 2,400 800 1,600 1,800
2005 2,500 800 1,700 1,900
2006 2,700 1,100 1,600 2,000
2007 2,700 1,400 1,300 2,000
2008 2,700 1,400 1,300 1,900
2009 2,500 1,100 1,400 1,800
2010 2,300 800 1,500 1,700
2011 2,200 900 1,300 1,700
2012 2,600 1,600 1,000 1,900
Table 4140 - City of Newman Historic Water Budget Data
Figure 26 - City Water Use Diagram
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7.2.2 Current Water Budget for the City of Newman
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER YEAR

PUMPAGE
(AF)

CITY EFFLUENT
(AF)

OUTDOOR USE
(AF)

CONSUMPTIVE

USE (AF)
2013 2,500 1,700 800 1,800
Table 4241 - City of Newman Current Water Budget Data

7.2.3 Projected Water Budget for the City of Newman
The City of Newman General Plan projects 2% annual growth, which was used in this plan to determine the projected baseline demand on water. The average annual pumping from the historic water budget was used as a baseline to project the demand on water through the planning and implementation horizon. The same data and methodologies described in Section 7.2.1 were used to determine consumptive use of groundwater. Below is a table of the projected water budget. The projected consumptive use is anticipated to increase by 1,500 AF/year to a total of 3,200 AF by 2070. Section 7.3 will discuss SMC in order for the City of Newman to be sustainable. Section 7.4 will discuss projects and management actions to offset the increased demand.
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WATER
YEAR

PROJECTED

PUMPAGE (AF)

PROJECTED CITY

EFFLUENT (AF)

PROJECTED

OUTDOOR USE (AF)

CONSUMPTIVE

USE (AF)
2014 2,300 1,500 800 1,700
2015 1,900 1,300 600 1,400
2016 2,000 1,000 1,000 1,500
2017 2,000 1,100 900 1,500
2018 2,300 1,100 1,200 1,700
2019 2,300 1,100 1,200 1,700
2020 2,400 1,100 1,300 1,800
2021 2,400 1,200 1,200 1,700
2022 2,500 1,200 1,300 1,800
2023 2,500 1,200 1,300 1,800
2024 2,600 1,200 1,400 1,800
2025 2,600 1,300 1,300 1,800
2026 2,700 1,300 1,400 1,800
2027 2,700 1,300 1,400 1,800
2028 2,800 1,300 1,500 1,900
2029 2,900 1,400 1,500 1,900
2030 2,900 1,400 1,500 1,900
2031 3,000 1,400 1,600 2,000
2032 3,000 1,500 1,500 1,900
2033 3,100 1,500 1,600 2,000
2034 3,200 1,500 1,700 2,100
2035 3,200 1,500 1,700 2,100
2036 3,300 1,600 1,700 2,100
2037 3,400 1,600 1,800 2,100
2038 3,400 1,600 1,800 2,100
2039 3,500 1,700 1,800 2,100
2040 3,600 1,700 1,900 2,200
2041 3,600 1,700 1,900 2,200
2042 3,700 1,800 1,900 2,200
2043 3,800 1,800 2,000 2,300
2044 3,800 1,800 2,000 2,300
2045 3,900 1,900 2,000 2,300
2046 4,000 1,900 2,100 2,300
2047 4,100 2,000 2,100 2,300
2048 4,200 2,000 2,200 2,400
2049 4,200 2,000 2,200 2,400
2050 4,300 2,100 2,200 2,400
2051 4,400 2,100 2,300 2,500
2052 4,500 2,200 2,300 2,500
2053 4,600 2,200 2,400 2,500
2054 4,700 2,200 2,500 2,600
2055 4,800 2,300 2,500 2,600
2056 4,900 2,300 2,600 2,700
2057 5,000 2,400 2,600 2,700
2058 5,100 2,400 2,700 2,800
2059 5,200 2,500 2,700 2,800
2060 5,300 2,500 2,800 2,800
2061 5,400 2,600 2,800 2,800
2062 5,500 2,600 2,900 2,900
2063 5,600 2,700 2,900 2,900
2064 5,700 2,700 3,000 3,000
2065 5,800 2,800 3,000 3,000
2066 6,000 2,800 3,200 3,100
2067 6,100 2,900 3,200 3,100
2068 6,200 3,000 3,200 3,100
2069 6,300 3,000 3,300 3,200
2070 6,400 3,100 3,300 3,200
Table 4342 – City of Newman Projected Water Budget Data 234
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7.3 Sustainable Management Criteria for the City of Newman The City of Newman has historically relied completely on groundwater extraction to meet water demand. Groundwater overdraft around the City has primarily been offset by recharge from the SJREC service area. As mentioned previously, the SJREC are invested in helping the City to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the City of Newman on Projects and Management actions to offset groundwater extractions above the sustainable yield of the City.

The historical consumptive use for the City of Newman was about 1,800 AF/year which equates to an average use of about 1.5 AF/acre. The sustainable yield for the city is about 500 AF/year, which leaves a 1,300 AF/year consumptive use deficit that needs to be met through projects and management actions.

While the City of Newman lies in the SJREC Management AreaMonitoring Zone A, different SMC is developed in order for the City to achieve collective and independent groundwater sustainability.

7.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the City are positively impacted through recharge from the SJREC. Water levels in the SJREC Management AreaMonitoring Zone A will be used to sustainably manage groundwater levels around the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

7.3.2 Reduction in Groundwater Storage
Groundwater storage under the City of Newman is positively impacted through recharge from the SJREC. Managing groundwater storage for the City will be accomplished through updated water budgets for the City. The SJREC are contributing recharge to maintain adequate groundwater storage to offset storage reductions caused by the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

7.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

7.3.4 Degraded Water Quality
The main concern for the City is the contamination resulting from naturally occurring constituents including nitrate, arsenic, hexavalent chromium, selenium, total dissolved solids, sulfate, chloride, and boron. These constituents are important in terms of developing public supply wells to meet Title 22 Standards. As part of the process to install new wells, the City does vertical trends in groundwater quality and completes the well opposite of the zones with quality concerns. One potential solution for water quality concerns and also to meet overdraft is for the City to receive a surface water transfer from the SJREC.

7.3.5 Land Subsidence
The City has two wells that solely tap strata in the lower aquifer and two composite wells that tap both the upper and lower aquifers. Wells pumping from a confined aquifer have the potential to cause inelastic land subsidence. To date, the land subsidence in and around the City has been minimal and is indicative that the City wells have not caused any significant land subsidence. The SJREC and the City 235
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will work together to ensure that significant and unreasonable land subsidence does not occur due to City pumping. Any future increase in pumping from below the Corcoran clay will be analyzed to determine the potential to cause land subsidence and appropriate mitigation measures will be implemented. One such mitigation measure could include a reduced pumping from the lower aquifer with the increase in demand offset by restricted watering and/or transfer of surface water to the City.

7.3.6 Depletions of Interconnected Surface Water
The presence of an undesirable result for depletions of interconnected surface water is not likely to occur in the City of Newman and therefore no SMC have been established for this sustainability indicator.

7.4 Projects and Management Actions for the City of Newman The City is actively pursuing water conservation. In order to maintain sustainability for each GSA in the SJREC GSP group, the City is committed to offsetting an increase in demand based on projected population growth, by developing certain projects. Each project will be analyzed jointly with the City and the SJREC to maximize the regional benefits. The City will develop projects to offset overdraft including; 1) storm water capture, 2) demand reduction through reduced watering, 3) surface water transfer, 4) purchasing groundwater credits, 5) participation in recharge projects 6) reclaimed water for outdoor watering and 7) the city will continue to investigate other types of projects.

The groundwater quality, under natural conditions, under the City has some constituents of concern discussed in Appendix Q. The City currently pumps certain wells as needed to meet Title 22 water quality standards for the consumer. If the groundwater quality were to naturally degrade and/or the Title 22 standards for drinking water were to be updated with lower MCL’s, the City may run the risk of exceeding allowable limits. In addition to the potential water quality concerns, with the SGMA, the City currently has a deficit water balance. To counteract both of these concerns, the City has started preliminary discussions with the SJREC on two possible projects mentioned above. One project to offset water quality concerns is to transfer surface water from the SJREC to the City in exchange for the City pumping groundwater into the CCID Main Canal.

Another project has been discussed to address both overdraft and water quality concerns for the City.

The SJREC would make surface water available for transfer to the City, thereby reducing the City’s need to pump groundwater while providing cleaner drinking water for the DAC’s residents. The City of Dos Palos has been receiving surface water from CCID for decades due to groundwater quality concerns.

The SJREC would anticipate mimicking that proven model to provide a sustainable water supply for the residents of Newman.

The SJREC will continue to work with the City to not only meet the requirements of the SGMA but more importantly, to maximize the benefits of local water resources and providing safe and clean drinking water for this disadvantaged community.

7.5 Plan Implementation for the City of Newman
The cost to develop and implement the GSP specific to the City of Newman has been cost shared at 50% between the SJREC GSA and the City of Newman GSA. Additionally, the SJREC GSA has participated in the Sustainable Groundwater Planning Grant Program (SGWP) on behalf of the SJREC GSP Group and will offset up to 50% of the plan development costs for the City of Newman GSA. The SJREC GSP Group has 236
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been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One groundwater management success story in the Newman area was the implementation of a representative well with a trigger level to limit groundwater transfers from the area. As a result of the annual groundwater investigations prepared by the SJREC, the problem presented itself along with a solution to mitigate the concern; resulting in the aquifer fully recovering after water levels dropped below established triggers and no long-term lowering of the aquifer was experienced. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the City, the SJREC will take the lead preparing annual reports consistent with SGMA regulations.
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8.0 CITY OF GUSTINE GSA AREA

8.1 Background for City of Gustine
The City of Gustine is an expanding urban area that relies entirely on groundwater. Mutual concerns of the quantity and quality of groundwater in terms of future growth, initiated conversations between CCID and the City to investigate the long-term reliability of the surrounding aquifer. In the early 1990’s, CCID and the City jointly participated in a study of the groundwater conditions in and around the City, (KDSA 1992; Gustine). Subsequent groundwater studies for the City of Gustine have been completed in cooperation with CCID.

Over the years, CCID has invested in helping cities monitor, understand and manage the aquifers for the communities near the district. The relationship has resulted in a common understanding of the aquifer and a partnership which is the foundation of the SJREC GSA and the City of Gustine GSA cooperating to develop this part of the GSP. Some potential impacts to the City include increased costs for the SWRCB to develop and implement a sustainable plan for the City and a standalone plan that isn’t synchronous with the lands surrounding the City. CCID recognized the potential impacts to the City of Gustine, a DAC, and worked with City leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the City. Ultimately, the City decided to form its’ own GSA with the help from the SJREC to appropriately file. The City of Gustine welcomed the SJREC’s assistance in developing the required elements in a GSP. It was mutually agreed that the SJREC will work with the City to develop the requirements in the GSP and to include this in a discrete Section in the SJREC GSP. This was a seamless process due to the decades of cooperation of managing groundwater for the region.

The SJREC are committed to assist this DAC to maintain sustainability through the planning and implementation horizon. The City of Gustine GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix R for a discussion on the basin setting, sustainable management criteria and projects & management actions specific to the City. Some further details are provided below.

8.2 Water Budgets for the City of Gustine
Presented herein is the compilation of the historic, current and projected water budgets specific to the City of Gustine GSA.

8.2.1 Historic Water Budget for the City of Gustine
The City of Gustine solely relies on groundwater to provide its residents drinking water. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. Groundwater pumping during this timeframe ranged from 1,000 to 1,500 AF/year with an average pumping of 1,300 AF/year. The City sends effluent to its Waste Water Treatment Facility (WWTF). The City was unable to provide historic records of effluent discharged over the historic period and the records from 2015 was used as a surrogate. The City is working with staff to maintain better records for subsequent groundwater reports. A total of about 625 acre-feet of City effluent was discharged in 2015. Once treated in the holding ponds, about 100-200 acre-feet of effluent water is 238
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used to irrigate hay and pasture. The remaining water is either evaporated or percolated. Due to the fine grained soils in the area, KDSA estimated the consumptive use of the City effluent to be about 80% or about 500 AF/year. In 2015, groundwater pumping was 20% lower than the historic average. The assumed consumptive use in the WWTF for the City during the historic water budget may be 20% higher than what was observed in 2015 or about 625 AF/year
The City water use that does not result in the production of effluent was used to water lawns, parks, etc.

The outdoor water use is the difference of pumpage and effluent and averaged about 525 AF/year.

Typically, a 70% irrigation efficiency is applied to urban landscape watering which results in an average annual consumptive use of about 365 AF/year.

The total average annual consumptive use from outdoor water use and crop demand at the WWTF is 1,000 AF/year. The City of Gustine GSA covers roughly 900 acres. The approximate sustainable yield for the City of Gustine GSA is 0.40 acre-feet/acre or about 400 acre-feet/year.

WATER YEAR

PUMPAGE
(AF)

CITY EFFLUENT
(AF)

OUTDOOR USE
(AF)

CONSUMPTIVE

USE (AF)
2003 1,400 800 600 1,000
2004 1,400 800 600 1,000
2005 1,300 800 500 1,000
2006 1,300 800 500 1,000
2007 1,500 800 700 1,100
2008 1,300 800 500 1,000
2009 1,000 800 200 800
2010 1,200 800 400 900
2011 1,200 800 400 900
2012 1,300 800 500 1,000
Table 4443 - City of Gustine Historic Water Budget Data 239
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Figure 27 - City Water Use Diagram

8.2.2 Current Water Budget for the City of Gustine
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER YEAR

PUMPAGE
(AF)

CITY EFFLUENT
(AF)

OUTDOOR USE
(AF)

CONSUMPTIVE

USE (AF)
2013 1,300 800 500 1,000
Table 4544 - City of Gustine Current Water Budget Data

8.2.3 Projected Water Budget for the City of Gustine
The City of Gustine General Plan projects 2.5% annual growth, which was used in this plan to determine the projected baseline demand on water. The average annual pumping from the historic water budget was used as a baseline to project the demand on water through the planning and implementation horizon. The same data and methodologies described in Section 8.2.1 were used to determine consumptive use of groundwater. Based on the Historic Water Budget, the effluent discharge is assumed at 60% of total groundwater pumping. Below is a table of the projected water budget. The projected consumptive use is anticipated to increase by 2,600 AF/year to a total of 3,600 AF by 2070.

Section 8.3 will discuss SMC in order for the City of Gustine to be sustainable. Section 8.4 will discuss projects and management actions to offset the increased demand. 240
143
WATER
YEAR

PROJECTED

PUMPAGE (AF)

PROJECTED CITY

EFFLUENT (AF)

PROJECTED

OUTDOOR USE (AF)

CONSUMPTIVE

USE (AF)
2014 1,100 700 400 800
2015 1,100 700 400 800
2016 1,200 700 500 900
2017 1,300 800 500 1,000
2018 1,300 800 500 1,000
2019 1,300 800 500 1,000
2020 1,400 800 600 1,100
2021 1,400 800 600 1,100
2022 1,400 800 600 1,100
2023 1,500 900 600 1,100
2024 1,500 900 600 1,100
2025 1,500 900 600 1,100
2026 1,600 1,000 600 1,200
2027 1,600 1,000 600 1,200
2028 1,700 1,000 700 1,300
2029 1,700 1,000 700 1,300
2030 1,700 1,000 700 1,300
2031 1,800 1,100 700 1,400
2032 1,800 1,100 700 1,400
2033 1,900 1,100 800 1,400
2034 1,900 1,100 800 1,400
2035 2,000 1,200 800 1,500
2036 2,000 1,200 800 1,500
2037 2,100 1,300 800 1,600
2038 2,100 1,300 800 1,600
2039 2,200 1,300 900 1,700
2040 2,200 1,300 900 1,700
2041 2,300 1,400 900 1,800
2042 2,400 1,400 1,000 1,800
2043 2,400 1,400 1,000 1,800
2044 2,500 1,500 1,000 1,900
2045 2,500 1,500 1,000 1,900
2046 2,600 1,600 1,000 2,000
2047 2,700 1,600 1,100 2,100
2048 2,700 1,600 1,100 2,100
2049 2,800 1,700 1,100 2,100
2050 2,900 1,700 1,200 2,200
2051 2,900 1,700 1,200 2,200
2052 3,000 1,800 1,200 2,300
2053 3,100 1,900 1,200 2,400
2054 3,200 1,900 1,300 2,400
2055 3,200 1,900 1,300 2,400
2056 3,300 2,000 1,300 2,500
2057 3,400 2,000 1,400 2,600
2058 3,500 2,100 1,400 2,700
2059 3,600 2,200 1,400 2,700
2060 3,700 2,200 1,500 2,800
2061 3,800 2,300 1,500 2,900
2062 3,900 2,300 1,600 3,000
2063 3,900 2,300 1,600 3,000
2064 4,000 2,400 1,600 3,000
2065 4,100 2,500 1,600 3,100
2066 4,300 2,600 1,700 3,300
2067 4,400 2,600 1,800 3,300
2068 4,500 2,700 1,800 3,400
2069 4,600 2,800 1,800 3,500
2070 4,700 2,800 1,900 3,600
Table 4645 - City of Gustine Projected Water Budget Data 241
144

8.3 Sustainable Management Criteria for the City of Gustine The City of Gustine has historically relied completely on groundwater extraction to meet water demand.

Groundwater overdraft around the City has primarily been offset by recharge from the SJREC service area. As mentioned previously, the SJREC are invested in helping the City to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the City of Gustine on Projects and Management actions to offset groundwater extractions by the City that is above their sustainable yield.

The historical consumptive use for the City of Gustine was about 1,000 AF/year which equates to an average use of about 1.1 AF/acre. The sustainable yield for the city is about 400 AF/year, which leaves a 600 AF/year consumptive use deficit that needs to be met through projects and management actions.

While the City of Gustine lies in the SJREC Management AreaMonitoring Zone B, different SMC is developed in order for the City to achieve collective and independent groundwater sustainability.

Additionally, the Gustine Drainage District was formed to lower the high-water table in the area to maintain productive soils.

8.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the City are positively impacted through recharge from the SJREC. Water levels in the SJREC Management AreaMonitoring Zone B will be used to sustainably manage groundwater levels around the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

8.3.2 Reduction in Groundwater Storage
Groundwater storage under the City of Gustine is positively impacted through recharge from the SJREC.

Managing groundwater storage for the City will be accomplished through updated water budgets for the City. The SJREC are contributing recharge to maintain adequate groundwater storage to offset storage reductions caused by the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

8.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

8.3.4 Degraded Water Quality
The main concern for the City is the contamination resulting from naturally occurring constituents including nitrate, arsenic, hexavalent chromium, selenium, total dissolved solids, sulfate, chloride, and boron. These constituents are important in terms of developing public supply wells to meet Title 22 Standards. As part of the process of installing new wells, the City does vertical trends in groundwater quality and completes the well opposite of the zones with quality concerns. One potential solution for water quality concerns and also to meet overdraft is for the City to receive a surface water transfer from the SJREC.

8.3.5 Land Subsidence
The City has one well that solely taps strata in the lower aquifer and four wells that solely tap strata in the upper aquifer. Wells pumping from a confined aquifer have the potential to cause inelastic land 242
145
subsidence. To date, the land subsidence in and around the City has been minimal and is indicative that the City wells have not caused any significant land subsidence. The SJREC and the City will work together to ensure that significant and unreasonable land subsidence does not occur due to City pumping. Any future increase in pumping from below the Corcoran clay will be analyzed to determine the potential to cause land subsidence and appropriate mitigation measures will be implemented. One such mitigation measure could include a reduced pumping from the lower aquifer with the increase in demand offset by restricted watering and/or transfer of surface water to the City.

8.3.6 Depletions of Interconnected Surface Water
The presence of an undesirable result for depletions of interconnected surface water is not likely to occur in the City of Gustine and therefore no SMC have been established for this sustainability indicator.

8.4 Projects and Management Actions for the City of Gustine The City is actively pursuing water conservation. In order to maintain sustainability for each GSA in the SJREC GSP group, the City is committed to offsetting an increase in demand based on projected population growth, by developing certain projects. Each project will be analyzed jointly with the City and the SJREC to maximize the regional benefits. The City will develop projects to offset overdraft including; 1) storm water capture, 2) demand reduction through reduced watering, 3) surface water transfer, 4) purchasing groundwater credits, 5) participation in recharge projects, 6) reclaimed water for outdoor watering and 7) the city will continue to investigate other types of projects.

The groundwater quality, under natural conditions, under the City has some constituents of concern discussed in Appendix R. The City currently pumps certain wells as needed to meet Title 22 water quality standards for the consumer. If the groundwater quality were to naturally degrade and/or the Title 22 standards for drinking water were to be updated with lower MCL’s, the City may run the risk of exceeding allowable limits. In addition to the potential water quality concerns, with the SGMA, the City currently has a deficit water balance. To counteract both of these concerns, the City has started preliminary discussions with the SJREC on two possible projects mentioned above. One project to offset water quality concerns is to transfer surface water from the SJREC to the City in exchange for the City pumping groundwater into the CCID Main Canal.

Another project has been discussed to address both overdraft and water quality concerns for the City.

The SJREC would anticipate mimicking that proven model to provide a sustainable water supply for the residents of Gustine.

8.5 Plan Implementation for the City of Gustine
The cost to develop and implement the GSP specific to the City of Gustine has been cost shared at 50% between the SJREC GSA and the City of Gustine GSA. Additionally, the SJREC GSA has participated in the Sustainable Groundwater Planning Grant Program (SGWP) on behalf of the SJREC GSP Group and will 243
146
offset up to 50% of the plan development costs for the City of Gustine GSA. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One groundwater management success story was the development of the Gustine Drainage District. The Gustine Drainage District was formed to provide drainage of good water quality to the area around Gustine to maintain healthy soils. This area receives significant recharge from CCID, the ephemeral streams and the GWD and the GDD has actively managed groundwater levels to maintain healthy soils.

The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the City, the SJREC will take the lead preparing annual reports consistent with SGMA regulations.
244
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9.0 CITY OF LOS BANOS GSA AREA

9.1 Background for City of Los Banos
The City of Los Banos is an expanding urban area that relies entirely on groundwater. Mutual concerns of the quantity and quality of groundwater in terms of future growth, initiated conversations between CCID and the City to investigate the long-term reliability of the surrounding aquifer. In the early 1990’s, CCID and the City jointly participated in a study of the groundwater conditions in and around the City, (KDSA 1991; Los Banos). Subsequent groundwater studies for the City of Los Banos have been completed in cooperation with CCID and the USBR.

Over the years, CCID has invested in helping cities monitor, understand and manage the aquifers for the communities near the district. The relationship has resulted in a common understanding of the aquifer and a partnership which is the foundation of the SJREC GSA and the City of Los Banos GSA cooperating to develop this GSP. Some potential impacts to the City include increased costs for the SWRCB to develop and implement a sustainable plan for the City and a standalone plan that isn’t synchronous with the lands surrounding the City. CCID recognized the potential impacts to the City of Los Banos, a DAC, and worked with City leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the City. Ultimately, the City decided to form its’ own GSA with the help from the SJREC to appropriately file. The City of Los Banos welcomed the SJREC’s assistance in developing the required elements in a GSP. It was mutually agreed that the SJREC will work with the City to develop the requirements in the GSP City and to include this in a discrete Section in the SJREC GSP. This was a seamless process due to the decades of cooperation of managing groundwater for the region.

The City of Los Banos, the largest City in the Delta-Mendota Subbasin, was originally a partner with the SJRECWA, GWD and SLWD on the Los Banos Creek Diversion Facility described in Section 4.1.1 of this GSP. The Los Banos Creek Recharge and Recovery Project developed jointly with the SJRECWA, GWD and SLWD, directly benefits the water quality for the City supply wells. The Hexavalent Chromium concentration dropped below the standard in one City well near the Los Banos Creek during the extended recharge in 2017. The City recognizes the value working with the local districts to jointly manage local water resources. In continuation of a great working relationship, the City has partnered with the SJREC GSA, GWD and SLWD to develop a sustainable plan for an area that extends beyond the City urban growth boundary and includes upgradient lands.

The SJREC are committed to assist this DAC to maintain sustainability through the planning and implementation horizon. The City of Los Banos GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix S for a discussion on the basin setting, sustainable management criteria and projects & management actions specific to the City. Some further details are provided below.
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9.2 Water Budgets for the City of Los Banos
Presented herein is the compilation of the historic, current and projected water budgets specific to the City of Los Banos GSA.

9.2.1 Historic Water Budget for the City of Los Banos
The City of Los Banos solely relies on groundwater to provide its residents drinking water. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. Groundwater pumping during this timeframe ranged from 6,400 to 9,100 AF/year with an average pumping of 7,900 AF/year. The City sends effluent to its Waste Water Treatment Facility (WWTF). They have about 200 acres of holding ponds at the WWTF. Once treated in the holding ponds, water is used to irrigate 350 acres of pasture. There is approximately 600 AF/year evaporation from the effluent ponds. The amount of effluent used for irrigation ranged from 2,600 to 4,000 AF/year with an average of 3,400 AF/year. The consumptive use of the pasture averaged about 3.3 AF/acre for an average consumptive use of about 1,100 AF/year.

The City water use that does not result in the production of effluent was used to water lawns, parks, etc.

The outdoor water use is the difference of pumpage and effluent and averaged about 4,000 AF/year.

Typically, a 70% irrigation efficiency is applied to urban landscape watering which results in an average annual consumptive use of about 2,800 AF/year.

The total average annual consumptive use from outdoor water use and crop demand at the WWTF is 4,500 AF/year. The City of Los Banos GSA covers roughly 5,800 acres. The approximate sustainable yield for the City of Los Banos GSA is 0.40 acre-feet/acre or about 2,300 acre-feet/year.

WATER YEAR

PUMPAGE
(AF)

CITY EFFLUENT
(AF)

OUTDOOR USE
(AF)

CONSUMPTIVE

USE (AF)
2003 6,400 3,200 3,200 4,000
2004 6,900 3,500 3,500 4,200
2005 7,200 3,600 3,600 4,200
2006 7,500 3,800 3,800 4,400
2007 9,100 4,600 4,600 4,900
2008 8,900 4,500 4,500 4,900
2009 8,300 4,200 4,200 4,700
2010 7,700 3,900 3,900 4,500
2011 7,800 3,900 3,900 4,500
2012 8,900 4,500 4,500 4,900
Table 4746 - City of Los Banos Historic Water Budget Data 246
149
Figure 28 - City Water Use Diagram

9.2.2 Current Water Budget for the City of Los Banos
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER YEAR

PUMPAGE
(AF)

CITY EFFLUENT
(AF)

OUTDOOR USE
(AF)

CONSUMPTIVE

USE (AF)
2013 8,500 4,300 4,300 4,700
Table 4847 - City of Los Banos Current Water Budget Data

9.2.3 Projected Water Budget for the City of Los Banos
The City of Los Banos General Plan projects 2% annual growth, which was used in this plan to determine the projected baseline demand on water. The average annual pumping from the historic water budget was used as a baseline to project the demand on water through the planning and implementation horizon. The same data and methodologies described in Section 9.2.1 were used to determine consumptive use of groundwater. Below is a table of the projected water budget. The projected consumptive use is anticipated to increase by 7,600 AF/year to a total of 12,100 AF by 2070. Section 9.3 will discuss SMC in order for the City of Los Banos to be sustainable. Section 9.4 will discuss projects and management actions to offset the increased demand.
247
150
WATER
YEAR

PROJECTED

PUMPAGE (AF)

PROJECTED CITY

EFFLUENT (AF)

PROJECTED

OUTDOOR USE (AF)

CONSUMPTIVE

USE (AF)
2014 7,900 4,000 3,900 4,500
2015 6,700 3,400 3,300 3,900
2016 6,100 3,100 3,000 3,600
2017 7,800 3,900 3,900 4,500
2018 8,000 4,000 4,000 4,600
2019 8,100 4,100 4,000 4,600
2020 8,300 4,100 4,200 4,800
2021 8,400 4,200 4,200 4,800
2022 8,600 4,300 4,300 4,900
2023 8,800 4,400 4,400 5,000
2024 9,000 4,500 4,500 5,100
2025 9,100 4,600 4,500 5,100
2026 9,300 4,700 4,600 5,200
2027 9,500 4,800 4,700 5,300
2028 9,700 4,800 4,900 5,500
2029 9,900 4,900 5,000 5,600
2030 10,100 5,000 5,100 5,700
2031 10,300 5,100 5,200 5,800
2032 10,500 5,200 5,300 5,900
2033 10,700 5,400 5,300 6,000
2034 10,900 5,500 5,400 6,100
2035 11,100 5,600 5,500 6,200
2036 11,400 5,700 5,700 6,400
2037 11,600 5,800 5,800 6,500
2038 11,800 5,900 5,900 6,600
2039 12,100 6,000 6,100 6,700
2040 12,300 6,100 6,200 6,900
2041 12,500 6,300 6,200 6,900
2042 12,800 6,400 6,400 7,100
2043 13,100 6,500 6,600 7,300
2044 13,300 6,700 6,600 7,300
2045 13,600 6,800 6,800 7,500
2046 13,900 6,900 7,000 7,700
2047 14,100 7,100 7,000 7,800
2048 14,400 7,200 7,200 7,900
2049 14,700 7,300 7,400 8,100
2050 15,000 7,500 7,500 8,300
2051 15,300 7,600 7,700 8,400
2052 15,600 7,800 7,800 8,600
2053 15,900 8,000 7,900 8,700
2054 16,200 8,100 8,100 8,900
2055 16,600 8,300 8,300 9,100
2056 16,900 8,400 8,500 9,300
2057 17,200 8,600 8,600 9,400
2058 17,600 8,800 8,800 9,600
2059 17,900 9,000 8,900 9,800
2060 18,300 9,100 9,200 10,000
2061 18,600 9,300 9,300 10,100
2062 19,000 9,500 9,500 10,400
2063 19,400 9,700 9,700 10,600
2064 19,800 9,900 9,900 10,800
2065 20,200 10,100 10,100 11,000
2066 20,600 10,300 10,300 11,200
2067 21,000 10,500 10,500 11,400
2068 21,400 10,700 10,700 11,600
2069 21,800 10,900 10,900 11,800
2070 22,300 11,100 11,200 12,100
Table 4948 – City of Los Banos Projected Water Budget Data 248
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9.3 Sustainable Management Criteria for the City of Los Banos The City of Los Banos has historically relied completely on groundwater extraction to meet water demand. Groundwater overdraft around the City has primarily been offset by recharge from the SJREC service area. As mentioned previously, the SJREC are invested in helping the City to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the City of Los Banos on Projects and Management actions to offset groundwater extractions by the City that is above their sustainable yield.

The historical consumptive use for the City of Los Banos was about 4,500 AF/year which equates to an average use of about 0.8 AF/acre. The sustainable yield for the city is about 2,300 AF/year, which leaves a 2,200 AF/year consumptive use deficit that needs to be met through projects and management actions. While the City of Los Banos lies in the SJREC Management AreaMonitoring Zone C, different SMC is developed in order for the City to achieve collective and independent groundwater sustainability.

9.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the City are positively impacted through recharge from the SJREC, SLWD and seepage in the Los Banos Creek. Water levels in the SJREC Management AreaMonitoring Zone C will be used to sustainably manage groundwater levels around the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

9.3.2 Reduction in Groundwater Storage
Groundwater storage under the City of Los Banos is positively impacted through recharge from the SJREC, SLWD and seepage in the Los Banos Creek. Managing groundwater storage for the City will be accomplished through updated water budgets for the City. The SJREC are contributing recharge to maintain adequate groundwater storage to offset storage reductions caused by the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

9.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

9.3.4 Degraded Water Quality
The main concern for the City is the contamination resulting from naturally occurring constituents including nitrate, arsenic, hexavalent chromium, selenium, total dissolved solids, sulfate, chloride, and boron. These constituents are important in terms of developing public supply wells to meet Title 22 Standards. As part of the process of installing new wells, the City does vertical trends in groundwater quality and completes the well opposite of the zones with quality concerns. One potential solution for water quality concerns and also to meet overdraft is for the City to receive a surface water transfer from the SJREC.
249
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9.3.5 Land Subsidence
The City has one active composite well that taps both the upper and lower aquifers. Wells pumping from a confined aquifer have the potential to cause inelastic land subsidence. To date, the land subsidence in and around the City has been minimal and is indicative that the City wells have not caused any significant land subsidence. The SJREC and the City will work together to ensure that significant and unreasonable land subsidence does not occur due to City pumping. Any future increase in pumping from below the Corcoran clay will be analyzed to determine the potential to cause land subsidence and appropriate mitigation measures will be implemented. One such mitigation measure could include a reduced pumping from the lower aquifer with the increase in demand offset by restricted watering and/or transfer of surface water to the City.

9.3.6 Depletions of Interconnected Surface Water
The presence of an undesirable result for depletions of interconnected surface water is not likely to occur in the City of Los Banos and therefore no SMC have been established for this sustainability indicator.

9.4 Projects and Management Actions for the City of Los Banos The City is actively pursuing water conservation. In order to maintain sustainability for each GSA in the SJREC GSP group, the City is committed to offsetting an increase in demand based on projected population growth, by developing certain projects. Each project will be analyzed jointly with the City and the SJREC to maximize the regional benefits. The City will develop projects to offset overdraft including; 1) storm water capture, 2) demand reduction through reduced watering, 3) surface water transfer, 4) purchasing groundwater credits, 5) participation in recharge projects and 6) the city will continue to investigate other types of projects.

The groundwater quality, under natural conditions, under the City has some constituents of concern discussed in Appendix S. The City currently pumps certain wells as needed to meet Title 22 water quality standards for the consumer. If the groundwater quality were to naturally degrade and/or the Title 22 standards for drinking water were to be updated with lower MCL’s, the City may run the risk of exceeding allowable limits, particularly for the hexavalent chromium standard. In addition to the potential water quality concerns, with the SGMA, the City currently has a deficit water balance. To counteract both of these concerns, the City has started preliminary discussions with the SJREC on two possible projects mentioned above. One project to offset water quality concerns is to transfer surface water from the SJREC to the City in exchange for the City pumping groundwater into the CCID Main Canal.

Another project has been discussed to address both overdraft and water quality concerns for the City.

The SJREC would anticipate mimicking that proven model to provide a sustainable water supply for the residents of Los Banos.

9.5 Plan Implementation for the City of Los Banos
The cost to develop and implement the GSP specific to the City of Los Banos has been cost shared at 25% between the SJREC GSA, SLWD, GWD and the City of Los Banos GSA. Additionally, the SJREC GSA has participated in the Sustainable Groundwater Planning Grant Program (SGWP) on behalf of the SJREC GSP Group and will offset up to 50% of the plan development costs for the City of Los Banos GSA. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One groundwater management success story in the Los Banos Creek area was the implementation of a representative well with a trigger level to limit groundwater transfers from the area. As a result of the annual groundwater investigations prepared by the SJREC, the problem presented itself along with a solution to mitigate the concern; resulting in the aquifer fully recovering after water levels dropped below established triggers and no long-term lowering of the aquifer was experienced. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the City, the SJREC will take the lead preparing annual reports consistent with SGMA regulations. 251
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10.0 CITY OF Dos Palos GSA AREA

10.1 Background for City of Dos Palos
The City of Dos Palos is a Severely Disadvantaged Community that has completely relied on treated surface water. The quality of the groundwater around the City of Dos Palos was not suitable for residential use. Through an agreement dated May 8, 1936 the San Joaquin & Kings River Canal & Irrigation Company, the predecessor to CCID, agreed to provide surface water to the City of Dos Palos through the Canal Company’s Colony Main Canal. Water deliveries from what is now the CCID Colony Main Canal continued until 1989 when the City of Dos Palos, through the Dos Palos Area JPA, worked with CCID and the USBR to change their point of diversion to the San Luis Canal (California Aqueduct). A pipeline was constructed to wheel water transferred from CCID from the San Luis Canal to the City’s water treatment facility. CCID and the SJREC have a long history working with the local communities to solve regional water problems.

Over the years, CCID has invested in helping cities monitor, understand and manage water resources for the communities near the district. The relationship has resulted in a common understanding of the groundwater conditions and a partnership which is the foundation of the SJREC GSA and the City of Dos Palos GSA cooperating to develop this part of the GSP. Some potential impacts to the City include increased costs for the SWRCB to develop and implement a sustainable plan for the City and a standalone plan that isn’t synchronous with the lands surrounding the City. CCID recognized the potential impacts to the City of Dos Palos, a SDAC, and worked with City leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the City. Ultimately, the City decided to form its’ own GSA with the help from the SJREC to appropriately file. The City of Dos Palos welcomed the SJREC’s assistance in developing the required elements in a GSP. The City requested the SJREC to develop the requirements in the GSP on behalf of the City and to include this in a discrete Section in the SJREC GSP. This was a seamless process due to the decades of cooperation of managing groundwater and surface water resources with the City and CCID.

The SJREC are committed to assist this SDAC to maintain sustainability through the planning and implementation horizon. The City of Dos Palos GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix T for a discussion on the basin setting, sustainable management criteria and projects & management actions specific to the City. Some further details are provided below.

10.2 Water Budgets for the City of Dos Palos
Presented herein is the compilation of the historic, current and projected water budgets specific to the City of Dos Palos GSA.

10.2.1 Historic Water Budget for the City of Dos Palos
The City of Dos Palos solely relies on treated surface water to provide its residents drinking water. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire DeltaMendota Subbasin. The surface water delivery to the City ranged from 1,200 to 1,700 AF/year with an 252
155
average delivery of 1,400 AF/year. The City sends effluent to its Waste Water Treatment Facility (WWTF). They have about 54 acres of ponds at the WWTF. The total City effluent is about 700 AF/year.

The evaporation from the ponds is approximately 300 AF/year. The remaining treated effluent, about 400 AF/year, is used to irrigate crops near the WWTF. The irrigation efficiency of the effluent water used to irrigate crops is assumed to be 70% which equates to a net crop evapotranspiration of about 300 AF/year, for a total consumptive use of City effluent of 600 AF/year.

The City water use that does not result in the production of effluent was used to water lawns, parks, etc.

The outdoor water use is the difference of pumpage and effluent and averaged about 700 AF/year.

Typically, a 70% irrigation efficiency is applied to urban landscape watering which results in an average annual consumptive use of about 500 AF/year.

The total average annual consumptive use from outdoor water use and crop demand at the WWTF is 1,100 AF/year. The City of Dos Palos GSA covers roughly 750 acres. Although the City of Dos Palos does not pump groundwater, the approximate sustainable yield for the City of Dos Palos GSA is 0.40 acrefeet/acre or about 300 acre-feet/year.

WATER YEAR

SURFACE
WATER

DELIVERY (AF)
CITY

EFFLUENT
(AF)

OUTDOOR

USE (AF)

CONSUMPTIVE

USE (AF)
2003 1,400 700 700 1,100
2004 1,500 700 800 1,200
2005 1,400 700 700 1,100
2006 1,500 700 800 1,200
2007 1,600 700 900 1,200
2008 1,700 700 1,000 1,300
2009 1,300 700 600 1,000
2010 1,300 700 600 1,000
2011 1,200 700 500 1,000
2012 1,300 700 600 1,000
Table 5049 – City of Dos Palos Historic Water Budget
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Figure 29 - City Water Use Diagram

10.2.2 Current Water Budget for the City of Dos Palos
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER YEAR

SURFACE
WATER

DELIVERY (AF)
CITY

EFFLUENT
(AF)

OUTDOOR USE
(AF)

CONSUMPTIVE

USE (AF)
2013 1,800 700 1,100 1,400
Table 5150 - City of Dos Palos Current Water Budget Data

10.2.3 Projected Water Budget for the City of Dos Palos The City of Dos Palos General Plan projects a 1% annual growth from 2025-2070, which was used in this plan to determine the projected baseline demand on water. The average annual pumping from the historic water budget was used as a baseline to project the demand on water through the planning and implementation horizon. The same data and methodologies described in Section 10.2.1 were used to determine the consumptive use. Below is a table of the projected water budget. The projected consumptive use is anticipated to increase by 500 AF/year to a total of 1,600 AF by 2070. Section 10.3 will discuss SMC in order for the City of Dos Palos to be sustainable. The current contract between CCID and the City of Dos Palos allows for the transfer of up to 2,500 AF/year of surface water which is below the total projected water delivery in 2070. The City of Dos Palos does not pump any groundwater and is sustainable. Section 10.4 will discuss projects and management actions to offset the increased demand. 254
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WATER
YEAR

PROJECTED

SURFACE WATER

DELIVERY (AF)

PROJECTED CITY

EFFLUENT (AF)

PROJECTED

OUTDOOR USE (AF)

CONSUMPTIVE

USE (AF)
2014 1,400 500 900 1,100
2015 1,000 500 500 800
2016 1,200 500 700 900
2017 1,400 700 700 1,100
2018 1,400 700 700 1,100
2019 1,400 700 700 1,100
2020 1,400 700 700 1,100
2021 1,400 700 700 1,100
2022 1,400 700 700 1,100
2023 1,400 700 700 1,100
2024 1,400 700 700 1,100
2025 1,400 700 700 1,100
2026 1,400 700 700 1,100
2027 1,400 700 700 1,100
2028 1,500 700 800 1,100
2029 1,500 700 800 1,100
2030 1,500 700 800 1,100
2031 1,500 800 700 1,100
2032 1,500 800 700 1,100
2033 1,500 800 700 1,100
2034 1,500 800 700 1,100
2035 1,600 800 800 1,200
2036 1,600 800 800 1,200
2037 1,600 800 800 1,200
2038 1,600 800 800 1,200
2039 1,600 800 800 1,200
2040 1,600 800 800 1,200
2041 1,700 800 900 1,300
2042 1,700 800 900 1,300
2043 1,700 800 900 1,300
2044 1,700 900 800 1,300
2045 1,700 900 800 1,300
2046 1,700 900 800 1,300
2047 1,800 900 900 1,400
2048 1,800 900 900 1,400
2049 1,800 900 900 1,400
2050 1,800 900 900 1,400
2051 1,800 900 900 1,400
2052 1,800 900 900 1,400
2053 1,900 900 1,000 1,400
2054 1,900 900 1,000 1,400
2055 1,900 1,000 900 1,400
2056 1,900 1,000 900 1,400
2057 1,900 1,000 900 1,400
2058 2,000 1,000 1,000 1,500
2059 2,000 1,000 1,000 1,500
2060 2,000 1,000 1,000 1,500
2061 2,000 1,000 1,000 1,500
2062 2,000 1,000 1,000 1,500
2063 2,100 1,000 1,100 1,600
2064 2,100 1,000 1,100 1,600
2065 2,100 1,100 1,000 1,600
2066 2,100 1,100 1,000 1,600
2067 2,100 1,100 1,000 1,600
2068 2,200 1,100 1,100 1,600
2069 2,200 1,100 1,100 1,600
2070 2,200 1,100 1,100 1,600
Table 5251 – City of Dos Palos Projected Water Budget Data 255
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10.3 Sustainable Management Criteria for the City of Dos Palos The City of Dos Palos has historically relied completely on treated surface water to meet demand. As mentioned previously, the SJREC are invested in helping each of the communities in our area to achieve sustainability. The SJREC GSP Group is currently sustainable; collectively.

The historical consumptive use for the City of Dos Palos was about 1,800 AF/year which equates to an average use of about 2.3 AF/acre which is met by the importation of surface water. While the City of Dos Palos lies in the SJREC Management AreaMonitoring Zone D, different SMC is developed in order for the City to achieve collective and independent groundwater sustainability.

10.3.1 Chronic Lowering of Groundwater Levels
The City does not own or operate production wells. Chronic lowering of groundwater levels for the City of Dos Palos GSA will not occur since the City doesn’t pump groundwater and therefore no SMC have been established for this sustainability indicator.

10.3.2 Reduction in Groundwater Storage
The City does not own or operate production wells. Reduction in Groundwater Storage for the City of Dos Palos GSA will not occur since the City doesn’t pump groundwater and therefore no SMC have been established for this sustainability indicator.

10.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

10.3.4 Degraded Water Quality
The City does not own or operate production wells. Degraded water Quality for the City of Dos Palos GSA will not occur since the City doesn’t pump groundwater and therefore no SMC have been established for this sustainability indicator. Additionally, due to the poor quality of groundwater the City of Dos Palos has relied on treated surface water from the Colony Main Canal dating back to at least 1936, and more recently received water directly from the San Luis Canal.

10.3.5 Land Subsidence
The City does not own or operate production wells. Land subsidence for the City of Dos Palos GSA will not occur since the City doesn’t pump groundwater and therefore no SMC have been established for this sustainability indicator.

10.3.6 Depletions of Interconnected Surface Water
The presence of an undesirable result for depletions of interconnected surface water is not likely to occur in the City of Dos Palos and therefore no SMC have been established for this sustainability indicator.

10.4 Projects and Management Actions for the City of Dos Palos The City of Dos Palos took a proactive roll reaching out to CCID and its predecessor to provide drinking water to the severely disadvantaged community residents through developing a surface water treatment facility and associated appurtenances. The City will continue to work with the SJREC to ensure regional sustainability.
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10.5 Plan Implementation for the City of Dos Palos
The cost to develop and implement the GSP specific to the City of Dos Palos has been cost shared at 50% between the SJREC GSA and the City of Dos Palos GSA. Additionally, the SJREC GSA has pursued additional grant funding to fully offset GSP development costs for SDAC’s. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the City, the SJREC will take the lead preparing annual reports consistent with SGMA regulations.
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11.0 CITY OF FIREBAUGH GSA AREA

11.1 Background for City of Firebaugh
The City of Firebaugh is a Severely Disadvantaged Community relies entirely on groundwater. In 2008 KDSA analyzed groundwater conditions in the vicinity of Firebaugh in support of the Draft EIR for the City’s General Plan. The quality of the groundwater around the City of Firebaugh on the west side of the San Joaquin River was not suitable for residential use. In the early 2000’s, the City of Firebaugh worked with Columbia Canal Company and the landowners on the east side of the river to drill domestic supply wells on the east side of the river where the water quality was significantly better. A pipeline was constructed to deliver water from lands in and adjacent to CCC (east side of the river) to the City (west side of the river). CCC and the SJREC have a long history working with the local communities to solve regional water problems. In this case, the district worked with the local landowners to provide sites for the City to construct wells to provide the residents with water.

Over the years, the CCC has invested in helping cities monitor, understand and manage the aquifers for the communities near the district. The relationship has resulted in a common understanding of the aquifer and a partnership which is the foundation of the SJREC GSA and the City of Firebaugh GSA cooperating to develop this part of the GSP. Some potential impacts to the City include increased costs for the SWRCB to develop and implement a sustainable plan for the City and a standalone plan that isn’t synchronous with the lands surrounding the City. CCID recognized the potential impacts to the City of Firebaugh, a SDAC, and worked with City leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the City. Ultimately, the City decided to form its’ own GSA with the help from the SJREC to appropriately file. The City of Firebaugh welcomed the SJREC’s assistance developing the required elements in a GSP. It was mutually agreed that the SJREC will work with the City to develop the requirements in the GSP and to include this in a discrete Section in the SJREC GSP. This was a seamless process due to the decades of cooperation of managing groundwater for the region.

The SJREC are committed to assist this SDAC to maintain sustainability through the planning and implementation horizon. The City of Firebaugh GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix U for a discussion on the basin setting, sustainable management criteria and projects & management actions specific to the City. Some further details are provided below.

11.2 Water Budgets for the City of Firebaugh
Presented herein is the compilation of the historic, current and projected water budgets specific to the City of Firebaugh GSA.

11.2.1 Historic Water Budget for the City of Firebaugh
The City of Firebaugh solely relies on groundwater to provide its residents drinking water. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. Groundwater pumping during this timeframe ranged from 2,400 to 2,600 AF/year with an 258
161
average pumping of 2,500 AF/year. The City sends effluent to its Waste Water Treatment Facility (WWTF). They have about 30 acres of holding ponds at the WWTF. The effluent ranges from 600 to 800 AF/year with an average effluent of 700 AF/year. Each year about 100 AF evaporates while the remaining 600 AF percolates in the ponded area. Additionally, the Tomatek processing plant provides about 500 AF/year of effluent which irrigates about 160 acres of sudan and cotton. The effluent water from Tomatek equates to a consumptive use of about 400 AF/year due to evapotranspiration. The total effluent consumptive use for the City of Firebaugh and Tomatek averages about 500 AF/year.

The City water use that does not result in the production of effluent was used to water lawns, parks, etc.

The outdoor water use is the difference of pumpage and effluent and averaged about 1,300 AF/year.

Typically, a 70% irrigation efficiency is applied to urban landscape watering which results in an average annual consumptive use of about 900 AF/year.

The City is adjacent to the San Joaquin River for about 4.5 river miles. The San Joaquin River is assumed to have about 4 cfs losses through this stretch, of which about 2 cfs is recharging the aquifer in the vicinity of the City. This stretch of river is typically wet year round which results in about 1,400 AF/year of recharge towards the City.

The total average annual consumptive use from outdoor water use and crop demand at the WWTF is 1,400 AF/year. The City of Firebaugh GSA covers roughly 1,850 acres. The approximate sustainable yield for the City of Firebaugh GSA is 0.40 acre-feet/acre or about 700 acre-feet/year in addition to recharge from the river of about 1,400 AF/year for a total of about 2,100 AF/year.

WATER
YEAR

PUMPAGE
(AF)
CITY

EFFLUENT
(AF)

TOMATEK

EFFLUENT
(AF)

OUTDOOR

USE (AF)

SEEPAGE

FROM THE SJR
(AF)

CONSUMPTIVE

USE (AF)
2003 2,400 800 500 1,100 1,400 1,300
2004 2,500 800 500 1,200 1,400 1,300
2005 2,400 800 500 1,100 1,400 1,300
2006 2,400 700 500 1,200 1,400 1,300
2007 2,600 800 500 1,300 1,400 1,400
2008 2,500 700 500 1,300 1,400 1,400
2009 2,500 600 500 1,400 1,400 1,500
2010 2,500 600 500 1,400 1,400 1,500
2011 2,500 600 500 1,400 1,400 1,500
2012 2,400 600 500 1,300 1,400 1,400
Table 5352 - City of Firebaugh Historic Water Budget Data 259
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Figure 30 - City Water Use Diagram

11.2.2 Current Water Budget for the City of Firebaugh
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER
YEAR

PUMPAGE
(AF)
CITY

EFFLUENT
(AF)

TOMATEK

EFFLUENT
(AF)

OUTDOOR

USE (AF)

SEEPAGE

FROM THE

SJR (AF)

CONSUMPTIVE

USE (AF)
2013 2,400 700 500 1,200 1,400 1,300
Table 5453 - City of Firebaugh Current Water Budget Data

11.2.3 Projected Water Budget for the City of Firebaugh The City of Firebaugh General Plan projects 1.8% annual growth, which was used in this plan to determine the projected baseline demand on water. The average annual pumping from the historic water budget was used as a baseline to project the demand on water through the planning and implementation horizon. The same data and methodologies described in Section 11.2.1 were used to determine consumptive use of groundwater. Below is a table of the projected water budget. The projected consumptive use is anticipated to increase by 2,000 AF/year to a total of 3,500 AF by 2070.

Section 11.3 will discuss SMC in order for the City of Firebaugh to be sustainable. Section 11.4 will discuss projects and management actions to offset the increased demand. 260
163
WATER
YEAR

PROJECTED

PUMPAGE (AF)

PROJECTED CITY

EFFLUENT (AF)

PROJECTED TOMATEK

EFFLUENT (AF)

PROJECTED

OUTDOOR USE (AF)

SEEPAGE FROM

THE SJR (AF) CONSUMPTIVE

USE (AF)
2014 2,600 700 500 1,400 1,400 1,500
2015 2,300 700 500 1,100 1,400 1,300
2016 2,200 700 500 1,000 1,400 1,200
2017 2,300 700 500 1,100 1,400 1,300
2018 2,500 700 500 1,300 1,400 1,400
2019 2,500 700 500 1,300 1,400 1,400
2020 2,600 700 500 1,400 1,400 1,500
2021 2,600 700 500 1,400 1,400 1,500
2022 2,700 800 500 1,400 1,400 1,500
2023 2,700 800 500 1,400 1,400 1,500
2024 2,800 800 500 1,500 1,400 1,600
2025 2,800 800 500 1,500 1,400 1,600
2026 2,900 800 500 1,600 1,400 1,600
2027 2,900 800 500 1,600 1,400 1,600
2028 3,000 800 500 1,700 1,400 1,700
2029 3,000 900 500 1,600 1,400 1,600
2030 3,100 900 500 1,700 1,400 1,700
2031 3,200 900 500 1,800 1,400 1,800
2032 3,200 900 500 1,800 1,400 1,800
2033 3,300 900 500 1,900 1,400 1,900
2034 3,300 900 500 1,900 1,400 1,900
2035 3,400 900 500 2,000 1,400 1,900
2036 3,400 1,000 500 1,900 1,400 1,900
2037 3,500 1,000 500 2,000 1,400 1,900
2038 3,600 1,000 500 2,100 1,400 2,000
2039 3,600 1,000 500 2,100 1,400 2,000
2040 3,700 1,000 500 2,200 1,400 2,100
2041 3,800 1,100 500 2,200 1,400 2,100
2042 3,800 1,100 500 2,200 1,400 2,100
2043 3,900 1,100 500 2,300 1,400 2,200
2044 4,000 1,100 500 2,400 1,400 2,200
2045 4,000 1,100 500 2,400 1,400 2,200
2046 4,100 1,200 500 2,400 1,400 2,200
2047 4,200 1,200 500 2,500 1,400 2,300
2048 4,300 1,200 500 2,600 1,400 2,400
2049 4,300 1,200 500 2,600 1,400 2,400
2050 4,400 1,200 500 2,700 1,400 2,500
2051 4,500 1,300 500 2,700 1,400 2,500
2052 4,600 1,300 500 2,800 1,400 2,500
2053 4,700 1,300 500 2,900 1,400 2,600
2054 4,800 1,300 500 3,000 1,400 2,700
2055 4,800 1,400 500 2,900 1,400 2,600
2056 4,900 1,400 500 3,000 1,400 2,700
2057 5,000 1,400 500 3,100 1,400 2,800
2058 5,100 1,400 500 3,200 1,400 2,800
2059 5,200 1,500 500 3,200 1,400 2,900
2060 5,300 1,500 500 3,300 1,400 2,900
2061 5,400 1,500 500 3,400 1,400 3,000
2062 5,500 1,500 500 3,500 1,400 3,100
2063 5,600 1,600 500 3,500 1,400 3,100
2064 5,700 1,600 500 3,600 1,400 3,100
2065 5,800 1,600 500 3,700 1,400 3,200
2066 5,900 1,600 500 3,800 1,400 3,300
2067 6,000 1,700 500 3,800 1,400 3,300
2068 6,100 1,700 500 3,900 1,400 3,400
2069 6,200 1,700 500 4,000 1,400 3,400
2070 6,300 1,800 500 4,000 1,400 3,500
Table 5554 – City of Firebaugh Projected Water Budget Data 261
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11.3 Sustainable Management Criteria for the City of Firebaugh The City of Firebaugh has historically relied completely on groundwater extraction to meet water demand. Groundwater overdraft around the City has primarily been offset by recharge from the SJREC service area and seepage from the San Joaquin River. As mentioned previously, the SJREC are invested in helping the City to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the City of Firebaugh on Projects and Management actions to offset groundwater extractions by the City that is above their sustainable yield.

The historical consumptive use for the City of Firebaugh was about 1,400 AF/year which equates to an average use of about 0.7 AF/acre. The sustainable yield for the City is 700 AF/year plus the river recharged approximated at 1,400 AF/year for a total of 2,100 AF/year. Through the planning an implementation horizon the city may have a consumptive use deficit that will need to be met through projects and management actions. While the City of Firebaugh lies near SJREC Management AreasMonitoring Zones F, G and J, different SMC is developed in order for the City to achieve collective and independent groundwater sustainability.

11.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the City are positively impacted through recharge from the SJREC and seepage from the San Joaquin River and have remained fairly stable. Water levels in the SJREC Management AreaMonitoring Zone J will be used to sustainably manage groundwater levels for the City since the City’s wells are located within that area. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

11.3.2 Reduction in Groundwater Storage
Groundwater storage under the City of Firebaugh is positively impacted through recharge from the SJREC and seepage from the San Joaquin River. Managing groundwater storage for the City will be accomplished through updated water budgets for the City. The SJREC are contributing recharge to maintain adequate groundwater storage to offset storage reduction caused by the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

11.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

11.3.4 Degraded Water Quality
The main concern for the City is the contamination resulting from naturally occurring constituents including nitrate, arsenic, hexavalent chromium, selenium, total dissolved solids, sulfate, chloride, and boron. These constituents are important in terms of developing public supply wells to meet Title 22 Standards. As part of the process of installing new wells, the City does vertical trends in groundwater quality and completes the well opposite of the zones with quality concerns. One potential solution for water quality concerns and also to meet overdraft is for the City to receive a surface water transfer from the SJREC.
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11.3.5 Land Subsidence
The City does not operate any wells perforated below the Corcoran Clay. As a result, inelastic land subsidence is unlikely to occur as a result of pumping from the City of Firebaugh wells. Therefore, no SMC have been established for this sustainability indicator. The SJREC and the City will work together to ensure that significant and unreasonable land subsidence does not occur due to City pumping.

11.3.6 Depletions of Interconnected Surface Water
The City of Firebaugh plans to work with the SJREC to sustainably manage interconnected surface water and groundwater. For more details refer to the following sections in this GSP: 3.2.6, 3.3.6, and 3.4.6.

11.4 Projects and Management Actions for the City of Firebaugh The City is actively pursuing water conservation. In order to maintain sustainability for each GSA in the SJREC GSP group, the City is committed to offsetting an increase in demand based on projected population growth, by developing certain projects. Each project will be analyzed jointly with the City and the SJREC to maximize the regional benefits. The City will develop projects to offset overdraft including; 1) storm water capture, 2) demand reduction through reduced watering, 3) surface water transfer, 4) purchasing groundwater credits, 5) participation in recharge projects, 6) reclaimed water for outdoor watering and 7) the city will continue to investigate other types of projects.

The groundwater quality, under natural conditions, under the City has some constituents of concern discussed in Appendix U. The City currently pumps certain wells as needed to meet Title 22 water quality standards for the consumer. If the groundwater quality were to naturally degrade and/or the Title 22 standards for drinking water were to be updated with lower MCL’s, the City may run the risk of exceeding allowable limits. In addition to the potential water quality concerns, with the SGMA, the City currently has a deficit water balance. To counteract both of these concerns, the City has started preliminary discussions with the SJREC on two possible projects mentioned above. One project to offset a water budget deficit would be for the City to work with the SJREC for groundwater recharge credits.

Another project has been discussed to address both overdraft and water quality concerns for the City.

The SJREC would make surface water available for transfer to the City, thereby reducing the City’s need to pump groundwater while providing cleaner drinking water for the DAC’s residents. The City of Firebaugh has moved its well field to the other side of the river due to groundwater quality concerns.

11.5 Plan Implementation for the City of Firebaugh
The cost to develop and implement the GSP specific to the City of Firebaugh has been cost shared at 50% between the SJREC GSA and the City of Firebaugh GSA. Additionally, the SJREC GSA has pursued additional grant funding to fully offset GSP development costs for SDAC’s. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One groundwater management success story in the Mendota area was the implementation of monitoring and management program for well water transfers near the Mendota Pool. The SJREC worked with the 263
166
regional water leaders to develop and implement a plan that would maximize water resources without sacrificing the needs of the local communities. As a result, water levels have remained fairly stable and none of the wells pumping as part of the program are contributing to land subsidence. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the City, the SJREC will take the lead preparing annual reports consistent with SGMA regulations.
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12.0 CITY OF MENDOTA GSA AREA

12.1 Background for City of Mendota
The City of Mendota is a Severely Disadvantaged Community relies entirely on groundwater. In 1999, KDSA analyzed groundwater conditions in the vicinity of the City of Mendota. The quality of the groundwater around the City of Mendota was not suitable for public supply. In the early 2000’s, the City of Mendota worked with Columbia Canal Company and the landowners on the east side of the river to drill domestic supply wells on the east side of the river where the water quality was significantly better.

A pipeline was constructed to deliver water from lands in and adjacent to CCC (east side of the river) to the City (west side of the river). Additionally, the landowners provided the City access to use the Mowry bridge to access the City wells across the San Joaquin River. CCC and the SJREC have a long history working with the local communities to solve regional water problems. In this case, the district worked with the local landowners to provide sites for the City to construct wells to provide the residents drinking water.

Over the years, the CCC has invested in helping cities monitor, understand and manage the aquifers for the communities near the district. The relationship has resulted in a common understanding of the aquifer and a partnership which is the foundation of the SJREC GSA and the City of Mendota GSA cooperating to develop this part of the GSP. Some potential impacts to the City include increased costs for the SWRCB to develop and implement a sustainable plan for the City and a standalone plan that isn’t synchronous with the lands surrounding the City. CCID recognized the potential impacts to the City of Mendota, a SDAC, and worked with City leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the City. Ultimately, the City decided to form its’ own GSA with the help from the SJREC to appropriately file. The City of Mendota welcomed the SJREC’s assistance in developing the required elements in a GSP. It was mutually agreed that the SJREC will work with the City to develop the requirements in the GSP and to include this in a discrete Section in the SJREC GSP. This was a seamless process due to the decades of cooperation of managing groundwater for the region.

The SJREC are committed to assist this SDAC to maintain sustainability through the planning and implementation horizon. The City of Mendota GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix V for a discussion on the basin setting, sustainable management criteria and projects & management actions specific to the City. Some further details are provided below.

12.2 Water Budgets for the City of Mendota
Presented herein is the compilation of the historic, current and projected water budgets specific to the City of Mendota GSA.

12.2.1 Historic Water Budget for the City of Mendota
The City of Mendota solely relies on groundwater to provide its residents clean drinking water. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta265 168
Mendota Subbasin. Groundwater pumping during this timeframe ranged from 1,600 to 1,800 AF/year with an average pumping of 1,700 AF/year. The City sends effluent its Waste Water Treatment Facility (WWTF). They have about 76 acres of percolation ponds at the WWTF. The effluent flow from the City averages 1,200 AF/year. Each year about 300 AF evaporates while the remaining 900 AF percolates in the ponded area. The total effluent consumptive use for the City of Mendota averages about 300 AF/year.

The City water use that does not result in the production of effluent was used to water lawns, parks, etc.

The outdoor water use is the difference of pumpage and effluent and averaged about 500 AF/year.

Typically, a 70% irrigation efficiency is applied to urban landscape watering which results in an average annual consumptive use of about 400 AF/year.

The total average annual consumptive use from outdoor water use and crop demand at the WWTF is 700 AF/year. The City of Mendota GSA covers roughly 2,100 acres. The approximate sustainable yield for the City of Mendota GSA is 0.40 acre-feet/acre or about 800 acre-feet/year.

WATER
YEAR

PUMPAGE
(AF)

CITY EFFLUENT
(AF)

OUTDOOR

USE (AF)

CONSUMPTIVE

USE (AF)
2003 1,600 1,200 400 600
2004 1,700 1,200 500 700
2005 1,600 1,200 400 600
2006 1,600 1,200 400 600
2007 1,700 1,200 500 700
2008 1,800 1,200 600 700
2009 1,700 1,200 500 700
2010 1,800 1,200 600 700
2011 1,700 1,200 500 700
2012 1,800 1,200 600 700
Table 5655 - City of Mendota Historic Water Budget Data 266
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Figure 31 - City Water Use Diagram

12.2.2 Current Water Budget for the City of Mendota
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER
YEAR

PUMPAGE
(AF)
CITY

EFFLUENT
(AF)

OUTDOOR

USE (AF)

CONSUMPTIVE

USE (AF)
2013 1,500 1,200 300 500
Table 5756 - City of Mendota Current Water Budget Data

12.2.3 Projected Water Budget for the City of Mendota
The City of Mendota General Plan projects the City to have a pumping demand of 10,600 AF by 2070 which equates to a 3.6% annual growth, which was used in this plan to determine the projected baseline demand on water. The average annual pumping from the historic water budget was used as a baseline to project the demand on water through the planning and implementation horizon. The same data and methodologies described in Section 12.2.1 were used to determine consumptive use of groundwater.

Below is a table of the projected water budget. The projected consumptive use is anticipated to increase by 3,300 AF/year to a total of 4,000 AF by 2070. Section 12.3 will discuss SMC in order for the City of Mendota to be sustainable. Section 12.4 will discuss projects and management actions to offset the increased demand.
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WATER
YEAR

PROJECTED

PUMPAGE (AF)

PROJECTED CITY

EFFLUENT (AF)

PROJECTED

OUTDOOR USE (AF)

CONSUMPTIVE

USE (AF)
2014 1,400 1,200 200 400
2015 1,400 1,200 200 400
2016 1,700 1,200 500 700
2017 1,800 1,200 600 700
2018 1,700 1,200 500 700
2019 1,800 1,200 600 700
2020 1,800 1,300 500 700
2021 1,900 1,300 600 700
2022 2,000 1,400 600 800
2023 2,000 1,400 600 800
2024 2,100 1,500 600 800
2025 2,200 1,500 700 900
2026 2,300 1,600 700 900
2027 2,300 1,600 700 900
2028 2,400 1,700 700 900
2029 2,500 1,800 700 900
2030 2,600 1,800 800 1,000
2031 2,700 1,900 800 1,000
2032 2,800 2,000 800 1,100
2033 2,900 2,000 900 1,100
2034 3,000 2,100 900 1,200
2035 3,100 2,200 900 1,200
2036 3,200 2,300 900 1,200
2037 3,300 2,300 1,000 1,300
2038 3,400 2,400 1,000 1,300
2039 3,600 2,500 1,100 1,400
2040 3,700 2,600 1,100 1,400
2041 3,800 2,700 1,100 1,400
2042 4,000 2,800 1,200 1,500
2043 4,100 2,900 1,200 1,600
2044 4,200 3,000 1,200 1,600
2045 4,400 3,100 1,300 1,700
2046 4,500 3,200 1,300 1,700
2047 4,700 3,300 1,400 1,800
2048 4,900 3,400 1,500 1,900
2049 5,100 3,600 1,500 2,000
2050 5,200 3,700 1,500 2,000
2051 5,400 3,800 1,600 2,100
2052 5,600 4,000 1,600 2,100
2053 5,800 4,100 1,700 2,200
2054 6,000 4,300 1,700 2,300
2055 6,200 4,400 1,800 2,400
2056 6,500 4,600 1,900 2,500
2057 6,700 4,700 2,000 2,600
2058 6,900 4,900 2,000 2,600
2059 7,200 5,100 2,100 2,700
2060 7,400 5,300 2,100 2,800
2061 7,700 5,400 2,300 3,000
2062 8,000 5,600 2,400 3,100
2063 8,300 5,800 2,500 3,200
2064 8,600 6,000 2,600 3,300
2065 8,900 6,300 2,600 3,400
2066 9,200 6,500 2,700 3,500
2067 9,500 6,700 2,800 3,600
2068 9,900 7,000 2,900 3,800
2069 10,200 7,200 3,000 3,900
2070 10,600 7,500 3,100 4,000
Table 5857 – City of Mendota Projected Water Budget Data 268
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12.3 Sustainable Management Criteria for the City of Mendota The City of Mendota has historically relied completely on groundwater extraction to meet water demand. Groundwater overdraft around the City has primarily been offset by recharge from the SJREC service area and seepage from the San Joaquin River. As mentioned previously, the SJREC are invested in helping the City to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the City of Mendota on Projects and Management actions to offset groundwater extractions by the City that is above their sustainable yield.

The historical consumptive use for the City of Mendota was about 700 AF/year which equates to an average use of about 0.3 AF/acre. The sustainable yield for the city is about 800 AF/year. Currently, the City of Mendota GSA is sustainable but will likely have a consumptive use deficit through the planning and implementation horizon that will need to be offset through projects and management actions.

While the City of Mendota lies near SJREC Management AreasMonitoring Zones G and J, different SMC is developed in order for the City to achieve collective and independent groundwater sustainability.

12.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the City are positively impacted through recharge from the SJREC and seepage from the San Joaquin River and have remained fairly stable. Water levels in the SJREC Management AreaMonitoring Zone J will be used to sustainably manage groundwater levels for the City since the City’s wells are located within that area. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

12.3.2 Reduction in Groundwater Storage
Groundwater storage under the City of Mendota is positively impacted through recharge from the SJREC and seepage from the San Joaquin River. Managing groundwater storage for the City will be accomplished through updated water budgets for the City. The SJREC will contribute to recharge to maintain adequate groundwater storage to offset reductions caused by the City. Sustainable groundwater management for the City is best achieved by offsetting overdraft through the implementation of projects and management actions.

12.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

12.3.4 Degraded Water Quality
The main concern for the City is the contamination resulting from naturally occurring constituents including nitrate, arsenic, hexavalent chromium, selenium, total dissolved solids, sulfate, chloride, and boron. These constituents are important in terms of developing public supply wells to meet Title 22 Standards. As part of the process of installing new wells, the City does vertical trends in groundwater quality and completes the well opposite of the zones with quality concerns. One potential solution for water quality concerns and also to meet overdraft is for the City to receive a surface water transfer from the SJREC.
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12.3.5 Land Subsidence
The City does not operate any wells perforated below the Corcoran Clay. As a result, inelastic land subsidence is unlikely to occur as a result of pumping from the City of Mendota wells. Therefore, no SMC have been established for this sustainability indicator. The SJREC will continue to work with the City to monitor subsidence and work with regional partners on solutions if subsidence is observed and may cause damage to critical infrastructure.

12.3.6 Depletions of Interconnected Surface Water
The City of Mendota plans to work with the SJREC to sustainably manage interconnected surface water and groundwater. For more details refer to the following Sections in this GSP: 3.2.6, 3.3.6, and 3.4.6.

12.4 Projects and Management Actions for the City of Mendota The City is actively pursuing water conservation. In order to maintain sustainability for each GSA in the SJREC GSP group, the City is committed to offsetting an increase in demand based on projected population growth, by developing certain projects. Each project will be analyzed jointly with the City and the SJREC to maximize the regional benefits. The City will develop projects including; 1) storm water capture, 2) demand reduction through reduced watering, 3) surface water transfer, 4) purchasing groundwater credits, 5) participation in recharge projects, 6) reclaimed water for outdoor watering and 7) the city will continue to investigate other types of projects.

The groundwater quality, under natural conditions, under the City has some constituents of concern discussed in Appendix V. The City currently pumps certain wells as needed to meet Title 22 water quality standards for the consumer. If the groundwater quality were to naturally degrade and/or the Title 22 standards for drinking water were to be updated with lower MCL’s, the City may run the risk of exceeding allowable limits. In addition to the potential water quality concerns, with the SGMA, the City poses the risk of having a deficit water balance in the future. To counteract both of these concerns, the City has started preliminary discussions with the SJREC on two possible projects mentioned above. One project to offset a water budget deficit would be for the City to work with the SJREC for groundwater recharge credits.

Another project has been discussed to address both overdraft and water quality concerns for the City.

The SJREC would make surface water available for transfer to the City, thereby reducing the City’s need to pump groundwater while providing cleaner drinking water for the DAC’s residents. The City of Firebaugh has moved its well field to the other side of the river due to groundwater quality concerns.

12.5 Plan Implementation for the City of Mendota
The cost to develop and implement the GSP specific to the City of Firebaugh has been cost shared at 50% between the SJREC GSA and the City of Firebaugh GSA. Additionally, the SJREC GSA has pursued additional grant funding to fully offset GSP development costs for SDAC’s. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One 270
173
groundwater management success story in the Mendota area was the implementation of monitoring and management program for well water transfers near the Mendota Pool. The SJREC worked with the regional water leaders to develop and implement a plan that would maximize water resources without sacrificing the needs of the local communities. As a result, water levels have remained fairly stable and none of the wells pumping as part of the program are contributing to land subsidence. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the City, the SJREC will take the lead preparing annual reports consistent with SGMA regulations.
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13.0 TURNER ISLAND WATER DISTRICT – 2 GSA AREA

13.1 Background for Turner Island Water District
The Turner Island Water District (TIWD) is in an area bound by the San Joaquin River to the north (boundary of the Delta-Mendota Subbasin) and the SJREC GSA to the east, west and south. Every acre of the area has historically been farmed. This area receives drain water (surface water spills) from the SLCC to meet the crop consumptive use.

Over the years, the SJREC have invested in working with other local agencies to monitor, understand and manage the aquifers around the Exchange Contractors service area. The SLCC has a long-standing relationship with TIWD to jointly manage water in the area including surface water, groundwater and drain water. This relationship has resulted in a common understanding of the local water resources and a partnership which is the foundation of the SJREC GSA and the Turner Island Water District - 2 GSA cooperating to develop this part of the GSP.

The SJREC and TIWD are committed to maintain sustainability through the planning and implementation horizon. The TIWD-2 GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix W for a discussion on the basin setting, sustainable management criteria and projects & management actions specific to the TIWD. Some further details are provided below.

13.2 Water Budgets for the Turner Island Water District Presented herein is the compilation of the historic, current and projected water budgets specific to the Turner Island Water District - 2 GSA.

13.2.1 Historic Water Budget for the Turner Island Water District TIWD relies on surface water from SLCC during non-critical years under the Exchange Contract. During Shasta Critical years, the TIWD supplements crop demand by pumping groundwater. Additionally, the TIWD pumps groundwater from their lands in the TIWD-2 GSA (Delta-Mendota Subbasin) and provides that water through an existing pipeline under the San Joaquin River to their lands on the other side of the river (Merced Subbasin). The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. Groundwater pumping during this timeframe ranged from 700 to 1,100 AF/year with an average pumping of 800 AF/year. Surface Water deliveries during this timeframe ranged from 4,300 to 6,500 AF/year with an average delivery of 5,600 AF/year.

The total crop demand of irrigation water (ETiw) ranged from 2,600 to 3,700 AF/year with an average ETiw of 3,200 AF/year. All of the crop ET was met with surface water. The change in groundwater storage during this timeframe averaged about +2,000 AF/year. The TIWD-2 GSA covers roughly 1,850 acres. The approximate sustainable yield for the Turner Island Water District – 2 GSA is 0.40 acrefeet/acre or about 700 acre-feet/year. 272
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WATER
YEAR
SHASTA

WATER YEAR

DESIGNATION

SURFACE
WATER

APPLIED

GROUNDWATER

PUMPING
TOTAL
CROP
ETc
TOTAL
CROP
ETiw
DEEP

PERCOLATION

OF IRRIGATION

CHANNEL

RECHARGE

CHANGE IN

GROUNDWATER

STORAGE
2003 Non-Critical 6,300 700 4,500 3,600 2,700 700 2,700 2004 Non-Critical 5,700 900 4,200 3,200 2,500 700 2,300 2005 Non-Critical 6,000 800 3,700 2,700 3,300 700 3,200 2006 Non-Critical 6,500 800 4,700 3,600 2,900 700 2,800 2007 Non-Critical 6,300 900 4,400 3,700 2,600 700 2,400 2008 Non-Critical 5,800 900 3,800 3,200 2,600 700 2,400 2009 Non-Critical 4,900 700 3,700 2,900 2,000 700 2,000 2010 Non-Critical 4,700 700 3,500 2,600 2,100 700 2,100 2011 Non-Critical 5,200 800 4,400 3,500 1,700 700 1,600 2012 Non-Critical 4,300 1,100 4,200 3,400 900 700 500
Table 5958 - TIWD Historic Water Budget Data

13.2.2 Current Water Budget for the Turner Island Water District The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER
YEAR
SHASTA

WATER YEAR

DESIGNATION

SURFACE
WATER

APPLIED

GROUNDWATER

PUMPING
TOTAL
CROP
ETc
TOTAL
CROP
ETiw
DEEP

PERCOLATION

OF IRRIGATION

CHANNEL

RECHARGE

CHANGE IN

GROUNDWATER

STORAGE
2013 Non-Critical 5,000 900 4,300 3,400 1,600 700 1,400 Table 6059 - TIWD Current Water Budget Data

13.2.3 Projected Water Budget for the Turner Island Water District The TIWD is currently fully planted. Any increase in demand is directly tied to Climate Change. The same process outlined in Section 2.2.3.3 was used to determine climate change factors. Below is a table of the projected water budget. The projected consumptive use of applied water is anticipated to increase from 3,200 AF/year to a maximum of 4,000 AF by 2070. Since the TIWD receives drain water in excess of 4,000 on an average annual basis, it is reasonable to assume that the TIWD water budget is sustainable. Section 13.3 will discuss SMC in order for TIWD to maintain sustainability. Section 13.4 will discuss projects and management actions.
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WATER
YEAR

HISTORICAL

REFERENCE

USED FOR

HYDROLOGY

HISTORICAL

REFERENCE FOR
WATER

DELIVERY/DEMAND
SHASTA

WATER YEAR

DESIGNATION

WATER YEAR TYPE
(SJ VALLEY)
2014 - 2014 Critical Critically Dry
2015 - 2015 Critical Critically Dry
2016 - 2016 Non-Critical Dry
2017 - 2011 Non-Critical Wet
2018 1979 2010 Non-Critical Above Normal
2019 1980 2011 Non-Critical Wet
2020 1981 2012 Non-Critical Dry
2021 1982 2011 Non-Critical Wet
2022 1983 2011 Non-Critical Wet
2023 1984 2010 Non-Critical Above Normal
2024 1985 2012 Non-Critical Dry
2025 1986 2011 Non-Critical Wet
2026 1987 2013 Non-Critical Critically Dry
2027 1988 2013 Non-Critical Critically Dry
2028 1989 2013 Non-Critical Critically Dry
2029 1990 2013 Non-Critical Critically Dry
2030 1991 2014 Critical Critically Dry
2031 1992 2015 Critical Critically Dry
2032 1993 2011 Non-Critical Wet
2033 1994 2013 Non-Critical Critically Dry
2034 1995 2011 Non-Critical Wet
2035 1996 2011 Non-Critical Wet
2036 1997 2011 Non-Critical Wet
2037 1998 2011 Non-Critical Wet
2038 1999 2010 Non-Critical Above Normal
2039 2000 2010 Non-Critical Above Normal
2040 2001 2012 Non-Critical Dry
2041 2002 2012 Non-Critical Dry
2042 2003 2003 Non-Critical Below Normal
2043 2004 2004 Non-Critical Dry
2044 2005 2005 Non-Critical Wet
2045 2006 2006 Non-Critical Wet
2046 2007 2007 Non-Critical Critically Dry
2047 2008 2008 Non-Critical Critically Dry
2048 2009 2009 Non-Critical Below Normal
2049 2010 2010 Non-Critical Above Normal
2050 2011 2011 Non-Critical Wet
2051 2001 2012 Non-Critical Dry
2052 1992 2013 Non-Critical Critically Dry
2053 1976 2014 Critical Critically Dry
2054 1977 2015 Critical Critically Dry
2055 2002 2016 Non-Critical Dry
2056 2011 2011 Non-Critical Wet
2057 1965 2011 Non-Critical Wet
2058 1966 2009 Non-Critical Below Normal
2059 1967 2011 Non-Critical Wet
2060 1968 2012 Non-Critical Dry
2061 1969 2011 Non-Critical Wet
2062 1970 2010 Non-Critical Above Normal
2063 1971 2009 Non-Critical Below Normal
2064 1972 2012 Non-Critical Dry
2065 1973 2010 Non-Critical Above Normal
2066 1974 2011 Non-Critical Wet
2067 1975 2011 Non-Critical Wet
2068 1976 2014 Critical Critically Dry
2069 1977 2015 Critical Critically Dry
2070 1978 2011 Non-Critical Wet
Table 6160 – TIWD Projected Water Budget Water Year Data 274
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WATER
YEAR

SURFACE
WATER

APPLIED

GROUNDWATER

PUMPING

CLIMATE
CHANGE
FACTOR
TOTAL

ETC WITH

CLIMATE
CHANGE
TOTAL

ETIW WITH

CLIMATE
CHANGE
DEEP

PERCOLATION

OF IRRIGATION
WATER

CHANNEL

SEEPAGE
(RECHARGE)

CHANGE IN

GROUNDWATER

STORAGE
2014 4,600 3,300 1.000 4,000 3,200 1,400 700 -1,200
2015 4,000 2,500 1.000 2,600 1,900 2,100 700 300
2016 4,400 1,400 1.000 3,900 3,000 1,400 700 700
2017 5,200 800 1.000 4,400 3,500 1,700 700 1,600
2018 4,700 700 1.034 3,600 2,700 2,000 700 2,000
2019 5,200 800 1.035 4,600 3,600 1,600 700 1,500
2020 4,300 1,100 1.037 4,400 3,500 800 700 400
2021 5,200 800 1.034 4,500 3,600 1,600 700 1,500
2022 5,200 800 1.037 4,600 3,600 1,600 700 1,500
2023 4,700 700 1.030 3,600 2,700 2,000 700 2,000
2024 4,300 1,100 1.038 4,400 3,500 800 700 400
2025 5,200 800 1.039 4,600 3,600 1,600 700 1,500
2026 5,000 900 1.033 4,400 3,500 1,500 700 1,300
2027 5,000 900 1.035 4,500 3,500 1,500 700 1,300
2028 5,000 900 1.033 4,400 3,500 1,500 700 1,300
2029 5,000 900 1.028 4,400 3,500 1,500 700 1,300
2030 4,600 3,300 1.029 4,100 3,300 1,300 700 -1,300
2031 4,000 2,500 1.032 2,700 2,000 2,000 700 200
2032 5,200 800 1.034 4,500 3,600 1,600 700 1,500
2033 5,000 900 1.035 4,500 3,500 1,500 700 1,300
2034 5,200 800 1.043 4,600 3,700 1,500 700 1,400
2035 5,200 800 1.028 4,500 3,600 1,600 700 1,500
2036 5,200 800 1.029 4,500 3,600 1,600 700 1,500
2037 5,200 800 1.035 4,600 3,600 1,600 700 1,500
2038 4,700 700 1.037 3,600 2,700 2,000 700 2,000
2039 4,700 700 1.034 3,600 2,700 2,000 700 2,000
2040 4,300 1,100 1.028 4,300 3,500 800 700 400
2041 4,300 1,100 1.029 4,300 3,500 800 700 400
2042 6,300 700 1.033 4,600 3,700 2,600 700 2,600
2043 5,700 900 1.028 4,300 3,300 2,400 700 2,200
2044 6,000 800 1.038 3,800 2,800 3,200 700 3,100
2045 6,500 800 1.038 4,900 3,700 2,800 700 2,700
2046 6,300 900 1.082 4,800 4,000 2,300 700 2,100
2047 5,800 900 1.079 4,100 3,500 2,300 700 2,100
2048 4,900 700 1.082 4,000 3,100 1,800 700 1,800
2049 4,700 700 1.086 3,800 2,800 1,900 700 1,900
2050 5,200 800 1.088 4,800 3,800 1,400 700 1,300
2051 4,300 1,100 1.074 4,500 3,700 600 700 200
2052 5,000 900 1.089 4,700 3,700 1,300 700 1,100
2053 4,600 3,300 1.087 4,300 3,500 1,100 700 -1,500
2054 4,000 2,500 1.082 2,800 2,100 1,900 700 100
2055 4,400 1,400 1.082 4,200 3,200 1,200 700 500
2056 5,200 800 1.088 4,800 3,800 1,400 700 1,300
2057 5,200 800 1.083 4,800 3,800 1,400 700 1,300
2058 4,900 700 1.086 4,000 3,100 1,800 700 1,800
2059 5,200 800 1.090 4,800 3,800 1,400 700 1,300
2060 4,300 1,100 1.086 4,600 3,700 600 700 200
2061 5,200 800 1.086 4,800 3,800 1,400 700 1,300
2062 4,700 700 1.080 3,800 2,800 1,900 700 1,900
2063 4,900 700 1.090 4,000 3,200 1,700 700 1,700
2064 4,300 1,100 1.078 4,500 3,700 600 700 200
2065 4,700 700 1.083 3,800 2,800 1,900 700 1,900
2066 5,200 800 1.086 4,800 3,800 1,400 700 1,300
2067 5,200 800 1.086 4,800 3,800 1,400 700 1,300
2068 4,600 3,300 1.087 4,300 3,500 1,100 700 -1,500
2069 4,000 2,500 1.082 2,800 2,100 1,900 700 100
2070 5,200 800 1.075 4,700 3,800 1,400 700 1,300
Table 6261 - TIWD Projected Water Budget
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13.3 Sustainable Management Criteria for the Turner Island Water District The TIWD is a conjunctive use area that relies primarily on surface water. Water levels around TIWD have been fairly stable due to surface water deliveries and seepage from the San Joaquin River. The SJREC GSP Group, collectively, is currently sustainable. The TIWD is currently sustainable and the SJREC will continue to monitor and manage jointly with TIWD to ensure that we maintain sustainability through annual review of groundwater conditions.

The historical consumptive use for the TIWD was about 3,200 AF/year which equates to an average use of about 1.7 AF/acre, with an average pumping of about 800 AF/year. While the TIWD lies near SJREC Management AreaMonitoring Zone H, different SMC is developed to specifically meet the needs of the district and to achieve collective and independent sustainability.

13.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the TIWD are positively impacted through recharge from the SJREC/TIWD and seepage from the San Joaquin River, and have remained fairly stable. Water levels in the SJREC Management AreaMonitoring Zone H will be used to analyze potential chronic lowering of groundwater levels. The total groundwater extractions for the TIWD are less than the deep percolation of applied surface water. This indicates that extractions from this area will not have a negative impact on groundwater levels. Even so, the TIWD will manage this potential undesirable result consistent with the groundwater management established for the SJREC Management AreaMonitoring Zone H; see Section

3. 13.3.2 Reduction in Groundwater Storage
Groundwater storage under the TIWD is positively impacted through recharge from the SJREC/TIWD and seepage from the San Joaquin River. Managing groundwater storage for the TIWD will be accomplished through updated water budgets for the district and offsetting storage reductions caused by TIWD.

13.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

13.3.4 Degraded Water Quality
TIWD is managing groundwater quality similar to the SJREC GSA. TIWD will monitor electrical conductivity and impose management actions as necessary. Currently no management actions are recommended to supplement the SJREC GSA management efforts. For more details refer to the following Sections in this GSP: 3.2.4, 3.3.4, and 3.4.4.

13.3.5 Land Subsidence
The TIWD does not operate any wells perforated below the Corcoran Clay. As a result, inelastic land subsidence is unlikely to occur as a result of pumping from the TIWD wells. Therefore, no SMC have been established for this sustainability indicator. The SJREC and the district will work together to ensure that significant and unreasonable land subsidence does not occur due to district pumping. 276
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13.3.6 Depletions of Interconnected Surface Water
The TIWD plans to work with the SJREC to sustainably manage interconnected surface water and groundwater. For more details refer to the following Sections in this GSP: 3.2.6, 3.3.6, and 3.4.6.

13.4 Projects and Management Actions for the Turner Island Water District The TIWD is in an area with shallow groundwater. One current management action that TIWD proposes is to continue to pump groundwater to lower the water table below the crop root zone in order to maintain healthy soils. This management is consistent with the Measurable Objectives defined in Section 3.2. The TIWD will continue to work with SLCC to maintain regional sustainability. The projected water budget for TIWD with climate change indicates that the district will contribute to a positive change in groundwater storage through the planning and implementation horizon.

13.5 Plan Implementation for the Turner Island Water District The cost to develop and implement the GSP specific to the TIWD-2 GSA has been solely funded by the TIWD-2 GSA. Additionally, the SJREC GSA has participated in the Sustainable Groundwater Planning Grant Program (SGWP) on behalf of the SJREC GSP Group and will offset up to 50% of the plan development costs for the TIWD-2 GSA. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort in this area, the SJREC will take the lead preparing annual reports consistent with SGMA regulations. 277
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14.0 MADERA COUNTY-3 GSA AREA

14.1 Background for County of Madera
There is about 3,100 acres of lands not in a public water district, white area, in the Madera County portion of the Delta-Mendota Subbasin. All of the lands with groundwater wells lie between the CCID and CCC. The historic groundwater management from the SJREC have directly and positively impacted the County islands within the SJREC service area. The SJREC worked with County leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the County White Areas.

It was mutually agreed that the SJREC will work with the County to develop the requirements in the GSP and to include this in a discrete section of this plan.

The SJREC are committed to assist the County to maintain sustainability through the planning and implementation horizon. The County of Madera-3 GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 of this GSP describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix I for a discussion on the basin setting for the SJREC GSA and surrounding areas including the County of Madera-3 GSA area. The Water Budget, Sustainable Management Criteria and Projects & Management Actions are included below.

14.2 Water Budgets for the County of Madera
Presented herein is the compilation of the historic, current and projected water budgets specific to the County of Madera - 3 GSA.

14.2.1 Historic Water Budget for the County of Madera
The County of Madera - 3 GSA encompasses about 3,100 acres of land. Of that, about 2,000 acres are actively farmed, 700 acres covers the Chowchilla Bypass channel and the remaining acres are small slivers of land that are not actively farmed and do not pump groundwater. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. It is assumed that all of the ETiw needed to grow the crops in the area was met by pumping groundwater.

Groundwater pumping during this timeframe ranged from 4,000 to 5,000 AF/year with an average pumping of 4,400 AF/year. The approximate sustainable yield for the County of Madera - 3 GSA is 0.40 acre-feet/acre or about 1,200 acre-feet/year.
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WATER YEAR

IRRIGATED
ACRES
ETc (AF) ETiw (AF) EFFECTIVE

PUMPING (AF)
2003 2,000 5,300 4,500 4,500
2004 2,000 5,100 4,300 4,300
2005 2,000 4,900 4,000 4,000
2006 2,000 4,700 4,000 4,000
2007 2,000 5,700 5,000 5,000
2008 2,000 4,900 4,300 4,300
2009 2,000 5,400 4,600 4,600
2010 2,000 5,500 4,700 4,700
2011 2,000 5,100 4,300 4,300
2012 2,000 5,400 4,700 4,700
Table 6362 - County of Madera Historic Water Budget Data

14.2.2 Current Water Budget for the County of Madera
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER YEAR

IRRIGATED
ACRES
ETC (AF) ETiw
(AF)

EFFECTIVE

PUMPING (AF)
2013 2,000 6,300 5,300 5,300
Table 6463 - County of Madera Current Water Budget Data

14.2.3 Projected Water Budget for the County of Madera
The County of Madera - 3 GSA area that can be used for production is currently fully planted. Any increase in demand is directly tied to Climate Change. The same process outlined in Section 2.2.3.3 was used to determine climate change factors. Below is a table of the projected water budget. The projected consumptive use of applied water is anticipated to increase by 500 AF/year on average. The net groundwater extraction is equal to consumptive use and ranges from 4,100 to 6,200 AF/year.

Section 14.3 will discuss SMC in order for the County of Madera - 3 GSA to be sustainable. Section 14.4 will discuss projects and management actions to offset the groundwater extractions in excess of the sustainable yield.
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WATER
YEAR

HISTORICAL

REFERENCE

USED FOR

HYDROLOGY

HISTORICAL

REFERENCE FOR
WATER

DELIVERY/DEMAND
SHASTA

WATER YEAR

DESIGNATION

WATER YEAR TYPE
(SJ VALLEY)
2014 - 2014 Critical Critically Dry
2015 - 2015 Critical Critically Dry
2016 - 2016 Non-Critical Dry
2017 - 2011 Non-Critical Wet
2018 1979 2010 Non-Critical Above Normal
2019 1980 2011 Non-Critical Wet
2020 1981 2012 Non-Critical Dry
2021 1982 2011 Non-Critical Wet
2022 1983 2011 Non-Critical Wet
2023 1984 2010 Non-Critical Above Normal
2024 1985 2012 Non-Critical Dry
2025 1986 2011 Non-Critical Wet
2026 1987 2013 Non-Critical Critically Dry
2027 1988 2013 Non-Critical Critically Dry
2028 1989 2013 Non-Critical Critically Dry
2029 1990 2013 Non-Critical Critically Dry
2030 1991 2014 Critical Critically Dry
2031 1992 2015 Critical Critically Dry
2032 1993 2011 Non-Critical Wet
2033 1994 2013 Non-Critical Critically Dry
2034 1995 2011 Non-Critical Wet
2035 1996 2011 Non-Critical Wet
2036 1997 2011 Non-Critical Wet
2037 1998 2011 Non-Critical Wet
2038 1999 2010 Non-Critical Above Normal
2039 2000 2010 Non-Critical Above Normal
2040 2001 2012 Non-Critical Dry
2041 2002 2012 Non-Critical Dry
2042 2003 2003 Non-Critical Below Normal
2043 2004 2004 Non-Critical Dry
2044 2005 2005 Non-Critical Wet
2045 2006 2006 Non-Critical Wet
2046 2007 2007 Non-Critical Critically Dry
2047 2008 2008 Non-Critical Critically Dry
2048 2009 2009 Non-Critical Below Normal
2049 2010 2010 Non-Critical Above Normal
2050 2011 2011 Non-Critical Wet
2051 2001 2012 Non-Critical Dry
2052 1992 2013 Non-Critical Critically Dry
2053 1976 2014 Critical Critically Dry
2054 1977 2015 Critical Critically Dry
2055 2002 2016 Non-Critical Dry
2056 2011 2011 Non-Critical Wet
2057 1965 2011 Non-Critical Wet
2058 1966 2009 Non-Critical Below Normal
2059 1967 2011 Non-Critical Wet
2060 1968 2012 Non-Critical Dry
2061 1969 2011 Non-Critical Wet
2062 1970 2010 Non-Critical Above Normal
2063 1971 2009 Non-Critical Below Normal
2064 1972 2012 Non-Critical Dry
2065 1973 2010 Non-Critical Above Normal
2066 1974 2011 Non-Critical Wet
2067 1975 2011 Non-Critical Wet
2068 1976 2014 Critical Critically Dry
2069 1977 2015 Critical Critically Dry
2070 1978 2011 Non-Critical Wet
Table 6564 – County of Madera Projected Water Budget Water Year Data 280
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WATER
YEAR

IRRIGATED
ACRES

CLIMATE
CHANGE
FACTOR
TOTAL ETc

WITH CLIMATE
CHANGE

TOTAL ETIW

WITH CLIMATE
CHANGE

EFFECTIVE

PUMPING
(AF)
2014 2,000 - 5,300 4,600 4,600
2015 2,000 - 5,500 4,700 4,700
2016 2,000 - 6,700 5,800 5,800
2017 2,000 - 5,100 4,300 4,300
2018 2,000 1.033 5,700 4,900 4,900
2019 2,000 1.034 5,300 4,400 4,400
2020 2,000 1.033 5,600 4,900 4,900
2021 2,000 1.028 5,200 4,400 4,400
2022 2,000 1.035 5,300 4,500 4,500
2023 2,000 1.027 5,600 4,800 4,800
2024 2,000 1.03 5,600 4,800 4,800
2025 2,000 1.037 5,300 4,500 4,500
2026 2,000 1.028 6,500 5,400 5,400
2027 2,000 1.027 6,500 5,400 5,400
2028 2,000 1.031 6,500 5,500 5,500
2029 2,000 1.024 6,500 5,400 5,400
2030 2,000 1.029 5,500 4,700 4,700
2031 2,000 1.03 5,700 4,800 4,800
2032 2,000 1.028 5,200 4,400 4,400
2033 2,000 1.03 6,500 5,500 5,500
2034 2,000 1.033 5,300 4,400 4,400
2035 2,000 1.028 5,200 4,400 4,400
2036 2,000 1.028 5,200 4,400 4,400
2037 2,000 1.032 5,300 4,400 4,400
2038 2,000 1.03 5,700 4,800 4,800
2039 2,000 1.033 5,700 4,900 4,900
2040 2,000 1.023 5,500 4,800 4,800
2041 2,000 1.028 5,600 4,800 4,800
2042 2,000 1.03 5,500 4,600 4,600
2043 2,000 1.028 5,200 4,400 4,400
2044 2,000 1.028 5,000 4,100 4,100
2045 2,000 1.033 4,900 4,100 4,100
2046 2,000 1.075 6,100 5,400 5,400
2047 2,000 1.078 5,300 4,600 4,600
2048 2,000 1.084 5,900 5,000 5,000
2049 2,000 1.082 6,000 5,100 5,100
2050 2,000 1.089 5,600 4,700 4,700
2051 2,000 1.07 5,800 5,000 5,000
2052 2,000 1.093 6,900 5,800 5,800
2053 2,000 1.081 5,700 5,000 5,000
2054 2,000 1.08 5,900 5,100 5,100
2055 2,000 1.07 7,200 6,200 6,200
2056 2,000 1.089 5,600 4,700 4,700
2057 2,000 1.083 5,500 4,700 4,700
2058 2,000 1.088 5,900 5,000 5,000
2059 2,000 1.085 5,500 4,700 4,700
2060 2,000 1.079 5,800 5,100 5,100
2061 2,000 1.086 5,500 4,700 4,700
2062 2,000 1.082 6,000 5,100 5,100
2063 2,000 1.088 5,900 5,000 5,000
2064 2,000 1.09 5,900 5,100 5,100
2065 2,000 1.083 6,000 5,100 5,100
2066 2,000 1.086 5,500 4,700 4,700
2067 2,000 1.093 5,600 4,700 4,700
2068 2,000 1.081 5,700 5,000 5,000
2069 2,000 1.08 5,900 5,100 5,100
2070 2,000 1.068 5,400 4,600 4,600
Table 6665 - County of Madera Projected Water Budget
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14.3 Sustainable Management Criteria for the County of Madera The County of Madera - 3 GSA has historically relied completely on groundwater extraction to meet demand. Groundwater overdraft in this area has primarily been offset by recharge from the SJREC service area and seepage from the San Joaquin River. The SJREC are invested in helping the County to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the County of Madera on Projects and Management actions to offset groundwater extractions by the County white area that is above their sustainable yield.

The historical consumptive use for the County of Madera was about 4,400 AF/year which equates to an average use of about 2.2 AF/acre for irrigated acres and about 1.4 AF/acre for the total area covered by the GSA. The sustainable yield for the County is 1,200 AF/year which leave a 3,200 AF/year consumptive use deficit that needs to me bet through projects and management actions. While the County of Madera - 3 GSA lies in the SJREC Management AreaMonitoring Zone J, different SMC is developed in order for the County to achieve independent groundwater sustainability.

14.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the County of Madera - 3 GSA are positively impacted through recharge from the SJREC and seepage from the San Joaquin River. Water levels in the SJREC Management AreaMonitoring Zone J will be used to sustainably manage groundwater levels around the County area.

Sustainable groundwater management for the County is best achieved by offsetting overdraft through the implementation of projects and management actions.

14.3.2 Reduction in Groundwater Storage
Groundwater storage under the County of Madera - 3 GSA is positively impacted through recharge from the SJREC and seepage from the San Joaquin River. Managing groundwater storage for the County will be accomplished through updated water budgets for the County white areas. Sustainable groundwater management for the County is best achieved by offsetting overdraft through the implementation of projects and management actions.

14.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

14.3.4 Degraded Water Quality
Madera County is managing groundwater quality similar to the SJREC GSA. Salinity is the major water quality concern in the area. Madera County will monitor electrical conductivity and impose management actions as necessary. Currently no management actions are recommended to supplement the SJREC GSA management efforts. For more details refer to the following Sections in this GSP: 3.2.4,

3.3.4, and 3.4.4.

14.3.5 Land Subsidence
It is anticipated that the County of Madera - 3 GSA does not operate any wells perforated below the Corcoran Clay. As a result, inelastic land subsidence is unlikely to occur as a result of pumping from the wells within the GSA area. Therefore, no SMC have been established for this sustainability indicator. 282
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The SJREC will continue to work with the County of Madera to monitor subsidence and work with regional partners on solutions if subsidence is observed and may cause damage to critical infrastructure.

14.3.6 Depletions of Interconnected Surface Water
The County of Madera plans to work with the SJREC to sustainably manage interconnected surface water and groundwater. For more details refer to the following Sections in this GSP: 3.2.6, 3.3.6, and

3.4.6. 14.4 Projects and Management Actions for the County of Madera In order to maintain sustainability for each GSA in the SJREC GSP group, the County is committed to offsetting estimated groundwater overdraft. Each project will be analyzed jointly with the County and the SJREC to maximize the regional benefits. The County is pursuing the following projects as a way to offset demand; 1) purchasing groundwater credits and 2) participation in recharge projects.

The SJREC will continue to work with the County to not only meet the requirements of the SGMA but more importantly, to maximize the benefits of local water resources.

14.5 Plan Implementation for the County of Madera
The cost to develop and implement the GSP specific to the County of Madera has been cost shared at 50% between the SJREC GSA and the County of Madera - 3 GSA. Additionally, the SJREC GSA has participated in the Sustainable Groundwater Planning Grant Program (SGWP) on behalf of the SJREC GSP Group and will offset up to 50% of the plan development costs for the County of Madera - 3 GSA. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One groundwater management success story in the Mendota area was the implementation of monitoring and management program for well water transfers near the Mendota Pool. The SJREC worked with the regional water leaders to develop and implement a plan that would maximize water resources without sacrificing the needs of the local communities. As a result, water levels have remained fairly stable and none of the wells pumping as part of the program are contributing to land subsidence. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the County, the SJREC will take the lead preparing annual reports consistent with SGMA regulations. 283
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15.0 PORTION OF MERCED COUNTY DELTA-MENDOTA GSA AREA

15.1 Background for County of Merced
There are 17,483 acres of lands not in a public water district, white area, in the portion of the County of Merced – Delta-Mendota GSA that has been included in the SJREC GSP; refer to Figure 2 for a graphical depiction of the area. The SJREC worked with County leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the County white areas. The County agreed to file as the GSA over the County white areas and worked with the SJREC and the GWD GSA to include the Merced County Delta-Mendota GSA lands in both the GGSA’s GSP and the SJREC GSP. It was mutually determined that the logical approach would be to include most of the farming and industry lands in the SJREC GSP and include the managed duck clubs in the GGSA’s GSP. The SJREC and the County of Merced agreed to include those lands in a discrete Section in the SJREC GSP.

The Merced County – Delta-Mendota GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 of this GSP describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix I for a discussion on the basin setting for the SJREC GSA and surrounding areas including the Portion of the County of Merced – Delta-Mendota GSA area in the SJREC GSP. The Water Budget, Sustainable Management Criteria and Projects & Management Actions are included below.

15.2 Water Budgets for the County of Merced
Presented herein is the compilation of the historic, current and projected water budgets specific to the portion of the County of Merced – Delta-Mendota GSA within the SJREC GSP.

Most of the data was collected using LandSAT, aerial imagery and local knowledge of the lands. While the portion of the County of Merced – Delta-Mendota GSA is fairly large, most of the lands aren’t irrigated agriculture and predominantly rely on precipitation or are not actively using groundwater.

15.2.1 Historic Water Budget for the County of Merced
The portion of the County of Merced – Delta-Mendota GSA in the SJREC GSP encompasses 17,483 acres of land. Of that, about 5,000 acres are actively farmed, 2,500 acres encompass the footprint of three tomato processing plants (Industry) and about 10,000 acres are not actively farmed and do not pump groundwater. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. There are three tomato processing plants that pump groundwater for plant operations. The process water is used to irrigate crops and the plants also treat the process water and use for habitat. The consumptive use for the Industry includes pond evaporation.

LandSAT data, aerial imagery and site visits were used to determine an approximated total irrigated acreage for this GSA. The crop coefficient method described in Section 2.2.3.1, similar to the SJREC GSA, was used to determine the crop consumptive use for irrigated agriculture. Consumptive use during this timeframe ranged from 6,100 to 8,000 AF/year with an average of approximately 7,000 AF/year. The approximate sustainable yield for the County of Merced – Delta-Mendota GSA is 0.40 acre-feet/acre or about 7,000 acre-feet/year. The estimated effective pumping of 7,000 AF/year is considered within the range of uncertainty of the estimate of sustainable yield for the portion of the Merced County – Delta284 187
Mendota GSA in the SJREC GSP. As such, no immediate actions are anticipated to reduce pumping or augment recharge in the GSA, and steps to achieve independent sustainability of the GSA are anticipated during Plan implementation.

WATER
YEAR
MERCED

COUNTY -

GSA ACRES

IRRIGATED

INDUSTRY
ACRES

IRRIGATED

AG ACRES
ETC
(AF) ETiw (AF)

EFFECTIVE

PUMPING
(AF)
2003 17,500 1,800 5,000 8,600 6,700 6,700
2004 17,500 1,800 5,000 10,100 8,000 8,000
2005 17,500 1,800 5,000 9,000 6,200 6,200
2006 17,500 1,800 5,000 9,000 6,100 6,100
2007 17,500 1,800 5,000 9,200 7,800 7,800
2008 17,500 1,800 5,000 10,000 8,000 8,000
2009 17,500 1,800 5,000 10,100 7,700 7,700
2010 17,500 1,800 5,000 9,700 7,400 7,400
2011 17,500 1,800 5,000 9,400 7,200 7,200
2012 17,500 1,800 5,000 10,000 7,600 7,600
Table 6766 - County of Merced Historic Water Budget Data

15.2.2 Current Water Budget for the County of Merced
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER
YEAR
MERCED

COUNTY -

GSA ACRES

IRRIGATED

INDUSTRY
ACRES

IRRIGATED

AG ACRES
ETC
(AF) ETiw (AF)

EFFECTIVE

PUMPING
(AF)
2013 17,500 1,800 5,000 9,900 7,500 7,500
Table 6867 - County of Merced Current Water Budget Data

15.2.3 Projected Water Budget for the County of Merced
The portion of the Merced County – Delta-Mendota GSA in the SJREC GSP, is not anticipated to increase the acreage of irrigated agriculture. Any increase in demand is more likely to be directly tied to Climate Change. The same process outlined in Section 2.2.3.3 was used to estimate climate change factors.

Below is a table of the projected water budget. The projected consumptive use of applied water is anticipated to increase slightly during the projected water budget. The consumptive use of applied water ranges from 6,300 to 8,600 AF/year with an average of 7,700 AF/year. Section 15.3 will discuss SMC in order for the portion of Merced County - Delta-Mendota GSA in the SJREC GSP, to be sustainable. Section 15.4 will discuss projects and management actions to offset groundwater extractions in excess of the sustainable yield.
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WATER
YEAR

HISTORICAL

REFERENCE

USED FOR

HYDROLOGY

HISTORICAL

REFERENCE FOR
WATER

DELIVERY/DEMAND
SHASTA

WATER YEAR

DESIGNATION

WATER YEAR TYPE
(SJ VALLEY)
2014 - 2014 Critical Critically Dry
2015 - 2015 Critical Critically Dry
2016 - 2016 Non-Critical Dry
2017 - 2011 Non-Critical Wet
2018 1979 2010 Non-Critical Above Normal
2019 1980 2011 Non-Critical Wet
2020 1981 2012 Non-Critical Dry
2021 1982 2011 Non-Critical Wet
2022 1983 2011 Non-Critical Wet
2023 1984 2010 Non-Critical Above Normal
2024 1985 2012 Non-Critical Dry
2025 1986 2011 Non-Critical Wet
2026 1987 2013 Non-Critical Critically Dry
2027 1988 2013 Non-Critical Critically Dry
2028 1989 2013 Non-Critical Critically Dry
2029 1990 2013 Non-Critical Critically Dry
2030 1991 2014 Critical Critically Dry
2031 1992 2015 Critical Critically Dry
2032 1993 2011 Non-Critical Wet
2033 1994 2013 Non-Critical Critically Dry
2034 1995 2011 Non-Critical Wet
2035 1996 2011 Non-Critical Wet
2036 1997 2011 Non-Critical Wet
2037 1998 2011 Non-Critical Wet
2038 1999 2010 Non-Critical Above Normal
2039 2000 2010 Non-Critical Above Normal
2040 2001 2012 Non-Critical Dry
2041 2002 2012 Non-Critical Dry
2042 2003 2003 Non-Critical Below Normal
2043 2004 2004 Non-Critical Dry
2044 2005 2005 Non-Critical Wet
2045 2006 2006 Non-Critical Wet
2046 2007 2007 Non-Critical Critically Dry
2047 2008 2008 Non-Critical Critically Dry
2048 2009 2009 Non-Critical Below Normal
2049 2010 2010 Non-Critical Above Normal
2050 2011 2011 Non-Critical Wet
2051 2001 2012 Non-Critical Dry
2052 1992 2013 Non-Critical Critically Dry
2053 1976 2014 Critical Critically Dry
2054 1977 2015 Critical Critically Dry
2055 2002 2016 Non-Critical Dry
2056 2011 2011 Non-Critical Wet
2057 1965 2011 Non-Critical Wet
2058 1966 2009 Non-Critical Below Normal
2059 1967 2011 Non-Critical Wet
2060 1968 2012 Non-Critical Dry
2061 1969 2011 Non-Critical Wet
2062 1970 2010 Non-Critical Above Normal
2063 1971 2009 Non-Critical Below Normal
2064 1972 2012 Non-Critical Dry
2065 1973 2010 Non-Critical Above Normal
2066 1974 2011 Non-Critical Wet
2067 1975 2011 Non-Critical Wet
2068 1976 2014 Critical Critically Dry
2069 1977 2015 Critical Critically Dry
2070 1978 2011 Non-Critical Wet
Table 6968 – County of Merced Projected Water Budget Water Year Data 286
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WATER
YEAR
MERCED

COUNTY -

GSA ACRES

IRRIGATED

INDUSTRY
ACRES

IRRIGATED

AG ACRES

CLIMATE
CHANGE
FACTOR
ETC
(AF)
ETiw
(AF)
TOTAL ETc

WITH CLIMATE
CHANGE

TOTAL ETIW

WITH CLIMATE
CHANGE

EFFECTIVE

PUMPING (AF)
2014 17,500 1,800 5,000 1 10,200 7,800 10,200 7,800 7,800 2015 17,500 1,800 5,000 1 8,800 6,700 8,800 6,700 6,700 2016 17,500 1,800 5,000 1 9,600 7,300 9,600 7,300 7,300 2017 17,500 1,800 5,000 1 9,400 7,200 9,400 7,200 7,200 2018 17,500 1,800 5,000 1.035 9,700 7,400 10,000 7,700 7,700 2019 17,500 1,800 5,000 1.034 9,400 7,200 9,700 7,400 7,400 2020 17,500 1,800 5,000 1.036 10,000 7,600 10,400 7,900 7,900 2021 17,500 1,800 5,000 1.034 9,400 7,200 9,700 7,400 7,400 2022 17,500 1,800 5,000 1.035 9,400 7,200 9,700 7,500 7,500 2023 17,500 1,800 5,000 1.026 9,700 7,400 10,000 7,600 7,600 2024 17,500 1,800 5,000 1.036 10,000 7,600 10,400 7,900 7,900 2025 17,500 1,800 5,000 1.041 9,400 7,200 9,800 7,500 7,500 2026 17,500 1,800 5,000 1.034 9,900 7,500 10,200 7,800 7,800 2027 17,500 1,800 5,000 1.032 9,900 7,500 10,200 7,700 7,700 2028 17,500 1,800 5,000 1.033 9,900 7,500 10,200 7,700 7,700 2029 17,500 1,800 5,000 1.027 9,900 7,500 10,200 7,700 7,700 2030 17,500 1,800 5,000 1.029 10,200 7,800 10,500 8,000 8,000 2031 17,500 1,800 5,000 1.034 8,800 6,700 9,100 6,900 6,900 2032 17,500 1,800 5,000 1.035 9,400 7,200 9,700 7,500 7,500 2033 17,500 1,800 5,000 1.031 9,900 7,500 10,200 7,700 7,700 2034 17,500 1,800 5,000 1.037 9,400 7,200 9,700 7,500 7,500 2035 17,500 1,800 5,000 1.029 9,400 7,200 9,700 7,400 7,400 2036 17,500 1,800 5,000 1.03 9,400 7,200 9,700 7,400 7,400 2037 17,500 1,800 5,000 1.033 9,400 7,200 9,700 7,400 7,400 2038 17,500 1,800 5,000 1.035 9,700 7,400 10,000 7,700 7,700 2039 17,500 1,800 5,000 1.034 9,700 7,400 10,000 7,700 7,700 2040 17,500 1,800 5,000 1.03 10,000 7,600 10,300 7,800 7,800 2041 17,500 1,800 5,000 1.032 10,000 7,600 10,300 7,800 7,800 2042 17,500 1,800 5,000 1.032 8,600 6,700 8,900 6,900 6,900 2043 17,500 1,800 5,000 1.027 10,100 8,000 10,400 8,200 8,200 2044 17,500 1,800 5,000 1.036 9,000 6,200 9,300 6,400 6,400 2045 17,500 1,800 5,000 1.034 9,000 6,100 9,300 6,300 6,300 2046 17,500 1,800 5,000 1.079 9,200 7,800 9,900 8,400 8,400 2047 17,500 1,800 5,000 1.077 10,000 8,000 10,800 8,600 8,600 2048 17,500 1,800 5,000 1.079 10,100 7,700 10,900 8,300 8,300 2049 17,500 1,800 5,000 1.083 9,700 7,400 10,500 8,000 8,000 2050 17,500 1,800 5,000 1.083 9,400 7,200 10,200 7,800 7,800 2051 17,500 1,800 5,000 1.074 10,000 7,600 10,700 8,200 8,200 2052 17,500 1,800 5,000 1.086 9,900 7,500 10,800 8,100 8,100 2053 17,500 1,800 5,000 1.086 10,200 7,800 11,100 8,500 8,500 2054 17,500 1,800 5,000 1.078 8,800 6,700 9,500 7,200 7,200 2055 17,500 1,800 5,000 1.081 9,600 7,300 10,400 7,900 7,900 2056 17,500 1,800 5,000 1.083 9,400 7,200 10,200 7,800 7,800 2057 17,500 1,800 5,000 1.083 9,400 7,200 10,200 7,800 7,800 2058 17,500 1,800 5,000 1.086 10,100 7,700 11,000 8,400 8,400 2059 17,500 1,800 5,000 1.083 9,400 7,200 10,200 7,800 7,800 2060 17,500 1,800 5,000 1.085 10,000 7,600 10,900 8,200 8,200 2061 17,500 1,800 5,000 1.086 9,400 7,200 10,200 7,800 7,800 2062 17,500 1,800 5,000 1.076 9,700 7,400 10,400 8,000 8,000 2063 17,500 1,800 5,000 1.087 10,100 7,700 11,000 8,400 8,400 2064 17,500 1,800 5,000 1.085 10,000 7,600 10,900 8,200 8,200 2065 17,500 1,800 5,000 1.081 9,700 7,400 10,500 8,000 8,000 2066 17,500 1,800 5,000 1.087 9,400 7,200 10,200 7,800 7,800 2067 17,500 1,800 5,000 1.084 9,400 7,200 10,200 7,800 7,800 2068 17,500 1,800 5,000 1.086 10,200 7,800 11,100 8,500 8,500 2069 17,500 1,800 5,000 1.078 8,800 6,700 9,500 7,200 7,200 2070 17,500 1,800 5,000 1.072 9,400 7,200 10,100 7,700 7,700 Table 7069 - County of Merced Projected Water Budget
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15.3 Sustainable Management Criteria for the County of Merced The portion of the Merced County – Delta-Mendota GSA in the SJREC GSP, has historically relied on groundwater extraction to meet demand due to lack of other supply options. Groundwater use in this area has primarily been offset by recharge from the SJREC service area, deep percolation from applied water and precipitation, and subsurface flows. The SJREC are invested in helping the Merced County – Delta-Mendota GSA to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the Merced County – Delta-Mendota GSA on Projects and Management actions to offset groundwater extractions by the County white area that are estimated to be above their sustainable yield.

Currently, the portion of the Merced County – Delta-Mendota GSA is sustainable from a water budget standpoint. The historical consumptive use for the County of Merced was about 7,000 AF/year which equates to an average use of about 1.0 AF/acre for irrigated acres and about 0.4 AF/acre for the total area covered by the GSA. The sustainable yield for the County is 7,000 AF/year. While a majority of the County of Merced GSA is mostly adjacent to the SJREC Management AreasMonitoring Zones B and C, different SMC is developed in order for the County to achieve independent groundwater sustainability.

15.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the portion of the County of Merced – Delta-Mendota GSA in the SJREC GSP are positively impacted through recharge from the SJREC service area. Water levels in the SJREC Management AreasMonitoring Zones will be used to sustainably manage groundwater levels around the County area. Sustainable groundwater management for the County is best achieved by offsetting use through the implementation of projects and management actions to avoid overdraft.

15.3.2 Reduction in Groundwater Storage
Groundwater storage under the portion of the Merced County – Delta-Mendota GSA in the SJREC GSP is positively impacted through recharge from the SJREC service area. Managing groundwater storage for the County will be accomplished through updated water budgets for the County white areas.

Sustainable groundwater management for the County is best achieved by offsetting use through the implementation of projects and management actions to avoid overdraft.

15.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

15.3.4 Degraded Water Quality
Merced County is managing groundwater quality similar to the SJREC GSA. Salinity is the major water quality concern in the area. Electrical conductivity will be monitored and management actions will be developed as necessary. Currently no management actions are recommended to supplement the SJREC GSA management efforts. For more details refer to the following Sections in this GSP: 3.2.4, 3.3.4, and

3.4.4. 288
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15.3.5 Land Subsidence
It is assumed that the portion of the Merced County – Delta-Mendota GSA in the SJREC GSP may have wells perforated below the Corcoran Clay. Even so, significant land surface subsidence has not been observed in this area. The SJREC GSA and the Merced County – Delta-Mendota GSA will work with the landowners to better understand well construction throughout the irrigated areas. The SJREC will continue to work with the County of Merced to monitor subsidence and work with regional partners on solutions if subsidence is observed and may cause damage to critical infrastructure.

15.3.6 Depletions of Interconnected Surface Water
The County of Merced plans to work with the SJREC to sustainably manage interconnected surface water and groundwater. The portion of the Merced County – Delta-Mendota GSA in the SJREC GSP Group does not include lands adjacent to interconnected surface water. For more details refer to the following Sections in this GSP: 3.2.6, 3.3.6, and 3.4.6.

15.4 Projects and Management Actions for the County of Merced In order to maintain sustainability for each GSA in the SJREC GSP group, the Merced County – DeltaMendota GSA is committed to offsetting groundwater extractions above their sustainable yield. Each project will be analyzed jointly with the County and the SJREC to maximize the regional benefits.

Options to offset demand include; 1) purchasing groundwater credits, 2) participation in recharge projects, and 3) reducing pumping elsewhere in the GSA.

The SJREC will continue to work with the County to not only meet the requirements of the SGMA but more importantly, to maximize the benefits of local water resources.

15.5 Plan Implementation for the County of Merced
The cost to develop and implement the GSP specific to the portion of the Merced County – DeltaMendota GSA has been fully funded by the County of Merced. The SJREC GSA has participated in the Sustainable Groundwater Planning Grant Program (SGWP) on behalf of the SJREC GSP Group and will offset up to 50% of the plan development costs for the portion of the Merced County – Delta-Mendota GSA in the SJREC GSP.

The SJREC GSP Group has been, and will continue to, sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One groundwater management success story in the Los Banos Creek area was the implementation of a representative well with a trigger level to limit groundwater transfers from the area. As a result of the annual groundwater investigations prepared by the SJREC, the problem presented itself along with a solution to mitigate the concern; resulting in the aquifer fully recovering after water levels dropped below established triggers and no long-term lowering of the aquifer was experienced. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns. Consistent with our decades long relationship of leading the groundwater management effort with the County, the SJREC will take the lead preparing annual reports consistent with SGMA regulations. 289
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16.0 PORTION OF FRESNO COUNTY MANAGEMENT AREA B GSA AREA

16.1 Background for County of Fresno
There is about 1,800 acres of lands not in a public water district, white area, in the Portion of the Fresno County Management Area B that has been included in the SJREC GSP; refer to Figure 2 for a graphical depiction of the area. The SJREC worked with County leaders and technical staff to understand the potential opportunities and constraints of the SGMA to the County White Areas. It was mutually agreed that the SJREC will work with the County to develop the requirements in the GSP and to include this in a discrete section of this plan.

The SJREC are committed to assist the County to maintain sustainability through the planning and implementation horizon. The Fresno County Management Area B GSA is a party to the Delta-Mendota Subbasin Coordination Agreement and Cost Sharing Agreement (Appendices B & C; respectively).

Section 1 of this GSP discusses the purpose of this plan, sustainability goal, agency information and the organization of this plan for all GSA’s in the SJREC GSP. Section 2.1 of this GSP describes the plan area for all of the GSA’s in the SJREC GSP. Refer to Appendix I for a discussion on the basin setting for the SJREC GSA and surrounding areas including the portion of the County of Fresno Management Area B GSA area in the SJREC GSP. The Water Budget, Sustainable Management Criteria and Projects & Management Actions are included below.

16.2 Water Budgets for the County of Fresno
Presented herein is the compilation of the historic, current and projected water budgets specific to the Portion of the County of Fresno – Management Area B GSA within the SJREC GSP.

16.2.1 Historic Water Budget for the County of Fresno
The portion of the County of Fresno Management Area B GSA in the SJREC GSP encompasses about 1,800 acres of land. Of that, about 550 acres are actively farmed and the remaining acres are not actively farmed and do not pump groundwater. The historic water budget from 2003-2012 is consistent with the historic range selected by the entire Delta-Mendota Subbasin. It is assumed that all of the ETiw needed to grow the crops in the area was met by pumping groundwater. Groundwater pumping during this timeframe ranged from 100 to 1,200 AF/year with an average pumping of 500 AF/year. The approximate sustainable yield for the Portion of the County of Fresno – Management Area B GSA is 0.40 acre-feet/acre or about 700 acre-feet/year.
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WATER YEAR

IRRIGATED
ACRES
ETc (AF) ETiw (AF) EFFECTIVE

PUMPING (AF)
2003 550 700 600 600
2004 550 800 700 700
2005 550 300 200 200
2006 550 300 200 200
2007 550 1,400 1,200 1,200
2008 550 1,100 900 900
2009 550 700 600 600
2010 550 200 100 100
2011 550 300 200 200
2012 550 900 700 700
Table 7170 - County of Fresno Historic Water Budget Data

16.2.2 Current Water Budget for the County of Fresno
The same data and methodologies from the Historic Water Budget was used to develop the Current Water Budget.

WATER YEAR

IRRIGATED
ACRES
ETC (AF) ETiw
(AF)

EFFECTIVE

PUMPING (AF)
2013 550 900 700 700
Table 7271 - County of Fresno Current Water Budget Data

16.2.3 Projected Water Budget for the County of Fresno
The Portion of the County of Fresno Management Area B GSA in the SJREC GSP, area that can be used for production is currently fully planted. Any increase in demand is directly tied to Climate Change. The same process outlined in Section 2.2.3.3 was used to determine climate change factors. Below is a table of the projected water budget. The projected consumptive use of applied water is anticipated to remain about the same during the projected water budget. The net groundwater extraction ranges from 100 to 1,300 AF/year. Section 16.3 will discuss SMC in order for the Portion of the County of Fresno Management Area B GSA in the SJREC GSP, to be sustainable. Section 16.4 will discuss projects and management actions to offset the groundwater extractions in excess of the sustainable yield. 291
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WATER
YEAR

HISTORICAL

REFERENCE

USED FOR

HYDROLOGY

HISTORICAL

REFERENCE FOR
WATER

DELIVERY/DEMAND
SHASTA

WATER YEAR

DESIGNATION

WATER YEAR TYPE
(SJ VALLEY)
2014 - 2014 Critical Critically Dry
2015 - 2015 Critical Critically Dry
2016 - 2016 Non-Critical Dry
2017 - 2011 Non-Critical Wet
2018 1979 2010 Non-Critical Above Normal
2019 1980 2011 Non-Critical Wet
2020 1981 2012 Non-Critical Dry
2021 1982 2011 Non-Critical Wet
2022 1983 2011 Non-Critical Wet
2023 1984 2010 Non-Critical Above Normal
2024 1985 2012 Non-Critical Dry
2025 1986 2011 Non-Critical Wet
2026 1987 2013 Non-Critical Critically Dry
2027 1988 2013 Non-Critical Critically Dry
2028 1989 2013 Non-Critical Critically Dry
2029 1990 2013 Non-Critical Critically Dry
2030 1991 2014 Critical Critically Dry
2031 1992 2015 Critical Critically Dry
2032 1993 2011 Non-Critical Wet
2033 1994 2013 Non-Critical Critically Dry
2034 1995 2011 Non-Critical Wet
2035 1996 2011 Non-Critical Wet
2036 1997 2011 Non-Critical Wet
2037 1998 2011 Non-Critical Wet
2038 1999 2010 Non-Critical Above Normal
2039 2000 2010 Non-Critical Above Normal
2040 2001 2012 Non-Critical Dry
2041 2002 2012 Non-Critical Dry
2042 2003 2003 Non-Critical Below Normal
2043 2004 2004 Non-Critical Dry
2044 2005 2005 Non-Critical Wet
2045 2006 2006 Non-Critical Wet
2046 2007 2007 Non-Critical Critically Dry
2047 2008 2008 Non-Critical Critically Dry
2048 2009 2009 Non-Critical Below Normal
2049 2010 2010 Non-Critical Above Normal
2050 2011 2011 Non-Critical Wet
2051 2001 2012 Non-Critical Dry
2052 1992 2013 Non-Critical Critically Dry
2053 1976 2014 Critical Critically Dry
2054 1977 2015 Critical Critically Dry
2055 2002 2016 Non-Critical Dry
2056 2011 2011 Non-Critical Wet
2057 1965 2011 Non-Critical Wet
2058 1966 2009 Non-Critical Below Normal
2059 1967 2011 Non-Critical Wet
2060 1968 2012 Non-Critical Dry
2061 1969 2011 Non-Critical Wet
2062 1970 2010 Non-Critical Above Normal
2063 1971 2009 Non-Critical Below Normal
2064 1972 2012 Non-Critical Dry
2065 1973 2010 Non-Critical Above Normal
2066 1974 2011 Non-Critical Wet
2067 1975 2011 Non-Critical Wet
2068 1976 2014 Critical Critically Dry
2069 1977 2015 Critical Critically Dry
2070 1978 2011 Non-Critical Wet
Table 7372 – County of Fresno Projected Water Budget Water Year Data 292
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WATER
YEAR

IRRIGATED
ACRES

CLIMATE
CHANGE
FACTOR
TOTAL ETc

WITH CLIMATE
CHANGE

TOTAL ETIW

WITH CLIMATE
CHANGE

EFFECTIVE

PUMPING
(AF)
2014 550 - 500 400 400
2015 550 - 300 300 300
2016 550 - 500 400 400
2017 550 - 300 200 200
2018 550 1.038 200 100 100
2019 550 1.034 300 200 200
2020 550 1.031 900 700 700
2021 550 1.034 300 200 200
2022 550 1.038 300 200 200
2023 550 1.035 200 100 100
2024 550 1.034 900 700 700
2025 550 1.038 300 200 200
2026 550 1.033 900 700 700
2027 550 1.027 900 700 700
2028 550 1.032 900 700 700
2029 550 1.03 900 700 700
2030 550 1.029 500 400 400
2031 550 1.032 300 300 300
2032 550 1.032 300 200 200
2033 550 1.031 900 700 700
2034 550 1.033 300 200 200
2035 550 1.026 300 200 200
2036 550 1.03 300 200 200
2037 550 1.034 300 200 200
2038 550 1.031 200 100 100
2039 550 1.033 200 100 100
2040 550 1.028 900 700 700
2041 550 1.028 900 700 700
2042 550 1.032 700 600 600
2043 550 1.032 800 700 700
2044 550 1.034 300 200 200
2045 550 1.03 300 200 200
2046 550 1.081 1,500 1,300 1,300
2047 550 1.081 1,200 1,000 1,000
2048 550 1.087 800 700 700
2049 550 1.088 200 100 100
2050 550 1.093 300 200 200
2051 550 1.08 1,000 800 800
2052 550 1.093 1,000 800 800
2053 550 1.084 500 400 400
2054 550 1.079 300 300 300
2055 550 1.075 500 400 400
2056 550 1.093 300 200 200
2057 550 1.093 300 200 200
2058 550 1.091 800 700 700
2059 550 1.087 300 200 200
2060 550 1.081 1,000 800 800
2061 550 1.089 300 200 200
2062 550 1.083 200 100 100
2063 550 1.093 800 700 700
2064 550 1.091 1,000 800 800
2065 550 1.084 200 100 100
2066 550 1.087 300 200 200
2067 550 1.098 300 200 200
2068 550 1.084 500 400 400
2069 550 1.079 300 300 300
2070 550 1.071 300 200 200
Table 7473 - County of Fresno Projected Water Budget
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16.3 Sustainable Management Criteria for the County of Fresno The portion of the County of Fresno Management Area B GSA in the SJREC GSP, has historically relied on groundwater extraction to meet demand. Groundwater overdraft in this area has primarily been offset by recharge from the SJREC service area and seepage from the San Joaquin River. The SJREC are invested in helping the County to monitor, understand and manage groundwater. The SJREC GSP Group, collectively, is currently sustainable. In order for the group to maintain sustainability, the SJREC will work with the County of Fresno on Projects and Management actions to offset groundwater extractions by the County white area that is above their sustainable yield.

The historical consumptive use for the County of Fresno was about 500 AF/year which equates to an average use of about 1.0 AF/acre for irrigated acres and about 0.3 AF/acre for the total area covered by the GSA. The sustainable yield for the County is 700 AF/year. While the County of Fresno GSA is mostly adjacent to the SJREC Management AreaMonitoring Zone J, different SMC is developed in order for the County to achieve independent groundwater sustainability.

16.3.1 Chronic Lowering of Groundwater Levels
Water levels in the vicinity of the portion of the County of Fresno Management Area B GSA in the SJREC GSP are positively impacted through recharge from the SJREC service area and seepage from the San Joaquin River. Water levels in the SJREC Management AreaMonitoring Zone J will be used to sustainably manage groundwater levels around the County area. Sustainable groundwater management for the County is best achieved by offsetting overdraft through the implementation of projects and management actions.

16.3.2 Reduction in Groundwater Storage
Groundwater storage under the portion of the County of Fresno Management Area B GSA in the SJREC GSP is positively impacted through recharge from the SJREC and seepage from the San Joaquin River.

Managing groundwater storage for the County will be accomplished through updated water budgets for the County white areas. Sustainable groundwater management for the County is best achieved by offsetting overdraft through the implementation of projects and management actions.

16.3.3 Seawater Intrusion
The Delta-Mendota Subbasin does not currently experience seawater intrusion and does not anticipate this occurring. The presence of an undesirable result for seawater intrusion is not likely to occur and therefore no SMC have been established for this sustainability indicator.

16.3.4 Degraded Water Quality
Fresno County is managing groundwater quality similar to the SJREC GSA. Salinity is the major water quality concern in the area. Fresno County will monitor electrical conductivity and impose management actions as necessary. Currently no management actions are recommended to supplement the SJREC GSA management efforts. For more details refer to the following Sections in this GSP: 3.2.4, 3.3.4, and

3.4.4. 16.3.5 Land Subsidence
It is anticipated that the portion of the County of Fresno Management Area B GSA in the SJREC GSP does not operate any wells perforated below the Corcoran Clay. As a result, inelastic land subsidence is unlikely to occur as a result of pumping from the wells within the GSA area. Therefore, no SMC have 294
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been established for this sustainability indicator. The SJREC will continue to work with the County of Fresno to monitor subsidence and work with regional partners on solutions if subsidence is observed and may cause damage to critical infrastructure.

16.3.6 Depletions of Interconnected Surface Water
The County of Fresno plans to work with the SJREC to sustainably manage interconnected surface water and groundwater. For more details refer to the following Sections in this GSP: 3.2.6, 3.3.6, and 3.4.6.

16.4 Projects and Management Actions for the County of Fresno In order to maintain sustainability for each GSA in the SJREC GSP group, the County is committed to offsetting groundwater extractions above their sustainable yield. Each project will be analyzed jointly with the County and the SJREC to maximize the regional benefits. The County is pursuing the following projects as a way to offset demand; 1) purchasing groundwater credits and 2) participation in recharge projects.

The SJREC will continue to work with the County to not only meet the requirements of the SGMA but more importantly, to maximize the benefits of local water resources.

16.5 Plan Implementation for the County of Fresno
The cost to develop and implement the GSP specific to the portion of the County of Fresno has been cost shared at 50% between the SJREC GSA and the County of portion of the County of Fresno Management Area B GSA in the SJREC GSP. Additionally, the SJREC GSA has participated in the Sustainable Groundwater Planning Grant Program (SGWP) on behalf of the SJREC GSP Group and will offset up to 50% of the plan development costs for the portion of the County of Fresno Management Area B GSA in the SJREC GSP. The SJREC GSP Group has been, and will continue to sustainably manage groundwater through the planning and implementation horizon. The SJREC have annually evaluated groundwater conditions in this area for decades and have a proven track record of successfully implementing criteria to offset groundwater problems. One groundwater management success story in the Mendota area was the implementation of monitoring and management program for well water transfers near the Mendota Pool. The SJREC worked with the regional water leaders to develop and implement a plan that would maximize water resources without sacrificing the needs of the local communities. As a result, water levels have remained fairly stable and none of the wells pumping as part of the program are contributing to land subsidence. The SJREC GSP group will continue to sharpen our pencils to provide safe and reliable water. Although we are sustainable, if any issues are identified in our annual evaluations, we will work with our regional partners to promptly address the concerns.

Consistent with our decades long relationship of leading the groundwater management effort with the County, the SJREC will take the lead preparing annual reports consistent with SGMA regulations. 295
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APPENDICES
Appendix A. Senate Bill 372
Appendix B. Delta-Mendota Subbasin Common Chapter (including Coordination Agreement)
Appendix C. Cost Sharing Agreement – Delta-Mendota Subbasin Coordination Appendix D. Notice of Intent to Develop a GSP
Appendix E. List of Public Meetings
Appendix F. List of Interested Parties
Appendix G. Delta-Mendota Subbasin Communications Plan
Appendix H. Comments Received
Appendix I. Hydrogeologic Conceptual Model and Groundwater Conditions for the San Joaquin River Exchange Contractors Service Area GSP
Appendix J. HCM BMP
Appendix K. Water Budget BMP
Appendix L. Modeling BMP
Appendix M. SMC BMP
Appendix N. Monitoring Protocols BMP
Appendix O. Monitoring Network BMP
Appendix P. Grassland Bypass Project Summary
Appendix Q. Update on Groundwater Conditions in the Newman Sub-Area of the SJREC GSP
Appendix R. Update on Groundwater Conditions in the Gustine Sub-Area of the SJREC GSP
Appendix S. Hydrogeologic Conceptual Model, Groundwater Conditions, and Water Budget for the City of Los Banos GSA
Appendix T. Groundwater Conditions in the Dos Palos Sub-Area of the SJREC GSP Appendix U. Updated Groundwater Conditions in the Vicinity of the City of Firebaugh Appendix V. Update on Groundwater Conditions in the Mendota Sub-Area of the SJREC GSP
Appendix W. Groundwater Conditions in the Turner Island Water District – 2 GSA 296
Appendix A. Senate Bill 372
297
Senate Bill No. 372
CHAPTER357
An act to amend Section 10723 of the Water Code, and to create the San Joaquin River Exchange Contractors Groundwater Sustainability Agency, and prescribing its boundaries, organization, operation, management, financing, and other powers and duties, relating to water districts, and declaring the urgency thereof, to take effect immediately. [Approved by Governor September 28, 2017. Filed with
Secretary of State September 28, 2017.)
LEGISLATIVI! COUNSEL'S DIGEST
SB 372, Cannella. San Joaquin River Exchange Contractors Groundwater Sustainability Agency.

Existing law, the Sustainable Groundwater Management Act, requires all groundwater basins designated as high- or medium-priority basins by the Department of Water Resources that are designated as basins subject to critical conditions of overdraft to be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans by January 31, 2020, and requires all other groundwater basins designated as high- or medium-priority basins to be managed under a groundwater sustainability plan or coordinated groundwater sustainability plans by January 31, 2022, except as specified. The act authorizes any local agency or combination of local agencies overlying a groundwater basin to decide to become a groundwater sustainability agency for that basin. The act deems certain agencies created by statute to manage groundwater the exclusive local agencies within their respective statutory boundaries with powers to comply with the act and authorizes these agencies to opt out of being the exclusive groundwater management agency.

This bill would create the San Joaquin River Exchange Contractors Groundwater Sustainability Agency as the exclusive groundwater sustainability agency and successor in interest to the agency that submitted a notice of intent to become a groundwater sustainability agency to the department on December 22, 2015. The bill would establish the boundaries of the agency and would authorize the agency's boundaries to be changed.

The bill would require the agency to develop and implement a groundwater sustainability plan to achieve sustainable groundwater management within the territory of the agency. The bill would generally specify the powers and purposes of the agency. The bill would prescribe the composition of the 4-member board of directors of the agency and would require members and alternates to be chosen by member agencies, as specified. By imposing duties on the agency and the member agencies, the bill would impose a state-mandated local program.
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Ch. 357 -2-
The California Constitution requires the state to reimburse local agencies and school districts for certain costs mandated by the state. Statutory provisions establish procedures for making that reimbursement.

This bill would provide that no reimbursement is required by this act for a specified reason.

This bill would declare that it is to take effect immediately as an urgency statute.

The people of the State of California do enact as follows:

SECTION 1. Section 10723 of the Water Code is amended to read:
10723. (a) Except as provided in subdivision (c), any local agency or combination of local agencies overlying a groundwater basin may decide to become a groundwater sustainability agency for that basin. (b) Before deciding to become a groundwater sustainability agency, and after publication of notice pursuant to Section 6066 of the Government Code, the local agency or agencies shall hold a public hearing in the county or counties overlying the basin.
(c) (1) Except as provided in paragraph (2), the following agencies created by statute to manage groundwater shall be deemed the exclusive local agencies within their respective statutory boundaries with powers to comply with this part:
(A) Alameda County Flood Control and Water Conservation District, Zone 7.
(B) Alameda County Water District.
(C) Desert Water Agency.
(D) Fox Canyon Groundwater Management Agency.
(E) Honey Lake Valley Groundwater Management District.
(F) Kings River East Groundwater Sustainability Agency. (G) Long Valley Groundwater Management District.
(H) Mendocino City Community Services District.
(I) Mono County Tri-Valley Groundwater Management District. (J) Monterey Peninsula Water Management District.
(K) North Fork Kings Groundwater Sustainability Agency. (L) Ojai Groundwater Management Agency.
(M) Orange County Water District.
(N) Pajaro Valley Water Management Agency.
(0) San Joaquin River Exchange Contractors Groundwater Sustainability Agency.
(P) Santa Clara Valley Water District.
(Q) Sierra Valley Groundwater Management District.
(R) Willow Creek Groundwater Management Agency.
(2) An agency identified in this subdivision may opt out of being the exclusive groundwater management agency within its statutory boundaries by sending a notice to the department, which shall be posted on the department's Internet Web site within 15 days of receipt. If an agency 93 299
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identified in paragraph (1) opts out of being the exclusive groundwater management agency, any other local agency or combination oflocal agencies operating within the statutory boundaries of the agency that has opted out may notify the department pursuant to Section 10723.8 ofits decision to be the groundwater sustainability agency.
(3) A local agency listed in paragraph (1) may comply with this part by meeting the requirements of Section 10733.6 or opting to become a groundwater sustainability agency pursuant to this section. A local agency with authority to implement a basin-specific management plan pursuant to its principal act shall not exercise any authorities granted in this part in a manner inconsistent with any prohibitions or limitations in its principal act unless the governing board of the local agency makes a finding that the agency is unable to sustainably manage the basin without the prohibited authority.
( d) The decision of a local agency or combination of agencies to become a groundwater sustainability agency shall take effect as provided in Section 10723.8.

SEC. 2. This section shall be known and may be cited as the San Joaquin River Exchange Contractors Groundwater Sustainability Agency Act.

San Joaquin River Exchange Contractors Groundwater Sustainability Agency Act
Article l. Findings and Declarations
101. The Legislature hereby finds and declares that the preservation of the groundwater resources within the boundaries of the agency is in the public interest and that the creation of the agency pursuant to this act is for the common benefit.
l 02. The Legislature further finds and declares that the groundwater management activities of the agency benefit all operators of groundwater extraction facilities within the boundaries of the agency. 103. The Legislature :further finds and declares that circumstances within the boundaries of the agency formed by this act, including longstanding joint action among the entities within the boundaries, justify the formation of the agency and the grant of powers contained in this act.

Article 2. Creation and Purposes
201. (a) A groundwater management agency is hereby created in the Counties of Fresno, Madera, Merced, and Stanislaus to be known as the San Joaquin River Exchange Contractors Groundwater Sustainability Agency.
(b) The agency shall be the successor in interest to the San Joaquin River Exchange Contractors Water Groundwater Sustainability Agency that 93 300
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submitted its notice of intent to become a groundwater sustainability agency to the Department of Water Resources on December 22, 2015. ( c) The agency shall only exercise the powers granted by this act and the Sustainable Groundwater Management Act (Part 2.74 (commencing with Section 10720) of Division 6 of the Water Code) for purposes of groundwater management activities within the boundaries of the agency, together with any other powers as are reasonably implied, necessary, and proper to carry out the objectives and purposes of the agency to implement the Sustainable Groundwater Management Act. The agency shall abide by the rules and regulations promulgated by the Department of Water Resources and the State Water Resources Control Board to implement the Sustainable Groundwater Management Act.

Article 3. Boundaries
301. {a) .!'or purposes of this act, the boundaries of the agency shall be as follows:
(1) All land located within the boundaries of Central California Irrigation District, including Class II lands.
(2) All land located within the boundaries of Firebaugh Canal Water District, including Class II lands.
(3) All land located within the boundaries of San Luis Canal Company. (4) All land located within the boundaries of Columbia Canal Company. (b) The lands included within the boundaries of the agency are depicted in the revised map submitted by the San Joaquin River Exchange Contractors Water Authority Groundwater Sustainability Agency to the Department of Water Resources on October 18, 2016.
( c) In the event of any ambiguity between the narrative boundary described in subdivision (a) and the map described in subdivision (b), the boundary depicted in the map shall control.
302. (a) The initial boundaries of the agency may be changed in accordance with either of the following procedures:
(1) Upon completion of a change of organization or a reorganization to the Central California Irrigation District or the Firebaugh Canal Water District pursuant to the Cortese-Knox-Hertzberg Local Government Reorganization Act of2000 (Division 3 (commencing with Section 56000) of Title 5 of the Government Code), the boundaries of the agency shall be automatically changed pursuant to Section 56120 of the Government Code. (2) Upon a proposal for a change of organization or reorganization initiated by the adoption of a resolution of application by the board and approval of the proposal by the local agency formation commission pursuant to Part 3 (commencing with Section 56650) of Division 3 of Title 5 of the Government Code.
(b) The boundaries of the agency shall not be adjusted to include an area of the basin within the management area of another groundwater sustainability agency unless the agency has entered into a memorandum of 93 301
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agreement or other legal agreement with that groundwater sustainability agency that permits the area to be included.

Article 4. Definitions
401. Unless otherwise indicated by their context, the definitions set forth in this article govern the interpretation of this act.
402. "Agency" means the San Joaquin River Exchange Contractors Groundwater Sustainability Agency established by this act. 403. "Basin" has the same meaning as defined in Section 10721 of the Water Code.
404. "Board" means the board of directors of the agency, as more particularly described in Section 501.
405. ''Delta-Mendota Subbasin" has the same meaning as described in the report entitled "California's Groundwater - Bulletin 118" updated in 2003, as it may be subsequently updated or revised by the Department of Water Resources in accordance with Section 12924 of the Water Code. 406. "Extraction" means the act of obtaining groundwater by pumping or other controlled means.
407. "Groundwater'' has the same meaning as defined in Section 10721 of the Water Code.
408. "Groundwater management activities" means programs, measures, or actions taken to preserve, protect, and enhance groundwater resources within the boundaries of the agency.
409. "Member agency" means the mutual water companies, irrigation district, and water district entitled to representation on the agency's board of directors as specified in Section 501.
410. "Operator" has the same meaning as defined in Section 10721 of the Water Code.
411. "Person" has the same meaning as defined in Section 10735 of the Water Code.
412. ''Plan" has the same meaning as defined in Section 10721 of the Water Code.

Article 5. General Provisions
501. (a) The agency shall be governed by a board of directors that shall consist of four members, as follows:
(1) One member shall be chosen by the Central California Irrigation District.
(2) One member shall be chosen by the Firebaugh Canal Water District. (3) One member shall be chosen by the San Luis Canal Company. (4) One member shall be chosen by the Columbia Canal Company. (b) The governing board of each member agency shall choose a board member for the purpose of subdivision (a) from the member agency's board members.
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( c) There shall be an alternate for each board member, chosen in the same manner and by the same entity as the board member. The alternate member shall act in place of the board member he or she is an alternate for in case of that board member's absence or inability to act. ( d) Initial members and their alternates shall be chosen on or before July 1, 2018.
502. It shall not be a conflict of interest for any board member to simultaneously serve on the agency board, the board of directors of the San Joaquin River Exchange Contractors Water Authority, and the board of directors of any member agency, or any combination of those offices. 503. Members of the board shall serve for a four-year term of office or until the member is no longer a board member of the member agency that appointed him or her. A member may serve for more than one term of office. 504. (a) The board may adopt an ordinance to provide compensation to members of the board in an amount not to exceed one hundred dollars ($100) per day for each day's attendance at meetings of the board or for each day's service rendered as a member of the board by request of the board. For purposes of this section, the determination of whether a board member's activities on any specific day are compensable shall be made pursuant to Article 2.3 (commencing with Section 53232) of Chapter 2 of Part I of Division 2 of Title 5 of the Government Code. (b) Reimbursement for expenses of members of the board is subject to Sections 53232.2 and 53232.3 of the Government Code.
( c) The board, by ordinance adopted pursuant to Chapter 2 ( commencing with Section 20200) of Division 10 of the Water Code, may increase the compensation received by members of the board above the amount of one hundred dollars ($100) per day. The increase shall not exceed an amount equal to 5 percent, for each calendar year following the operative date of the last adjustment, of the compensation that is received when the ordinance is adopted.
( d) A board member shall not be compensated for more than a total of 10 days in any calendar month.
505. (a) The board may adopt ordinances for the purpose ofregulating, conserving, managing, and controlling the use and extraction of groundwater within the boundary of the agency.
(b) An ordinance adopted by the board shall become effective 30 days from the date of its passage.
( c) All ordinances shall be adopted at noticed, public hearings by a majority vote of the board. No ordinance shall be adopted by the board except at a public hearing. Notice of the hearing shall be published in a newspaper of general circulation pursuant to Section 6066 of the Government Code.
( d) The board shall provide notice of the adoption of all ordinances. 506. No provision of this act shall be construed as denying any member agency or the San Joaquin River Exchange Contractors Water Authority any rights or powers that they already have or that they may be granted. 93 303
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507. The agency may hire contractors and consultants as it considers appropriate.
508. The agency shall enter into a coordination agreement with other local agencies for purposes of coordinating the agency's plan with other agencies or groundwater sustainability plans within the Delta-Mendota Subbasin as required by the Sustainable Groundwater Management Act (Part 2.74 (commencing with Section 10720) of Division 6 of the Water Code).
509. The agency may exclude from any of the requirements of this act, or the operation of any ordinance, any operator who annually extracts less than a minimum amount of groundwater as specified by an ordinance adopted by the board.

Article 6. Studies and Investigations
601. The agency may collect data and conduct technical and other investigations of all kinds in order to carry out the provisions of this act.

All hydrological investigations and studies carried out by or on behalf of the agency shall be constructed by or under the supervision of licensed engineers, licensed hydrogeologists, or other persons qualified in groundwater geology or hydrology.
602. The agency may recommend and encourage water recycling and other water development projects, where those projects will enhance and contribute to the responsible management of groundwater resources, as part of its annual plan for implementation of groundwater management objectives.

Article 7. Sustainable Groundwater Management Powers
70 l. The agency shall develop and implement a groundwater sustainability plan pursuant to Chapter 6 ( commencing with Section l 0727) of Part 2.74 of Division 6 of the Water Code to achieve sustainable groundwater management within the territory of the agency. 702. The agency shall be the exclusive groundwater sustainability agency pursuant to Chapter 4 (commencing with Section 10723) of Part 2.74 of Division 6 of the Water Code for that portion of the Delta-Mendota Subbasin that lies within the boundaries of the agency.
703. The agency may exercise any of the powers described in Chapter 5 ( commencing with Section I 0725) of Part 2. 7 4 of Division 6 of the Water Code and the enforcement powers described in Chapter 9 ( commencing with Section 10732) of Part 2.74 of Division 6 of the Water Code.

Article 8. Fee Authority
801. Pursuant to Chapter 8 (commencing with Section 10730) of Part

2.74 ofDivision 6 of the Water Code, the agency may impose fees, including, but not limited to, permit fees and fees on groundwater extraction or other 93 304
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regulated activity, to fund the costs of a groundwater sustainability program, that include, but are not limited to, the preparation, adoption, and amendment of a groundwater sustainability plan, investigations, inspections, compliance assistance, enforcement, and program administration, including a prudent reserve.

Article 9. Miscellaneous
901. The agency shall have the authority to sue and to be sued, including, but not limited to, as a party to an action pursuant to Chapter 7 ( commencing with Section 830) of Title IO of Part 2 of the Code of Civil Procedure. 902. In the event of any conflict between the San Joaquin River Exchange Contractors Groundwater Sustainability Agency Act and the provisions of the Sustainable Groundwater Management Act (Part 2.74 (commencing with Section 10720) of Division 6 of the Water Code), the provisions of the Sustainable Groundwater Management Act shall prevail.

SEC. 3. No reimbursement is required by this act pursuant to Section 6 of Article XIII B of the California Constitution because a local agency or school district has the authority to levy service charges, fees, or assessments sufficient to pay for the program or level of service mandated by this act, within the meaning of Section 17556 of the Government Code.

SEC. 4. This act is an urgency statute necessary for the immediate preservation of the public peace, health, or safety within the meaning of Article IV of the California Constitution and shall go into immediate effect.

The facts constituting the necessity are:

In order for the San Joaquin River Exchange Contractors Groundwater Sustainability Agency to establish itself as a groundwater sustainability agency and to begin managing the area within its boundaries without interrupting local control, it is necessary that this act take effect immediately. 0 93
305
Appendix B. Delta-Mendota Subbasin
Common Chapter

306
Delta-Mendota
Groundwater Subbasin
Groundwater Sustainability Plan:

Revised Common Chapter
August 2019; Revised June 2022
Prepared by:
307
Difficulty Accessing Material
If you have difficulty accessing any material in this document, please contact us in writing or via telephone and we will work with you to make the information available. You can direct your request to:

ATTN: Andrew GarciaJohn Brodie
San Luis and Delta-Mendota Water Authority
842 6th Street
Los Banos, CA 93635
Telephone (209) 826-1872(209) 832-6229
Email: [email protected]
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Table of Contents
DISCLAIMER........................................................................................................................................... IV

1. INTRODUCTION ............................................................................................................................. 1

1.1 Purpose of Common Chapter .......................................................................................... 1

1.2 Delta-Mendota Subbasin................................................................................................. 1

1.3 Disadvantaged Communities within the Delta-Mendota Subbasin....................................... 2

1.4 Economically Disadvantaged Areas within the Delta-Mendota Subbasin ............................. 4

2. DELTA-MENDOTA SUBBASIN GOVERNANCE .................................................................... 11

2.1 GSA and GSP Coordination and Governance ................................................................. 16

2.1.1 Delta-Mendota Subbasin SGMA Governance Structure ....................................... 16

2.1.2 Intra-Basin Coordination................................................................................... 21

2.1.3 Inter-basin Agreements ..................................................................................... 27

3. DELTA-MENDOTA SUBBASIN PLAN AREA .......................................................................... 28

3.1 Plan Area Definition .................................................................................................... 28

3.2 Plan Area Setting ......................................................................................................... 31

3.3 General Plans in Plan Area ........................................................................................... 48

3.4 Existing Land Use Plans and Impacts to Sustainable Groundwater Management ................ 50

3.5 Existing Water Resources Monitoring and Management Programs ................................... 50

3.6 County Well Construction/Destruction Standards and Permitting ..................................... 52

4. SUBBASIN SETTING .................................................................................................................... 54

4.1 Hydrogeologic Conceptual Model ................................................................................. 54

4.1.1 Regional Geologic and Structural Setting ........................................................... 54

4.1.2 Geologic History .............................................................................................. 56

4.1.3 Geologic Formations and Stratigraphy ............................................................... 58

4.1.4 Faults and Structural Features............................................................................ 59

4.1.5 Basin Boundaries ............................................................................................. 59

4.1.6 Definable Bottom of Basin ................................................................................ 61

4.1.7 Principal Aquifers and Aquitards ....................................................................... 61

4.1.8 Structural Properties and Restricted Groundwater Flow ....................................... 75

4.1.9 Water Quality .................................................................................................. 75

4.1.10 Topography, Surface Water, Recharge, and Imported Supplies ............................. 77

4.2 Delta-Mendota Subbasin Groundwater Conditions .......................................................... 87

4.2.1 Useful Terminology ......................................................................................... 87

4.2.2 Groundwater Elevations.................................................................................... 88

4.2.3 Groundwater Storage ...................................................................................... 102 309
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4.2.4 Seawater Intrusion.......................................................................................... 103

4.2.5 Groundwater Quality ...................................................................................... 103

4.2.6 Land Subsidence ............................................................................................ 103

4.2.7 Interconnected Surface Water Systems ............................................................. 119

4.2.8 Data Gaps ..................................................................................................... 137

4.3 Delta-Mendota Subbasin Water Budgets ...................................................................... 137

4.3.1 Coordinated Assumptions ............................................................................... 138

4.3.2 GSP-Level Water Budgets .............................................................................. 148

4.3.3 Coordinated Water Budgets ............................................................................ 148

4.3.4 Sustainable Yield ........................................................................................... 163

5. SUSTAINABLE MANAGEMENT CRITERIA ........................................................................ 168

5.1 Coordinated Assumptions and Data ............................................................................. 168

5.2 Coordinated Sustainability Goal and Undesirable Results .............................................. 168

5.3 GSP-Level Sustainable Management Criteria ............................................................... 169

5.4 Delta-Mendota Subbasin Sustainable Management Criteria ........................................... 170

5.4.1 Chronic Lowering of Groundwater Levels ........................................................ 170

5.4.2 Reduction in Groundwater Storage .................................................................. 204

5.4.3 Degraded Groundwater Quality ....................................................................... 205

5.4.4 Inelastic Land Subsidence ............................................................................... 213

5.4.5 Depletion of Interconnected Surface Water ....................................................... 219

6. SUBBASIN MONITORING PROGRAM .................................................................................. 234

6.1.1 Coordinated Assumptions and Data ................................................................. 234

6.1.2 Coordinated Monitoring Activities ................................................................... 234

6.1.3 GSP-Level Monitoring Networks .................................................................... 238

6.1.4 Delta-Mendota Subbasin Monitoring Networks................................................. 238

7. SUBBASIN DATA COLLECTION AND MANAGEMENT .................................................... 245

8. STAKEHOLDER OUTREACH .................................................................................................. 247

8.1 Situation Assessment and Communications Plan ........................................................... 247

8.2 Public Noticing and Information.................................................................................. 248

8.3 List of Public Meetings Where the GSPs were Discussed .............................................. 248

8.4 Comments Regarding the GSPs ................................................................................... 250

8.5 Subbasin Decision Making Process.............................................................................. 250

8.6 Opportunities for Public Engagement and How Public Input was Used ........................... 250

8.6.1 Opportunities for Public Engagement ............................................................... 251

8.6.2 How Public Input and Response was Used in the Development of the GSP.......... 252

8.7 Revisions to Common Chapter and Subbasin GSPs ....................................................... 252 310
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9. REFERENCES .............................................................................................................................. 254 DISCLAIMER ............................................................................................................................................ IX

1. INTRODUCTION .............................................................................................................................. 1

1.1 Purpose of Common Chapter ............................................................................................... 1

1.2 Delta-Mendota Subbasin ....................................................................................................... 1

1.3 Disadvantaged Communities within the Delta-Mendota Subbasin ................................. 2

1.4 Economically Disadvantaged Areas within the Delta-Mendota Subbasin ..................... 4

2. DELTA-MENDOTA SUBBASIN GOVERNANCE ...................................................................... 8

2.1 GSA and GSP Coordination and Governance ................................................................. 13

2.1.1 Delta-Mendota Subbasin SGMA Governance Structure ................................... 13

2.1.2 Intra-Basin Coordination ......................................................................................... 18

2.1.3 Inter-basin Agreements .......................................................................................... 24

3. DELTA-MENDOTA SUBBASIN PLAN AREA ......................................................................... 25

3.1 Plan Area Definition .............................................................................................................. 25

3.2 Plan Area Setting .................................................................................................................. 28

3.3 General Plans in Plan Area ................................................................................................. 44

3.4 Existing Land Use Plans and Impacts to Sustainable Groundwater Management .... 46

3.5 Existing Water Resources Monitoring and Management Programs ............................. 46

3.6 County Well Construction/Destruction Standards and Permitting ................................. 48

4. SUBBASIN SETTING ................................................................................................................... 50

4.1 Hydrogeologic Conceptual Model ...................................................................................... 50

4.1.1 Regional Geologic and Structural Setting ............................................................ 50

4.1.2 Geologic History ....................................................................................................... 52

4.1.3 Geologic Formations and Stratigraphy ................................................................. 54

4.1.4 Faults and Structural Features .............................................................................. 55

4.1.5 Basin Boundaries ..................................................................................................... 55

4.1.6 Definable Bottom of Basin ...................................................................................... 57

4.1.7 Principal Aquifers and Aquitards ........................................................................... 57

4.1.8 Structural Properties and Restricted Groundwater Flow ................................... 71

4.1.9 Water Quality ............................................................................................................ 71

4.1.10 Topography, Surface Water, Recharge, and Imported Supplies ..................... 73

4.2 Delta-Mendota Subbasin Groundwater Conditions ......................................................... 83

4.2.1 Useful Terminology ................................................................................................. 83

4.2.2 Groundwater Elevations ......................................................................................... 84

4.2.3 Groundwater Storage .............................................................................................. 98

4.2.4 Seawater Intrusion ................................................................................................... 99 311
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4.2.5 Groundwater Quality ............................................................................................... 99

4.2.6 Land Subsidence ..................................................................................................... 99

4.2.7 Interconnected Surface Water Systems ............................................................ 114

4.2.8 Data Gaps ............................................................................................................... 130

4.3 Delta-Mendota Subbasin Water Budgets........................................................................ 130

4.3.1 Coordinated Assumptions .................................................................................... 131

4.3.2 GSP-Level Water Budgets ................................................................................... 131

4.3.3 Coordinated Water Budgets ................................................................................. 131

4.3.4 Sustainable Yield ................................................................................................... 140

5. SUSTAINABLE MANAGEMENT CRITERIA .......................................................................... 143

5.1 Coordinated Assumptions and Data ................................................................................ 143

5.2 Coordinated Sustainability Goal and Undesirable Results .......................................... 143

5.3 GSP-Level Sustainable Management Criteria ............................................................... 144

5.4 Delta-Mendota Subbasin Sustainable Management Criteria ....................................... 144

6. SUBBASIN MONITORING PROGRAM ................................................................................... 155

6.1.1 Coordinated Assumptions and Data ................................................................... 155

6.1.2 Coordinated Monitoring Activities ........................................................................ 155

6.1.3 GSP-Level Monitoring Networks ......................................................................... 159

6.1.4 Delta-Mendota Subbasin Monitoring Networks................................................. 159

7. SUBBASIN DATA COLLECTION AND MANAGEMENT ..................................................... 166

8. STAKEHOLDER OUTREACH................................................................................................... 168

8.1 Situation Assessment and Communications Plan ......................................................... 168

8.2 Public Noticing and Information ........................................................................................ 169

8.3 List of Public Meetings Where the GSPs were Discussed ........................................... 169

8.4 Comments Regarding the GSPs ...................................................................................... 171

8.5 Subbasin Decision Making Process ................................................................................ 171

8.6 Opportunities for Public Engagement and How Public Input was Used .................... 171

8.6.1 Opportunities for Public Engagement ................................................................. 172

8.6.2 How Public Input and Response was Used in the Development of the GSP .................................................................................................................................. 173

9. REFERENCES ............................................................................................................................. 174 312
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Tables
Table CC-1: DACs as a Percentage of the Delta-Mendota Subbasin ..................................................... 3 Table CC-2: DAC and SDAC Census Designated Places in Delta-Mendota Subbasin ............................ 3 Table CC-3: EDAs as a Percentage of the Delta-Mendota Subbasin ..................................................... 4 Table CC-4: Delta-Mendota Subbasin Coordination Committee Members .......................................... 17 Table CC-5: Subsidence Monitoring Trends ................................................................................... 104 Table CC-6: Estimated Quantity of Gains/Depletions for Interconnected Stream Reaches, San Joaquin River .................................................................................................................. 121 Table CC-7: List of Potential Freshwater Species ........................................................................... 126 Table CC-8: Historical and Current Water Budgets Data Sources ..................................................... 146 Table CC-9: Projected Water Budgets Data Sources ....................................................................... 147 Table CC-10: Delta-Mendota Subbasin Historical Water Budget, Land Surface Budget ..................... 150 Table CC-11: Delta-Mendota Subbasin Historical Water Budget, Groundwater Budget...................... 150 Table CC-12: Delta-Mendota Subbasin Current Water Budget, Land Surface Budget ........................ 152 Table CC-13: Delta-Mendota Subbasin Current Water Budget, Groundwater System......................... 152 Table CC-14: Delta-Mendota Subbasin Projected Water Budget, Land Surface Budget ...................... 153 Table CC-15: Delta-Mendota Subbasin Projected Water Budget, Groundwater Budget ...................... 157 Table CC-16: Delta-Mendota Subbasin SMC ................................................................................ 197 Table CC-17: Numeric SMC for the Chronic Lowering of Groundwater Levels ................................ 199 Table CC-18: Delta-Mendota Subbasin SMC ................................................................................ 205 Table CC-19: Delta-Mendota Subbasin SMC ................................................................................ 207 Table CC-20: Numeric SMC for Degraded Groundwater Quality ..................................................... 208 Table CC-21: Delta-Mendota Subbasin SMC ................................................................................ 213 Table CC-22: Numeric SMC for Inelastic Land Subsidence ............................................................. 216 Table CC-23: Delta-Mendota Subbasin SMC ................................................................................ 219 Table CC-24: Coordinated Public Workshops ................................................................................ 249 Table CC-1: DACs as a Percentage of the Delta-Mendota Subbasin ............................................... 3 Table CC-2: DAC and SDAC Census Designated Places in Delta-Mendota Subbasin ................. 3 Table CC-3: EDAs as a Percentage of the Delta-Mendota Subbasin ............................................... 4 Table CC-4: Delta-Mendota Subbasin Coordination Committee Members .................................... 14 Table CC-5: Subsidence Monitoring Trends ...................................................................................... 100 Table CC-6: Estimated Quantity of Gains/Depletions for Interconnected Stream Reaches, San Joaquin River ................................................................................................................ 116 Table CC-7: List of Potential Freshwater Species ............................................................................ 121 Table CC-8: Delta-Mendota Subbasin Historical Water Budget, Land Surface Budget ............. 133 313
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Table CC-9: Delta-Mendota Subbasin Historical Water Budget, Groundwater Budget .............. 133 Table CC-10: Delta-Mendota Subbasin Current Water Budget, Land Surface Budget .............. 134 Table CC-11: Delta-Mendota Subbasin Current Water Budget, Groundwater System .............. 134 Table CC-12: Delta-Mendota Subbasin Projected Water Budget, Land Surface Budget ........... 135 Table CC-13: Delta-Mendota Subbasin Projected Water Budget, Groundwater Budget ........... 137 Table CC-14: Delta-Mendota Subbasin SMC for Chronic Lowering of Groundwater Levels .... 145 Table CC-15: Delta-Mendota Subbasin SMC for Reduction in Groundwater Storage ................ 147 Table CC-16: Delta-Mendota Subbasin SMC for Degraded Water Quality ................................. 149 Table CC-17: Delta-Mendota Subbasin SMC for Land Subsidence .............................................. 151 Table CC-18: Delta-Mendota Subbasin SMC for Depletions of Interconnected Surface Water 153 Table CC-19: Coordinated Public Workshops ................................................................................... 170 Figures
Figure CC-1: Delta-Mendota Subbasin and GSP Regions .................................................................... 6 Figure CC-2: Disadvantaged and Severely Disadvantaged Communities in the Delta-Mendota Subbasin . 8 Figure CC-3: Economically Distressed Areas in the Delta-Mendota Subbasin ..................................... 10 Figure CC-4: GSAs in the Delta-Mendota Subbasin – Stanislaus County ............................................ 13 Figure CC-5: GSAs in the Delta-Mendota Subbasin – Merced County ................................................ 14 Figure CC-6: GSAs in the Delta-Mendota Subbasin – Fresno and Madera Counties ............................. 15 Figure CC-7: Governance Structure of the Delta-Mendota Subbasin ................................................... 20 Figure CC-8: Neighboring Subbasins of the Delta-Mendota Subbasin ................................................ 29 Figure CC-9: Delta-Mendota Groundwater Subbasin Plan Area ......................................................... 30 Figure CC-10: Local Watersheds .................................................................................................... 32 Figure CC-11: Wildlife Refuges and Wetland Habitat Areas in the Delta-Mendota Subbasin ................ 33 Figure CC-12: Communities Dependent on Groundwater .................................................................. 36 Figure CC-13: Domestic Well Density in the Delta-Mendota Subbasin ............................................... 37 Figure CC-14: Production Well Density in the Delta-Mendota Subbasin ............................................. 38 Figure CC-15: Public Well Density in the Delta-Mendota Subbasin ................................................... 39 Figure CC-16: 100-Year Floodplain, Delta-Mendota Subbasin........................................................... 43 Figure CC-17: Typical Land Use .................................................................................................... 44 Figure CC-18: Land Use Planning Entities ....................................................................................... 45 Figure CC-19: Federal and State Lands............................................................................................ 47 Figure CC-20: 2014 Land Use in the Delta-Mendota Subbasin........................................................... 49 Figure CC-21: Regional Geologic Setting ........................................................................................ 55 Figure CC-22: Generalized Geology................................................................................................ 57 314
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Figure CC-23: Subbasin Faults ....................................................................................................... 60 Figure CC-24: Representative Cross-Sections .................................................................................. 65 Figure CC-25: Cross-Section A-A’ (Hotchkiss, 1972) ....................................................................... 66 Figure CC-26: Cross-Section B-B’ (Hotchkiss, 1972) ....................................................................... 67 Figure CC-27: Cross-Section C-C’ (Hotchkiss, 1972) ....................................................................... 68 Figure CC-28: Cross-Section D-D’ (Hotchkiss & Balding, 1971) ....................................................... 68 Figure CC-29: Cross-Section E-E’ (Hotchkiss & Balding, 1971) ........................................................ 69 Figure CC-30: Cross-Section F-F’ (Hotchkiss, 1972) ........................................................................ 70 Figure CC-31: Depth to Corcoran Clay ............................................................................................ 71 Figure CC-32: Non-Corcoran Clay Layers ....................................................................................... 72 Figure CC-33: Thickness of Corcoran Clay ...................................................................................... 73 Figure CC-34: Soil Hydraulic Conductivity ..................................................................................... 74 Figure CC-35: Ground Surface Elevation ......................................................................................... 79 Figure CC-36: Surface Water Features ............................................................................................ 80 Figure CC-37: SAGBI Soils Map .................................................................................................... 83 Figure CC-38: Tile Drains .............................................................................................................. 84 Figure CC-39: Recharge Areas, Seeps and Springs ........................................................................... 85 Figure CC-40: Imported Supplies .................................................................................................... 86 Figure CC-41: Wells with Known Screened Interval Depths .............................................................. 94 Figure CC-42: Select Graphs of Groundwater Elevations, Upper Aquifer ........................................... 95 Figure CC-43: Select Graphs of Groundwater Elevations, Various Depths .......................................... 96 Figure CC-44: Select Graphs of Groundwater Elevations, Lower Aquifer ........................................... 97 Figure CC-45: Spring 2013 Upper Aquifer Groundwater Contour Map............................................... 98 Figure CC-46: Fall 2013 Upper Aquifer Groundwater Contour Map................................................... 99 Figure CC-47: Spring 2013 Lower Aquifer Groundwater Elevation Measurements ............................ 100 Figure CC-48: Fall 2013 Lower Aquifer Groundwater Elevation Measurements ................................ 101 Figure CC-49: Calculated Upper Aquifer Change in Storage, Annual and Cumulative ....................... 102 Figure CC-50: Calculated Lower Aquifer Change in Storage, Annual and Cumulative ....................... 103 Figure CC-51: UNAVCO and Delta-Mendota Canal Subsidence Monitoring Locations ..................... 108 Figure CC-52: Vertical Elevation Change at UNAVCO CGPS P255, Spring 2007 to 2018 ................. 109 Figure CC-53: Vertical Elevation Change at UNAVCO CGPS P259, Spring 2006 to 2018 ................. 110 Figure CC-54: Vertical Elevation Change at UNAVCO CGPS P252, Spring 2006 to 2018 ................. 111 Figure CC-55: Vertical Elevation Change at UNAVCO CGPS P303, Spring 2006 to 2018 ................. 112 Figure CC-56: Vertical Elevation Change at UNAVCO CGPS P301, Spring 2005 to 2018 ................. 113 Figure CC-57: Vertical Elevation Change at UNAVCO CGPS P304, Spring 2005 to 2018 ................. 114 Figure CC-58: Land Subsidence, December 2011 to December 2014 ............................................... 115 315
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Figure CC-59: Recent Land Subsidence at Key San Joaquin Valley Locations .................................. 116 Figure CC-60: Vertical Displacement, April 2015 to April 2016 ...................................................... 117 Figure CC-61: Elevation Change along the Delta-Mendota Canal, 2014 through 2018 ....................... 118 Figure CC-62: Groundwater Dependent Ecosystems, Wetlands........................................................ 124 Figure CC-63: Groundwater Dependent Ecosystems, Vegetation ..................................................... 125 Figure CC-64: Change in Storage, Delta-Mendota Subbasin Projected Water Budget......................... 162 Figure CC-65: Groundwater Level Representative Monitoring Locations with SMC – Upper Aquifer . 202 Figure CC-66: Groundwater Level Representative Monitoring Locations with SMC – Lower Aquifer 203 Figure CC-67: Groundwater Quality Representative Monitoring Locations with SMC – Upper Aquifer .......................................................................................................................... 211 Figure CC-68: Groundwater Quality Representative Monitoring Locations with SMC – Lower Aquifer .......................................................................................................................... 212 Figure CC-69: Land Subsidence Representative Monitoring Locations with SMC ............................. 218 Figure CC-70: Interconnected Surface Water Representative Monitoring Locations with SMC ........... 222 Figure CC-71: Data Flow in Delta-Mendota Subbasin ..................................................................... 236 Figure CC-72: Delta-Mendota Monitoring and Data Management Roles and Responsibilities ............. 237 Figure CC-73: Upper Aquifer Groundwater Level Monitoring Network ........................................... 239 Figure CC-74: Lower Aquifer Groundwater Level Monitoring Network ........................................... 240 Figure CC-75: Upper Aquifer Groundwater Quality Monitoring Network ......................................... 241 Figure CC-76: Lower Aquifer Groundwater Quality Monitoring Network ........................................ 242 Figure CC-77: Interconnected Surface Water Monitoring Network................................................... 243 Figure CC-78: Land Surface Elevation Monitoring Network............................................................ 244 Figure CC-1: Delta-Mendota Subbasin and GSP Regions ........................................................... 5 Figure CC-2: Disadvantaged and Severely Disadvantaged Communities in the Delta-Mendota Subbasin ............................................................................................................... 6 Figure CC-3: Economically Distressed Areas in the Delta-Mendota Subbasin............................. 7 Figure CC-4: GSAs in the Delta-Mendota Subbasin – Stanislaus County .................................. 10 Figure CC-5: GSAs in the Delta-Mendota Subbasin – Merced County ...................................... 11 Figure CC-6: GSAs in the Delta-Mendota Subbasin – Fresno and Madera Counties ................ 12 Figure CC-7: Governance Structure of the Delta-Mendota Subbasin ......................................... 17 Figure CC-8: Neighboring Subbasins of the Delta-Mendota Subbasin ....................................... 26 Figure CC-9: Delta-Mendota Groundwater Subbasin Plan Area ................................................ 27 Figure CC-10: Local Watersheds ................................................................................................ 29 Figure CC-11: Wildlife Refuges and Wetland Habitat Areas in the Delta-Mendota Subbasin .... 30 Figure CC-12: Communities Dependent on Groundwater .......................................................... 33 Figure CC-13: Domestic Well Density in the Delta-Mendota Subbasin ...................................... 34 316
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Figure CC-14: Production Well Density in the Delta-Mendota Subbasin .................................... 35 Figure CC-15: Public Well Density in the Delta-Mendota Subbasin ........................................... 36 Figure CC-16: 100-Year Floodplain, Delta-Mendota Subbasin .................................................. 39 Figure CC-17: Typical Land Use ................................................................................................. 40 Figure CC-18: Land Use Planning Entities ................................................................................. 41 Figure CC-19: Federal and State Lands ..................................................................................... 43 Figure CC-20: 2014 Land Use in the Delta-Mendota Subbasin .................................................. 45 Figure CC-21: Regional Geologic Setting ................................................................................... 51 Figure CC-22: Generalized Geology ........................................................................................... 53 Figure CC-23: Subbasin Faults ................................................................................................... 56 Figure CC-24: Representative Cross-Sections ........................................................................... 61 Figure CC-25: Cross-Section A-A’ (Hotchkiss, 1972) ................................................................. 62 Figure CC-26: Cross-Section B-B’ (Hotchkiss, 1972) ................................................................. 63 Figure CC-27: Cross-Section C-C’ (Hotchkiss, 1972) ................................................................. 64 Figure CC-28: Cross-Section D-D’ (Hotchkiss & Balding, 1971) ................................................ 64 Figure CC-29: Cross-Section E-E’ (Hotchkiss & Balding, 1971) ................................................. 65 Figure CC-30: Cross-Section F-F’ (Hotchkiss, 1972) ................................................................. 66 Figure CC-31: Depth to Corcoran Clay ....................................................................................... 67 Figure CC-32: Non-Corcoran Clay Layers .................................................................................. 68 Figure CC-33: Thickness of Corcoran Clay ................................................................................ 69 Figure CC-34: Soil Hydraulic Conductivity .................................................................................. 70 Figure CC-35: Ground Surface Elevation ................................................................................... 75 Figure CC-36: Surface Water Features ...................................................................................... 76 Figure CC-37: SAGBI Soils Map ................................................................................................. 79 Figure CC-38: Tile Drains ........................................................................................................... 80 Figure CC-39: Recharge Areas, Seeps and Springs .................................................................. 81 Figure CC-40: Imported Supplies ............................................................................................... 82 Figure CC-41: Wells with Known Screened Interval Depths ....................................................... 90 Figure CC-42: Select Graphs of Groundwater Elevations, Upper Aquifer .................................. 91 Figure CC-43: Select Graphs of Groundwater Elevations, Various Depths ................................ 92 Figure CC-44: Select Graphs of Groundwater Elevations, Lower Aquifer .................................. 93 Figure CC-45: Spring 2013 Upper Aquifer Groundwater Contour Map ...................................... 94 Figure CC-46: Fall 2013 Upper Aquifer Groundwater Contour Map ........................................... 95 Figure CC-47: Spring 2013 Lower Aquifer Groundwater Elevation Measurements.................... 96 Figure CC-48: Fall 2013 Lower Aquifer Groundwater Elevation Measurements ........................ 97 Figure CC-49: Calculated Upper Aquifer Change in Storage, Annual and Cumulative .............. 98 317
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Figure CC-50: Calculated Lower Aquifer Change in Storage, Annual and Cumulative .............. 99 Figure CC-51: UNAVCO and Delta-Mendota Canal Subsidence Monitoring Locations ........... 103 Figure CC-52: Vertical Elevation Change at UNAVCO CGPS P255, Spring 2007 to 2018 ...... 104 Figure CC-53: Vertical Elevation Change at UNAVCO CGPS P259, Spring 2006 to 2018 ...... 105 Figure CC-54: Vertical Elevation Change at UNAVCO CGPS P252, Spring 2006 to 2018 ...... 106 Figure CC-55: Vertical Elevation Change at UNAVCO CGPS P303, Spring 2006 to 2018 ...... 107 Figure CC-56: Vertical Elevation Change at UNAVCO CGPS P301, Spring 2005 to 2018 ...... 108 Figure CC-57: Vertical Elevation Change at UNAVCO CGPS P304, Spring 2005 to 2018 ...... 109 Figure CC-58: Land Subsidence, December 2011 to December 2014 .................................... 110 Figure CC-59: Recent Land Subsidence at Key San Joaquin Valley Locations ....................... 111 Figure CC-60: Vertical Displacement, April 2015 to April 2016 ................................................ 112 Figure CC-61: Elevation Change along the Delta-Mendota Canal, 2014 through 2018 ........... 113 Figure CC-62: Groundwater Dependent Ecosystems, Wetlands .............................................. 119 Figure CC-63: Groundwater Dependent Ecosystems, Vegetation ........................................... 120 Figure CC-64: Change in Storage, Delta-Mendota Subbasin Projected Water Budget ............ 139 Figure CC-65: Data Flow in Delta-Mendota Subbasin .............................................................. 157 Figure CC-66: Delta-Mendota Monitoring and Data Management Roles and Responsibilities 158 Figure CC-67: Upper Aquifer Groundwater Level Monitoring Network ..................................... 160 Figure CC-68: Lower Aquifer Groundwater Level Monitoring Network ..................................... 161 Figure CC-69: Upper Aquifer Groundwater Quality Monitoring Network .................................. 162 Figure CC-70: Lower Aquifer Groundwater Quality Monitoring Network .................................. 163 Figure CC-71: Interconnected Surface Water Monitoring Network ........................................... 164 Figure CC-72: Land Surface Elevation Monitoring Network ..................................................... 165 318
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Appendices
Appendix A – Coordination Agreement
Appendix B – Common Technical Memoranda
Appendix C – - Preparation Checklist for GSP Submittal
Appendix D – Interbasin Agreements
Appendix E – Delta-Mendota Subbasin Communications Plan Appendix F – Summaries of Coordinated Public Workshops
Appendix G – Examples of Promotional Materials from Public Workshops Appendix H – List of Stakeholders and Community Organizations Contacted 319
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Acronyms
AB 3030 1992 California Assembly Bill 3030
AWMP Agriculturale Water Management Plan
BMP Best Management Practice
CASGEM California Statewide Groundwater Elevation Monitoring CCC Columbia Canal Company
CCF Climate Change Factors
CCID Central California Irrigation District
CDEC California Data Exchange Center
CDFW California Department of Fish and Wildlife
cfs cubic feet per second
CVO Central Valley Operations
CVP Central Valley Project
CVRWQCB Central Valley Regional Water Quality Control Board DAC Disadvantaged Community
DMC Delta-Mendota Canal
DPWD Del Puerto Water District
DWR California Department of Water Resources
ET Evapotranspiration
ETc Total Crop Evapotranspiration
ETiw Crop Evapotranspiration of Irrigation Water
ETmisc Miscellaneous Evapotranspiration including; canal evaporation, consumptive use of phreatophytes, etc.

FCWD Firebaugh Canal Water District
FNF Full Natural Flow
GAMA Groundwater Ambient Monitoring and Assessment
gpm gallons per minute
GRCD Grassland Resource Conservation District
GSA Groundwater Sustainability Agency
GSP Groundwater Sustainability Plan
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Acronyms
GWD Grassland Water District
HCM Hydrogeologic Conceptual Model
HMRD Henry Miller Reclamation District
IM interim milestone
IRWM Integrated Regional Water Management
JPA Joint Powers Authority
KDSA Kenneth D. Schmidt and Associates
MAF million acre-feet
MO measurable objective
MSL Mean Sea Level
MT minimum threshold
NASA JPL National Aeronautics and Space Administration Jet Propulsions Laboratory P&P Provost and Pritchard Consulting Group
RCD Resource Conservation District
RWQCB Regional Water Quality Control Board
SB 372 2017 California Senate Bill 372
SGMA Sustainable Groundwater Management Act
SGWP Sustainable Groundwater Planning
SJREC San Joaquin River Exchange Contractors
SJRECWA San Joaquin River Exchange Contractors Water Authority SJRIP San Joaquin River Improvement Program
SJRRP San Joaquin River Restoration Program
SLDMWA San Luis & Delta-Mendota Water Authority
SMC Sustainable Management Criteria
SWP State Water Project
SWRCB State Water Resources Control Board
TAF thousand acre-feet
TDS Total Dissolved Solids
TIWD Turner Island Water District
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Acronyms
TNC The Nature Conservancy
UNAVCO University NAVSTAR Consortium
USACE U.S. Army Corps of Engineers
USBR U.S. Bureau of Reclamation
USF&WS U.S. Fish & Wildlife Service
USGS United States Geological Survey
UWMP Urban Water Management Plan
WDL Water Data Library
WMP Water Management Plan
WSIP Water Storage Investment Program
WWD Westlands Water District
WY Water Year
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DISCLAIMER
The work products presented in this Common Chapter and associated Technical Memoranda (Appendix B) are a compilation of work completed by the six (6) individual Groundwater Sustainability Plan (GSP) regions under the direction of a Professional Geologist (PG) or Professional Engineer (PE) as indicated by the stamps on the respective GSP Executive Summaries. The signature here represents work completed in compiling the Common Chapter from these individual GSPs, and the signing Professional Engineer assumes no responsibility for any errors or misleading statements presented therein. Compilation of the Common Chapter, exclusive of work conducted for the individual GSPs, and revisions to this Common Chapter haves been prepared under the oversight of Leslie Dumas, P.E. and the signature below is specifically for that compilation.

Responsible
Engineer
Seal
(If required)
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1. INTRODUCTION

1.1 Purpose of Common Chapter
The 23 Groundwater Sustainability Agencies (GSAs) overlying the Delta-Mendota Subbasin (Subbasin) have prepared six Groundwater Sustainability Plans (GSPs) that, together, encompass the entire Subbasin area (Figure CC-1Figure CC-1). These GSPs have been prepared in a coordinated manner under the oversight of the Delta-Mendota Subbasin Coordination Committee (Coordination Committee) and in accordance with the Delta-Mendota Subbasin Coordination Agreement (Coordination Agreement) for the Subbasin. This Common Chapter has been prepared as means of integrating key parts of the six GSPs to meet subbasin-level requirements per the Sustainable Groundwater Management Act (SGMA) and the Emergency GSP regulations (DWR, 2016).

On January 21, 2022, the Subbasin received a Consultation Initiation Letter (CIL) from the California Department of Water Resources (DWR). The CIL identified four potential deficiencies across the six Subbasin GSPs which may preclude DWR’s approval, as well as potential corrective actions to address each potential deficiency. The CIL thus initiated consultation between DWR, the Subbasin Point of Contact, Plan Managers, and the Subbasin’s GSAs. This Common Chapter has been revised to incorporate changes required to reflect the Subbasin’s response to the deficiencies identified in the CIL, based on direction provided by the Coordination Committee, the Delta-Mendota Technical Working Group (Technical Working Group), the Subbasin GSAs and DWR. This revised Common Chapter, along with the attached cover letter, are intended to document how the deficiencies identified in the CIL were addressed in the revised Subbasin GSPs and this revised Common Chapter.

This revised Common Chapter, along with the six Subbasin GSPs, Coordination Agreement (Appendix A) and Common Technical Memoranda (Appendix B), meets regulatory requirements established by the California Department of Water Resources (DWR) as shown in the completed Preparation Checklist for GSP Submittal (Appendix C). The Common Technical Memoranda summarize the common data sets, assumptions and methodologies used during preparation of the six Subbasin GSPs. The reader is referred to the individual GSP (and their associated Executive Summaries) for information, data, and GSP requirements specific to each GSP Plan Area.

1.2 Delta-Mendota Subbasin
The Delta-Mendota Subbasin (DWR Basin 5-022.07) is located in the San Joaquin Valley Groundwater Basin and adjoins nine (9) subbasins of the San Joaquin Valley Groundwater Basin. The Delta-Mendota Subbasin boundaries generally corresponds to DWR’s California’s Groundwater Bulletin 118 – Update 2003 (Bulletin 118) groundwater basin boundaries. Changes made to the Subbasin boundaries as part of the SGMA planning process include the following:
 A jurisdictional internal boundary modification made in 2016 to extend the boundary of the Delta-Mendota Subbasin eastward to include all of Aliso Water District.  A jurisdictional internal boundary modification made in 2016 to bring areas that straddle the Delta-Mendota Subbasin and adjacent subbasins fully within the Delta-Mendota Subbasin. This 324
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modification adjusted areas from the southern boundary of the Delta-Mendota Subbasin and the Westside Subbasin in coordination with Westlands Water District, and moved the eastern boundary of the Delta-Mendota Subbasin from the Madera Subbasin into the Delta-Mendota Subbasin in coordination with Aliso Water District. The modification also moved areas from the Tracy Subbasin into the Delta-Mendota Subbasin so that Del Puerto Water District and West Stanislaus Irrigation District were fully within the Delta-Mendota Subbasin, and cleaned up boundaries between the Delta-Mendota Subbasin and the Kings Subbasin to conform with the boundaries of Tranquillity Irrigation District and the Traction Ranch property (bounded on the east by Mid-Valley Water District).
 A jurisdictional internal boundary modification made in 2018 to modify the boundary between the Delta-Mendota and the Chowchilla Subbasins to follow the western boundary of Triangle T Water District and the southern boundary of Clayton Water District. This modification moved approximately 700 acres of land from the Chowchilla Subbasin into the Delta-Mendota Subbasin.

The western San Joaquin Valley is a highly agricultural region with an economy dependent on that industry. There are no large cities or industries in the Delta-Mendota Subbasin to provide an alternative economic base; hence the availability of Central Valley Project (CVP) imported supplies and surface water supplies (primarily from the San Joaquin and Kings River) are essential elements to the economic health of the region. Other uses of CVP and surface water in the Subbasin are for municipal and industrial (M&I) purposes and wildlife refuge water supply.

Groundwater is a key component of overall water supplies in the Delta-Mendota Subbasin. Agricultural and wildlife refuge needs may be supplemented by groundwater for areas with access to CVP water.

Other landowners within the Subbasin may rely wholly on groundwater for irrigation and/or potable purposes. Municipal and industrial (M&I) water use, which is a small share of total water use in the Subbasin, occurs primarily within the cities, and predominantly uses groundwater to meet those demands.

The largest M&I use areas in the Delta-Mendota Subbasin, based on 2015 population estimates from the U.S. Census Bureau, are the cities of Patterson (population 21,498) and Los Banos (population 37,457) (U.S. Census Bureau, 2015).

As previously noted, most communities within the Delta-Mendota Subbasin have economies greatly dependent on agricultural production. These communities include Patterson, Grayson, Tranquillity, Mendota, Firebaugh, Dos Palos, Los Banos, Santa Nella, Newman, Gustine, Crows Landing, Westley, Volta, and Vernalis.

1.3 Disadvantaged Communities within the Delta-Mendota Subbasin A disadvantaged community (DAC) is defined as a community with a Median Household Income (MHI) less than 80% of the California statewide MHI. The California Department of Water Resources (DWR) compiled U.S. Census Bureau’s American Community Survey (ACS) data from 2012 to 2016; these data were used in GIS to identify DACs within the Delta-Mendota Subbasin. California’s average statewide MHI from 2012 to 2016 is $63,783; thus, a community with an MHI less than or equal to $51,026 is considered a DAC. Based on these criteria, 93% of the geographic area of the Subbasin is considered disadvantaged. Furthermore, a community with an MHI of less than 60% of the California statewide 325
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MHI, meaning an MHI of less than or equal to $38,270, is considered a severely disadvantaged community (SDAC). According to the U.S. Census ACS 2012-2016 data, there are a number of SDACs throughout the Subbasin. See Figure CC-2Figure CC-2 for a map of the DACs and SDACs throughout the Delta-Mendota Subbasin.

As noted above, a significant portion of the Subbasin contains DACs. Of the total population of 117,120 within the Subbasin, 80% of the population lives within a DAC, with 93% of the Subbasin’s total geographic area consisting of DACs. Table CC-1Table CC-1 includes the proportion of DACs in the Subbasin based on population and geographic area.

Table CC-1: DACs as a Percentage of the Delta-Mendota Subbasin Area
Geographic Area
(Square Miles)
% Based on
Geographic Area Population
% Based on
Population
DAC (including SDAC) 1,109 93% 93,786 80%
Delta-Mendota Subbasin 1,194 117,120
Table CC-2Table CC-2 includes Census Designated Places that are DACs in the Delta-Mendota Subbasin, with their associated MHIs and percentage of the California MHI from the ACS 5-Year 2012- 2016 average. Several DACs in the Subbasin have considerably lower MHI than 80% of the California Statewide MHI and are further designated as Severely Disadvantaged Communities (SDACs). In Table CC-2Table CC-2, SDACs are indicated in bold text. Note that according to the U.S. Department of the Interior Indian Affairs, as of January 2017, there are no listed federally recognized tribes within the Region (Mosley, 2017).

Table CC-2: DAC and SDAC Census Designated Places in Delta-Mendota Subbasin Census
Designated Place
(CDP)
Median
Household
Income
(MHI)
% of CA MHI
City of Dos Palos $36,509 57%
City of Firebaugh $36,181 57%
City of Gustine $37,770 59%
City of Los Banos $45,751 72%
City of Mendota $26,094 41%
City of Newman $52,783 83%
Crows Landing $26,786 42%
Dos Palos Y (CDP) $16,656 26%
Grayson $29,787 47%
Madera County $45,490 74%
Merced County $43,066 70%
Fresno County $45,963 72%
Santa Nella $27,778 44%
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Census
Designated Place
(CDP)
Median
Household
Income
(MHI)
% of CA MHI
South Dos Palos $41,992 66%
Tranquillity $30,441 48%
Volta $48,250 76%
Westley $23,375 37%
Data Sources:

1. U.S. Census ACS data from 2012 to 2016 provided by DWR Mapping Tool.

2. MHI data are from the 2016 Census, and percent of CA MHI is calculated based on the 2012-2016 Statewide MHI. Bold rows indicate severely disadvantaged communities (less than 60% of CA Statewide MHI).

1.4 Economically Disadvantaged Areas within the Delta-Mendota Subbasin An economically distressed area (EDA) is defined by the State of California as a “municipality with a population of 20,000 persons or less, a rural county, or a reasonably isolated and divisible segment of a larger municipality where the segment of the population is 10,000 persons or less, with an annual median household income that is less than 85% of the statewide median household income, and with one or more of the following conditions as determined by the (sic) Department of Water Resources:

1. Financial hardship

2. Unemployment rate at least two percent higher than the statewide average

3. Low population density (CA Assembly, 2014).”
U.S. Census GIS data provided by DWR were used to identify EDAs in the Delta-Mendota Subbasin.

Figure CC-3Figure CC-3 shows the location of EDAs within the Delta-Mendota Subbasin A significant portion of the Subbasin contains EDAs. Of the total population of 117,120 within the Subbasin, 87% live in areas that meet EDA Criterion 2, 20% live in areas that meet EDA Criterion 3, and 87% live in areas that meet Criteria 2 or 3. In all, 93% of the geographic area within the Subbasin consists of areas considered to meet either EDA Criteria 2 or 3. Table CC-3Table CC-3 includes the proportion of EDAs in Subbasin based on population and geographic area.

Table CC-3: EDAs as a Percentage of the Delta-Mendota Subbasin Area
Geographic Area
(Square Miles)
% Based on
Geographic Area Population
% Based on
Population
EDA Criterion 2 1,112 93% 102,407 87%
EDA Criterion 3 1,004 84% 23,688 20%
EDA Criteria 2 or 3 1,112 93% 102,407 87%
Delta-Mendota Subbasin 1,194 117,120
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Figure CC-1: Delta-Mendota Subbasin and GSP Regions
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Figure CC-2: Disadvantaged and Severely Disadvantaged Communities in the DeltaMendota Subbasin 331
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Figure CC-3: Economically Distressed Areas in the Delta-Mendota Subbasin 333
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2. DELTA-MENDOTA SUBBASIN GOVERNANCE
This section includes information pursuant to Article 5. Plan Contents, Subarticle 1. Administrative Information, § 354.6 (Agency Information) as well as Subarticle 8. Interagency Agreements (§ 357.2 Interbasin Agreements and § 357.4 Coordination Agreements), as required by the Groundwater Sustainability Plan (GSP) Regulations. Agency Contact information for the Delta-Mendota Subbasin and the plan manager is included in this section. The organization and management structure, as well as the legal authority of each Groundwater Sustainability Agency (GSA) in the Delta-Mendota Subbasin, is detailed and accompanied by GSA boundary maps and a description of intra-basin and inter-basin coordination agreements in place for the development and implementation of the GSPs overlying the Delta-Mendota Subbasin.

Agency Contact Information
This Common Chapter to the six GSPs for the Delta-Mendota Subbasin has been prepared in a cooperative manner by the following GSAs in the Delta-Mendota Subbasin:

Northern & Central Delta-Mendota Region GSP
 Patterson Irrigation District GSA
 West Stanislaus Irrigation District GSA
 DM-II GSA
 City of Patterson GSA
 Northwestern Delta-Mendota GSA
 Central Delta-Mendota GSA
 Widren Water District GSA
 Oro Loma Water District GSA
San Joaquin River Exchange Contractors (SJREC) GSP
 San Joaquin River Exchange Contractors Water Authority GSA  Turner Island Water District-2 GSA
 City of Mendota GSA
 City of Firebaugh GSA
 City of Los Banos GSA
 City of Dos Palos GSA
 City of Gustine GSA
 City of Newman GSA
 Madera County -– 3 GSA
 Portion of Merced County – Delta-Mendota GSA
 Portion of Fresno County Management Area B GSA
Grassland GSP
 Grassland GSA
 Portion of Merced County – Delta-Mendota GSA
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Aliso Water District GSP
 Aliso Water District GSA
Farmers Water District GSP
 Farmers Water District GSA
Fresno County GSP
 Fresno County Management Area A GSA
 Portion of Fresno County Management Area B GSA
The plan areas covered by each of the six Subbasin GSPs is show in Figure CC-1Figure CC-1. Figure CC-4Figure CC-4 through Figure CC-6Figure CC-6 show the location of the GSAs comprising the six GSP regions. These GSAs are coordinating development and implementation of the six GSPs under the Coordination Agreement, as described below in Section 2.1.

The initial current Plan Manager for the coordinated Delta-Mendota Subbasin GSPs is Andrew GarciaJohn Brodie, Water Resources Program Manager Senior Civil Engineer for San Luis & DeltaMendota Water Authority (SLDMWA). Mr. Garcia Brodie can be contacted as follows:

Mr. Andrew GarciaJohn Brodie, Plan Manager
Delta-Mendota Subbasin
842 6th Street
Los Banos, CA 93635
Phone: (209) -826-1872832-6200 / Fax (209) -833-1034
Error! Hyperlink reference not [email protected] Contact information for each GSP plan administrator can be found in the respective GSPs. The DWR Point of Contact is shown below.

Department of Water Resources (DWR) Point of Contact
The point of contact for the Delta-Mendota Subbasin is:

Christopher Olvera
Department of Water Resources
[email protected]
(559) 230-3373
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Figure CC-4: GSAs in the Delta-Mendota Subbasin – Stanislaus County 336
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Figure CC-5: GSAs in the Delta-Mendota Subbasin – Merced County 337
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Figure CC-6: GSAs in the Delta-Mendota Subbasin – Fresno and Madera Counties 338
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2.1 GSA and GSP Coordination and Governance
This section includes a description of intra-basin coordination agreements, which are required where there is more than one GSP prepared for a groundwater basin, and inter-basin coordination agreements, which are optional agreements between neighboring groundwater subbasins, pursuant to Article 8. Interagency Agreements, § 357.4. Coordination Agreements and § 357.2 Interbasin Agreements.

2.1.1 Delta-Mendota Subbasin SGMA Governance Structure
The GSAs within the Delta-Mendota Subbasin adopted and executed a Coordination Agreement on December 12, 2018 to comply with the SGMA requirement that multiple GSAs within a given subbasin must coordinate when developing and implementing their GSPs (see Intra-Agency Coordination subsection above for more information). Additionally, a Cost Sharing Agreement was signed and executed by the same parties on December 12, 2018. Figure CC-5 shows the SGMA governance structure within the Delta-Mendota Subbasin. In addition to the two members appointed to represent each of the Northern & Central Delta-Mendota GSP Region and the San Joaquin River Exchange Contractors (SJREC) GSP Region on the Delta-Mendota Subbasin Coordination Committee as voting members, the Grassland GSP Region, Farmers Water District GSP Region, Fresno County Management Areas A & B GSP Region, and Aliso Water District GSP Region all have appointed one voting member each for a total of eight voting members.

Three working groups were formed under the auspices of the Delta-Mendota Subbasin Coordination Committee: the Technical Working Group, the Communications Working Group and the DMS Working Group. Representatives of each GSP region participate ion each working group. 339
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Table CC-4: Delta-Mendota Subbasin Coordination Committee Members GSP GSA Agency
Coordination Committee Members
Primary Alternate
Northern & Central DeltaMendota Region GSP
Northern Delta Mendota Region Management Committee
Patterson Irrigation District GSA
Patterson Irrigation District
Vince Lucchesi Walt Ward
Twin Oaks Irrigation District
West Stanislaus Irrigation District GSA
West Stanislaus Irrigation District

DM-II GSA
Del Puerto Water District
Oak Flat Water District
City of Patterson GSA City of Patterson Northwestern DeltaMendota GSA Merced County Fresno County Central DeltaMendota Region Management Committee
Central Delta-Mendota GSA
San Luis Water District
Ben Fenters Lacey Kiriakou
Panoche Water District Tranquillity Irrigation District Fresno Slough Water District Eagle Field Water District Pacheco Water District Santa Nella County Water DistrictMercy Springs Water District Merced County Fresno County Widren Water District GSA Widren Water District
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GSP GSA Agency
Coordination Committee Members
Primary Alternate
Oro Loma Water District GSA Oro Loma Water District
San Joaquin River Exchange Contractors GSP
San Joaquin River Exchange Contractors Water Authority GSA Central California Irrigation District
Jarrett Martin, Alejandro Paolini
Chris White, John Wiersma
Columbia Canal Company Firebaugh Canal Water DistrictSan Luis Canal Company Turner Island Water District-2 GSA Turner Island Water District City of Mendota GSA City of Mendota City of Firebaugh GSA City of Firebaugh City of Los Banos GSA City of Los Banos City of Dos Palos GSA City of Dos Palos City of Gustine GSA City of Gustine City of Newman GSA City of Newman County of Madera -– 3 GSA County of Madera Portion of Merced County – Delta-Mendota GSA County of Merced Portion of Fresno County Management Area B GSA County of Fresno Grassland GSP
Grassland GSA
Grassland Water District
Ric Ortega Ken Swanson
Grassland Resource Conservation District
Portion of Merced County Delta-Mendota GSA County of Merced 341
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GSP GSA Agency
Coordination Committee Members
Primary Alternate
Farmers Water District GSP Farmers Water District GSA Farmers Water District Jim Stilwell Don Peracchi Fresno County GSP Fresno County -–
Management Area A County of Fresno Buddy Mendes Glenn Allen or Fresno County -– Augustine Ramirez Management Area B County of Fresno Aliso Water District GSP Aliso Water District GSA Aliso Water District Joe Hopkins Board Secretary (Ross Franson) 342
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Figure CC-7: Governance Structure of the Delta-Mendota Subbasin 343

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2.1.2 Intra-Basin Coordination
The Delta-Mendota Subbasin Coordination Agreement (Coordination Agreement), effective as of December 12, 2018, has been signed by all participating agencies in the Delta-Mendota Subbasin; a copy of this agreement is included in Appendix A. The purpose of the Agreement, including technical reports to be developed after the initial execution of this Agreement, is to comply with SGMA requirements and to ensure that the multiple GSPs within the Subbasin are developed and implemented utilizing the same datasets, methodologies and assumptions, that the elements of the GSPs are appropriately coordinated to support sustainable subbasin management of groundwater resources, and to ultimately set forth the information necessary to show how the multiple GSPs in the Subbasin will achieve the sustainability goal as determined for the Subbasin in compliance with SGMA and its associated regulations.

A key goal of basin-wide coordination is to ensure that the Subbasin GSPs utilize the same data and methodologies during their plan development and that elements of the Plans necessary to achieve the sustainability goal for the basin are based upon consistent interpretations of the basin setting, as required by SGMA and associated regulations. The Coordination Agreement defines how the coordinated efforts will be achieved and documented, and also sets out the process for identifying the Plan Manager. The Coordination Agreement is part of each individual GSP within the Delta-Mendota Subbasin.

The Coordination Agreement for the Delta-Mendota Subbasin covers the following topics:

1. Purpose of the Agreement, including:
a. Compliance with SGMA and
b. Description of Criteria and Function;

2. General Guidelines, including:
a. Responsibilities of the Parties and
b. Adjudicated or Alternative Plans in the Subbasin;

3. Role of San Luis & Delta-Mendota Water Authority (SLDMWA), including:
a. Agreement to Serve,
b. Reimbursement of SLDMWA, and
c. Termination of SLDMWA’s Services;

4. Responsibilities for Key Functions, including:
a. Coordination Committee,
b. Coordination Committee Officers,
c. Coordination Committee Authorized Action and Limitations, d. Subcommittees and Workgroups,
e. Coordination Committee Meetings, and
f. Voting by Coordination Committee;

5. Approval by Individual Parties;

6. Exchange of Data and Information, including:
a. Exchange of Information and
b. Procedure for Exchange of Information;

7. Methodologies and Assumptions, including:
a. SGMA Coordination Agreements,
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b. Pre-GSP Coordination, and
c. Technical Memoranda Required;

8. Monitoring Network

9. Coordinated Water Budget

10. Coordinated Data Management System

11. Adoption and Use of the Coordination Agreement, including:
a. Coordination of GSPs and
b. GSP and Coordination Agreement Submission;

12. Modification and Termination of the Coordination Agreement, including:
a. Modification or Amendment of Exhibit “A” (Groundwater Sustainability Plan Groups including Participation Percentages),
b. Modification or Amendment of Coordination Agreement, and c. Amendment for Compliance with Law;

13. Withdrawal, Term, and Termination;

14. Procedures for Resolving Conflicts;

15. General Provisions, including:
a. Authority of Signers,
b. Governing Law,
c. Severability,
d. Counterparts, and
e. Good Faith; and

16. Signatories of all Parties
Coordination During GSP Implementation
The Coordination Agreement ensures that the multiple GSAs are working cooperatively and collaboratively to ensure GSPs within the Subbasin are developed and implemented utilizing the same methodologies and assumptions and to ultimately establish the processes necessary to show how the multiple GSPs in the Subbasin will be sustainably managed to achieve the Delta-Mendota Subbasin’s sustainability goal. The Coordination Committee intends to continue to meet and confer following the submittal of the Subbasin’s GSPs and will develop guidelines for GSP implementation between the GSP Groups and update the Coordination Agreement as the Parties to the Agreement deem necessary.

The Coordination Committee will continue meeting regularly following submittal of the Subbasin GSPs in order to develop the guidelines for coordinated implementation of GSPs. The intent of the guidelines will be to outline processes that will ensure the GSAs are progressing toward the Subbasin sustainability goal, while meeting the Annual Reporting requirements or any other requirements agreed upon for purposes of coordination.

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Agency Responsibilities
In meeting the terms of the Coordination Agreement, all Parties (meaning the Delta-Mendota Subbasin GSAs) agree to work collaboratively to meet the objectives of SGMA and the Coordination Agreement.

Each Party to the Agreement is a GSA and acknowledges that it is bound by the terms of the Coordination Agreement as an individual party.

The Parties have established a Coordination Committee to provide a forum to accomplish the coordination obligations of SGMA. The Coordination Committee operates in full compliance with the Brown Act and is composed of a Chairperson and Vice Chairperson, Secretary, Plan Manager, and a GSP Group Representative and Alternate Representative for each of the six GSP groups. The Chairperson and Vice Chairperson are rotated annually among GSP Groups in alphabetical order. The Secretary assumes primary responsibility for Brown Act compliance. The GSP Group Representatives, who are identified in Table CC-4Table CC-4, are selected by each respective GSP Group at the discretion of the respective GSP Group, and such appointments are effective upon providing written notice to the Secretary and to each Group Contact. The Coordination Committee recognizes each GSP Group Representative and GSP Group Alternate Representative until the Group Contact provides written notice of removal and replacement to the Secretary and to every other Group Contact. Each GSP Group is required to promptly fill any vacancy created by the removal of its Representative or Alternate Representative so that each GSP Group has the number of validly designated representatives.

Each GSP Group Representative is entitled to one vote at the Coordination Committee, where the Alternate Representative is authorized to vote in the absence of the GSP Group Representative. The unanimous vote of the GSP Representatives from all GSP Groups is required on most items upon which the Coordination Committee is authorized to act, with the exception of certain ministerial and administrative items. Voting procedures to address a lack of unanimity take place upon a majority vote of a quorum of the Coordination Committee and include: straw polls, provisional voting, and delay of voting (see Section 5.6.3 – Voting Procedures to Address Lack of Unanimity of the Coordination Agreement).

Where the law or the Coordination Agreement require separate written approval by each of the Parties, such approval is evidenced in writing by providing the resolution, Motion, or Minutes of their respective Board of Directors to the Secretary of the Coordination Committee. Minutes of the Coordinate Committee are kept and prepared by the Secretary’s appointee and maintained by the Secretary as Coordination Agreement records and are available to the Parties and the public upon request. Meeting agenda and minutes are posted on the Delta-Mendota website (www.deltamendota.org).

The Coordination Committee may appoint subcommittees, working groups, and otherwise direct staff made available by the Parties. Subcommittees or working groups may include qualified individuals possessing the knowledge and expertise to advance the goals of the Coordination Agreement on the topics being addressed by the subcommittee or working group, whether or not such individuals are GSP Group Representatives or Alternate Representatives. Tasks assigned to subcommittees, working groups, or staff made available by the Parties may include developing technical data, supporting information, and/or recommendations on specialized matters to the Coordination Committee. One GSP Group Representative or Alternate Representative is required to vote on behalf of the GSP Group at the subcommittee level. If no GSP Group Representative or Alternate Representative is present, one individual working on a subcommittee on behalf of the Parties in a GSP Group votes on behalf of the GSP Group. Subcommittees report voting results and provide information to the Coordination Committee but are not entitled to make determinations or decisions that are binding on the Parties.

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The Coordination Committee is authorized to act upon the following items:

1. The Coordination Committee reviews, and consistent with the requirements of SGMA, approves the Technical Memoranda that compose the Common Chapter (see Coordinated Data and Methodology);

2. The Coordination Committee is responsible for ongoing review and updating of the Technical Memoranda as needed; assuring submittal of annual reports; providing five-year assessments and recommending any needed revisions to the Coordination Agreement; and providing review and assistance with coordinated projects and programs, once the GSPs have been submitted to and approved by DWR;

3. The Coordination Committee reviews and approves work plans, and in accordance with the budgetary requirements of the respective Parties, approves annual budget estimates of Coordinated Plan Expenses presented by the Secretary and any updates to such estimates provided that such estimates or updates with supporting documentation are circulated to all Parties for comment at least thirty (30) days in advance of the meeting at which the Coordination Committee will consider approval of the annual estimate;

4. The Coordination Committee is authorized to approve changes to Exhibit “A” (Groundwater Sustainability Plan Groups including Participation Percentages) to the Agreement and to recommend amendments to terms of the Agreement;

5. The Coordination Committee may assign work to subcommittees and workgroups as needed, provide guidance and feedback and ensure that subcommittees and workgroups prepare work products in a timely manner;

6. The Coordination Committee directs the Plan Manager in the performance of its duties under SGMA; and

7. The Coordination Committee provides direction to its Officers concerning other administrative and ministerial issues necessary for the fulfillment of the above-enumerated tasks.

Additional information regarding the roles, responsibilities, and duties of the Coordination Committee can be found in Section 5 – Responsibilities for Key Functions of the Coordination Agreement.

Exchange of Information
Timely exchange of information is a critical aspect of GSP coordination. All parties to the Coordination Agreement have agreed to exchange public and non-privileged information through collaboration and/or informal requests made at the Coordination Committee level or through subcommittees designated by the Coordination Committee. To the extent it is necessary to make a written request for information to another Party, each Party designates a representative to respond to information requests and provides the name and contact information of the designee to the Coordination Committee. Requests may be communicated in writing and transmitted in person or by mail, facsimile machine, or other electronic means to the appropriate representative as named in the Coordination Agreement. The designated representative is required to respond in a reasonably timely manner. Nothing in the Agreement shall be construed to prohibit any Party from voluntarily exchanging information with any other Party by any other mechanism separate from the Coordination Committee.

The Parties agree that each GSP Group shall provide the data required to develop the Subbasin-wide coordinated water budget but, unless required by law, will not be required to provide individual well or parcel-level information in order to preserve confidentiality of individuals to the extent authorized by law, 347

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including but not limited to Water Code Section 10730.8, subdivision (b). To the extent that a court order, subpoena, or the California Public Records Act is applicable to a party, the Party in responding to a request made pursuant to that Act for release of information exchanged from another Party shall notify each other Party in writing of its proposed release of information in order to provide the other Parties with the opportunity to seek a court order preventing such release of information.

Dispute Resolution
Procedures for conflict resolution have been established within the Coordination Agreement. In the event that a dispute arises among Parties as it relates to the Coordination Agreement, the disputing Party or Parties are to provide written notice of the basis of the dispute to the other Parties within thirty (30) calendar days of the discovery of the events giving rise to the dispute. Within thirty (30) days after such written notice, all interested Parties are to meet and confer in good faith to informally resolve the dispute.

All disputes that are not resolved informally shall be settled by arbitration. In such an event, within ten (10) days following the failed informal proceedings, each interested Party is to nominate and circulate to all other interested Parties the name of one arbitrator. Within ten (10) days following the nominations, the interested Parties are to rank their top three among all nominated arbitrators, awarding three points to the top choice, two points to the second choice, and one point to the third choice and zero points to all others.

Each interested Party will then forward its tally to the Secretary, who tabulates the points and notifies the interested Parties of the arbitrator with the highest cumulative score, who shall be the selected arbitrator.

The Secretary may also develop procedures for approval by the Parties for selection of an arbitrator in the case of tie votes or in order to replace the selected arbitrator in the event such arbitrator declines to act.

The arbitration is to be administered in accordance with the procedures set forth in the California Code of Civil Procedure, Section 1280, et seq., and of any state or local rules then in effect for arbitration pursuant to said section. Upon completion of arbitration, if the controversy has not been resolved, any Party may exercise all rights to bring legal action relating to the controversy.

Coordinated Data and Methodology
Pursuant to SGMA, the Coordination Agreement ensures that the individual GSPs utilize the same data and methodologies for developing assumptions used to determine: 1) groundwater elevation; 2) groundwater extraction data; 3) surface water supply; 4) total water use; 5) changes in groundwater storage; 6) water budgets; and 7) sustainable yield. The Parties have agreed to develop agreed-upon methodologies and assumptions for the aforementioned items prior to or concurrent with the individual development of GSPs. This development is facilitated through the Coordination Committee’s delegation to a subcommittee or working group of the technical staff provided by some or all of the Parties. The basis upon which the methodologies and assumptions have been developed includes existing data/information, best management practices, and/or best modeled or projected data available and may include consultation with DWR as appropriate.

The data and methodologies for assumptions describeddescribed in Water Code Section 10727.6 and Title 23, California Code of Regulations, Section 357.4 to prepare coordinated plans are set forth in Technical Memoranda prepared by the Coordination Committee for each of the following elements: Data and Assumptions; Hydrogeologic Conceptual Model; Coordinated Water Budgets; Sustainable Management Criteria (SMC); Coordinated Monitoring Network; Coordinated Data Management System, and Adoption and Use of the Coordination Agreement. The Technical Memoranda have been subject to the unanimous approval of the Coordination Committee and once approved, have been attached to and incorporated by reference into the Coordination Agreement without formal amendment of the Coordination Agreement being required. The Parties have agreed that they will not submit this Coordination Agreement to DWR until the Technical Memoranda described herein have been added to the Coordination Agreement. The Technical Memoranda created pursuant to the Coordination Agreement are to be utilized by the Parties 348

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during the development and implementation of their individual GSPs in order to assure coordination of the GSPs is in compliance with SGMA. The Technical Memoranda have been included as an appendix to this GSP as a part of the Common Chapter.

Plan Implementation and Submittal
Under the Coordination Agreement, the Parties have agreed to submit their respective GSPs to DWR through the Coordination Committee and Plan Manager, in accordance with all applicable requirements.

Subject to the subsequent attachment of the Technical Memoranda as appendices to the Common Chapter, the Parties intend that the described Coordination Agreement fulfill the requirements of providing an explanation of how the GSPs implemented together satisfy the requirements of SGMA for the entire Subbasin. The Coordination Agreement does not otherwise affect each Party’s responsibility to implement the terms of its respective GSP in accordance with SGMA. Rather, this Coordination Agreement is the mechanism through which the Parties will coordinate their respective GSPs to the extent necessary to ensure that such GSP coordination complies with SGMA.

Each Party is responsible for ensuring that its own GSP complies with the statutory requirements of SGMA, including but not limited to the filing deadline. The Parties to this Coordination Agreement intend that their individual GSPs be coordinated together in order to satisfy the requirements of SGMA and to be in substantial compliance with the California Code of Regulations. The collective GSPs will satisfy the requirements of Water Code Sections 10727.2 and 10727.4 by providing a description of the physical setting and characteristics of the separate aquifer systems within the Subbasin, the measurable objectives for each such GSP, interim milestones (IMs), and monitoring protocols that together provide a detailed description of how the Subbasin as a whole will be sustainably managed.

The Parties agree to submit their respective GSPs to DWR through the Coordination Committee and Plan Manager, in accordance with all applicable requirements. The Coordination Committee is responsible for assuring submittal of annual reports, five-year updates, and for providing assessments recommending any needed revisions to the Coordination Agreement.

Coordinated Data Management System
The Delta-Mendota Subbasin GSAs have developed and will maintain a coordinated Data Management System that is capable of storing and reporting information relevant to the reporting requirements and/or implementation of the GSPs and monitoring network of the Subbasin.

The Parties may also develop and maintain separate Data Management Systems. Each separate Data Management System developed for each GSP will store information related to implementation of each individual GSP, monitoring network data and monitoring sites requirements, and water budget data requirements. Each system will be capable of reporting all pertinent information to the Coordination Committee. After providing the Coordination Committee with data from the individual GSPs, the Coordination Committee will ensure the data are stored and managed in a coordinated manner throughout the Subbasin and reported to DWR on an annual basis.

Adjudicated Areas and Alternative Plans
There are no adjudicated areas within the Delta-Mendota Subbasin, and no Alternative Plans have been submitted by the local agencies within the Subbasin.

Legal Bindings of the Delta-Mendota Subbasin Coordination Agreement The Coordination Agreement, as contained herein, is reflected in the same manner and form as in the six Subbasin GSPs. All parties understand that the Delta-Mendota Subbasin Coordination Agreement is part 349

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of the GSPs for participating Subbasin GSAs and will be a primary mechanism by which the six Subbasin GSPs will be implemented in a coordinated fashion. Further, all parties to the Coordination Agreement understand that DWR will evaluate the agreement for compliance with the procedural and technical requirements of GSP Regulations § 357.4 (Coordination Agreement) to ensure that the agreement is binding on all parties and that provisions of the agreement are sufficient to address any disputes between or among parties to the agreement.

The Coordination Agreement will continue to be the framework under which the six Delta-Mendota Subbasin GSPs will be implemented and will be reviewed as part of the five-year assessment and revised as necessary, dated, and signed by all parties.

2.1.3 Inter-basin Agreements
SLDMWA, on behalf of the Northern and Central Delta-Mendota Regions, and the SJREC GSA executed inter-basin data sharing agreements with Westlands Water District (the lead entity encompassing the adjoining Westside Subbasin). The purpose of the agreement is to establish a set of common assumptions on groundwater conditions on either side of the boundary between the Westside Subbasin and the DeltaMendota Subbasin to be used for the development of GSPs in support of implementation of SGMA. In this agreement, the parties agree to provide each other with recorded, measured, estimated, and/or simulated modeling data located within five (5) miles of the boundary between the Westside Subbasin and the Delta-Mendota Subbasin. A list of data types to be shared between the parties to the agreement can be found in Appendix D.

Data provided under this agreement are understood to be shared with consultants and other stakeholders in the respective basins (Delta-Mendota Subbasin and Westside Subbasin), and that the information will be made public through the development of the respective Parties’ (meaning SLDMWA/SJREC and Westlands Water District) GSPs and the supporting documentation of the GSPs. Other than publishing information for those purposes, neither Party will disclose the other Party’s information to any third party, except if the other Party determines, at its sole discretion, the disclosure is required by law. Each Party may review preliminary results before publishing the information.

It is recognized that many of the sustainability indicators, notably groundwater quality, inelastic land subsidence and change in storage, are regional issues that may require future inter-basin discussions and coordination. Memorandum of Intent (MOI) are being discussed with the surrounding subbasins to demonstrate/confirm the subbasins’ desires to coordinate during GSP implementation. These agreements, to be discussed further following submittal of GSPs, will allow for thoughtful consideration of the intent, structure, and need for future coordination with respect to data collection, reporting, regular meetings, and updates prior to annual reporting.
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3. DELTA-MENDOTA SUBBASIN PLAN AREA
This section describes the Delta-Mendota Subbasin, including major streams and creeks, institutional entities, agricultural and urban land uses, locations of state lands (including wetlands), and geographic boundaries of surface water runoff areas. The reader is referred to the individual Subbasin GSPs for descriptions of existing surface water and groundwater monitoring programs, existing water management programs, and general plans in the individual GSP Plan Areas. The information contained in this section reflects information from publicly available sources and may not reflect all information that will be used for GSP technical analysis.

This section of the GSP satisfies Section 354.8 of the SGMA regulations.

3.1 Plan Area Definition
The Plan Area for the six coordinated GSPs is the Delta-Mendota Subbasin (DWR Basin 5-022.07). As previously noted, the Delta-Mendota Subbasin is one of nine subbasins that lie completely within the San Joaquin Valley Hydrologic Region and adjoins the following subbasins (Figure CC-8Figure CC-8):
 Tracy
 Eastern San Joaquin
 Modesto
 Turlock
 Merced
 Chowchilla
 Madera
 Kings
 Westside
As described in California’s Groundwater, DWR Bulletin 1188 (2016), the Delta-Mendota Subbasin is in the San Joaquin Valley Groundwater Basin, located along the western edge of the San Joaquin Valley and includes portions of San Joaquin, Stanislaus, Merced, Fresno, San Benito, and Madera Counties. The northern boundary begins just south of Tracy in San Joaquin County, and the eastern boundary generally follows the San Joaquin River and Fresno Slough. The southern boundary is near the small town of San Joaquin, and the Subbasin is bounded on the west by the Coast Range. The Subbasin boundaries are further described in Section 4.1.5, Basin Boundaries, and is shown in relation to each of the six counties in Figure CC-9Figure CC-9.
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Figure CC-8: Neighboring Subbasins of the Delta-Mendota Subbasin 352
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Figure CC-9: Delta-Mendota Groundwater Subbasin Plan Area 353
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3.2 Plan Area Setting
As previously noted, the Delta-Mendota Subbasin lies along the western margin of the San Joaquin Valley. This valley is part of the large, northwest-to-southeast-trending asymmetric trough of the Central Valley, which has been filled with up to six vertical miles of sediment. This sediment includes both marine and continental deposits ranging in age from Jurassic to Holocene. The San Joaquin Valley lies between the Coast Range Mountains on the west and the Sierra Nevada on the east and extends northwestward from the San Emigdo and Tehachapi Mountains to the Sacramento-San Joaquin Delta (Delta) near the City of Stockton. The San Joaquin Valley is 250 miles long and 50 to 60 miles wide. The relatively flat alluvial floor is interrupted occasionally by low hills. Foothills adjacent on the west are composed of folded and faulted beds of mainly marine shale in the north and sandstone and shale in the south.

The San Joaquin Valley floor is divided into several geomorphic land types, including dissected uplands, low alluvial fans and plains, river floodplains and channels, and overflow lands and lake bottoms.

Alluvial plains cover most of the valley floor and comprise some of the most intensely developed agricultural lands in the San Joaquin Valley. In general, alluvial sediments of the western and southern parts of the San Joaquin Valley tend to have lower permeability than east side deposits.

This section provides additional information relating to water resources in and around the Delta-Mendota Subbasin.

Watersheds
The Delta-Mendota Subbasin lies in the Middle San Joaquin-Lower Merced-Lower Stanislaus watershed and the Middle San Joaquin-Lower Chowchilla watershed (Figure CC-10Figure CC-10). Historically, the San Joaquin Valley Basin was a large floodplain of the San Joaquin River that supported vast expanses of permanent and seasonal marshes, lakes, and riparian areas. Approximately 90 percent of the basin’s wetlands have been lost, with approximately 58,000 flooded acres remaining on State, federal and private wildlife refuges. Approximately 100,000 acres of managed wetland, upland and riparian habitat is found within the Grassland Plan area, and together with the 12,000-acre Mendota Wildlife Area (found in the Fresno County Plan area), encompasses the vast majority of the remaining wetlands found in the basin (Figure CC-11Figure CC-11).

The San Joaquin River Basin (Basin) includes the entire area drained by the San Joaquin River. The San Joaquin River Basin drains 13,513 square miles (mi2
) before it flows into the Sacramento-San Joaquin
Delta near the town of Vernalis. The Merced, Tuolumne and Stanislaus Rivers are the three major tributaries that join the mainstream San Joaquin River from the east before it flows into the Delta. 354
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Figure CC-10: Local Watersheds
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Figure CC-11: Wildlife Refuges and Wetland Habitat Areas in the Delta-Mendota Subbasin 356
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Surface Water Use
Surface water is a primary water supply for agriculture within the Delta-Mendota Subbasin. Surface water supplies are brought into the Subbasin using an extensive series of water systems relied upon by multiple water agencies, cities, and private water users. Major water-related infrastructure in the Subbasin includes the facilities required to deliver Central Valley Project (CVP) supplies to CVP water supply contractors, in addition to key infrastructure of the State Water Project (SWP) utilized to deliver water to SWP water supply contractors and surface water diversions (e.g. intakes) to divert and distribute water from the San Joaquin and Kings Rivers.

The San Luis & Delta-Mendota Water Authority (SLDMWA) is a joint powers authority consisting of 28 member agencies that provide water to approximately 1.2 million acres of highly productive farmland, 2 million California residents, and millions of waterfowl dependent upon the nearly 200,000 acres of managed wetlands within this area of the Pacific Flyway. The SLDMWA operates and maintains portions of the CVP, including the Delta Cross Channel, the C.W. “Bill” Jones Pumping Plant, the Delta-Mendota Canal (DMC), O’Neill Pumping-Generating Plant, and the San Luis Drain, and provides emergency assistance when requested on the Delta Cross Channel and the Tracy Fish Collection Facility. The California Department of Water Resources (DWR) operates and maintains the SWP facilities, designed to deliver nearly 4.2 million acre-feet of water per year to 29 long-term SWP water supply contractors. Joint federal-state facilities include the California Aqueduct, Banks Pumping Plant, O’Neill Dam and Forebay, Sisk Dam and San Luis Reservoir, and Dos Amigos Pumping Plant. Surface water diversion facilities are owned and operated by individual water and irrigation districts and typically include some form of intake (e.g. fish screen, open water intake, flumes) plus facilities to convey the diverted surface water to a distribution system.

Groundwater Use
Groundwater is a key component of water supplies in the Delta-Mendota Subbasin. To protect the longterm sustainability of groundwater resources, pumping has significantly reduced in past years (2017- 2019), allowing the groundwater levels in the Subbasin to recover to some extent. During the most recent drought period, groundwater was heavily relied upon throughout the Subbasin for irrigation as surface water deliveries were significantly severely reduced for many water users (especially those with junior surface water rights), resulting in increased groundwater pumping.

There are many communities within the Subbasin that are partially or completely reliant on groundwater for municipal and domestic water supplies, including the cities of Patterson, Newman, Gustine, Los Banos, Firebaugh, and Mendota and the communities of Grayson, Westley, Crows Landing, Santa Nella, Volta, Dos Palos Y, and Tranquillity (Figure CC-12Figure CC-12). Other unincorporated areas of the Subbasin also rely on groundwater as the sole water supply source. There are several areas of de minimis groundwater extractors in the Subbasin, which are defined as well owners who extracts two acre-feet or less per year from a parcel for domestic purposes (SWRCB, n.d. (a)).

Figure CC-13Figure CC-13, Figure CC-14Figure CC-14, and Figure CC-15Figure CC-15 show the density per square mile (PLSS Section) of domestic, production, and public wells in the Delta-Mendota Subbasin as identified by DWR’s Well Completion Report Map Application. Domestic wells are defined as individual domestic wells which supply water for the domestic needs of an individual residence or systems of four or less service connections (DWR, 1981). Within the Delta-Mendota Subbasin, the majority of PLSS Sections contain five or fewer domestic wells (Figure CC-13Figure CC-13).

Production well statistics include wells that are designated as irrigation, municipal, public, and industrial on well completion reports, generally indicating wells designed to obtain water from productive zones 357
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containing good-quality water (DWR, 1991). The majority of PLSS Sections in the Subbasin contain only zero, one, or two production wells (Figure CC-14Figure CC-14). The highest concentration of production wells can be found in the south of the Subbasin, near Mendota. Public wells are defined as wells that provide water for human consumption to 15 or more connections or regularly serves 25 or more people daily for at least 60 days out of the year (SWRCB, n.d. (b)). Compared to domestic and production wells, public wells are less common in the Subbasin. The status of the wells (e.g. active, abandoned, destroyed) contained in the DWR Well Completion Report Map Application has not been independently confirmed. Additionally, the reader is referred to each of the six Subbasin GSPs for more information regarding wells in the Delta-Mendota Subbasin.
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Figure CC-12: Communities Dependent on Groundwater
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Figure CC-13: Domestic Well Density in the Delta-Mendota Subbasin 360
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Figure CC-14: Production Well Density in the Delta-Mendota Subbasin 361
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Figure CC-15: Public Well Density in the Delta-Mendota Subbasin 362
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Flood Management
In general, the Delta-Mendota Subbasin slopes toward the San Joaquin River with steeper slopes along the western boundary (near the Coast Range), tapering off closer to the San Joaquin River. The flood management system in the San Joaquin Valley includes reservoirs to regulate snowmelt from elevations greater than 5,000 feet, bypasses at lower elevations, and levees that line major rivers.

Severe rain events in 1997/98, 2005/2006, 2011 and 2017 flooded communities, agricultural lands and refuges adjacent to the San Joaquin River in the Delta-Mendota Subbasin (specifically the communities of Firebaugh, Newman, Gustine and Mendota) and produced some localized flooding of farmland and refuges caused by runoff impoundment by elevated canal banks. Based on the recent historical events, the primary threat of flooding to urban areas will be for those along (and immediately adjacent to) the San Joaquin River. Areas within the 100-year floodplain within the Subbasin are shown in Figure CC16Figure CC-16.

Major Land Use Divisions
The Delta-Mendota Subbasin consists mostly of agricultural land use types (Figure CC-17Figure CC17). Typical land uses are described in the following sections and consist predominantly of the following:
 Pasture/Rangeland
 Agricultural Land (including rice, field crops and grains)  Deciduous Forest
 Idle and Retired Farmland/Rangeland
 Riparian/Wetland
 Urban
The primary land use planning entities in the Delta-Mendota Subbasin include San Joaquin, Stanislaus, Merced, Fresno, and Madera Counties, as well as the cities of Patterson, Newman, Gustine, Los Banos, Dos Palos, Firebaugh, and Mendota, and Community of Santa Nella, as shown in Figure CC-18Figure CC-18.

Pasture/Rangeland
Grasslands in the Central Valley were originally dominated by native perennial grasses such as needlegrass and alkali sacaton. Currently, grassland vegetation is characterized by a predominance of annual or perennial grasses in an area with few or no trees and shrubs. Annual grasses found in grassland vegetation include wild oats, soft chess, ripgut grass, medusa head, wild barley, red brome, and slender fescue. Perennial grasses found in grassland vegetation are purple needlegrass, Idaho fescue, and California oatgrass. Forbs commonly encountered in grassland vegetation include long-beaked filaree, redstem filaree, dove weed, clovers, Mariposa lilies, popcornflower, and California poppy. Vernal pools found in small depressions with an underlying impermeable layer are isolated wetlands within grassland vegetation. Pastures can consist of both irrigated and unirrigated lands dominated by perennial grasses used predominantly for grazing.

Rangeland communities are composed of similar grasses, grass-like plants, forbs, or shrubs which are grazed by livestock. Rangelands are classified into three basic types: shrub and brush rangeland, mixed rangeland, and herbaceous rangeland. The shrub and brush rangeland is dominated by woody vegetation and is typically found in arid and semiarid regions. Mixed rangelands are ecosystems where more than one-third of the land supports a mixture of herbaceous species and shrub or brush rangeland species. 363
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Herbaceous rangelands are dominated by naturally occurring grasses and forbs as well as some areas that have been modified to include grasses and forbs as their principal cover. Rangelands are, by definition, areas where a variety of commercial livestock are actively maintained.

Agricultural Land
General agricultural types occurring in the Delta-Mendota Subbasin include row crops, grains, orchards, and vineyards. Management of agricultural lands often includes intensive management, including soil preparation activities, crop rotation, grazing, and the use of chemicals.

Row Crops
Most row crops grown in the San Joaquin Valley and harvested for food are annual species and are managed with a crop rotation system. During the year, several different crops may be produced on a given parcel of land either concurrently or in succession. Typical crops grown in the Delta-Mendota Subbasin include tomatoes, melons, grain crops (such as barley, wheat, corn, and oats), rice, cotton, and beans.

Orchards and Vineyards
Orchard and vineyards consist of cultivated fruit or nut-bearing trees or grapevines. Orchards are typically open, single-species, tree-dominated habitats and are planted in a uniform pattern and intensively managed. Understory vegetation is usually sparse. Vineyards are typically managed in a similar manner for producing grapes for wine and/or direct consumption.

Deciduous Forest
Deciduous forests are composed of trees that lose their leaves in the winter. These include species such as the various California oaks, California buckeye, Fremont Cottonwoods, Goodding Willows, and California Sycamores. The interior live oak, which is not deciduous, is also found in deciduous forests.

Valley oak woodlands are found in the Sacramento and San Joaquin Valleys and usually occur below elevations of 2,000 feet.

Idle or Retired Farmland/Rangeland
Lands of this category are similar to abandoned farmlands in ruderal (disturbed) areas. Plants on these parcels may consist of either native and/or non-native species.

Riparian/Wetland
Riparian and wetland communities are both natural and man-made. Managed wetlands are classified as riparian and are flooded for overwintering migratory bird habitat. In the spring the wetlands are drained to promote grasses such as swamp timothy and watergrass which are an important waterfowl food supply.

Although some grazing continues on managed wetlands, historically, many of these lands were irrigated and used as rangeland throughout the summer months. Today, managed wetlands are irrigated in the spring to maximize wetland productivity and provide nesting and sensitive species habitat. Managed wetlands also contain emergent vegetation such as cattail and tule and are often adjacent to riparian corridors.

Urban
Urban land uses include cities and smaller communities, in addition to other lands used for industrial and/or commercial practices.
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Figure CC-16: 100-Year Floodplain, Delta-Mendota Subbasin 366
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Figure CC-17: Typical Land Use
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Figure CC-18: Land Use Planning Entities
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Regional Economic Issues and Trends
The western San Joaquin Valley is a highly agricultural region. There are no large cities or industries in the Subbasin to provide an alternative economic base. The economy of this region is predominately driven by agricultural production and therefore, the availability of surface water supplies (predominantly in the form of CVP agricultural water and diversions from the San Joaquin and Kings Rivers) is an essential element to the economic health of the region. Other uses of surface water in the Subbasin are used for M&I purposes and wildlife refuge water supply.

Depending on water supply conditions, about 800,000 acres in the Delta-Mendota Subbasin are partially or solely irrigated with surface water. Other economic base industries include travel on the Interstate 5 (I5) corridor, some petroleum extraction, and tourism. State, federal, and private wildlife refuges benefit local economies by attracting hunters, anglers, outdoor recreationists to the region. Managed wetland water conveyance infrastructure is maintained and improved by many contractors and local agency staff.

Large scale conveyance improvements and habitat restoration projects, including mitigation banks, are also common throughout the Subbasin. M&I water use, which is a small share of total water use in the Subbasin, occurs primarily within the cities and smaller communities. The largest M&I use areas in the Delta-Mendota Subbasin, based on 2018 population estimates from the U.S. Census Bureau, are the cities of Patterson (population 22,352) and Los Banos (population 30,074) (U.S. Census Bureau, 2017).

All communities within the Delta-Mendota Subbasin have economies greatly dependent on agricultural production. These communities include Patterson, Tranquillity, Grayson, Mendota, Firebaugh, Dos Palos, Los Banos, Santa Nella, Newman, Gustine, Crows Landing, and Westley. All of these communities are strongly affected by the reliability of agricultural water supplies. Some of them are dependent upon groundwater for M&I use.

Plan Area Jurisdictional Boundaries
Jurisdictional areas within the Delta-Mendota Subbasin include counties, cities, water districts, irrigation districts, mutual water companies, and federal and state agencies. There are no federal- or staterecognized tribal communities in the Subbasin. Federal and State Lands are shown in Figure CC19Figure CC-19. More detail on specific jurisdictional areas within each GSP area can be found in the respective GSP.

In general, all municipal, water/irrigation districts and counties within the Delta-Mendota Subbasin are participating in GSP development either as a separate GSA or as members of a GSA. The California Department of Fish and Wildlife boundaries and the U.S. Fish and Wildlife Service boundaries overlay the wildlife refuges and areas and state parks within the Subbasin. DWR manages the SWP and the California Aqueduct, and the U.S. Bureau of Reclamation (USBR), through the SLDMWA, manages the CVP and the Delta-Mendota Canal. The California Department of Transportation (Caltrans) is responsible for managing the State and Interstate highways in the Subbasin, including Interstate- (I-) 5, and State Highways 132, 33, 140, 152, and 165.

Figure CC-9Figure CC-9 depicts the Subbasin’s extent relative to the boundaries of the various counties that overlie the Subbasin. Merced County has jurisdiction over the largest portion of the Subbasin (525 square miles), in the central portion of the Subbasin. Stanislaus County has jurisdiction over most of the area on the northern end of the Subbasin (covering 223 square miles). Fresno and Madera Counties have jurisdiction over the southern extent of the Delta-Mendota Subbasin (400 square miles). Finally, San Benito County covers the smallest portion of the Subbasin (5 square miles) in the southwestern portion of the Subbasin near San Luis Reservoir.
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Figure CC-19: Federal and State Lands
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Land Use Elements
Land use in the Delta-Mendota Subbasin is predominantly agricultural with wildlife habitat areas and areas of municipal, industrial, and commercial use. Predominant crops grown in the region include grain and hay crops, nut and fruit trees, and row crops. Figure CC-20Figure CC-20 shows the distribution of different land use types across the Delta-Mendota Subbasin.

Conjunctive use of surface water and groundwater is practiced throughout much of the Delta-Mendota Subbasin. Urban centers, such as the City of Patterson, and most unincorporated county areas rely solely on groundwater for their water supplies. Several water and irrigation districts hold water rights to divert from the San Joaquin River and/or the Kings Rivers. Other water purveyors receive water from the CVP and use groundwater and non-CVP-acquired surface waters to supplement demand, while some water districts rely solely on groundwater for their supplies. Refer to each GSP for detailed discussions of the water sources used by each agricultural, wetland, and urban water supplier.

Agriculture is the predominant water use sector throughout the Delta-Mendota Subbasin (Figure CC20Figure CC-20). Urban water uses are mostly concentrated within and surrounding cities (such as Patterson and Los Banos). Non-irrigated land includes any idle or native riparian land classifications, which are scattered throughout the Regions.

3.3 General Plans in Plan Area
Within each GSP, General Plans and/or Community Specific Plans overlie the area. These include County general plans for Fresno, Merced, San Benito, San Joaquin, Stanislaus, and Madera Counties, and specific plans for cities and communities. Each GSP contains a detailed list of General Plan policies and objectives relevant to water resources management in the applicable GSP area. Refer to discussions in the individual GSPs which satisfy §354.8(f) of the GSP Emergency Regulations under SGMA. 371
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Figure CC-20: 2014 Land Use in the Delta-Mendota Subbasin 372
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3.4 Existing Land Use Plans and Impacts to Sustainable Groundwater Management
Numerous policies in each County’s and Community’s General Plan compliment the GSPs’ plans to conserve and sustainably manage groundwater resources. In general, the County and City General Plans guide future growth and development (and associated demands) within their respective jurisdictional areas. This additional growth may impact groundwater sustainability by placing additional demands on groundwater resources in an area where surface water resources are scarce or are otherwise unavailable.

The General Plans also promote water conservation (in both the urban and agricultural sectors), which could potentially offset the additional demands associated with future urban development. In addition to conservation, some (though not all) General Plans promote groundwater recharge, the protection of recharge areas and wetlands, and the use of water transfers to further benefit groundwater sustainability.

Most General Plans within the Delta-Mendota Subbasin include goals focused on preserving agriculture, efficient use of existing and future water sources in both the urban and agricultural sectors, connecting smaller rural communities to larger water systems, and water quality protection. With respect to the protection of water quality and groundwater dependent ecosystems, the General Plans generally protect riparian and wetland habitats, encourage the protection of water quality (including through the remediation of contamination that may impact groundwater quality, requiring the use of septic systems in rural areas that are designed to be protective of groundwater quality and/or the use of community wastewater systems in urban areas), and promote flood control and management (including the associated impacts of erosion and sedimentation of surface water-courses).

The Fresno County General Plan, in particular, promotes sustainability by managing new wells in urban areas, supporting monitoring of water resources and associated habitats, and through the formation of a water resources document repository.

While the magnitude of impacts of these policies over the planning and implementation horizon are not known, such policies have been considered in this GSP, primarily through the use of the General Plans and associated zoning maps to identify future land use types and projected growth areas. These General Plans and mapping were used along with available water master plans, urban water management plans, agricultural water management plans, and other relevant planning documents to determine projected future land use and estimate future water demands by land use sector for use in the projected future water budgets.

Just as the General Plans complement the GSPs, the GSPs in the Delta-Mendota Subbasin may influence the General Plans’ goals and policies. Sustainable management of groundwater resources through a GSP may change the pace, location, and type of development and/or land use that will occur in the Subbasin.

GSP implementation is anticipated to be consistent with the General Plans’ goals to sustainably manage land development and water resources in the Subbasin.

3.5 Existing Water Resources Monitoring and Management Programs As required by §354.8(c)I and (d) of the GSP Emergency Regulations, the following section describes key existing water resources-related management and monitoring programs, and a discussion of how these programs will either impact GSP implementation and/or will be incorporated into the GSPs. The information shown below is a high-level summary of key existing programs; please see the individual GSPs for additional relevant management and monitoring programs. 373
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Irrigated Lands Regulatory Program (ILRP)
In 1999, the California Legislature passed Senate Bill 390, which eliminated a blanket waiver of water quality regulations for agricultural waste discharges. The Bill required the Regional Water Quality Control Boards to develop a program to regulate agricultural lands under the Porter-Cologne Water Quality Control Act. In 2003, the Central Valley Regional Water Quality Control Board (CV-RWQCB) issued an order that sets Waste Discharge Requirements (WDRs) for irrigated lands to protect both surface and groundwater throughout the Central Valley, primarily to address nitrates, pesticides, and sediment discharge. The resulting Irrigated Lands Regulatory Program (ILRP) regulates wastes from commercial irrigated lands that discharge into surface and groundwater. The program is administered by the CV-RWQCB working directly with a regional or crop-based coalition as well as directly with irrigators. The goal of the ILRP is to protect surface water and groundwater and to reduce impacts of irrigated agricultural discharges to waters of the State. As a result of the ILRP, monitoring reports, assessment reports, management plans, surface water quality data, and groundwater quality data are made available to the public.

Implementation of the IRLP in the Delta-Mendota Subbasin is managed primarily by the Westside San Joaquin River Watershed Coalition and the Grassland Drainage Area Coalition under the San Joaquin Valley Drainage Authority, a California Joint Powers Authority (JPA). This region specifically emphasizes nitrogen, sediment, and erosion control.

CV-SALTS
The Central Valley Salinity Alternatives for Long-Term Sustainability (CV-SALTS) is an initiative to reduce salt and nitrate impacts, restore groundwater quality, and provide safe drinking water supplies.

Developed by a group of stakeholders (federal, state, and local agencies, dischargers and growers, and environmental groups) called the Central Valley Salinity Coalition, the Central Valley Salt and Nitrate Management Plan (SNMP) was released in 2017.

The Central Valley SNMP recommends revised and flexible regulations for existing Basin Plans and includes recommended interim solutions for salt and nutrient management in high priority basins in addition to long-term salt management strategies. Under the Central Valley SNMP, dischargers are provided two compliance pathways: (1) traditional permitting as an individual discharger or as a coalition (i.e. irrigated lands coalition), or (2) groundwater management zone permitting. Zone permitting allows dischargers to work as a collective in collaboration with the CV-RWQCB to provide safe drinking water with the option to extend time to achieve nitrogen balance. At this time, the Central Valley SNMP is not currently enforced.

Integrated Regional Water Management Program
Three Integrated Regional Water Management Plans (IRWMPs) overlie the Delta-Mendota Subbasin.

The Westside-San Joaquin IRWMP covers most of the Subbasin, while smaller portions of the Subbasin are covered by the East Stanislaus and Madera IRWM Plans.

Integrated Regional Water Management (IRWM) is a collaborative effort to identify and implement water management solutions on a regional scale that increase regional self-reliance, reduce conflict, and manage water to concurrently achieve social, environmental, and economic objectives. Developed by Regional Water Management Groups, the IRWMPs seek to deliver higher value for investments in water resources and management by considering all interests, providing multiple benefits, and working across jurisdictional boundaries. Examples of multiple benefits include improved water quality, better flood 374
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management, restored and enhanced ecosystems, and more reliable surface and groundwater supplies.

Please see the individual GSPs for additional details regarding the IRWM program in their GSP Plan areas.

California State Groundwater Elevation Monitoring Program (CASGEM) Since 2009, the California Statewide Groundwater Elevation Monitoring (CASGEM) Program has tracked seasonal and long-term groundwater elevation trends in groundwater basins statewide. The program’s mission is to establish a permanent, locally-managed program of regular and systematic monitoring in all of California'sCalifornia’s alluvial groundwater basins. This early attempt to monitor groundwater continues to exist as a tool to help achieve the goals set out under the Sustainable Groundwater Management Act (SGMA) with mandatory annual water elevation monitoring and reporting.

San Joaquin River Restoration Program (SJRR)
The San Joaquin River Restoration Program (SJRRP) is a comprehensive, long-term effort to restore flows to the San Joaquin River from Friant Dam to the confluence of Merced River and restore a selfsustaining Chinook salmon fishery in the river while reducing or avoiding adverse water supply impacts from Restoration Flows. The program has two general goals resulting from the San Joaquin River Restoration Settlement reached in 2006:
 Restoration: To restore and maintain fish populations in “good condition” in the main stem of the San Joaquin River below Friant Dam to the confluence of the Merced River, including naturally reproducing and self-sustaining populations of salmon and other fish.  Water Management: To reduce or avoid adverse water supply impacts to all of the Friant Division long-term contractors that may result from the Interim Flows and Restoration Flows provided for in the Settlement.

The program includes the implementation of projects, reintroduction activities and associated monitoring to assess progress towards achieving the Settlement goals.

USGS Land Subsidence Monitoring
The USGS maintains and monitors a large system of monitoring locations nationwide using interferometric synthetic aperture radar (InSAR), continuous GPS (CGPS) measurements, campaign global positioning system (GPS) surveying, and spirit-leveling surveying. Aquifer-system compaction is measured by using extensometers to aid in the understanding of the depths at which compaction is occurring. The USGS shares these results to support decision making relative to groundwater basin management with the goal of minimizing future inelastic land subsidence.

3.6 County Well Construction/Destruction Standards and Permitting DWR has developed well standards for the state per California Water Code Sections 13700 to 13806.

These standards have been adopted by the State Water Resources Control Board (SWRCB) into a statewide model well ordinance (Resolution No. 89-98) for use by the Regional Boards for enforcing well construction standards where no local well design ordinance exists that meets or exceeds the DWR standards. DWR’s Well Standards are presented in Bulletin 74-81 and Bulletin 74-90. 375
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Each GSP lists the counties within their GSP Plan areas and the respective permitting agencies and local ordinances for well construction and destruction standards. Discussion of these standards and the respective permitting process as well as well abandonment and destruction procedures can be found in the individual GSPs.

3.7 Existing and Planned Conjunctive Use Programs
Conjunctive use programs in the Subbasin are currently implemented and planned by single agencies as well as through multi-agency partnerships. Maximizing the beneficial use of surface water, groundwater, and recycled water resources is of critical concern to water managers throughout the Delta-Mendota Subbasin with the ultimate goal of using all of these water sources more efficiently to avoid overdraft and to sustainably manage groundwater resources. Each GSP describes efforts to utilize existing water resources conjunctively and demonstrate feasibility to continue to implement conjunctive use projects in the future. These may include projects such as groundwater recharge and conveyance facilities, new wells, improved monitoring systems, improved delivery efficiency, water recycling, and water quality improvements and treatment.

Underground recharge and storage occurs throughout the Delta-Mendota Subbasin through stormwater applied water and managed wetland recharge. Stormwater collects both naturally and artificially and eventually percolates through the ground and into aquifers for beneficial use for both urban and agriculture. Recharge from agricultural and wetland water conveyance and irrigation percolates into the ground and eventually into aquifers where it can be pumped again for use. This natural and unmanaged recharge creates future opportunities for conjunctive use programs; however, this recharge may decline as farmers move toward more precise and water efficient irrigation methods.

3.8 Plan Elements from California Water Code Section 10727.4 Each GSP may contain, as deemed appropriate, a detailed discussion of the additional plan elements as identified in California Water Code (CWC) Section 10727.4. These elements are:
 Control of saline water intrusion
 Wellhead protection areas and recharge areas
 Migration of contaminated groundwater
 Well abandonment and well destruction programs
 Activities implementing, opportunities for, and removing impediments to conjunctive use or underground storage
 Measures addressing groundwater contamination cleanup, groundwater recharge, in-lieu use, diversions to storage, conservation, water recycling, conveyance, and extraction projects  Efficient Water Management Practices, as defined in Section 10902, for the delivery of water and water conservation methods to improve the efficiency of water use  Efforts to develop relationships with state and federal regulatory agencies  Processes to review land use plans and efforts to coordinate with land use planning agencies to assess activities that potentially create risk to groundwater quality or quantity  Impacts on Groundwater Dependent Ecosystems
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4. SUBBASIN SETTING
This Delta-Mendota Subbasin Settings section contains three main subsections as follows:
 Hydrogeologic Conceptual Model (HCM) – The HCM section (Section 4.1) provides the geologic information needed to understand the framework that water moves through in the Subbasin. It focuses on geologic formations, aquifers, structural features, and topography.  Groundwater Conditions – The Groundwater Conditions section (Section 4.2) describes and presents groundwater trends, levels, hydrographs and level contour maps, estimates changes in groundwater storage, identifies groundwater quality issues, addresses subsidence, and addresses surface water interconnection.
 Water Budget – The Water Budget section (Section 4.3) describes the data used to develop the water budget. Additionally, this section discusses how the budget was calculated, provides water budget estimates for historical conditions, and current conditions and projected conditions

4.1 Hydrogeologic Conceptual Model
This section describes the hydrogeologic conceptual model (HCM) for the Delta-Mendota Subbasin based on technical studies and qualified maps that characterize the physical components and interaction of the surface water and groundwater systems, pursuant to Article 5, Plan Contents, Subarticle 2, Basin Setting, § 354.14 Hydrogeologic Conceptual Model of the GSP Emergency Regulations. The physical description of the Delta-Mendota Subbasin is based on information originally published in the Western San Joaquin River Watershed Groundwater Quality Assessment Report (GAR) (LSCE, 2015), Grassland Drainage Area Groundwater Quality Assessment Report (LSCE, 2016), and Groundwater Overdraft in the DeltaMendota Subbasin (KDSA, 2015).

4.1.1 Regional Geologic and Structural Setting
The Delta-Mendota Subbasin is located in the northwestern portion of the San Joaquin Valley Groundwater Basin within the southern portion of the Central Valley (Figure CC-21Figure CC-21). The San Joaquin Valley is a structural trough up to 200 miles long and 70 miles wide filled with up to 32,000 feet of marine and continental sediments deposited during periodic inundation by the Pacific Ocean and by erosion of the surrounding Sierra Nevada and Coast Range mountains, respectively (DWR, 2006).

Continental deposits shed from the surrounding mountains form an alluvial wedge that thickens from the valley margins toward the axis of the structural trough. This depositional axis is slightly west of the series of rivers, lakes, sloughs, and marshes which mark the current and historic axis of surface drainage in the San Joaquin Valley.

The Delta-Mendota Subbasin (DWR Basin No. 5-22.07) is bounded on the west by the tertiary and older marine sediments of the Coast Ranges, on the north generally by the San Joaquin-Stanislaus County line, on the east generally by the San Joaquin River and Fresno Slough, and on the south by the Tranquillity Irrigation District boundary near the community of San Joaquin. Surface waters converge from the Fresno, Merced, Tuolumne, and Stanislaus Rivers into the San Joaquin River, which drains to the north toward the Sacramento-San Joaquin Delta.
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Figure CC-21: Regional Geologic Setting
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4.1.2 Geologic History
Approximately three million years ago, tectonic movement of the Oceanic and Continental plates associated with the San Andreas Fault system resulted in the formation of the Coast Range which sealed off the Central Valley from the Pacific Ocean (LSCE, 2015). As this occurred, the floor of the San Joaquin Valley began to transition from a marine depositional environment to a freshwater system with ancestral rivers bringing alluvium to saltwater bodies (Mendenhall et al., 1916). The Coast Ranges on the western side of the San Joaquin Valley consist mostly of complexly folded and faulted consolidated marine and non-marine sedimentary and crystalline rocks ranging from Jurassic to Tertiary age, dipping eastward and overlying the basement complex in the region (Croft, 1972; Hotchkiss and Balding, 1971).

The Central Valley Floor, in which the Delta-Mendota Subbasin lies, consists of Tertiary and Quaternaryaged alluvial and basin fill deposits (Figure CC-22Figure CC-22). The fill deposits mapped throughout much of the valley extend vertically for thousands of feet, and the texture of sediments varies in the eastwest direction across the valley. Coalescing alluvial fans have formed along the sides of the valley created by the continuous shifting of distributary stream channels over time. This process has led to the development of thick fans of generally coarse texture along the margins of the valley and a generally fining texture towards the axis of the valley (Faunt et al., 2009 and 2010).

Deposits of Coast Range and Sierra Nevada sources interfinger within the Delta-Mendota Subbasin.

Steeper fan surfaces, with slopes as high as 80 feet per mile, exist proximal to the Coast Range, whereas more distal fan surfaces consist of more gentle slopes of 20 feet per mile (Hotchkiss and Balding, 1971).

In contrast to the east side of the valley, the more irregular and ephemeral streams on the western side of the valley floor have less energy and transport smaller volumes of sediment resulting in less developed alluvial features, including alluvial fans which are less extensive, although steeper, than alluvial fan features on the east side of the valley (Bertoldi et al., 1991). Lacustrine and floodplain deposits also exist closer to the valley axis as thick silt and clay layers. Lakes present during the Pleistocene epoch in parts of the San Joaquin Valley deposited great thicknesses of clay sediments. 379
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Figure CC-22: Generalized Geology
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4.1.3 Geologic Formations and Stratigraphy
Distinct geomorphic units exist within the Delta-Mendota Subbasin defining areas of unique hydrogeologic environments. The geomorphic units are mapped and described by Hotchkiss and Balding (1971) and Davis et al. (1959) and are shown in Figure CC-22Figure CC-22. The two primary geomorphic units within the Central Valley Floor area of the Delta-Mendota Subbasin include the overflow lands geomorphic unit and the alluvial fans and plains geomorphic unit. Overflow lands are defined as areas of relatively poorly draining soils with a shallow water table. The overflow lands geomorphic unit is located in the southeastern portion of the Subbasin and is dominated by finer-grained floodplain deposits that are the result of historical episodic flooding of this low-land area. This has formed poorly-draining soils with generally low hydraulic conductivity characteristics. In contrast, the alluvial fans and plains geomorphic unit is characterized by relatively better drainage conditions, with sediments comprised of coalescing and somewhat coarser-grained alluvial fan materials deposited by higher-energy streams flowing out of the Coast Range (Hotchkiss and Balding, 1971). The alluvial fans and plains geomorphic unit covers much of the Delta-Mendota Subbasin along the western margins of the Central Valley Floor at the base of the Coast Range.

The primary groundwater bearing units within the Delta-Mendota Subbasin consist of Tertiary and Quaternary-aged unconsolidated continental deposits and older alluvium of the Tulare Formation.

Subsurface hydrogeologic materials covering the Central Valley Floor consist of lenticular and generally poorly sorted clay, silt, sand, and gravel that make up the alluvium and Tulare Formation. These deposits are thickest along the axis of the valley with thinning along the margins towards the Coast Range mountains (DWR, 2003; Hotchkiss and Balding, 1971). A zone of very shallow groundwater, generally within 25 feet of the ground surface, exists throughout large areas of the Subbasin, with considerable amounts (greater than 50 percent) of farmland in the area estimated to have very shallow depths to groundwater of less than 10 feet (Hotchkiss and Balding, 1971). Many of these areas are naturally swampy lands adjacent to the San Joaquin River.

The Tulare Formation extends to several thousand feet in depth and to the base of freshwater throughout most of the area and consists of interfingered sediments ranging in texture from clay to gravel of both Sierra Nevadan and Coast Range origin. The formation is composed of beds, lenses, and tongues of clay, sand, and gravel that have been alternatively deposited in oxidizing and reducing environments (Hotchkiss and Balding, 1971).

Terrace deposits of Pleistocene age lie up to several feet higher than present streambeds and are comprised of yellow, tan, and light-to-dark brown silt, sand, and gravel with a matrix that varies from sand to clay (Hotchkiss and Balding, 1971). The water table generally lies below the bottom of the terrace deposits; however, the relatively large grain size of the terrace deposits suggests their value as possible recharge sites. Alluvium is composed of interbedded, poorly to well-sorted clay, silt, sand, and gravel and is divided based on its degree of dissection and soil formation. The flood-basin deposits are generally composed of light-to-dark brown and gray clay, silt, sand, and organic material with locally high concentrations of salt and alkali. Stream channel deposits of coarse sand and gravel are also included.

The Tulare Formation also includes the Corcoran Clay (E-Clay) member, a diatomaceous clay or silty clay of lake bed origin which is a prominent aquitard in the San Joaquin Valley, separating the upper zone from the lower zone and distinguishing the semi-confined Upper Aquifer from the confined Lower Aquifer (Hotchkiss and Balding, 1971). The depth and thickness of the Corcoran Clay are variable within the Central Valley Floor, and it is not present in peripheral areas (outside the Central Valley Floor) of the Subbasin. Within the Upper Aquifer, additional clay layers exist and also provide varying degrees of confinement, including other clay members of the Tulare Formation and layers of white clay identified by 381
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Hotchkiss and Balding (1971). These clays are variable in extent and thickness, but the white clay is noted to be as much as 60 feet thick in areas providing very effective confinement of underlying zones (Croft, 1972; Hotchkiss and Balding, 1971). The Tulare Formation is hydrologically the most important geologic formation in the Delta-Mendota Subbasin because it contains most of the fresh water-bearing deposits. Most of the natural recharge that occurs in the Subbasin is in the alluvial fan apex areas along Coast Range stream channels (Hotchkiss and Balding, 1971).

4.1.4 Faults and Structural Features
The valley floor portion of the Delta-Mendota Subbasin contains no known major faults and is fairly geologically inactive. There are few faults along the western boundary of the Subbasin within the Coast Range mountains, but they are not known to inhibit groundwater flow or impact water conveyance infrastructure (Figure CC-23Figure CC-23).

4.1.5 Basin Boundaries
The Delta-Mendota Subbasin is defined by both geological and jurisdictional boundaries. The DeltaMendota Subbasin borders all subbasins within the San Joaquin Valley Hydrologic Region with the exception of the Cosumnes Subbasin. The following subsections describe the lateral boundaries of the Subbasin, boundaries with neighboring subbasins, and the definable bottom of the Delta-Mendota Subbasin.

Lateral Boundaries
The Delta-Mendota Subbasin is geologically and topographically bounded to the west by the Tertiary and older marine sediments of the Coast Ranges, and to the east generally by the San Joaquin River. The northern, central, and southern portion of the eastern boundary are dictated by jurisdictional boundaries of water purveyors within the Delta-Mendota Subbasin.

As described in California’s Groundwater, DWR Bulletin 118 (2016), the Delta-Mendota Subbasin is in the San Joaquin Valley Groundwater Basin, located along the western edge of the San Joaquin Valley.

The northern boundary begins just south of Tracy in San Joaquin County. The eastern boundary generally follows the San Joaquin River and Fresno Slough. The southern boundary is near the small town of San Joaquin. The subbasin is bounded on the west by the coast range. The Subbasin boundary is defined by 20 segments detailed in the descriptions below. The Delta-Mendota Subbasin extends into six (6) counties:

San Joaquin, Stanislaus, Merced, Fresno, San Benito, and Madera and is shown in relation to each of the six counties in Figure CC-9Figure CC-9.
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Figure CC-23: Subbasin Faults
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4.1.6 Definable Bottom of Basin
In the San Joaquin Valley, the bottom of the Delta-Mendota Subbasin is defined as the interface of saline water of marine origin (base of fresh water) within the uppermost beds of the Tulare Formation. The Tulare Formation is characterized by blue and green fine-grained rocks and principally composed of finegrained silty sands, silt, and clay (Foss and Blaisdell 1968). The Tulare Formation is predominantly marine in origin and is considered late Pliocene and possibly early Pleistocene in age. This formation is the upper shaley part of the Pliocene sequence. The top of the Tulare Formation is generally encountered around -2,000 feet mean sea level throughout the Delta-Mendota Subbasin. As agreed upon by the DeltaMendota Subbasin GSP Groups, the base of freshwater is specifically defined by an electrical conductivity of 3,000 micromhos per centimeter at 25 °C, as presented by Page (1973). If and when significant use of water beyond the defined bottom takes place, the definition of the bottom will be revised appropriately.

4.1.7 Principal Aquifers and Aquitards
DWR’s Groundwater Glossary defines an aquifer as “a body of rock or sediment that is sufficiently porous and permeable to store, transmit, and yield significant or economic quantities of groundwater to wells, and springs”. There are two primary aquifers within the Delta-Mendota Subbasin: a semi-confined aquifer above the Corcoran Clay and a confined aquifer below the Corcoran Clay, with the Corcoran Clay acting as the principal aquitard within the Delta-Mendota Subbasin. Figure CC-24Figure CC-24 shows the locations of the representative cross-sections for the Delta-Mendota Subbasin, where Figure CC25Figure CC-25 through Figure CC-30Figure CC-30 show the hydrostratigraphy of the representative cross-sections.

While the two-aquifer system described above is generally true across the Delta-Mendota Subbasin, there are portions of the Subbasin where the Corcoran Clay does not exist (predominantly along the western margin of the Subbasin) and hydrogeology is generally controlled by localized interfingering clays, and/or where local hydrostratigraphy results in shallow groundwater conditions that differ, to some extent, from that seen in the Subbasin as a whole. Additionally, in the southern portion of the Subbasin in the Mendota, Aliso and Tranquillity areas, there are A and C Clay layers in addition to the Corcoran Clay that inhibit vertical groundwater flow. However, while there are localized complexities throughout the Subbasin, the Corcoran Clay (or E Clay) extends through much of the Delta-Mendota Subbasin, generally creating a two-aquifer system.

Principal Aquifers
In the Delta-Mendota Subbasin, there are two primary aquifers composed of alluvial deposits separated by the Corcoran Clay (KDSA, 2015): a semi-confined Upper Aquifer (generally the ground surface to the top of the Corcoran Clay), and a confined Lower Aquifer starting at the bottom of the Corcoran Clay to the base of fresh water. However, as previously described, the localized presence of the A and C Clay layers in the southern portion of the Subbasin, the absence of the Corcoran Clay at the western margin of the Subbasin, and/or local hydrostratigraphy result in differing shallow groundwater conditions and/or perched groundwater conditions in some portions of the Subbasin. See the individual GSPs for more detailed descriptions of hydrostratigraphy in the respective Plan areas. 384
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Upper Aquifer
The Upper Aquifer is represented by materials extending from the upper groundwater table to the top of the Corcoran Clay. The Upper Aquifer includes shallow geologic units of younger and older alluvium and upper parts of the Tulare Formation. Sediments within the upper Tulare Formation have variable sources, and subdivision of units can be distinguished between eastern and western sourced materials. Alluvial fan materials above the Corcoran Clay in the Delta-Mendota Subbasin are generally more extensive than older alluvial fan deposits within the Tulare Formation below the Corcoran Clay. As shown in Figure CC31Figure CC-31 by the depth to the top of the Corcoran Clay, the Upper Aquifer extends to depths ranging between approximately 150 feet and greater than 350 feet. Other notable mapped clay units also exist within the upper part of the Tulare Formation in the Delta-Mendota Subbasin, including the A and C Clay members of the Tulare Formation and a white clay mapped by Hotchkiss and Balding (1971).

Lower Aquifer
The Lower Aquifer is the portion of the Tulare Formation that is confined beneath the Corcoran Clay, extending downward to the underlying San Joaquin Formation and the interface of saline water of marine origin within its uppermost beds. The Lower Aquifer is generally characterized by groundwater that tends to be dominantly sodium-sulfate type, which is often of better quality than the Upper Aquifer (Davis et al., 1957; Hotchkiss and Balding, 1971). Exceptions to this quality do exist in the Subbasin, particularly in the southwestern portion of the Subbasin. Because of its relatively shallow depth within the DeltaMendota Subbasin and lower salinity in areas when compared to other groundwater resources, the Lower Aquifer is heavily utilized as a source of groundwater for agricultural and drinking water uses within the Subbasin.

The base of the Lower Aquifer generally decreases from south to north, changing in depth from about 1,100 to 1,200 feet deep in the south to about 600 feet to the north. Depth to the top of the Corcoran Clay ranges from less than 100 feet on the west near Interstate 5 (I-5) to more than 500 feet in the area near Tranquillity. The Corcoran Clay pinches out or is above the water level near the California Aqueduct in the western part of the Subbasin, where the Upper and Lower Aquifers merge into interfingered layers of sand, gravel, and clay.

Corcoran Clay
The Corcoran Clay, as a regional aquitard, is a notable hydrogeologic feature throughout most of the Delta-Mendota Subbasin, impeding vertical flow between the Upper and Lower Aquifers. The Corcoran Clay is present at varying depths across most of the Central Valley floor (Figure CC-31Figure CC-31 and Figure CC-33Figure CC-33). The depths to the top of the Corcoran Clay ranges between approximately 100 and 500 feet below the ground surface throughout most of the Subbasin, with a general spatial pattern of deepening to the south and east. In the far southeastern area of the Subbasin, in the vicinity of Mendota and Tranquillity, the top of the Corcoran Clay is at depths of greater than 350 feet (Figure CC-31Figure CC-31). The thickness of the Corcoran Clay, which likely influences the degree of hydraulic separation between the Upper and Lower Aquifers, is greater than 50 feet across most of the Delta-Mendota Subbasin with thicknesses of more than 75 feet in central Subbasin areas in the vicinity of Los Banos and Dos Palos, and 140 feet in the eastern portions of the Subbasin. The Corcoran Clay appears thinner in areas north of Patterson, between Patterson and Gustine, and also in the vicinity of Tranquillity to the south (Figure CC-33Figure CC-33). Along the westernmost portions of the DeltaMendota Subbasin, the Corcoran Clay layer is generally non-existent or it exists as Corcoran-equivalent clays (clays existing at the same approximate depth but not part of the mapped aquitard). 385
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Aquifer Properties
The following subsections include discussion of generalized aquifer properties within the Delta-Mendota Subbasin. These include hydraulic conductivity, transmissivity, specific yield and specific storage.

DWR defines hydraulic conductivity as the “measure of a rock or sediment’s ability to transmit water” and transmissivity as the “aquifer’s ability to transmit groundwater through its entire saturated thickness” (DWR, 2003). High hydraulic conductivity values correlate with areas of transmissive groundwater conditions with transmissivity generally equaling hydraulic conductivity times the saturated thickness of the formation. Storage of water within the aquifer system can be quantified in terms of the specific yield for unconfined groundwater flow and the storage coefficient for confined flow, respectively (Faunt et al., 2009). Specific yield represents gravity-driven dewatering of shallow, unconfined sediments at a declining water table, but also accommodates a rising water table. The specific yield is dimensionless and represents the volume of water released from or taken into storage per unit head change per unit area of the water table. Specific yield is a function of porosity and specific retention of the sediments in the zone of water-table fluctuation.

Where the aquifer system is confined, storage change is governed by the storage coefficient, which is the product of the thickness of the confined-flow system and its specific storage. The specific storage is the sum of two component specific storages – the fluid (water) specific storage and the matrix (skeletal) specific storage, which are governed by the compressibility of the water and skeleton, respectively (Jacob, 1940). Specific storage has units of 1 over length and represents the volume of water released from or taken into storage in a confined flow system per unit change in head per unit volume of the confined flow system (Faunt et al., 2009). Therefore, the storage coefficient of a confined flow system is dimensionless and, similar to specific yield, represents the volume of water released from or taken into storage per unit head change.

Hydraulic Conductivity
Figure CC-34Figure CC-34 shows the saturated C-horizon hydraulic conductivity of surficial soils within the Delta-Mendota Subbasin based on the National Resource Conservation Service (NRCS) Soil Survey Geographic Database (SSURGO). Soil survey data for counties within the Subbasin were combined using the weighted harmonic mean of these representative layers to depict the saturated hydraulic conductivity of the C-horizon for each soil map unit. The soil profile represented by these data is variable but commonly extends to a depth of six or more feet.

Floodplain deposits are evident as soils with relatively low hydraulic conductivity (less than 0.5 feet per day [ft/day]) blanket much of the Central Valley Floor, although localized areas of soils with higher hydraulic conductivity are present in association with modern and ancient surface waterways and alluvial fan features (Figure CC-34Figure CC-34). Coarse soils of distributary alluvial fan sediments deposited by Del Puerto Creek, Orestimba Creek, Los Banos Creek, Ortigalita Creek, and Little Panoche Creek, in addition to other ephemeral northeasterly creek flows off the Coast Ranges, are notably apparent as areas of soils of high hydraulic conductivity located along active and inactive stream channels extending eastward from the fan apex areas along the Valley Floor margins to the current alignment of the San Joaquin River in the valley axis. Additionally, soils in areas adjacent to the active channel of the San Joaquin River also exhibit high hydraulic conductivities, including values of greater than 4 ft/day which are particularly apparent in an area north of Mendota. Soils of similarly high hydraulic conductivity trending as linear features in a general northwest-southeast alignment to the north of Dos Palos and Los Banos are likely the result of historical depositional processes and paleochannels associated with the San Joaquin River (Figure CC-34Figure CC-34). In areas peripheral to the Central Valley floor, soils tend to 386
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be characterized by relatively low hydraulic conductivity, although soils of somewhat higher hydraulic conductivity associated with distinct geologic units are mapped across much of the peripheral area to the west of Patterson and Gustine and also in localized bands associated with surface water courses.

Transmissivity
Transmissivity varies greatly above the Corcoran Clay, within the Corcoran Clay, and below the Corcoran Clay within the Delta-Mendota Subbasin, with transmissivities in the confined Lower Aquifer generally being larger than those in the semi-confined Upper Aquifer. Based on testing conducted at multiple locations within both the Upper and Lower Aquifers of the Delta-Mendota Subbasin, average transmissivities in the Subbasin are approximately 109,000 gallons per day per square foot (gpd/ft2 )
(KDSA, 1997b).

Specific Yield
DWR defines specific yield as the “amount of water that would drain freely from rocks or sediments due to gravity and describes the proportion of groundwater that could actually be available for extraction” (DWR, 2003). Specific yield is a measurement specific to unconfined aquifers.

The estimated specific yield of the Delta-Mendota Subbasin is 0.118 (DWR, 2006). Within the southern portion of the Delta-Mendota Subbasin, specific yield ranges from 0.2 to 0.3 (Belitz et al., 1993). Specific yield estimates for the Delta-Mendota Subbasin are fairly limited in literature since the Upper Aquifer above the Corcoran Clay is semi-confined and the Lower Aquifer below the Corcoran Clay is confined.

Therefore, specific yield values only characterize the shallow, unconfined groundwater within the Subbasin.

Specific Storage
Values for specific storage were extracted from the Central Valley Hydrologic Model 2 (CVHM2), which is currently under development by the United States Geological Survey (USGS) and includes refinements for the Delta-Mendota Subbasin. Specific storage varies above, within, and below the Corcoran Clay with CVMH2. Above the Corcoran Clay, specific storage ranges from 1.34 x 10-6 to 6.46 x 10-2 meters-1 (m-1) with average values ranging from 6.16 x 10-3 to 1.97 x 10-2 m-1. Specific storage within the Corcoran Clay is considerably smaller than above the Corcoran Clay, ranging between 1.41 x 10-6 and 2.35 x 10-6 m-1 and average values between 1.96 x 10-6 and 2.02 x 10-6 m-1. Below the Corcoran Clay, specific storage is comparable to within the Corcoran Clay with overall ranges the same as within the Corcoran Clay and average values ranging from 1.86 x 10-6 to 2.01 x 10-6 m-1. Therefore, specific storage is greatest within the semi-confined aquifer overlying the Corcoran Clay layer, with considerably smaller specific storage values within the low permeability Corcoran Clay and confined aquifer underlying the Corcoran Clay layer.
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Figure CC-24: Representative Cross-Sections
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Figure CC-25: Cross-Section A-A’ (Hotchkiss, 1972)
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Figure CC-26: Cross-Section B-B’ (Hotchkiss, 1972)
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Figure CC-27: Cross-Section C-C’ (Hotchkiss, 1972)
Figure CC-28: Cross-Section D-D’ (Hotchkiss & Balding, 1971) 391
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Figure CC-29: Cross-Section E-E’ (Hotchkiss & Balding, 1971) 392
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Figure CC-30: Cross-Section F-F’ (Hotchkiss, 1972)
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Figure CC-31: Depth to Corcoran Clay
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Figure CC-32: Non-Corcoran Clay Layers
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Figure CC-33: Thickness of Corcoran Clay
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Figure CC-34: Soil Hydraulic Conductivity
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4.1.8 Structural Properties and Restricted Groundwater Flow Under natural (pre-development) conditions, the prevailing groundwater flow within the Upper and Lower Aquifer systems of the western San Joaquin Valley was predominantly in a generally northeasterly direction from the Coast Range towards and parallel to the San Joaquin River and the Sacramento-San Joaquin Delta (LSCE, 2015; Hotchkiss and Balding, 1971; KDSA, 2015). Historically, numerous flowing artesian wells within the Lower Aquifer existed throughout the Delta-Mendota Subbasin (Mendenhall et al., 1916) and the pressure gradient for groundwater flow was upward from the Lower Aquifer to the Upper Aquifer. These flowing artesian conditions have disappeared in many areas as a result of increased development of groundwater resources within the Tulare Formation (Hotchkiss and Balding, 1971).

Additionally, the Delta-Mendota Subbasin has experienced periods of considerable decline in groundwater levels during which hydraulic heads in the Lower Aquifer decreased considerably in some areas due to heavy pumping (Bertoldi et al., 1991).

Despite the presence of local pumping depressions within parts of the Subbasin, the prevailing northeastward flow direction for groundwater in the Upper Aquifer within the region has remained (AECOM, 2011; DWR, 2010; Hotchkiss and Balding, 1971). Groundwater generally flows outward from the Delta-Mendota Subbasin, except along the southern and western margins where there is some recharge from local streams and canal seepage (KDSA, 2015), in addition to northward subbasin boundary flows. Within the Upper Aquifer, there are similar groundwater flow directions in most of the Subbasin with groundwater outflow to the northeast or towards the San Joaquin River in much of the Subbasin during wet and normal periods. One exception is in the Orestimba Creek area west of Newman where groundwater flows to the west during drought conditions and east during wet periods. Calculations based on aquifer transmissivity indicate the net groundwater outflow in the Upper Aquifer has been about three times greater during drought periods than during normal periods (KDSA, 1997a and 1997b).

Within the Lower Aquifer, there is a groundwater divide generally in the area between Mendota and the point near the San Joaquin River in the Turner Island area, northeast of Los Banos. Groundwater southwest of this divide generally flows southwest toward Panoche Water District and Westlands Water District. Groundwater northeast of this divide flows to the northeast into Madera and Merced Counties.

Net groundwater outflow in the Lower Aquifer under drought conditions has been about two and a half times greater than for normal conditions (KDSA, 1997a and 1997b). Based on current and historical groundwater elevation maps, groundwater barriers do not appear to exist in the Delta-Mendota Subbasin (DWR, 2006).

The combined effect of pumping below the Corcoran Clay and increased leakage from the Upper Aquifer to the Lower Aquifer where the Corcoran Clay does not exist or has been perforated has developed a generally downward flow gradient in the Tulare Formation which changes with variable pumping and irrigation over time (Bertoldi et al., 1991). Periods of great groundwater level declines have also resulted in inelastic compaction of fine-grained materials in some locations, particularly between Los Banos and Mendota, potentially resulting in considerable decreases (between 1.5 and 6 times) in permeability of clay members within the Tulare Formation, including the Corcoran Clay (Bertoldi et al., 1991). However, the number of wells penetrating the Corcoran Clay may be enabling vertical hydraulic communication across the Corcoran Clay aquitard and other clay layers (Davis et al., 1959; Davis et al., 1964).

4.1.9 Water Quality
Groundwater in the Delta-Mendota Subbasin is characterized by mixed sulfate to bicarbonate water types in the northern and central portion of the Subbasin, with areas of sodium chloride and sodium sulfate waters in the central and southern portions (DWR, 2003). Total Dissolved Solids (TDS) values range 398
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from 400 to 1,600 mg/L in the northern portion, and 730 to 6,000 mg/L in the southern portion of the Delta-Mendota Subbasin (Hotchkiss and Balding, 1971). The Department of Health Services (currently the Division of Drinking Water), which monitors Title 22 water quality standards, reports TDS values in 44 public supply wells in the Subbasin ranging in value from 210 to 1,750 mg/L, with an average value of 770 mg/L. Shallow, saline groundwater also occurs within about 10 feet of the ground surface over a large portion of the Delta-Mendota Subbasin. There are also localized areas of high iron, fluoride, nitrate, selenium, and boron in the Delta-Mendota Subbasin (Hotchkiss and Balding, 1971).

Alluvial sediments derived from west-side streams are composed of material from serpentine, shale, and sandstone parent rock, which results in soil and groundwater types entirely different from those on the east side of the San Joaquin Valley (LSCE, 2015). In contrast with the siliceous mineralogy of the alluvial sands and gravels on the eastern side of the Central Valley that are derived from the Sierra granitic rocks (which are coarser and more resistant to chemical dissolution), the sulfate and carbonate shales and sandstones of Coast Range sediments on the western side are more susceptible to dissolution processes.

Some soils and sediments within the western San Joaquin Valley that are derived from marine rocks of the Coast Range have notably high concentrations of naturally-occurring nitrogen, with particularly higher nitrate concentrations in younger alluvial sediments (Strathouse and Sposito, 1980; Sullivan et al., 1979). These naturally-occurring nitrogen sources may contribute to nitrate concentrations in groundwater within the Delta-Mendota Subbasin, although it is not well known where this may occur and to what degree. Naturally-high concentrations of TDS in groundwater are known to have existed historically within parts of the Subbasin due to the geochemistry of the Coast Range rocks and the marine depositional environment, the resulting naturally-high TDS of recharge derived from Coast Range streams, the dissolvable materials within the alluvial fan complexes, and the naturally-poor draining conditions which tend to concentrate salts in the system. The chemical quality of waters in the Coast Range streams can be closely correlated with the geologic units within their respective catchments.

Groundwater flows discharging from these marine and non-marine rocks into streams introduce a variety of dissolved constituents resulting in variable groundwater types. The water quality and chemical makeup in westside streams can be highly saline, especially in more northern streams, including Corral Hollow, Panoche and Del Puerto Creeks, where historical baseflow TDS concentrations have typically exceeded 1,000 mg/L with measured concentrations as high as 1,790 mg/L (Hotchkiss and Balding, 1971). This is in contrast with TDS concentrations typically below 175 mg/L in streams draining from the Sierras. The contribution of water associated with these Coast Range sediments has resulted in naturally-high salinity in groundwater within and around the Delta-Mendota Subbasin, which has been recognized as early as the 1900s (Mendenhall et al., 1916). Groundwater in some areas within the immediate vicinity of the San Joaquin River is influenced by lower-salinity surface water discharging from the east side of the San Joaquin Valley Groundwater Basin (Davis et al., 1957).

Areas of historical high saline groundwater documented by Mendenhall et al. (1916) indicate somewhat high TDS concentrations approaching or greater than 1,000 mg/L in wells sampled throughout many parts of the Delta-Mendota Subbasin. Areas of locally higher TDS concentrations (1,500-2,400 mg/L) have existed between Mendota and Los Banos; whereas the trend in deeper groundwater (average well depth of 450 feet) south of Mendota near Tranquillity indicates slightly lower historical salinity conditions, but still somewhat high with an average TDS concentration of greater than 1,000 mg/L. In the northern part of the Subbasin, north of Gustine, the average historical TDS concentration of wells was also relatively high (930 mg/L). Historically low TDS concentrations (<500 mg/L) existed in groundwater from wells with an average depth of 209 feet in the central Subbasin area between Los Banos and Gustine.

The general chemical composition of groundwater in the Subbasin is variable based on location and depth. Groundwater within the Upper Aquifer is largely characterized as transitional type with less area characterized as predominantly of chloride, bicarbonate, and sulfate water types. Transitional water types, 399
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in which no single anion represents more than 50 percent of the reactive anions, occurs in many different combinations with greatly ranging TDS concentrations. Chloride-type waters occur generally in grassland areas east of Gustine and around Dos Palos, with sodium chloride water present in northern areas near Tracy and also extending south from Dos Palos. These waters also exhibit greatly varying salinity with typical TDS concentrations, ranging from less than 500 mg/L to greater than 10,000 mg/L and of high sodium makeup (50-75 percent of cations present) (Hotchkiss and Balding, 1971). Areas of bicarbonate groundwater within the Upper Aquifer of relatively lower TDS concentrations are directly associated with intermittent streams of the Coast Range near Del Puerto, Orestimba, San Luis, and Los Banos Creeks.

Sulfate water in the central and southern Subbasin areas has TDS concentrations decreasing from west (1,200 mg/L) to east (700 mg/L) towards the San Joaquin River, similar to the bicarbonate water areas, although areas of sulfate water south of Dos Palos have much higher TDS concentrations (1,900 to 86,500 mg/L) (Hotchkiss and Balding, 1971).

Groundwater in the Lower Aquifer below the Corcoran Clay is also spatially variable, consisting of mostly transitional sulfate waters in the northern part of the Delta-Mendota Subbasin to more sodium-rich water further south in the grassland areas. In the northern part of the Delta-Mendota Subbasin, the Lower Aquifer exhibits relatively lower TDS concentrations, ranging from 400 to 1,600 mg/L, with a sulfatechloride type makeup near the valley margin trending to sulfate-bicarbonate type near the valley axis.

Farther south, TDS concentrations in the Lower Aquifer increase (Hotchkiss and Balding, 1971).

Natural conditions of groundwater salinity exist throughout the Upper and Lower Aquifers as a result of the contribution of salts from recharge off the Coast Range mountains. Surface water and groundwater flowing over and through Coast Range sediments of marine origin have dissolved naturally-occurring salts, contributing to the historical and current presence of salinity in groundwater within the DeltaMendota Subbasin. In addition to natural salinity contributed from the Coast Range sediments, a number of other mechanisms are believed to further contribute to increased salinity in the groundwater in the region. Poorly draining soil conditions are extensive within some of the southern and eastern areas of the Subbasin, extending from the vicinity of Tranquillity to near Gustine, and these types of soil, combined with a shallow water table, contribute to a build-up of soil salinity.

4.1.10 Topography, Surface Water, Recharge, and Imported Supplies This section describes the topography, surface water, soils, and groundwater recharge potential in the Delta-Mendota Subbasin.

Topography
As previously described, the Delta-Mendota Subbasin lies on the western side of the Central Valley and extends from the San Joaquin River on the east, along the axis of the Valley, to the Coast Range on the west side (LSCE, 2015). The Subbasin has ground surface elevations ranging from less than 100 feet above mean sea level (msl) along parts of the eastern edge to greater than 1,600 feet msl in the Coast Range mountains (Figure CC-35Figure CC-35). Most of the lower elevation areas occur east of Interstate 5, in the eastern parts of the Delta-Mendota Subbasin; although some lower elevation areas also extend westward into the Coast Range, such as in Los Banos Creek Valley. Low elevation areas generally coincide with the extent of the Central Valley floor. Topography within the Delta-Mendota Subbasin consists largely of flat areas across the Central Valley floor, where slopes are generally less than 2 percent, with steepening slopes to the west. The topography outside of the Central Valley floor in the Coast Range mountains is characterized by steeper slopes, generally greater than 6 percent. 400
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Surface Water Bodies
The San Joaquin River and its tributaries is the primary natural surface water feature within the DeltaMendota Subbasin, flowing from south to north along the eastern edge of the Subbasin (LSCE, 2015).

During the 1960s, the San Joaquin River exhibited gaining flow conditions through much of the Subbasin (Hotchkiss and Balding, 1971). Numerous intermittent streams from the Coast Range enter the DeltaMendota Subbasin from the west; however, none of these maintain perennial flow and only Orestimba Creek, Los Banos Creek and Del Puerto Creek have channels that extend eastward to a junction with the San Joaquin River. Most of the flow in other notable west-side creeks, including Quinto Creek, San Luis Creek, Little Panoche Creek, and Ortigalita Creek, is lost to infiltration (Hotchkiss and Balding, 1971).

Flow from Los Banos and San Luis Creeks are impounded by dams on their respective systems. When flood releases are made from Los Banos Creek Reservoir, the vast majority of flows pass through Grassland Water District to the San Joaquin River as they tend to occur during times when agricultural and wetland demand is low. San Luis Reservoir on San Luis Creek, which is located along the western boundary of the Delta-Mendota Subbasin, is an artificial water storage facility for the Central Valley Project and California State Water Project and has no notable natural surface water inflows. Outflows from the reservoir go into the system of federal- and state-operated canals and aqueducts comprising the Central Valley and State Water Projects. Surface water use within the Delta-Mendota Subbasin is derived largely from water deliveries provided by these projects, including from the California Aqueduct (referred to as San Luis Canal in the joint-use area of the California Aqueduct) and Delta-Mendota Canal, and also from the San Joaquin River (Figure CC-36Figure CC-36).
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Figure CC-35: Ground Surface Elevation
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Figure CC-36: Surface Water Features
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Soils
The NRCS provides soil mapping in the region. One of the combining soil groupings mapped includes hydrologic groups. The predominant soil hydrologic groups within the Delta-Mendota Subbasin are soil types C and D (Figure CC-37Figure CC-37). Group C soils have moderately high runoff potential when thoroughly wet (NRCS, 2009) with water transmission through the soil somewhat restricted. Group C soils typically have between 20 percent and 40 percent clay and less than 50 percent sand and have loam, silt loam, sandy clay loam, clay loam, and silty clay loam textures. Group D soils have a high runoff potential when thoroughly wet and water movement through the soil is restricted or very restricted. Group D soils typically have greater than 40 percent clay, less than 50 percent sand, and have clayey textures. In some areas, they also have high shrink-swell potential.

Soil hydraulic conductivity groups are closely related to soil drainage characteristics and hydraulic conductivity. The fine-grained floodplain deposits present across much of the southeastern area of the Subbasin are evidenced as soils with lower hydraulic conductivity in Figure CC-37Figure CC-37 and accordingly, these characteristics also make these areas poorly drained. Poorly draining soil conditions are extensive within the southern and eastern areas of the Subbasin, extending from the vicinity of Tranquillity to near Gustine (Fio, 1994; Hotchkiss and Balding, 1971). Soils in the northern and western parts of the Delta-Mendota Subbasin exhibit better drainage characteristics, although areas of poorly drained soils are also present in the north and west in proximity to surface water courses, including most notably directly adjacent to portions of the San Joaquin River and Los Banos Creek channels. Many of the upland soils, which are of generally coarser texture and located proximal to sediment sources derived from the Coast Range hill slopes, are characterized as moderately well drained.

In areas with low hydraulic conductivity, corresponding to areas without adequate natural drainage, tile drains are present to remove shallow groundwater from the rooting zone. Known tile drain locations are shown in Figure CC-38Figure CC-38, which are primarily located along the eastern boundary of the Delta-Mendota Subbasin as well as the southern portion of the Subbasin in the Grassland Drainage Area.

The Grassland Drainage Area contains a tile drainage system connected to the San Joaquin River Improvement Project, which uses tile drainage water for irrigated agriculture with a high salinity tolerance.

Areas of Recharge, Potential Recharge, and Groundwater Discharge Areas The primary process for groundwater recharge within the Central Valley floor area is from percolation of applied irrigation water and seepage from canals and stream beds, although some groundwater recharge does occur in the Delta-Mendota Subbasin along the western boundary of the Subbasin due to mountain front recharge. In sandier areas, recharge ponds have been constructed within certain districts (CCC, Aliso Water District, CCID and Del Puerto Water District) to promote managed aquifer recharge.

Groundwater recharge potential on agricultural land based on the Soil Agricultural Groundwater Banking Index (SAGBI) is shown in Figure CC-39Figure CC-39. The SAGBI is based on five major factors:
deep percolation, root zone residence time, topography, chemical limitations, and soil surface conditions.

Within the Delta-Mendota Subbasin, SAGBI data categorizes 160,248 acres out of 744,237 acres (21%) of agricultural and grazing land within the regions as having Excellent, Good, and Moderately Good (Figure CC-39Figure CC-39) recharge properties, and 571,573 acres out of 744,237 acres (or 77%) of agricultural and grazing land as having Moderately Poor, Poor, or Very Poor recharge properties. “Modified” SAGBI data shows higher potential for recharge than unmodified SAGBI data because the modified data assumes that soils have been or will be ripped to a depth of six feet, which can break up fine grained materials at the surface to improve percolation. The modified data set was determined to 404
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more accurately represent the Delta-Mendota Subbasin due to the heavy presence of agriculture. In almost all cases, recharge from applied water on irrigated lands recharges the Upper Aquifer of the Subbasin.

However, the use of percolation ponds and other managed aquifer recharge techniques must consider existing water quality in addition to soil composition and may be limited in areas where poor water quality currently exists.

The Corcoran Clay is a known barrier restricting vertical flow between the Upper and Lower Aquifers; therefore, natural recharge of the Lower Aquifer from downward percolating water is most likely restricted where the Corcoran Clay is present, including across most of the Central Valley floor. Primary recharge areas to the Lower Aquifer are most likely in western parts of the Central Valley floor where percolating water can enter formations feeding the Lower Aquifer, particularly in the vicinity and west of Los Banos, Orestimba, and Del Puerto Creeks, along the western margin of the Subbasin.

Groundwater discharge areas are identified as springs located within the Delta-Mendota Subbasin and the San Joaquin River. Figure CC-39Figure CC-39 shows the location of historic springs identified by USGS. There are only six springs/seeps identified by USGS in their National Hydrograph Dataset, which are located in the southwestern corner of the Subbasin. The springs shown represent a dataset collected by USGS and are not a comprehensive map of springs in the Subbasin.

Imported Supplies
Both the California Aqueduct and Delta-Mendota Canal run the length of the Delta-Mendota Subbasin, primarily following the Interstate 5 corridor (Figure CC-40Figure CC-40). The following water purveyors in the Delta-Mendota Subbasin are SLDMWA Member Agencies and thus receive water from the Central Valley Project via the Delta-Mendota Canal: California Department of Fish and Wildlife, Central California Irrigation District, Columbia Canal Company, Del Puerto Water District, Eagle Field Water District, Firebaugh Canal Water District, Fresno Slough Water District, Grassland Water District, Laguna Water District, Mercy Springs Water District, Oro Loma Water District, Pacheco Water District, Panoche Water District, Patterson Irrigation District, San Luis Canal Company, San Luis Water District, Tranquillity Irrigation District, Turner Island Water District, U.S. Fish and Wildlife Service, and West Stanislaus Irrigation District. Oak Flat Water District is the only recipient of State Water Project (SWP) water in the Delta-Mendota Subbasin; Oak Flat Water District initially bought into the SWP in 1968. 405
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Figure CC-37: SAGBI Soils Map
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Figure CC-38: Tile Drains
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Figure CC-39: Recharge Areas, Seeps and Springs
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Figure CC-40: Imported Supplies
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4.2 Delta-Mendota Subbasin Groundwater Conditions
This section describes the current and historic groundwater conditions in the Delta-Mendota Subbasin, including data from January 1, 2015 to recent conditions for the following parameters: groundwater elevations, groundwater storage, groundwater quality, land subsidence, interconnected surface water systems, and groundwater dependent ecosystems (GDEs) (pursuant to Article 5 Plan Contents, Subarticle 2 Basin Setting, § 354.16 Groundwater Conditions of the GSP Emergency Regulations). Seawater intrusion is not discussed herein as the Delta-Mendota Subbasin is inland and is not impacted by seawater intrusion. For the purposes of this GSP, “current conditions” is represented by Water Year (WY) 2013 conditions, which is consistent with the year representing the Current Conditions Water Budget (see Section 4.3 for more information about Water Budgets). Data post-WY 2013 through present day are presented when available.

The purpose of describing groundwater conditions, as contained in this section and described in the individual GSPs, is to establish baseline conditions that will be used to monitor changes relative to measurable objectives (MOs) and minimum thresholds (MTs). Therefore, these established baseline conditions will help support monitoring to demonstrate measurable efforts in achieving the sustainability goal for the Delta-Mendota Subbasin.

4.2.1 Useful Terminology
This groundwater conditions section includes descriptions of the amounts, quality, and movement of groundwater, among other related components. A list of technical terms and a description of the terms are listed below. The terms and their descriptions are identified here to guide readers through the section and are not a definitive definition of each term:
 Depth to Groundwater – The distance from the ground surface to first-detected non-perched groundwater, typically reported at a well.
 Upper Aquifer – The alluvial aquifer above the Corcoran Clay (or E-clay) layer.  Lower Aquifer – The alluvial aquifer below the Corcoran Clay (or E-clay) layer.  Horizontal gradient – The slope of the groundwater surface from one location to another when one location is higher or lower than the other. The gradient is shown on maps with an arrow showing the direction of groundwater flow in a horizontal direction.  Vertical gradient – Describes the movement of groundwater perpendicular to the ground surface. Vertical gradient is measured by comparing the elevations of groundwater in wells that are of different depths. A downward gradient is one where groundwater is moving down into the ground towards deeper aquifers and an upward gradient is one where groundwater is upwelling towards the ground surface.
 Contour Map – A contour map shows changes in groundwater elevations by interpolating groundwater elevations between monitoring sites. The elevations are shown on the map with the use of a contour line, which represents groundwater being at the indicated elevation along the contour line. Contour maps can be presented in two ways:
o Elevation of groundwater above mean sea level (msl), which can be used to identify the horizontal gradients of groundwater, and
o Depth to water (i.e. the distance from the ground surface to groundwater), which can be used to identify areas of shallow or deep groundwater.
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 Hydrograph – A graph that shows the changes in groundwater elevation or depth to groundwater over time at a specific location. Hydrographs show how groundwater elevations change over the years and indicate whether groundwater is rising or descending over time.  Maximum Contaminant Level (MCL) – MCLs are standards that are set by the State of California and the U.S. Environmental Protection Agency for drinking water quality. MCLs are legal threshold limits on the amount of an identified constituent that is allowed in public drinking water systems. At both the State and Federal levels, there are Primary MCLs, set to be protective of human health, and Secondary MCLs for constituents that do not pose a human health hazard but do pose a nuisance through either smell, odor, taste, and/or color. MCLs are different for different constituents and have not been established for all constituents potentially found in groundwater.
 Elastic Land Subsidence – Reversible and temporary fluctuations in the elevation of the earth’s surface in response to seasonal periods of groundwater extraction and recharge.  Inelastic Land Subsidence – Irreversible and permanent decline in the elevation of the earth’s surface resulting from the collapse or compaction of the pore structure within the fine-grained portions of an aquifer system. This form of subsidence is what is required by SGMA to be monitored and reported.
 Gaining Stream – A stream in which groundwater flows into a streambed and contributes to a net increase in surface water flows across an identified reach.  Losing Stream – A stream in which surface water is lost through the streambed to the groundwater, resulting in a net decrease in surface water flows across an identified reach.  Conjunctive Use – The combined use of surface water and groundwater supplies, typically with more surface water use in wet years and more groundwater use in dry years.

4.2.2 Groundwater Elevations
This section describes groundwater elevation data utilized and elevation trends in the Delta-Mendota Subbasin. Groundwater conditions vary widely across the Subbasin. Historic groundwater conditions through present day conditions, the role of imported surface water in the Subbasin, and how conjunctive use has impacted groundwater trends temporally and spatially are discussed. Groundwater elevation contour maps associated with current seasonal high and seasonal low for each principal aquifer, as well as hydrographs depicting long-term groundwater elevations, historical highs and lows, and hydraulic gradients (both horizontal and vertical), are also described.

Available Data
Groundwater elevation data, and accompanying well construction information, within the Delta-Mendota Subbasin from the following sources and associated programs were utilized in the development of the Delta-Mendota Subbasin GSPs:
 California Department of Water Resources (DWR)
o California Statewide Groundwater Elevation Monitoring Program (CASGEM) o Water Data Library (WDL)
 Water level data from local monitoring programs
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Data provided by these sources included well information (such as location, well construction, owner, ground surface elevation and other related components), as well as groundwater elevation data (including information such as date measured, depth to water, groundwater surface elevation, questionable measurement code, and comments). At the time that these analyses were performed, groundwater elevation data were available for the time period from 1930 through 2018. There are many wells with monitoring data from some time in the past but no recent data, while a small number of wells have monitoring data recorded for periods of greater than 50 years.

Not all groundwater elevation data received were used in preparing the groundwater elevation contour maps for both principal aquifers (defined in this Common Chapter as the Upper and Lower Aquifers which are divided by the Corcoran Clay or E-clay layer). Some groundwater elevation data were associated with wells with unknown screened depths and/or composite well screens constructed across the Corcoran Clay. Groundwater elevation data associated with wells with composite screens and/or unknown screened depths were removed from the data set in most instances, along with any data point that appears to be an outlier when compared with surrounding data from the same period. Select wells with unknown construction were evaluated for inclusion in contour mapping efforts in areas of limited data. Duplicate well measurements were also removed prior to contouring and only one observation for a given well was used for the identified season, rather than averaging all measurements at a given well during the same season.

Figure CC-41Figure CC-41 shows the locations of wells with known screened depths within the DeltaMendota Subbasin as well as known spatial gaps where no well information is currently available. These wells include those monitored under CASGEM, the Delta-Mendota Canal Well Pump-in Program, and by local owners or agencies. Monitoring data available for these wells varies by local owner and agency.

Well locations were provided by local agencies to the best of their knowledge at the time of writing and may include wells that have been destroyed or are no longer in service.

Historic Conditions
Historic groundwater trends changed significantly with the first deliveries of imported water deliveries to the Delta-Mendota Subbasin. Construction of the Delta-Mendota Canal and the California Aqueduct heralded the introduction of significant surface water supplies into the Subbasin and reduced dependence on groundwater as the primary water supply. These conveyance systems have resulted in significant increases in the conjunctive use of surface water and groundwater throughout the Subbasin. Various drought periods and regulations reducing delivery of supplies from the Sacramento-San Joaquin Delta also punctuate critical understandings of groundwater use patterns throughout the Subbasin, as well as what is known regarding response and recovery of groundwater levels following notable droughts.

Prior to Imported Water Deliveries (1850-1950s)
Prior to 1850, the majority of agriculture and development in the San Joaquin Valley consisted of rain-fed grain and cattle production, with irrigated development beginning sporadically during this time via river (primarily San Joaquin River) and perennial stream diversions (SWRCB, 2011). Construction of the railroad through the San Joaquin Valley from 1869 through 1875 increased demand for more extensive agriculture, making markets in larger coastal cities more accessible to valley farmers. Significant irrigation sourced from surface water and resulting production began in the western side of the San Joaquin Valley in 1872 when the San Joaquin River was diverted through the Miller and Lux canal system west of Fresno (DWR, 1965). By the 1890s and early 1900s, sizable areas of the southern San Joaquin Valley were being forced out of production by salt accumulation and shallow water tables. Much of this land lay idle until the 1920s when development of reliable electric pumps and the energy to power 412
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them accelerated the expansion of irrigated agriculture with the availability of vast groundwater resources. The resultant groundwater pumping lowered the water table in many areas (SWRCB, 1977 and Ogden, 1988) and allowed the leaching of salts, particularly near the valley trough and western side of the valley. Groundwater pumping for irrigation from around 1920 to 1950 drew the water table down as much as 200 feet in areas along the westside of the San Joaquin River (Belitz and Heimes, 1990).

Declining water tables were causing higher pumping costs and land subsidence, and farmers were finding poorer quality water as water tables continued to decline. These issues created a desire for new surface water supplies, which would be fulfilled by the Central Valley Project.

Post-Imported Water Deliveries (1950s-2012)
Surface water deliveries from the Central Valley Project via the DMC began in the early 1950s, and from the State Water Project via the California Aqueduct in the early 1970s (Sneed et al., 2013). The CVP is the primary source of imported surface water in the Delta-Mendota Subbasin, where only Oak Flat Water District receives deliveries from the SWP. Introduction of imported water supplies to the Delta-Mendota Subbasin resulted in a decrease in groundwater pumping from some parts of the Subbasin and the greater Central Valley, which was accompanied by a steady recovery of water levels. During the droughts of 1976-1977 and 1987-1992, diminished deliveries of imported surface water prompted increased pumping of groundwater to meet irrigation demands, bringing water levels to near-historic lows. Following periods of drought, recovery of pre-drought water levels has been rapid, especially in the Upper Aquifer. This trend has been observed in historic hydrographs for wells across the Subbasin.

Current Conditions
Trends similar to historic drought and subsequent recovery conditions were observed during the 2012 to 2016 drought and the 2016 to present recovery period.

Recent Drought (2012-2016)
During the most recent drought, from 2012 through 2016, similar groundwater trends were observed as during the 1976-1977 and 1987-1992 droughts. With diminished imported surface water deliveries, groundwater pumping increased throughout the Subbasin to meet irrigation needs. This resulted in historic or near-historic low groundwater levels during the height of the drought in 2014 and 2015, when CVP and SWP allocations for agricultural water service contractors were 0%, Exchange Contractors and refuge deliveries were less than 75%, and post-1914 surface water rights in the San Joaquin River watershed were curtailed. In June 2015, senior water rights holders with a priority date of 1903 or later in the San Joaquin and Sacramento watersheds and the Delta were ordered by the State Water Resources Control Board to curtail diversions (State of California, 2015). This marked the first time in recent history that pre-1914 water rights holders were curtailed.

Post-Drought (2016-present)
With wetter conditions following the 2012-2016 drought, groundwater levels began to recover. This was largely a result of increased surface water availability with CVP allocations reaching 100% and full water rights supplies available for diversion from the San Joaquin River in 2017. Additionally, inelastic land subsidence rates also drastically decreased in 2017 as imported water supplies were once again available, resulting in decreased groundwater pumping particularly from the Lower Aquifer. This pattern of increased drought-driven groundwater pumping, accompanied by declining groundwater elevations, followed by recovery is a predominant factor to be considered in the sustainable management of the Delta-Mendota Subbasin. Furthermore, subsidence mitigation projects were developed which drastically reduced the observed subsidence rate on the eastern and southern boundaries of the Subbasin. 413
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Groundwater Trends
Groundwater levels can fluctuate greatly throughout time due to various natural and anthropogenic factors, including long-term climatic conditions, adjacent well pumping, nearby surface water flows, and seasonal groundwater recharge or depletion (LSCE, 2015). As discussed in the Hydrogeologic Conceptual Model section of this Common Chapter (Section 4.1), the Delta-Mendota Subbasin is generally a twoaquifer system consisting of an Upper and Lower Aquifer that are subdivided by the Corcoran Clay layer, a regional aquitard. The Corcoran Clay layer, or E-Clay equivalent, restricts flow between the upper semiconfined aquifer and lower confined aquifer. The presence of a tile drain network along the Grassland Drainage Area and the Subbasin’s eastern boundary affects the lateral and vertical water movement in the shallow groundwater zone (LSCE, 2016).

The Delta-Mendota Subbasin has a general flow direction to the east in the Upper Aquifer, where it loses groundwater to the San Joaquin River and its neighboring subbasins. Most recharge throughout the Subbasin is attributed to applied irrigation water, where other sources of recharge include local streams, canal seepage, and infiltration along the western margin of the Subbasin from the Coast Range. The figures that follow were developed for inclusion in the Western San Joaquin River Watershed Groundwater Quality Assessment Report (LSCE, 2015) and the Grassland Drainage Area Groundwater Quality Assessment Report (LSCE, 2016) and are included herein with the intent of demonstrating general trends in groundwater elevations around the Delta-Mendota Subbasin. These figures are not to scale.

Please see the individual GSPs for more specific information relating to similar trends in those respective GSP Plan areas. Additionally, it is important to note that groundwater trends, such as these, are dependent on climatic conditions and are not necessarily representative of the historic and current water budgets for those respective GSP Plan areas.

Upper Aquifer
For the Upper Aquifer, Figure CC-42Figure CC-42 presents select hydrographs illustrating temporal groundwater level trends in the Upper Aquifer wells within the Subbasin. Hydrographs shown on Figure CC-42Figure CC-42 are displayed with different ranges of elevation values on the vertical axes. Wells in the Upper Aquifer exhibit decreasing trends to somewhat stable water levels until the mid-1980s, and increasing or stable water levels thereafter.

Similarly, Figure CC-43Figure CC-43 presents select hydrographs illustrating temporal groundwater level trends in the areas covered by the Central Delta-Mendota, Oro Loma Water District, and Widren Water District GSAs in the Northern & Central Delta-Mendota Region GSP Group at various depths. The three select hydrographs representing wells in the Upper Aquifer each show less than 10 years of available data with two wells showing slight declines of about 10 feet or less from about 2003 through 2013, and one well showing a more drastic elevation change, ranging from 100 feet above mean sea level (ft msl) to -20 ft msl over a 5-year period from 2010 to 2016.

Lower Aquifer
Figure CC-44Figure CC-44 presents select hydrographs illustrating temporal groundwater level trends in Lower Aquifer wells within the Subbasin. Note, hydrographs shown on Figure CC-44Figure CC-44 displayed different ranges of elevation on the vertical axes. In the Lower Aquifer, piezometric head typically increased or remained relatively stable during the period from the 1980s through the early 2000s.
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Again, similarly, Figure CC-43Figure CC-43 presents select hydrographs illustrating temporal groundwater level trends in the Central Delta-Mendota, Oro Loma Water District, and Widren Water District GSA areas of the Northern & Central Delta-Mendota Region GSP Group at various depths. The two select hydrographs representing wells in the Lower Aquifer each show similar elevation patterns post-2010 with a total elevation change of 50 ft msl or more. USGS1000489 shows stable and increasing groundwater elevation trends from the late 1950s through the mid-1980s with a data gap from the mid1980s through 2010, whereafter 2010 groundwater levels have a steep decline through 2016.

Vertical Gradients
Throughout most of the Delta-Mendota Subbasin, the Corcoran Clay layer acts as a regional aquitard, limiting the vertical migration of groundwater. In areas outside the Corcoran Clay layer (along the western margin of the Subbasin), localized interfingered clays minimize the downward migration of groundwater; although in areas where the clay layers are not competent or non-existent, groundwater migrates from shallower to deeper groundwater zones. Similarly, in areas where the Corcoran Clay has been compromised (due to well construction across the clay), groundwater generally flows from the Upper Aquifer to the Lower Aquifer, especially in areas where the Lower Aquifer is actively used as a water supply (lowering the potentiometric head in that zone).

Groundwater Contours
The Subbasin-wide groundwater contours reflected in Figure CC-45Figure CC-45 and Figure CC46Figure CC-46 evaluate the seasonal high (Spring 2013) and seasonal low (Fall 2013) conditions of the current year (defined as WY2013 for the GSP analyses) for the Upper Aquifer. Spring is defined as groundwater surface elevation measurements collected between January 1 and April 8; where Fall is defined as groundwater surface elevation measurements collected between September 1 and October 31.

For wells where multiple Spring 2013 or Fall 2013 measurements were available, the highest elevation for each season was used for contouring. Gaps in data and contours can be attributed to a lack of wells present, level measurements, or requirements to report level readings groundwater level data. Consistent with traditional contouring efforts, the quality of outlier water level data was investigated. In instances of poor quality data, the associated data was eliminated for the groundwater contouring effort. Furthermore, implementation of the CASGEM program in 2014 has reduced temporal and spatial gaps in groundwater level datasets, and implementation of the Delta-Mendota Subbasin GSPs’ monitoring programs will add to the improved data quantity and quality.

In the Upper Aquifer, during Spring 2013, the general flow of groundwater in the Delta-Mendota Subbasin was from the Coast Range along the western boundary of the Subbasin toward the San Joaquin River along the eastern boundary. Groundwater elevations tend to increase moving south throughout the Subbasin. Within Stanislaus County, groundwater elevations are the lowest, ranging between 40 and 80 feet above msl, becoming increasingly higher in Madera County, ranging between 80 and 100 feet above msl, and in Merced and Fresno counties, ranging between 80 and 140 feet above msl (Figure CC45Figure CC-45). Similar flow directions (west to east and northeast) are observed in the Fall 2013.

Within Stanislaus County, groundwater elevations are the lowest ranging between 40 and 80 feet above msl, showing little difference compared to Spring 2013; become increasingly higher in Madera County ranging between 60 and 100 feet above msl; in Merced County ranging between 60 and 140 feet above msl; and in Fresno County ranging from 60 and 120 feet above msl (Figure CC-46Figure CC-46). Both maps indicate a prevailing southwest to northeast flow gradient above the Corcoran Clay. In general, little variation is apparent in groundwater elevation between seasonal high and low periods in 2013.

Due to insufficient data, groundwater elevation contour maps for the Lower Aquifer for the seasonal high and low (Spring 2013 and Fall 2013, respectively) could not be accurately prepared. Figure CC415 Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
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47Figure CC-47 and Figure CC-48Figure CC-48 show the available groundwater elevation measurements for Spring 2013 and Fall 2013. Available Spring 2013 measurements range from -127 to 12 feet above msl in Stanislaus County, -65 to 124 feet above msl in Merced County, and -5 to 88 feet above msl in Fresno County (Figure CC-47Figure CC-47), where no measurements are available for this time period in Madera County. Available Fall 2013 measurements range from -138 to 156 feet above msl in Stanislaus County, -94 to 19 feet above msl in Merced County, and -72 to -4 feet above msl in Fresno County (Figure CC-48Figure CC-48), where no measurements are available for this time period in Madera County. The Lower Aquifer exhibits less seasonal difference in groundwater elevations than the Upper Aquifer. Throughout most of the Subbasin, the Lower Aquifer shows lower piezometric heads than the Upper Aquifer suggesting that potential exists for downward vertical gradient. 416
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Figure CC-41: Wells with Known Screened Interval Depths 417
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Note: Figure not to scale.

Source: Western San Joaquin River Watershed Groundwater Quality Assessment Report, 2016 Figure CC-42: Select Graphs of Groundwater Elevations, Upper Aquifer 418
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Note: Figure not to scale. Source: Western San Joaquin River Watershed Groundwater Quality Assessment Report, 2016.

Figure CC-43: Select Graphs of Groundwater Elevations, Various Depths 419
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Note: Figure not to scale.

Source: Western San Joaquin River Watershed Groundwater Quality Assessment Report, 2016.

Figure CC-44: Select Graphs of Groundwater Elevations, Lower Aquifer 420
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Figure CC-45: Spring 2013 Upper Aquifer Groundwater Contour Map 421
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Figure CC-46: Fall 2013 Upper Aquifer Groundwater Contour Map 422
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Figure CC-47: Spring 2013 Lower Aquifer Groundwater Elevation Measurements 423
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Figure CC-48: Fall 2013 Lower Aquifer Groundwater Elevation Measurements 424
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4.2.3 Groundwater Storage
Annual changes in groundwater storage for both the Upper and Lower Aquifers in the Delta-Mendota Subbasin were estimated as part of the development of the Historic (WY2003-2012), Current (WY2013) and Projected Water Budgets (WY2014-2070). For information on how change in storage was calculated, refer to Section 4.3.2 – Water Budgets of this Common Chapter. Figure CC-49Figure CC-49 and Figure CC-50Figure CC-50 show annual change in storage, cumulative change in storage, and water year type for the Upper Aquifer and Lower Aquifer, respectively, from WY 2003 through 2013 for the Delta-Mendota Subbasin. For the purposes of the water budget four water year types were utilized, wet, average (corresponding to above and below normal water years), dry (corresponding to dry and critical water years) and Shasta critical.

Change in storage is negative for 6 out of the 11-year historic and current water budget period for the Upper Aquifer, and 9 out of 11 years for the Lower Aquifer. Despite periods of wet conditions with recharge outpacing extractions, an overall declining trend in groundwater storage can be observed in both the Upper Aquifer and Lower Aquifer. Cumulative change in storage declined more rapidly in the Upper Aquifer compared to the Lower Aquifer, declining by about 1,300624,0000 AF in the Upper Aquifer and 678375,000 AF in the Lower Aquifer between WY2003 to 2013.

Figure CC-49: Calculated Upper Aquifer Change in Storage, Annual and Cumulative 425
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Figure CC-50: Calculated Lower Aquifer Change in Storage, Annual and Cumulative

4.2.4 Seawater Intrusion
Seawater intrusion is not an applicable sustainability indicator for the Delta-Mendota Subbasin. The Subbasin is located inland from the Pacific Ocean; thus, groundwater conditions related to seawater intrusion are not applicable to the Delta-Mendota Subbasin.

4.2.5 Groundwater Quality
Groundwater quality varies considerably from west to east and north to south throughout the DeltaMendota Subbasin. In general, Upper Aquifer water quality has historically been impacted by overlying land uses with some areas showing increasing concentrations of nitrate and TDS. Areas of elevated salt concentrations can be found in the Subbasin, generally along the southern portion of the San Joaquin River and in the southern portion of the Subbasin. Lower Aquifer groundwater has, and remains in most cases, to be of generally good quality. For more information about historic and current conditions relative to groundwater quality in each GSP Group area, refer to the individual GSPs.

4.2.6 Land Subsidence
Long-term groundwater level declines can result in a one-time release of “water of compaction” from compacting silt and clay layers (aquitards) resulting in inelastic land subsidence (Galloway et al., 1999).

There are several other types of subsidence in the San Joaquin Valley, including subsidence related to hydrocompaction of moisture-deficient deposits above the water table, subsidence related to fluid withdrawal from oil and gas fields, subsidence caused by deep-seated tectonic movements, and subsidence caused by oxidation of peat soils that is a major factor in the Sacramento-San Joaquin Delta (Sneed et al., 2013). However, aquifer-system compaction caused by groundwater pumping causes the largest magnitude and areal extent of land subsidence in the San Joaquin Valley (Poland et al., 1975; Ireland et al., 1984; Farrar and Bertoldi, 1988; Bertoldi et al., 1991; Galloway and Riley, 1999). 426
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Land subsidence is a prevalent issue in the Delta-Mendota Subbasin as it has impacted prominent infrastructure of statewide importance, namely the DMC and the California Aqueduct, as well as local canals, causing serious operational, maintenance, and construction-design issues (Sneed et al., 2013).

Reduced freeboard and flow capacity for the DMC and California Aqueduct have rippling effects on imported water availability throughout the State. Even small amounts of subsidence in critical locations, especially where canal gradients are small, can impact canal operations (Sneed and Brandt, 2015). While some subsidence is reversible (referred to as elastic subsidence), inelastic or irreversible subsidence is caused mainly by pumping groundwater from below the Corcoran Clay, thus causing compaction and reducing storage in the fine-grained materials in the lower confined aquifer as well as damaging well infrastructure. As a result, important and extensive damages and repairs have resulted in the loss of conveyance capacity in canals that deliver water or remove floodwaters, the realignment of canals as their constant gradient becomes variable, the raising of infrastructure such as canal check stations, and the releveling of furrowed fields.

Available Data
There are six UNAVCO Continuous GPS (CGPS) locations that monitor subsidence within the DeltaMendota Subbasin (Figure CC-51Figure CC-51). Changes in land surface elevation have also been measured at DMC Check Structures. Figure CC-52Figure CC-52 through Figure CC-57Figure CC-57 show the vertical change in land surface elevation from a given time point (specified on charts) for the UNAVCO CGPS stations within the Delta-Mendota Subbasin, along with annual CVP allocations. Table CC-5Table CC-5 summarizes the greatest monthly land subsidence rate and corresponding year(s) of that change at each UNAVCO CGPS station. Overall, the greatest monthly subsidence rates occurring after January 1, 2015 occurred during the Spring of 2016 to the Spring of 2017. Land subsidence rates (in feet per year), as measured by USBR from December 2011 to December 2014, are shown in Figure CC58Figure CC-58. Based on these data, within the majority of the Delta-Mendota Subbasin, annual subsidence rates were between -0.15 and -0.3 feet/year during this period (or between -0.45 and -0.9 feet of total subsidence over this three-year period).

Table CC-5: Subsidence Monitoring Trends
UNAVCO CGPS Stations
Station ID
Greatest Monthly Land
Subsidence Rate as of
January 1, 2015 (feet)
Year(s) of Greatest Monthly
Subsidence Rate
P255 -0.0292 Spring 2016 to 2017
P259 -0.0183 Spring 2016 to 2017
P252 -0.033 Spring 2016 to 2017
P303 -0.2190 Spring 2016 to 2017
P301 -0.0029 Spring 2016 to 2017
P304 -0.0003 Spring 2013 to 2017
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Historic Conditions
Along the DMC, in the northern portion of the San Joaquin Valley, extensive groundwater extraction from unconsolidated deposits caused subsidence exceeding 8.5 meters (or about 28 feet) between 1926 and 1970 (Poland et al., 1975), reaching 9 meters (or about 30 feet) in 1980 (Ireland, 1986). Land subsidence from groundwater pumping began in the San Joaquin Valley in the mid-1920s (Poland et al., 1975; Bertoldi et al., 1991; Galloway and Riley, 1999), and by 1970, about half of the San Joaquin Valley had land subsidence of more than 0.3 meters (or about 1 foot) (Poland et al., 1975). When groundwater pumping decreased in the Delta-Mendota Subbasin following imported water deliveries from the CVP via the dMC DMC in the early 1950s, compaction rates were reduced in certain areas and water levels recovered. Notable droughts of 1976-1977 and 1987-1992 saw renewed compaction during these periods, with increased groundwater pumping as imported supplies were reduced or unavailable. However, following these droughts, compaction virtually ceased and groundwater levels rose to near pre-drought levels quite rapidly (Swanson, 1998; Galloway et al., 1999).

Subsidence contours for 1926-1970 (Poland et al., 1975) show the area of maximum active subsidence was southwest of the community of Mendota. Historical subsidence rates in the Mendota area exceeded 500 millimeters/year (or about 20 inches/year) during the mid-1950s and early 1960s (Ireland et al., 1984). The area southwest of Mendota has experienced some of the highest levels of subsidence in California, where from 1925 to 1977, this area sustained over 29 feet of subsidence (USGS, 2017).

Historical subsidence rates along Highway 152 calculated from leveling-survey data from 1972, 1988, and 2004 show that for the two 16-year periods (1972-1988 and 1988-2004), maximum subsidence rates of about 50 millimeters/year (or about 2 inches/year) were found just south of El Nido (Sneed et al., 2013). Geodetic surveys completed along the DMC in 1935, 1953, 1957, 1984, and annually from 1996- 2001 indicated that subsidence rates were greatest between 1953 and 1957 surveys, and that the maximum subsidence along the DMC (about 3 meters, or about 10 feet) was just east of DMC Check Structure Number 18.

After 1974, land subsidence was demonstrated to have slowed or largely stopped (DWR, June 2017); however, land subsidence remained poised to resume under certain conditions. Such an example includes the severe droughts that occurred between 1976 and 1977 and between 1987 and 1991. Those droughts, along with other corroborating factors, led to diminished deliveries of imported water which prompted some water agencies and farmers (especially in the western Valley) to refurbish old pumps, drill new water wells, and begin pumping groundwater to make up for cutbacks in the imported water supply. The decisions to renew groundwater pumping were encouraged by the fact that groundwater levels had recovered to near-predevelopment levels. CGPS data collected between 2007 to 2014 show seasonally variable subsidence and compaction rates, including uplift as elastic rebound occurs during the fall and winter (Sneed and Brandt, 2015). Vertical displacement at P303, near Los Banos, indicates subsidence at fairly consistent rates during and between drought periods (Sneed and Brandt, 2015). Vertical displacement at P304, near Mendota, indicates that most subsidence occurred during drought periods with very little occurring between drought periods. Finally, data from extensometers 12S/12E-16H2, located on the DMC west of Los Banos, and 14S/13E-11D6, located between the DMC and California Aqueduct west of Mendota, showed subsidence rate increases during 2014, the third year of the most recent drought (Sneed and Brandt, 2015).

Subsidence impacts to the California Aqueduct, which runs parallel and in close proximity to the DeltaMendota Canal across the Subbasin, is of statewide importance. During the construction of the California Aqueduct, it was thought that subsidence within the San Joaquin Valley would cease with the delivery of water from the Central Valley Project, though additional freeboard was incorporated into the design and construction of the Aqueduct in an attempt to mitigate for future subsidence (DWR, June 2017). After 428
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water deliveries from the Aqueduct began, subsidence rates decreased to an average of less than 0.1 inches/year during normal to wet hydrologic years. During dry to critical hydrologic years, subsidence increased to an average of 1.1 inches per year. The 2012-2015 drought produced subsidence similar to those seen before the Aqueduct began delivering water, with some areas experiencing nearly 1.25 inches of sinking per month (based on NASA UAVSAR flight measurements). Dry and critically dry water years since Aqueduct deliveries began have resulted in extensive groundwater withdrawals, causing some areas near the Aqueduct to subside nearly 6 feet.

Current Conditions
Based on subsidence rates observed over the last decade, it is anticipated that without mitigation, subsidence will continue to impact operations of the DMC and California Aqueduct. For example, recently, Reach 4A of the San Joaquin River near Dos Palos experienced between 0.38 and 0.42 feet/year in subsidence between 2008 and 2016. As a result of subsidence, freeboard in Reach 4A is projected to be reduced by 0.5 foot by 2026 as compared to 2016, resulting in a 50 percent reduction in designed flow capacity (DWR, May 2018). Reduced flow capacities in the California Aqueduct will impact deliveries and transfers throughout the State and result in the need to pump more groundwater, thus contributing to further subsidence.

More recent subsidence measuring indicates subsidence hot spots within the Subbasin include the area east of Los Banos and the Tranquillity Irrigation District (TRID) area. USGS began periodic measurements of the land surface in parts of the San Joaquin Valley over the last decade. Between December 2011 and December 2014, total subsidence in the area east of Los Banos, located within the Merced Subbasin (also referred to as the El Nido-Red Top area), over the three-year period ranged from

0.15 to 0.75 feet, or 1.8 to 9 inches respectively (KDSA, 2015). The Jet Propulsion Laboratory (JPL) at the California Institute of Technology has also been monitoring subsidence in California using interferometric synthetic aperture radar (or InSAR), and a recent progress report documenting data for the period from May of 2015 to September of 2016 indicates that the two previously-identified primary subsidence areas near the community of Corcoran and centered on El Nido was joined by a third area of significant subsidence near TRID. For the study period (as shown in Figure CC-59Figure CC-59), maximum total subsidence of 22 inches was measured near Corcoran, while the El Nido area subsided 15 inches and the TRID area subsided around 20 inches. Analyses at two particular stations near El Nido show interesting trends. At Station P303, between 2007 and 2014, 50 mm (or nearly 2 inches) of subsidence occurred at this location. Vertical displacement at P303 (Figure CC-55Figure CC-55) show subsidence at fairly consistent rates during and between drought periods, indicating that these areas continued to pump groundwater despite climatic variations (possibly due to a lack of surface water availability) (Sneed and Brandt, 2015). Residual compaction may also be a factor. Vertical displacement at Station P304 indicated that most subsidence in this particular area occurred during drought periods and very little occurred between drought periods (Figure CC-57Figure CC-57). This suggests that this area received other sources of water (most likely surface water available between drought periods) and that residual compaction was not very important in this area. These two areas demonstrate a close link between the availability of surface water, groundwater pumping, and inelastic land subsidence.

Total land subsidence from April 2015 to April 2016 in the San Joaquin Valley is shown in Figure CC-60: Vertical Displacement, April 2015 to April 2016 Figure CC-60: Vertical Displacement, April 2015 to April 2016 . Subsidence monitoring in the DeltaMendota Subbasin, and in the San Joaquin Valley as a whole, demonstrated significant inelastic land subsidence as a result of the last drought, with effects continuing to the present time (as evidenced by 429
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continued subsidence between 2016 and 2018 through surveys of the DMC). While the impacts appeared to have slowed, the temporal and spatial impacts of continued subsidence have not yet been evaluated. 430
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Figure CC-51: UNAVCO and Delta-Mendota Canal Subsidence Monitoring Locations 431
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Figure CC-52: Vertical Elevation Change at UNAVCO CGPS P255, Spring 2007 to 2018 432
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Figure CC-53: Vertical Elevation Change at UNAVCO CGPS P259, Spring 2006 to 2018 433
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Figure CC-54: Vertical Elevation Change at UNAVCO CGPS P252, Spring 2006 to 2018 434
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Figure CC-55: Vertical Elevation Change at UNAVCO CGPS P303, Spring 2006 to 2018 435
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Figure CC-56: Vertical Elevation Change at UNAVCO CGPS P301, Spring 2005 to 2018 436
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Figure CC-57: Vertical Elevation Change at UNAVCO CGPS P304, Spring 2005 to 2018 437
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Figure CC-58: Land Subsidence, December 2011 to December 2014 438
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Source: Progress Report: Subsidence in California, March 2015 – September 2016, Farr et. Al. JPL, 2017 Figure CC-59: Recent Land Subsidence at Key San Joaquin Valley Locations 439
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Figure CC-60: Vertical Displacement, April 2015 to April 2016 440
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Figure CC-61: Elevation Change along the Delta-Mendota Canal, 2014 through 2018 441
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4.2.7 Interconnected Surface Water Systems
Understanding the location, timing and magnitude of groundwater pumping impacts on interconnected surface water systems is important for the proper management of groundwater resources in order to minimize impacts on interconnected surface waters and the biological communities and permitted surface water diverters that rely on those resources. Historically, throughout the San Joaquin Valley, many interconnected stream reaches have transitioned from net-gaining to net-losing streams (TNC, 2014).

Gaining streams occur when streamflows increase as a result of groundwater contribution and losing streams occur when streamflows decrease due to infiltration into the bed of the stream (McBain & Trush, Inc., 2002). Increased groundwater pumping has the ability to contribute to the depletion of interconnected waters with the nature, rate, and location of increased pumping being a function of distance to the river, as well as depth, timing, and rate of groundwater pumping.

Available Data
Two communities in the Delta-Mendota Subbasin are likely most vulnerable to the loss of interconnected surface water as a result of groundwater pumping: San Joaquin River surface water diverters and groundwater dependent ecosystems (GDEs). These communities represent the primary beneficial users of interconnected surface water and groundwater. Streams stemming from the west side of the DeltaMendota Subbasin are ephemeral in nature, and only two of these creeks reach the San Joaquin River (Del Puerto Creek and Orestimba Creek). These creeks lose their flows to the underlying vadose zone (netlosing streams) and therefore do not represent areas of potential GDEs.

Groundwater dependent ecosystems are defined under Article 2 Definitions, § 351 Definitions of the GSP Emergency Regulations as “ecological communities or species that depend on groundwater emerging from aquifers or on groundwater occurring near the ground surface.” The Natural Communities Commonly Associated with Groundwater (NCCAG) dataset (2018) provided by DWR in conjunction with The Nature Conservancy (TNC) was initially used to identify GDEs within the Delta-Mendota Subbasin, following the associated guidance document provided by TNC (Rohde et al., 2018). Local verification efforts were conducted in the Delta-Mendota Subbasin by different GSA representatives to ground-truth GDEs based on local knowledge. Specifically, areas where natural communities have been urbanized or otherwise modified prior to 2015 were eliminated from the data set used to identify GDEs.

Identification of Interconnected Surface Water Systems
The San Joaquin River and Fresno Slough are the primary surface water bodies interconnected with Delta-Mendota Subbasin groundwater. For information about the sources used to determine the interconnected segments of the San Joaquin River and Fresno Slough within the Delta-Mendota Subbasin, refer to the individual GSPs.

Historic Conditions
The San Joaquin River and its tributaries drain approximately 13,500 mi2 (measured at the USGS gaging station at Vernalis) along the western flank of the Sierra Nevada and eastern flank of the Coast Range, and flows northward into the Sacramento-San Joaquin Delta where it is joined by the Calaveras and Mokelumne Rivers before combining with the Sacramento River. Typical of Mediterranean climate catchments, river flows vary widely seasonally and from year to year. Three major tributaries join the San Joaquin from the east: the Merced, Tuolumne, and Stanislaus Rivers. Smaller tributaries include the Fresno River, Chowchilla River, Bear Creek, and Fresno Slough (from the Kings River). Precipitation is 442
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predominantly snow above about 5,500 to 6,000 feet in the Sierra Nevada, with rain in the middle and lower elevations of the Sierra foothills and in the Coast Range. As a result, the natural hydrology historically reflected a mixed runoff regime dominated by winter-spring rainfall runoff and springsummer snowmelt runoff. Most flow is derived from snowmelt from the Sierra Nevada, with relatively little runoff contributed from the western side of the drainage basin in the rain shadow of the Coast Range. The unimpaired average annual water yield (WY1906-2002) of the San Joaquin River, as measured immediately above Millerton Reservoir, is 1,801,000 acre-feet (USBR, 2002); the post-Friant Dam average annual water yield (WY 1950-2000) to the lower San Joaquin River is 695,500 acre-feet (USGS, 2000). As average precipitation decreases from north to south, the San Joaquin River basin (including the Stanislaus, Tuolumne, and Merced Rivers) contributes about 22% of the total runoff to the Delta (DWR, 1998).

Current Conditions
Historically, most of the San Joaquin River, which forms the great majority of the Delta-Mendota Subbasin’s eastern border, was a gaining reach. Snowmelt runoff during the spring and early summer resulted in these conditions through a good portion of the year. However, significant decreases in groundwater elevations due to a myriad of factors, including pumping, tile drains, the channelizing of flood flows, and upstream diversions on the river, have reversed this condition so most reaches are now losing reaches. Some localized gaining reaches still remain on the lower river, such as between the Stanislaus and Merced Rivers; however, many reaches along these rivers (and along localized streams) may transition from gaining to losing depending on hydrology.

Estimates of Timing and Quantity of Depletions
Using available data and where feasible, each Delta-Mendota Subbasin GSP Group quantified the gains and/or losses from the groundwater at each interconnected reach of the San Joaquin River adjoining the Delta-Mendota Subbasin. Table CC-6Table CC-6 summarizes these estimates. For more information about the sources or methods used to estimate the timing and quantity of depletions, refer to the individual GSPs.
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Table CC-6: Estimated Quantity of Gains/Depletions for Interconnected Stream Reaches, San Joaquin River Landmark River Mile GSP Group Interconnected? Gaining or Losing? Quantity Gained/Loss (cfs) Notes REACH 1 267.5 to
229.0
Located outside the Delta-Mendota Subbasin
A Friant Dam 267.5
North Fork Road Bridge 266.8 Cobb Island Bridge 259.0 State Route 41 (Lanes Bridge) 255.2 Scout Island Bend 250.0 ATSF Railroad Bridge 245.0 B State Route 99 243.2
Southern Pacific Railroad 243.2 State Route 145 Bridge (Skaggs Bridge) 234.1 Gravelly Ford 229.0 REACH 2 229.0 to
204.8
A Gravelly Ford 229.0 Yes Losing when flowing
Upstream Limit of Right Bank Levee 227.0 Upstream Limit of Left Bank Levee 225.0 B Chowchilla Bypass Control Structure 216.1 Farmers
Water District
Yes Losing when flowing -4 2003 to 2013 average. High in 2010 (-8 cfs), low in 2004 and 2009 (-1 cfs)
Mendota Dam 204.8 Mendota Pool Yes Losing -40 -29,000 AFY REACH 3 204.8 to
182.0
Yes Losing -25 -18.000 AFY
Mendota Dam 204.8 Avenue 7.5 Bridge (Firebaugh) 195.2 Sack Dam 182.0 REACH 4 182.0 to
135.8
-5–0 - 0 Losses when wet; gaining in some areas (but
unquantifiable)
A Sack Dam 182.0 Ye–s - first 2
miles
N–o - next 1.5
miles
Ye–s - remaining
miles
Losing
State Route 152 Bridge 173.9 Yes Gaining
B Sand Slough Control Structure 168.5
Mariposa Slough Control Structure 168.4 Turner Island Road Bridge 157.2 444
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Landmark River Mile GSP Group Interconnected? Gaining or Losing? Quantity Gained/Loss (cfs) Notes Mariposa Bypass confluence 147.2 Bear Creek/Eastside Bypass confluence 135.8 REACH 5 135.8 to
118.0
Yes Gaining unquantifiable Likely gaining from ag/refuge draining but unquantifiable
Bear Creek/Eastside Bypass confluence 135.8 State Route 165 Bridge (Lander Avenue) 132.9 Salt Slough con fluence 127.7 State Route 140 Bridge (Fremont Ford) 125.1 Mud Slough confluence 121.2 Merced River confluence (Hills Ferry Bridge) 118.0 Newman to Crows Landing Northern & Central DeltaMendota
Yes Gaining 50 50
Crows Landing to Patterson Northern &
Central DeltaMendota
Region
Yes Gaining -50 to 200 -50 to 200
Patterson to Vernalis Northern &
Central DeltaMendota
Region
Yes Gaining 190 6.1 cfs/mi for 30.8 miles. Based on Cooley, W. 2001.

Groundwater flow net analysis for lower San Joaquin
River Basin. Memo to CRWQCB, August 8, 2001
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Groundwater Dependent Ecosystems
A groundwater dependent ecosystem (GDE) is defined under the GSP Emergency Regulations as referring “to ecological communities or species that depend on groundwater emerging from aquifers or on groundwater occurring near the ground surface” (§351(m)). Under §354.16(g) of the GSP Emergency Regulations, each Plan is required to identify GDEs within the subbasin utilizing data provided by DWR or the best available information. The following section describes the process for verifying GDEs within the Delta-Mendota Subbasin and the location of verified and potential GDEs.

The Natural Communities Commonly Associated with Groundwater (NCCAG) dataset (2018c) provided by DWR was used in conjunction with information provided by The Nature Conservancy (TNC) to identify GDEs within the Delta-Mendota Subbasin. To further screen available information regarding GDEs, each GSP Group developed individualized criteria. Additional details regarding the screening process implemented by each GSP can be found in the individual GSPs.

Based on the screening process implemented by each individual GSP Group, GDE polygons determined not to be GDEs were removed from the mapping. Figure CC-62Figure CC-62 and Figure CC-63Figure CC-63 summarize the results of the GDE analysis for the Subbasin. Results are compiled into two habitat classes: wetlands (Figure CC-62Figure CC-62) and vegetation (Figure CC-63Figure CC-63). Wetland features are commonly associated with surface expression of groundwater under natural, unmodified conditions. Vegetation feature types are commonly associated with the sub-surface presence of groundwater (phreatophytes – deep rooted plants). Confirmed GDEs have been grouped into larger polygons based on proximity and aquifer connection.

In general, identified Possible GDEs are primarily located along the San Joaquin River corridor, within the northern portion of the Northern & Central Delta-Mendota Region GSP, the SJREC GSP, the Grassland GSP, and the Fresno GSP Plan Areas, where some possible GDEs have been identified along ephemeral streams that originate from the Coast Range. Table CC-7Table CC-7 includes all freshwater species within the Delta-Mendota Subbasin as identified by TNC (2018). Per TNC data, these species (listed in Table CC-7Table CC-7) have either been observed or have the potential to exist within the Delta-Mendota Subbasin; however, the actual presence of these species have not been verified. As a result of the identification of Possible GDEs for the purpose of SGMA, no land use protections for GDEs are conveyed unless otherwise required. Additionally, the Delta Mendota Subbasin recognizes the opportunity to present further-refined GDE delineations in the subsequent GSP Updates. 446
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Figure CC-62: Groundwater Dependent Ecosystems, Wetlands 447
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Figure CC-63: Groundwater Dependent Ecosystems, Vegetation 448
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Table CC-7: List of Potential Freshwater Species
Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Actitis macularius Spotted Sandpiper Birds Aechmophorus clarkii Clark'sClark’s Grebe Birds Aechmophorus occidentalis Western Grebe Birds Agelaius tricolor Tricolored Blackbird Birds Bird of Conservation Concern Special Concern
Aix sponsa Wood Duck Birds Anas acuta Northern Pintail Birds Anas americana American Wigeon Birds Anas clypeata Northern Shoveler Birds Anas crecca Green-winged Teal Birds Anas cyanoptera Cinnamon Teal Birds Anas discors Blue-winged Teal Birds Anas platyrhynchos Mallard Birds Anas strepera Gadwall Birds Anser albifrons Greater Whitefronted Goose Birds
Ardea alba Great Egret Birds Ardea herodias Great Blue Heron Birds Aythya affinis Lesser Scaup Birds Aythya americana Redhead Birds Special Concern
Aythya collaris Ring-necked Duck Birds Aythya marila Greater Scaup Birds Aythya valisineria Canvasback Birds Special Botaurus lentiginosus American Bittern Birds Bucephala albeola Bufflehead Birds Bucephala clangula Common Goldeneye Birds Butorides virescens Green Heron Birds 449
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Calidris alpina Dunlin Birds Calidris mauri Western Sandpiper Birds Calidris minutilla Least Sandpiper Birds Chen caerulescens Snow Goose Birds Chen rossii Ross’s Goose Birds Chlidonias niger Black Tern Birds Special Concern
Chroicocephalus philadelphia Bonaparte’s Gull Birds Cistothorus palustris Marsh Wren Birds Cygnus columbianus Tundra Swan Birds Cypseloides niger Black Swift Birds Bird of Conservation Concern Special Concern
Dendrocygna bicolor
Fulvous WhistlingDuck Birds Special Concern
Egretta thula Snowy Egret Birds Empidonax traillii Willow Flycatcher Birds Bird of Conservation Concern Endangered Fulica americana American Coot Birds Gallinago delicata Wilson’s Snipe Birds Gallinula chloropus Common Moorhen Birds Geothlypis trichas Common Yellowthroat Birds
Grus canadensis Sandhill Crane Birds Haliaeetus leucocephalus Bald Eagle Birds Bird of Conservation Concern Endangered Himantopus mexicanus Black-necked Stilt Birds Icteria virens Yellow-breasted Chat Birds
Special Concern
Limnodromus scolopaceus
Long-billed Dowitcher Birds
Lophodytes cucullatus Hooded Merganser Birds
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Megaceryle alcyon Belted Kingfisher Birds Mergus merganser Common Merganser Birds Mergus serrator Red-breasted Merganser Birds
Numenius americanus Long-billed Curlew Birds Numenius phaeopus Whimbrel Birds Nycticorax nycticorax Black-crowned Night-Heron Birds
Oxyura jamaicensis Ruddy Duck Birds Pandion haliaetus Osprey Birds Watch listPelecanus erythrorhynchos American White Pelican Birds
Special Concern
Phalacrocorax auritus
Double-crested Cormorant Birds
Phalaropus tricolor Wilson’s Phalarope Birds Plegadis chihi White-faced Ibis Birds Watch listPluvialis squatarola Black-bellied Plover Birds Podiceps nigricollis Eared Grebe Birds Podilymbus podiceps Pied-billed Grebe Birds Porzana carolina Sora Birds Rallus limicola Virginia Rail Birds Recurvirostra americana American Avocet Birds Riparia riparia Bank Swallow Birds Threatened Setophaga petechia Yellow Warbler Birds Tachycineta bicolor Tree Swallow Birds Tringa melanoleuca Greater Yellowlegs Birds Tringa semipalmata Willet Birds Tringa solitaria Solitary Sandpiper Birds Vireo bellii Bell’s Vireo Birds Vireo bellii pusillus Least Bell’s Vireo Birds Endangered Endangered 451
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Xanthocephalusxanthocephalus
Yellow-headed Blackbird Birds
Special Concern
Artemia franciscana
San Francisco Brine Shrimp Crustaceans
Branchinecta conservatio
Conservancy Fairy Shrimp Crustaceans Endangered Special Branchinecta lindahli
Versatile Fairy Shrimp Crustaceans
Branchinecta longiantenna
Longhorn Fairy Shrimp Crustaceans Endangered Special
Branchinecta lynchi
Vernal Pool Fairy Shrimp Crustaceans Threatened Special Lepidurus packardi
Vernal Pool Tadpole Shrimp Crustaceans Endangered Special Linderiella occidentalis
California Fairy Shrimp Crustaceans Special
Oncorhynchus mykis–s - CV
Central Valley steelhead Fishes Threatened Special Oncorhynchus mykiss irideus Coastal rainbow trout Fishes
Pogonichthys macrolepidotus Sacramento splittail Fishes Special Concern
Actinemys marmorata Western Pond Turtle Herps
Special Concern
Ambystoma californiense
California Tiger Salamander Herps Threatened Threatened Anaxyrus boreas Boreal Toad Herps Pseudacris regilla
Northern Pacific Chorus Frog Herps
Rana boylii
Foothill Yellowlegged Frog Herps Under Review in the Candidate or Petition Process Special Concern Rana draytonii
California Redlegged Frog Herps Threatened Special Concern 452
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Spea hammondii Western Spadefoot Herps
Under Review in the Candidate or Petition Process
Special Concern
Thamnophis atratus
Santa Cruz Gartersnake Herps
Thamnophis elegans
Mountain Gartersnake Herps
Thamnophis gigas Giant Gartersnake Herps Threatened Threatened Thamnophis hammondii Two-striped Gartersnake Herps
Special Concern
Thamnophis sirtalis
Common Gartersnake Herps
Aeshnidae fam. Aeshnidae fam.

Insects & other inverts
Anax junius
Common Green Darner
Insects & other inverts
Brillia spp. Brillia spp.

Insects & other inverts
Callicorixa spp. Callicorixa spp.

Insects & other inverts
Capnia hitchcocki Arroyo Snowfly
Insects & other inverts
Chironomus spp. Chironomus spp.

Insects & other inverts
Coenagrionidae fam. Coenagrionidae fam.

Insects & other inverts
Corisella spp. Corisella spp.

Insects & other inverts
Cricotopus spp. Cricotopus spp.

Insects & other inverts
Ischnura cervula Pacific Forktail
Insects & other inverts
Ischnura denticollis
Black-fronted Forktail
Insects & other inverts
453
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Mesocapnia bulbosa Bulbous Snowfly
Insects & other inverts
Paraleptophlebia associata A Mayfly
Insects & other inverts
Paratanytarsus spp. Paratanytarsus spp.

Insects & other inverts
Phaenopsectra spp. Phaenopsectra spp.

Insects & other inverts
Procladius spp. Procladius spp.

Insects & other inverts
Psectrocladius spp. Psectrocladius spp.

Insects & other inverts
Tanypus spp. Tanypus spp.

Insects & other inverts
Tipulidae fam. Tipulidae fam.

Insects & other inverts
Trichocorixa spp. Trichocorixa spp.

Insects & other inverts
Castor canadensis American Beaver Mammals Lontra canadensis North American River Otter Mammals
Neovison vison American Mink Mammals Ondatra zibethicus Common Muskrat Mammals Anodonta californiensis California Floater Mollusks Special Margaritifera falcata Western Pearlshell Mollusks Special Pyrgulopsis diablensis Diablo Range Pyrg Mollusks Special Alopecurus saccatus Pacific Foxtail Plants Ammannia coccinea Scarlet Ammannia Plants Anemopsis californica Yerba Mansa Plants Arundo donax NA Plants Azolla filiculoides NA Plants 454
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Azolla microphylla
Mexican mosquito fern Plants Special
Baccharis salicina Plants Bacopa eisenii
Gila River Waterhyssop Plants
Bidens laevis
Smooth Burmarigold Plants
Bolboschoenus glaucus NA Plants Bolboschoenus maritimus paludosus NA Plants Callitriche marginata Winged Waterstarwort Plants
Ceratophyllum demersum Common Hornwort Plants
Chloropyresclle hispidum Plants Special
Chloropyron palmatum NA Plants Endangered Special Cotula coronopifolia NA Plants Crassula aquatica Water Pygmyweed Plants Crypsis vaginiflora NA Plants Cyperus erythrorhizos Red-root Flatsedge Plants Cyperus squarrosus Awned Cyperus Plants Downingia bella Hoover’s Downingia Plants Downingia pulchella Flat-face Downingia Plants Echinodorus berteroi Upright Burhead Plants Elatine brachysperma Shortseed Waterwort Plants Elatine californica California Waterwort Plants Eleocharis acicularis Least Spikerush Plants Eleocharis atropurpurea Purple Spikerush Plants Eleocharis coloradoensis Plants Eleocharis macrostachya Creeping Spikerush Plants 455
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Eleocharis montevidensis Sand Spikerush Plants Eleocharis quadrangulata NA Plants Elodea canadensis Broad Waterweed Plants Epilobium cleistogamum Cleistogamous Spike-primrose Plants
Eragrostis hypnoides Teal Lovegrass Plants Eryngium castrense Great Valley Eryngo Plants Eryngium racemosum Delta Coyote-thistle Plants Endangered Eryngium spinosepalum Spiny Sepaled Coyote-thistle Plants Special
Eryngium vaseyi vallicola Plants Eryngium vaseyi
Vasey’s Coyotethistle Plants
Euthamia occidentalis
Western Fragrant Goldenrod Plants
Hydrocotyle verticillata
Whorled Marshpennywort Plants
Juncus acuminatus Sharp-fruit Rush Plants Juncus xiphioides Iris-leaf Rush Plants Lasthenia ferrisiae Ferris’' Goldfields Plants Special Lasthenia fremontii Fremont’s Goldfields Plants Lemna aequinoctialis Lesser Duckweed Plants Lemna gibba Inflated Duckweed Plants Lemna minor Lesser Duckweed Plants Lepidium jaredii Jared’s Peppergrass Plants Special
Lepidium oxycarpum
Sharp-pod Peppergrass Plants
456
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Limnanthes douglasii
Douglas’' Meadowfoam Plants
Limosella acaulis Southern Mudwort Plants Lipocarpha micrantha Dwarf Bulrush Plants Ludwigia peploides NA Plants Ludwigia repens Creeping Seedbox Plants Lythrum californicum California Loosestrife Plants Marsilea vestita NA Plants Mimulus cardinalis Scarlet Monkeyflower Plants
Mimulus guttatus
Common Large Monkeyflower Plants
Montia fontana
Fountain Miner’slettuce Plants
Myosurus minimus NA Plants Myosurus sessilis Sessile Mousetail Plants Myriophyllum aquaticum NA Plants Najas guadalupensis Southern Naiad Plants Navarretia heterandra Tehama Navarretia Plants Navarretia leucocephala White-flower Navarretia Plants
Navarretia prostrata Prostrate Navarretia Plants Special Neostapfia colusana Colusa Grass Plants Threatened Endangered Panicum dichotomiflorum NA Plants Paspalum distichum Joint Paspalum Plants Persicaria hydropiperoides Plants Persicaria lapathifolia Plants Persicaria maculosa NA Plants Persicaria pensylvanica NA Plants 457
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Phacelia distans NA Plants Phyla lanceolata Fog-fruit Plants Phyla nodiflora Common Frog-fruit Plants Pilularia americana NA Plants Plagiobothrys acanthocarpus Adobe Popcornflower Plants
Plagiobothrys greenei
Greene’s Popcornflower Plants
Plagiobothrys humistratus
Dwarf Popcornflower Plants
Plagiobothrys leptocladus Alkali Popcorn-flower Plants Plantago elongata Slender Plantain Plants Pluchea odorata Scented Conyza Plants Pogogyne douglasii NA Plants Pogogyne zizyphoroides Plants Potamogeton diversifolius Water-thread Pondweed Plants
Potamogeton foliosus Leafy Pondweed Plants Potamogeton nodosus Longleaf Pondweed Plants Potamogeton pusillus Slender Pondweed Plants Psilocarphus brevissimus Dwarf Woolly-heads Plants Psilocarphus oregonus Oregon Woollyheads Plants
Psilocarphus tenellus NA Plants Puccinellia simplex Little Alkali Grass Plants Ranunculus sceleratus NA Plants Rorippa curvisiliqua Curve-pod Yellowcress Plants
Rorippa palustris Bog Yellowcress Plants
458
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Scientific Name Common Name Group Federal Protection Status State
Protection
Status
Rotala ramosior Toothcup Plants Ruppia cirrhosa Widgeon-grass Plants Ruppia maritima Ditch-grass Plants Sagittaria longiloba Longbarb Arrowhead Plants Sagittaria montevidensis calycina Plants Salix exigua Narrowleaf Willow Plants Salix gooddingii Goodding’s Willow Plants Schoenoplectus acutus occidentalis Hardstem Bulrush Plants Schoenoplectus americanus Three-square Bulrush Plants
Sinapis alba NA Plants Sparganium eurycarpum Plants Stuckenia pectinata Plants Typha domingensis Southern Cattail Plants Typha latifolia Broadleaf Cattail Plants Veronica americana American Speedwell Plants Wolffiella lingulata Tongue Bogmat Plants Zannichellia palustris Horned Pondweed Plants Source: The Nature Conservancy (TNC). 2018. Identifying Environmental Surface Water User–s - Freshwater Species List for Each Groundwater Basin dataset. https://groundwaterresourcehub.org/gde-tools/environmental-surface-water-beneficiaries/ 459
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4.2.8 Data Gaps
The Delta-Mendota Subbasin is an extensive subbasin covering a large area extending along the northwestern end of the San Joaquin Valley. While there is a significant amount of data available regarding various groundwater-related aspects of the Subbasin, much is still not known in multiple locations around the Subbasin. To this end, the following data gaps have been identified and will be addressed as part of the interim period between adoption of this GSP and its first 5-year update.  Information regarding subsidence varies in extent around the region. While there is a large amount of land elevation survey data available in association with the DMC and the San Joaquin River Restoration Program, other areas in the Delta-Mendota Subbasin require additional data collection to both further establish and monitor future land subsidence rates.  Only three shallow groundwater wells exist proximate to the northern end of the San Joaquin River (outside of the area being addressed by the San Joaquin River Restoration Program). Additional nested or clustered monitoring wells are required adjacent to the river on the northern end of the Subbasin to evaluate horizontal and vertical groundwater gradients, and in connection with river stage monitoring, to assess the interconnection between the San Joaquin River and the northeastern end of the Delta-Mendota Subbasin.
 There are a large number of wells in the Delta-Mendota Subbasin where no well construction information exists or is readily available. Video surveys and other surveys should be conducted on selected wells that may potentially be added to the Subbasin monitoring network to (1) identify where the wells are screened, and (2) determine if the well(s) are appropriate as additions to the GSP Groups’ groundwater monitoring programs.
 Mapping of GDEs in the Delta-Mendota Subbasin, as contained in this Common Chapter, is an initial assessment of their location. This mapping may be refined using most recent groundwater elevation/depth to water contour mapping.
 Monitoring networks contained herein are preliminary and were formulated based on existing well information. As additional wells are installed in the Subbasin and additional well construction information is obtained for existing wells, these networks may need to be refined to improve on the spatial (areal and vertical) distribution of monitoring points and the data collected for evaluation of conditions of the groundwater basin.
 The sustainable yield estimates and water budgets contained in this Common Chapter for both the Upper and Lower Aquifers were developed using limited data. As additional data are collected over the first five years, improved sustainable yield estimates and estimates of water in storage in both principle aquifers should be prepared utilizing the new data.

In addition to these Subbasin-level data gaps, additional data gaps have been identified for each GSP Plan Area. Please see the individual GSPs for additional identified data gaps.

4.3 Delta-Mendota Subbasin Water Budgets
This section describes the common coordinated assumptions agreed upon and utilized by each GSP Group in the Delta-Mendota Subbasin in developing the historical, current, and projected water budgets for their respective GSP Plan Areas. These coordinated historical, current, and projected water budgets 460
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were then compiled to prepare the subbasin-level water budgets required under the GSP Regulations § 357.4(b)(3)(B), presented below. The sustainable yield for the Upper Aquifer and Lower Aquifer developed at the Subbasin-level and agreed upon by all GSP Groups in the Delta-Mendota Subbasin is also presented along with a description as to how the sustainable yield for each primary aquifer was calculated.

4.3.1 Coordinated Assumptions
All common coordinated assumptions agreed upon and utilized by each GSP Group in preparing their respective historical, current, and projected water budgets are presented in Technical Memoranda 3 (Assumptions for the Historical, Current, and Projected Water Budgets of the Delta-Mendota Subbasin), which is included in Appendix B of this Common Chapter.

The data and methodologies used to develop the water budgets in the six individual GSPs (and compiled herein as the Subbasin Water Budgets) were coordinated with the express objective to “rely on the best available information and best available science to quantify the water budget for the basin” (Title 23 of the California Code of Regulations [23 CCR] § 354.18(e)). Given the complex nature of the Subbasin, different data sets and methodologies were appropriate for and/or available in different portions of the Subbasin. As such, a significant effort was made by the Subbasin GSAs to: (1) identify the different sources and accuracy of the available data; (2) consolidate these data and associated methodologies into a general hierarchy for use by the GSAs to honor the local conditions, while maintaining consistency with the intent of 23 CCR § 354.18(e); and (3) standardize the terminology for purposes of the Common Chapter presentation of the Subbasin Water Budget. These standardized water budget components and data sources are presented in Table CC-8 and Table CC-9 for the historic and current, and projected water budgets, respectively, and are further described below, while acknowledging that significant additional detail is presented in the six underlying GSPs. In some cases, data were not available or applicable, as acknowledged below and in the tables. Additionally, in some cases the specific terminology and/or the details of the calculations included in each underlying GSP remains unique relative to the standardized terminology and descriptions presented below; a full reconciliation of water budget nomenclature will be conducted as part of the 2025 GSP updates, as well as updates to the datasets and methodologies employed. Water use in the Subbasin is largely for agricultural purposes, with local municipal and industrial (M&I) uses. As appropriate, these M&I uses were quantified and incorporated in the individual GSP water budgets.

LAND SURFACE WATER BUDGET
The data sources/methodologies used to estimate the six major components of the Historical and Current Land Surface Water Budgets are summarized in Table CC-8 and for the Projected Land Surface Water Budgets in Table CC-9. A general description of each component and the data hierarchy that was applied by the GSAs is provided below, with further detail provided in the Water Budget sections of the six underlying GSPs. For purposes of the Subbasin GSPs, the Historical and Current Water Budgets represent Water Year (WY) 2003-2013, where the historical period is WY 2003-2012 and the current year is WY 2013. The Projected Water Budgets reflect projected conditions through 20701and consider the impacts 1 The Subbasin GSAs agreed to use actual data from WYs 2014-2017 and assume a repeat of the historical hydrology for the years WY 2018-2070. The selected period for the projected water budgets meets SGMA 461
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of climate change and projects and management actions (PMAs). To the extent possible the data sources and methodology used were consistent with those identified by the California Department of Water Resources (DWR) in Table 2 – Potential Data Sources to Support Water Budget Development and other sections of the Best Management Practices (BMP) –4 - Water Budget.1 As applicable and available, models and tools (e.g., the Central Valley Hydrologic Model 2 [CVHM2]) were used to support the local sources and assumptions incorporated into the development of the Subbasin Groundwater Water Budget. (1) Precipitation (Inflow). For the Historical and Current Land Surface Water Budgets, total precipitation across the Subbasin was estimated using either: (1) PRISM: the PrecipitationElevation Regressions on Independent Slopes Model (PRISM); (2) CIMIS: area-weighted data from the California Irrigation Management Information System (CIMIS) stations located in the Subbasin; California Data Exchange Center (CDEC) and/or (3) data from the National Water Service Station located in Los Banos, CA. Total precipitation was further parsed into effective and non-effective precipitation, as applicable to each GSP area, based on assumptions regarding deep percolation percentages and other losses.

For the Projected Land Surface Water Budgets, for WY 2014-2017, actual data were provided consistent with the process described above for the Historical and Current Water Budgets. For the projected WY 2018-2070 period, the 2030 Central Tendency and 2070 Central Tendency climate change factors and guidance provided by DWR were applied to the historical precipitation record to project the impact of climate change on precipitation across the Subbasin. For example, either (1) the Gridded Statewide Precipitation and Change Factors developed for the Water Storage Investment Program (WSIP) using the Variable Infiltration Capacity (VIC) Macroscale Hydrology Model (DWR, 2018) were applied to the available precipitation data sets for the Subbasin, or (2) recommendations from the Perspectives and Guidance for Climate Change Analysis document prepared by the DWR Climate Change Technical Advisory Group (CCTAG) were incorporated (DWR CCTAG, 2015).
(2) Applied Water – Groundwater (Inflow). To estimate the volume of applied groundwater for the Historical and Current Land Surface Water Budgets (including both agricultural and M&I pumping, as applicable to each GSP area), the total pumping within the Subbasin was estimated using the following hierarchy of sources, depending upon existing records: (1) Flow meters:
volumetric flow meter records from pumping wells; (2) Power bills: electricity bills from pumping wells (wherein information related to the number of kilowatt-hours used was converted to a pumping volume based on assumptions related to pumping lift and efficiency); and/or (3) Consumptive use: reported crop acreages and consumptive use data based on either Irrigation requirements by establishing a 50-year period, where the timeframe is continuous between the historic, current, and projected water budgets. The historic hydrologic period for simulating the projected water budget hydrologic schema was chosen as WY 1979-2017, then wrapping around to include WY 1965-1978 hydrology. Actual data and hydrology were used for WY 2014- 2017 with the representative water years simulating WY 2018 and beyond (e.g., WY2018 is represented by the hydrology from WY1979; WY2019 is represented by the hydrology from WY1980, and so forth, with the caveat that 1979 would represent the fifth year of the projection and following sequentially the historical water year 1965 would represent the forty-fourth year of the projection). 1 https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Groundwater-Management/SustainableGroundwater-Management/Best-Management-Practices-and-Guidance-Documents/Files/BMP-4-WaterBudget_ay_19.pdf 462
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Training and Research Center (ITRC)1 Mapping of Evapotranspiration with Internal Calibration (METRIC) procedure or crop coefficient methodologies (e.g., those provided in the Food and Agricultural Organization of the United States (FAO) Irrigation and Drainage Paper No. 56 (FAO-56) (Snyder et. al., 2000, Snyder and Bali, 2008) or the ITRC Crop Coefficient data for Zone 14), corrected as applicable, for applied local and imported surface water. This volume of applied groundwater is consistent with the volume estimated under Water Budget Component (9) Extraction of the Groundwater Water Budget (see below).

For the Projected Land Surface Water Budgets, for WY 2014-2017, actual data were provided, consistent with the process described above for the Historical and Current Water Budgets. For the projected (WY 2018-2070) period, the volume of applied groundwater was estimated using various, complementary methods, including: (1) as the difference between projected demand and the assumed volumes of precipitation, surface water deliveries, and tile drainage available to meet the demand, or (2) assuming future groundwater production rates would be equivalent to historical extractions for a given year type (e.g., future dry year production rates would be equivalent to average dry year production rates over the historical record). Climate change impacts and the effects of the planned projects and management actions (PMAs) are implicitly, rather than explicitly, accounted for (i.e., to the extent that climate change and PMAs increase or decrease the amount of water otherwise available to meet applied water demands, the volume of applied groundwater will be adjusted accordingly). Total inflow to Shasta Lake dictates the amount of imported surface water available for use in the Subbasin. The WSIP model was used to analyze the impacts of climate change on the Subbasin and anticipate projected inflow to Shasta Lake, and as to whether or not the water year would be classified as Shasta Critical under the Exchange Contract, the Refuge Contract, and by municipal users. (3) Surface Water Inflow (Inflow). Surface water serves as an inflow to Subbasin water budget as both applied surface water and as seepage from streams and rivers. To estimate the volume of applied surface water for the Historical and Current Land Surface Water Budgets, the total diversions within the Subbasin over the historical and current water budget time periods were reported using the best available data for each source. Deliveries from the Central Valley Project (CVP), State Water Project (SWP), the San Joaquin River, and other local streams and rivers were compiled from records from the following sources, including, but not limited to: State Water Resources Control Board (SWRCB) diversion reports; United States Bureau of Reclamation (USBR) Central Valley Operations (CVO); Meyers Water Bank Records; CVP refuge water supply delivery data; and GSA member agency records.

To account for seepage of surface water into the Subbasin from streams and rivers for the Historical and Current Water Budgets, California Data Exchange Center (CDEC) data were used (i.e., by comparing the reductions in measured flow at successive gauging stations after accounting for other diversions) and/or from estimates of seepage losses from certain water bodies from prior water infiltration studies or modeling efforts, as described in the individual GSPs. Seepage from streams and rivers is counted either towards the Groundwater Water Budget directly or towards the Land Surface Water Budget and then, because of the lack of storage capacity in the land surface system and by way of mass balance principles, some or all of this 1 California Polytechnic State University, San Luis Obispo 463
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water adds to the Groundwater Water Budget through Water Budget Component (6) Deep Percolation (see below).

For the Projected Land Surface Water Budgets, the volume of applied surface water was estimated as (1) the records of actual delivery data as available for the respective service areas for WY 2014-2017; and (2) estimates of anticipated future deliveries by WY type for WY 2018- 2070, inclusive of climate change considerations to the extent they could be reasonably estimated (i.e., directly modeled based on data provided by DWR and the USBR), or using water year types as a proxy (i.e., future dry year deliveries would reflect historical average dry year deliveries over the historical record). The impacts of planned PMAs on the availability of applied surface water volumes were also incorporated, as applicable.

For the Projected Land Surface Water Budgets, the volume of surface water seepage was adjusted, as applicable and available, based on climate change factors provided by DWR.

Changes to surface water seepage were directly estimated as a result of PMAs or other program implementation (e.g., the impact on seepage resulting from the San Joaquin River Restoration Program [SJRRP] implemented by the USBR).
(4) Surface Water Outflow (Outflow). As described above, total precipitation was parsed into effective and non-effective precipitation (i.e., the latter being that portion of the total precipitation that cannot be used by the plants because it either runs off or percolates beyond the root zone).

Similarly, a portion of the applied water can run off or deep percolate (typically termed “irrigation inefficiency”). Other surface water outflows (losses) from the Subbasin Land Surface Water Budget include agency-measured or estimated “spills” (i.e., outflow from tile drained fields, canal spills, field runoff, and precipitation runoff) and stream gauge readings, flow meter readings, and transfer pumping data. These collective data sets, sources, and methodologies were used to estimate the historical and current outflows from this component of the Subbasin Land Surface Water Budget.

For the Projected Land Surface Water Budgets, for WY 2014-2017, the data were provided consistent with the process described above for the Historical and Current Water Budgets. For the projected (WY 2018-2070) period, the volume of surface water outflows were estimated based on estimates provided by the GSA member agencies (using water year types as a proxy), while those components that may be impacted by climate change (e.g., runoff) were adjusted to reflect changes to precipitation and reference evapotranspiration (ETo). Changes to surface water outflows were directly estimated as a result of PMAs or other program implementation (e.g., water conservation programs to reduce spills) as information was available. (5) Evapotranspiration (Outflow). The largest outflow for the Historical and Current Land Surface Water Budget is evapotranspiration (consumptive use) by crops. As such, a combination of CIMIs ETo data, crop acreage, and crop coefficient data and methodologies (e.g., ITRC data and methodologies) were utilized to estimate the consumptive use, including municipal uses, of water in the Subbasin. In addition, direct evaporation from surface water bodies and phreatophytes (i.e., groundwater dependent ecosystems [GDEs]) was estimated based on the surface area and time period it was wetted.

For the Projected Land Surface Water Budgets, for WY 2014-2017, the actual data were provided consistent with the process described above for the Historical and Current Water Budgets. For the projected (WY 2018-2070) period, the 2030 Central Tendency and 2070 Central Tendency climate change factors or guidance provided by DWR were applied to the historical ETo record to 464
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project the impact of climate change on ETo across the Subbasin. For example, either the Gridded Statewide Precipitation and Change Factors developed for the WSIP using the VIC Macroscale Hydrology Model (DWR, 2018) were applied to the available ETo data sets for the Subbasin, or (2) recommendations from the Perspectives and Guidance for Climate Change Analysis document prepared by the DWR CCTAG (2015) were incorporated. (6) Deep Percolation (Outflow). For the Historical, Current, and Projected Land Surface Water Budgets, this water budget component is estimated as the sum of the other Outflow components (Water Budget Components 4 and 5) of the Land Surface Water Budget subtracted from the sum of the Inflow components (Water Budget Components 1 through 3) and represents the total volume of water that seeps past the root zone and into the Subbasin aquifer(s). This includes applied water seepage, as well as stream seepage (from the San Joaquin River, Delta-Mendota Canal, and California Aqueduct, and other canals), and delivery losses. To the extent that climate change and PMA implementation affects the volumes of Water Budget Components 1 through 5, these impacts are reflected in the resultant Outflow component, Water Budget Component (6) Deep Percolation, which serves as the inflow component, and Water Budget Component (7) Deep Percolation to the Groundwater Water Budget (see below).

GROUNDWATER WATER BUDGET
The data sources/methodologies used to estimate the Historical and Current Groundwater Water Budgets are summarized in Table CC-8 and for the Projected Groundwater Water Budgets in Table CC-9. A general description of each component and the data hierarchy that was applied by the GSAs is provided below, with further detail provided in the Water Budget sections of the six underlying GSPs. The time periods for the Groundwater Water Budgets are consistent with those used for the Land Surface Water Budgets, and likewise, to the extent possible, the data sources and methodology used were consistent with those identified by DWR in Table 2 – Potential Data Sources to Support Water Budget Development and other sections of the BMP –4 - Water Budget.1 As identified in Table CC-8 and Table CC-9, significant data gaps were identified in several of the GSPs on key aspects of the Groundwater Water Budget; additional efforts are on-going to address those data gaps and refine the water budgets as part of the 2025 GSP update. As applicable and available, models and tools (e.g., CVHM2, Westside Subbasin Groundwater Model, and a numerical flow model for the Farmers Water District and Fresno County areas) were used to validate the local sources and support assumptions used to develop the Subbasin Groundwater Water Budget.
(7) Deep Percolation (Inflow). In all instances, this component of the Groundwater Water Budget is directly linked to the Water Budget Component (6) Deep Percolation of the Land Surface Water Budget. To the extent that climate change is factored into the Historical, Current, and Projected Land Surface Water Budgets, those impacts are reflected in the varying volumes of deep percolation that are assumed to recharge the aquifer system(s) via infiltration. 1 https://water.ca.gov/-/media/DWR-Website/Web-Pages/Programs/Groundwater-Management/SustainableGroundwater-Management/Best-Management-Practices-and-Guidance-Documents/Files/BMP-4-WaterBudget_ay_19.pdf 465
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(8) Lateral Subsurface Flow (Inflow). For the Historical and Current Groundwater Water Budgets, this component is estimated somewhat differently for the Upper and Lower Aquifer portions of the Subbasin.
8A. Upper Aquifer. For the Upper Aquifer, lateral inflows were generally estimated using Darcy’s equation1 and estimated aquifer characteristics, or a groundwater flow model, as available.

Aquifer transmissivity values were compiled from aquifer tests, model parameters and other sources, while observed or simulated water level maps for wet, normal, and dry water year types and hydrographs were prepared to determine the elevation and direction of groundwater flow between GSP areas within the Subbasin and across Subbasin boundaries. Mountain front recharge from the Coastal Range was also assumed to provide an additional source of inflow to the Upper Aquifer.
8B. Lower Aquifer. To the extent possible, lateral inflows to the Lower Aquifer were estimated, primarily using Darcy’s equation and estimated aquifer characteristics, and coarse assumptions regarding contributions of other sources of inflow, or via a groundwater flow model, as available.

However, this portion of the Groundwater Budget was acknowledged as a significant data gap, which the GSAs are working to address through the collection of additional data, etc.

In instances where there was significant downward flow between the Upper and Lower Aquifers, vertical flow was estimated using Darcy’s equation, estimated aquifer characteristics, and groundwater gradients. Aquifer transmissivity values were compiled from aquifer tests, model parameters and other sources, while water level maps for wet, normal, and dry water year types were prepared to determine the elevation and groundwater gradient. Furthermore, flow to the Lower Aquifer from the Upper Aquifer is acknowledged as a data gap.

Projected Groundwater Water Budget. For the Projected Groundwater Water Budgets, for WY 2014-2017, the data were provided consistent with the process described above for the Historical and Current Water Budgets. For the projected (WY 2018-2070) period, this component is generally estimated using historical inflows by water year type as a proxy (i.e., the underflows used in the Historical and Current Water Budgets were averaged by WY type and used throughout the Projected Water Budget period). Impacts of climate change are implicitly incorporated, and expected increases in inflows as a result of PMAs (including projected groundwater banking activities) are directly incorporated to the extent the information was provided by the GSAs. As additional data are obtained during implementation of the GSPs, the inputs will be updated and improved to revise the Projected Groundwater Water Budget. (9) Extraction (Outflow). Consistent with the methodology used to estimate Water Budget Component (2), Applied Groundwater, of the Historical and Current Land Surface Water Budgets, the total pumping from the Subbasin aquifers was estimated using the following hierarchy of sources depending upon available records: (1) Flow meters: Volumetric flow meter records from pumping wells; (2) Power bills: Electricity bills from pumping wells (wherein information related to the number of kilowatt-hours used was converted to a pumping volume based on assumptions related to pumping lift and efficiency and duration of operation); and/or (3) 1 Darcy’s equation in which groundwater flow velocity is identified as a function of the aquifer hydraulic conductivity and hydraulic gradient based upon measured water levels and aquifer properties. Freeze, R.A. and Cherry, J.A. 1979. Groundwater. Prentice Hall, Inc. Englewood Cliffs, NJ. p 16. 466
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Consumptive use: crop acreages and consumptive use data based on either ITRC-METRIC or crop coefficient methodologies. While the exact distribution of pumping from the Upper and Lower Aquifers is acknowledged as a data gap, total extractions were assumed to be partitioned between the aquifers, with the majority of extractions (80-90%) occurring in the Upper Aquifer.

Information regarding well construction obtained and compiled from the local and Subbasin Well Census and Inventory projects completed by the GSAs in 2022 will be used to further improve the estimated allocation of groundwater extraction between the aquifers in the 2025 GSP update.

For the Projected Groundwater Water Budgets, for WY 2014-2017, the data were provided, consistent with the process described above for the Historical and Current Water Budgets. For the projected (WY 2018-2070) period, the volume of pumped groundwater was estimated using various, complimentary methods, including (1) as the difference between projected demand and the assumed volumes of precipitation, surface water deliveries, and tile drainage available to meet the demand, or (2) assuming future groundwater production would be equivalent to historical extractions for a given year type (e.g., future dry year production rates would be equivalent to average dry year production rates over the historical record, with the exception of M&I pumping which was projected based on information provided in various source documents such as Urban Water Management Plans). Climate change impacts and the effect of the planned PMAs are implicitly, rather than explicitly, accounted for.
(10) Lateral Subsurface Flow (Outflow). For the Historical and Current Groundwater Water Budgets, this component was estimated somewhat differently for the Upper and Lower Aquifer portions of the Subbasin, but similarly to Water Budget Component (8) of the Groundwater Water Budget.
10A. Upper Aquifer. Lateral outflows were generally estimated using Darcy’s equation and estimated aquifer characteristics, and validated by a groundwater flow model, as available.

Aquifer transmissivity values were compiled from aquifer tests, model parameters and other sources, while observed or simulated water level maps for wet, normal, and dry water year types and hydrographs were prepared to determine the elevation and direction of groundwater flow between GSP areas within the Subbasin and across Subbasin boundaries. 10B. Lower Aquifer. To the extent possible, lateral outflows from the Lower Aquifer were estimated, primarily using Darcy’s equation and estimated aquifer characteristics, and validated by a groundwater flow model, as available. However, this portion of the Groundwater Water Budget was acknowledged as a significant data gap which the GSAs are working to address through the collection and evaluation of additional data, etc.

Projected Groundwater Water Budget. For the Projected Groundwater Water Budgets, for WY 2014-2017, the data were provided, consistent with the process described above for the Historical and Current Water Budgets. For the projected (WY 2018-2070) period, this component is generally estimated using historical outflows by water year type as a proxy (i.e., the underflows used in the Historical and Current Water Budgets were averaged by WY type and used throughout the Projected Water Budget period). Impacts of climate change are implicitly incorporated, and expected increases in outflows as a result of PMAs (including projected groundwater banking activities) are directly incorporated to the extent the information was provided by the GSAs.
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(11) Change in Storage. For the Historical and Current Groundwater Water Budgets, this component was estimated somewhat differently for the Upper and Lower Aquifer portions of the Subbasin.
11A. Upper Aquifer. A sum of the Outflow components (Water Budget Components 9 through 10) of the Groundwater Water Budget was subtracted from the Inflow components (Water Budget Components 7 and 8) to assess the change in storage. These estimates were also compared in some of the GSPs to the available hydrographs, water level contour maps, and assumed aquifer storativity values from local data sets and models to assess and confirm change in storage, and assumed consumptive use data.
11B. Lower Aquifer. Approaches varied among the GSPs given the limited available data, which the GSAs are working to address through the collection of additional data, etc. Change in storage was estimated using measured subsidence as a proxy (i.e., due to compaction caused by inelastic land subsidence), as the difference between inflows and outflows based on modeled results, or as an assumed proportion of overall groundwater change in storage. These estimates were also compared in some of the GSPs to the available hydrographs, water level contour maps, and assumed aquifer storativity values from local data sets and models to assess and confirm change in storage, and assumed consumptive use data.

Projected Groundwater Water Budgets. For the Projected Groundwater Water Budgets, for WY 2014-2017, the data were provided, consistent with the process described above for the Historical and Current Water Budgets. For the projected (WY 2018-2070) period, the change in storage volumes used in the Historical and Current Water Budgets were averaged by water year type and used throughout the projected water budget period, or were calculated as the difference between inflows and outflows.
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Table CC-8: Historical and Current Water Budgets Data Sources Water Budget Flow Direction Flow Budget Category Aliso Water District Farmers Water District Fresno County Grassland Northern & Central Delta- Mendota San Joaquin River Exchange Contractors Land Surface Inflow Precipitation
Precipitation-Elevation Regressions on Independent Slopes Model (PRISM) and California Irrigation Management Information System (CIMIS) PRISM PRISM and CIMIS PRISM and CIMIS CIMIS and National Weather Service (NWS) Land Surface Inflow Applied Water - Groundwater Consumptive use Flow meters Flow meters, power bills, and consumptive use
Flow meters and consumptive use Flow meters
Land Surface Inflow Surface Water Inflow
State Water Resources Control Board (SWRCB) diversion reports; landowner records San Joaquin River inflows
United States Bureau of Reclamation (USBR) Central Valley Operations (CVO); Meyers Water Bank Records Central Valley Project (CVP) refuge water supply delivery data USBR CVO and SWRCB diversion reports
USBR CVO; California Data Exchange Center (CDEC) where available, water infiltration study used otherwise Land Surface Outflow Surface Water Outflow Non-effective precipitation Transfer pumping and San Joaquin River outflows
Transfer pumping that exceeds applied groundwater
Non-effective precipitation and agency measured spills
Evapotranspiration and noneffective precipitation) Non-effective precipitation and flow meter readings Land Surface Outflow Evapotranspiration Vegetation coefficients and CIMIS Land Surface Outflow Deep Percolation Land Surface Budget Inflow- Outflow Groundwater Inflow Infiltration Land Surface Budget Inflow - Outflow Groundwater Inflow Lateral subsurface flow - Upper Aquifer Darcy’s equation (groundwater levels and transmissivities) Groundwater Inflow Lateral subsurface flow - Lower Aquifer Unused - Data Gap Darcy’s equation (groundwater levels and transmissivities) Data G–p - Assumed 20% of total inflows. Darcy’s equation (groundwater levels and transmissivities) Groundwater Outflow Extraction - Upper Aquifer Consumptive use and irrigation efficiency Flow meters Flow meters, power bills and consumptive use Flow meters and consumptive use Flow meters Groundwater Outflow Extraction - Lower Aquifer Unused - Data Gap Flow meters Flow meters, power bills and consumptive use
Flow meters and consumptive use Assumed 10% of total pumping Groundwater Outflow Lateral subsurface flow - Upper Aquifer Darcy’s equation (groundwater levels and transmissivities) Groundwater Outflow Lateral subsurface flow - Lower Aquifer Unused - Data Gap Darcy’s equation (groundwater levels and transmissivities) Groundwater Change in Storage Upper Aquifer Inflow - Outflow Groundwater Change in Storage Lower Aquifer Land subsidence as proxy Inflow - Outflow Land subsidence as proxy 469
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Table CC-9: Projected Water Budgets Data Sources
Water Budget Flow Direction Flow Budget Category Aliso Water District Farmers Water District Fresno County Grassland Northern & Central Delta- Mendota San Joaquin River Exchange Contractors Land Surface Inflow Precipitation Precipitation-Elevation Regressions on Independent Slopes Model (PRISM), applying climate change factors (CCF) PRISM and California Irrigation Management Information System (CIMIS), applying CCF CIMIS and National Weather Service (NWS), applying CCF Land Surface Inflow Applied Water - Groundwater Consumptive use Flow meters and consumptive use Flow meters Land Surface Inflow Surface Water Inflow State Water Resources Control Board (SWRCB) diversion reports, using water year (WY) types as a proxy San Joaquin River inflows (CDEC and United States Geological Survey [USGS]) Mendota Pool Infloww - USBR CVO
USBR CVO and SWRCB diversion reports, using WY types as a proxy
USBR CVO; California Data Exchange Center (CDEC) where available, using WY types as a proxy; Water infiltration study used otherwise Land Surface Outflow Surface Water Outflow
Non-effective precipitation calculated with CCF and WY types as a proxy for quantity San Joaquin River outflows (CDEC and USGS)
Mendota Pool outflows (USBR CVO)
Non-effective precipitation and agency measured spills calculated with CCF and WY types as a proxy for quantity Non-effective precipitation
calculated with CCF and WY types
as a proxy for quantity
Non-effective precipitation and
agency measured spills calculated
with CCF and WY types as a
proxy for quantity
Land Surface Outflow Evapotranspiration Vegetation coefficients and CIMIS (calculated with CCFs and WY types as a proxy) Land Surface Outflow Deep Percolation Land Surface Inflow - Outflow Groundwater Inflow Infiltration Land Surface Budget Inflow - Outflow Groundwater Inflow Lateral subsurface flow - Upper Aquifer Darcy’s equation (groundwater levels and transmissivities) using WY types as a proxy Groundwater Inflow Lateral subsurface flow - Lower Aquifer Unused - Data Gap Darcy’s equation (groundwater levels and transmissivities) using WY types as a proxy Data Gap - Assumed 20% of total inflows. Darcy’s equation (groundwater levels and transmissivities) using WY types as a proxy Groundwater Outflow Extractiono - Upper Aquifer Consumptive use and irrigation efficiency using WY type as a proxy with CCFs and PMAs Adjusted historic metered data using WY type as
a proxy with CCFs and PMAs Adjusted historic metered data and consumptive use using WY type as a proxy with CCFs and PMAs Groundwater Outflow Extractiono - Lower Aquifer Unused - Data Gap Not Applicable Unused - Data Gap Adjusted historic metered data and consumptive use using WY type as a proxy with CCFs and PMAs Groundwater Outflow Lateral subsurface flow - Upper Aquifer Darcy’s equation (groundwater levels and transmissivities) using WY types as a proxy with CCFs Groundwater Outflow Lateral subsurface flow - Lower Aquifer Unused – Data Gap Darcy’s equation (groundwater levels and transmissivities) using WY types as a proxy with CCFs Data Gap - Assumed 20% of total inflows. Darcy’s equation (groundwater levels and transmissivities) with CCFs Groundwater Change in Storage Upper Aquifer Inflow - Outflow Groundwater Change in Storage Lower Aquifer Unused – Data Gap Inflow - Outflow Projected land subsidence and WY types used as a proxy with CCFs and PMAs Inflow - Outflow
Projected land subsidence and WY types used as proxy with CCFs and PMAs 470
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4.3.2 GSP-Level Water Budgets
Individual historical, current, and projected water budgets were developed by each GSP Group for their respective Plan Area. For more information on the development of those water budgets, as well as tabular and graphical representation of the results, refer to the respective sections of the individual GSPs.

All historical, current, and projected water budgets developed within the Delta-Mendota Subbasin are consistent with GSP Regulations § 354.18 Water Budget, and DWR’s Best Management Practices for the Sustainable Management of Groundwater Water Budget BMP (2016c) document was used when and where applicable at the discretion of each GSP Group.

4.3.3 Coordinated Water Budgets
The land surface budget, groundwater budget, and annual change in storage for the historical water budget, current water budget, and projected water budget with climate change factors (CCFs) and projects and management actions for the Delta-Mendota Subbasin were developed by compiling the water budgets prepared by each of GSP Group. The land surface budget is an accounting of water flows into and out of the land surface above an aquifer within with Delta-Mendota Subbasin, where inflows and outflows include flow between GSP Groups and neighboring subbasins, the atmosphere, and the groundwater aquifer below. The groundwater budget is an accounting of groundwater flows into and out of the two principal groundwater aquifers (Upper Aquifer and Lower Aquifer) within the Delta-Mendota Subbasin, where inflows and outflows include flow between GSP Groups and neighboring subbasins as well as the above land surface.

Subsequent to the submittal of the Delta-Mendota GSP in January 2022, and in response to the Consultation Initiation Letter (CIL) received from DWR on January 21, 2022 in which DWR stated that, while the same data may have been used in developing the water budgets, the terminology used to describe those data sets were not consistent across the basin, the Delta-Mendota Subbasin GSAs acknowledge additional detail was needed to demonstrate that all water budget components across the six Subbasin GSPs utilize the same data and methodologies. As such, subsequent to receipt of the CIL, the Technical Working Group and Coordination Committee met to identify the specific data used and to develop a consistent terminology for the various water budget components. Additionally, the Technical Working Group attempted to simplify the presentation of the Subbasin water budgets through a reduction in the number of water budget components. The mapping of the original GSP water budget components into the revised simplified coordinated water budget component terminology is discussed in the prior section (Section 4.3.1 of this revised Common Chapter).

After agreeing to the set of common simplified definitions for water budget components, the six DeltaMendota GSP groups mapped their prior water budget components to the new common definitions.

The revised land surface budget and groundwater budget are presented respectively for the historical water budget in Table CC-10Table CC-8 and Table CC-11Table CC-9, for the current water budget in Table CC-12Table CC-10 and Table CC-13Table CC-11, and for the projected water budget with climate change factors and projects and management actions in Table CC-14Table CC-12 and Table CC-15Table CC-13. All categories presented in the land surface budget and groundwater budget tables were agreed upon by all Delta-Mendota GSP Groups, with representatives from each GSP group tasked with filling out these budget tables as appropriate to account for the unique hydrology, land use, and water use within their respective GSP regions. The tables below are simply compilations of the individual 471
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GSP water budget data as provided by their respective plan preparers, and no water budget data were modified during the mapping process.

Individual GSAs and agencies in the Delta-Mendota Subbasin understand that the historical, current, and projected water budgets were completed using best available science and data, and efforts were made to use the same data sources throughout the Subbasin where available, though due to variability in data availability throughout the Subbasin, the best available data were used and characterized appropriately.

Where data gaps exist, the individual GSAs and agencies intend to conduct the work necessary to substantiate or improve the estimates and assumptions developed for determining their water budgets.

Nothing in this part, or in any groundwater sustainability plan adopted pursuant to this part, determines, or alters surface water rights or groundwater rights under common law or any provision of law that determines or grants surface water rights.
. Figure CC-64Figure CC-64 shows the revised average annual and cumulative change in storage in both principal aquifers under the Subbasin projected water budget (including application of climate change factors and the addition of projects and management actions).

Individual GSAs and agencies in the Delta-Mendota Subbasin understand that the historical, current and projected water budgets were completed using best available science and data. Where data gaps exist, the individual GSAs and agencies intend to conduct the work necessary to substantiate or improve the estimates and assumptions developed for determining their water budgets. Nothing in this part, or in any groundwater sustainability plan adopted pursuant to this part, determines or alters surface water rights or groundwater rights under common law or any provision of law that determines or grants surface water rights.
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Table CC-108: Delta-Mendota Subbasin Historical Water Budget, Land Surface Budget Land Surface Budget
Water Year Water Year Type
Inflows Outflows
Precipitation Applied Wat–r - Groundwater Surface Water Inflows Total Inflows Surface Water Outflows Evapotranspiration Deep Percolation Total Outflows 2003 N 450,000 395,000 2,501,000 3,346,000 1,306,000 1,772,000 293,000 3,371,000 2004 D 412,000 417,000 2,433,000 3,262,000 1,206,000 1,760,000 315,000 3,281,000 2005 W 739,000 303,000 2,764,000 3,806,000 1,614,000 1,810,000 352,000 3,776,000 2006 W 571,000 293,000 3,311,000 4,175,000 2,111,000 1,804,000 296,000 4,211,000 2007 D 258,000 474,000 2,485,000 3,217,000 1,230,000 1,701,000 310,000 3,241,000 2008 D 328,000 527,000 2,295,000 3,150,000 1,140,000 1,769,000 331,000 3,240,000 2009 N 304,000 511,000 2,191,000 3,006,000 1,017,000 1,813,000 327,000 3,157,000 2010 N 539,000 380,000 2,637,000 3,556,000 1,515,000 1,655,000 406,000 3,576,000 2011 W 626,000 279,000 3,283,000 4,188,000 2,013,000 1,799,000 414,000 4,226,000 2012 D 275,000 470,000 2,582,000 3,327,000 1,301,000 1,679,000 355,000 3,335,000 Water Year Water Year Type Precipitation Applied Wate–r - Groundwater Applied Wate–r - Imported Surface Water Total Inflows Runoff Evapotranspiration Surface Water Outflows Deep Percolation Total Outflows 2003 Normal 451,000 382,000 1,485,000 2,364,000 310,000 1,771,000 31,000 291,000 2,403,000 2004 Dry 412,000 398,000 1,486,000 2,341,000 263,000 1,764,000 31,000 304,000 2,362,000 2005 Wet 739,000 285,000 1,483,000 2,567,000 357,000 1,811,000 35,000 338,000 2,541,000 2006 Wet 572,000 270,000 1,499,000 2,399,000 318,000 1,795,000 34,000 289,000 2,436,000 2007 Dry 259,000 471,000 1,499,000 2,275,000 240,000 1,724,000 31,000 307,000 2,302,000 2008 Dry 329,000 529,000 1,382,000 2,288,000 224,000 1,797,000 30,000 327,000 2,378,000 2009 Normal 304,000 517,000 1,360,000 2,227,000 191,000 1,843,000 30,000 321,000 2,385,000 2010 Normal 538,000 371,000 1,392,000 2,354,000 283,000 1,669,000 30,000 394,000 2,376,000 2011 Wet 626,000 259,000 1,556,000 2,518,000 321,000 1,794,000 34,000 402,000 2,551,000 2012 Dry 276,000 471,000 1,505,000 2,303,000 223,000 1,709,000 30,000 353,000 2,315,000 Table CC-119: Delta-Mendota Subbasin Historical Water Budget, Groundwater Budget Groundwater Budget
Water Year Water Year Type
Inflows Outflows Change in Storage
Infiltration
Lateral Subsurface Flow
Total Inflows
Groundwater Extraction Lateral Subsurface Flow
Total Outflows
Estimated Annual Change in Groundwater
Storage
Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Total 2003 N 324,000 196,000 117,000 637,000 357,000 39,000 260,000 106,000 762,000 17,000 5,000 22,000 2004 D 345,000 180,000 114,000 639,000 376,000 42,000 286,000 132,000 836,000 (180,000) (48,000) (228,000) 473
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-151
June 2022
Common Chapter August 2019June 2022
2005 W 424,000 223,000 128,000 775,000 268,000 36,000 269,000 78,000 651,000 223,000 14,000 237,000 2006 W 394,000 203,000 120,000 717,000 260,000 34,000 264,000 75,000 633,000 18,000 (23,000) (5,000) 2007 D 358,000 161,000 99,000 618,000 431,000 48,000 280,000 130,000 889,000 (282,000) (67,000) (349,000) 2008 D 371,000 169,000 106,000 646,000 481,000 55,000 293,000 141,000 970,000 (341,000) (80,000) (421,000) 2009 N 361,000 195,000 112,000 668,000 466,000 53,000 273,000 117,000 909,000 (134,000) (28,000) (162,000) 2010 N 470,000 211,000 124,000 805,000 350,000 39,000 264,000 116,000 769,000 180,000 (4,000) 176,000 2011 W 515,000 205,000 124,000 844,000 248,000 32,000 277,000 83,000 640,000 125,000 (23,000) 102,000 2012 D 417,000 168,000 107,000 692,000 432,000 45,000 288,000 141,000 906,000 (171,000) (62,000) (233,000) Groundwater Budget
Water Year Water Year Type
Inflows Outflows Change in Storage
Deep Percolation
Subsurface
Groundwater
Inflows Seepage
through
Corcoran
Clay
Other
Direct
Recharge
Total
Inflows
Groundwater
Extraction from
Upper Aquifer
Groundwater
Extraction from
Lower Aquifer
Subsurface
Groundwater
Outflows
Total
Outflows
Estimated Annual Change in Groundwater Storage
Precipitation
Infiltration
Surface
Water
Infiltration
Applied
Water
Infiltration
Upper
Aquifer
Lower
Aquifer
Upper
Aquifer
Lower
Aquifer Inflows Outflows
Change in
Storag–e -
Upper
Aquifer
Change in
Storag–e -
Lower
Aquifer
Change in
Storag–e -
Total
2003 Normal 51,000 66,000 174,000 206,000 68,000 45,000 32,000 642,000 350,000 49,000 210,000 105,000 759,000 641,000 759,000 20,000 5,000 24,000 2004 Dry 36,000 65,000 204,000 184,000 64,000 45,000 30,000 628,000 365,000 49,000 233,000 131,000 823,000 628,000 822,000 (183,000) (50,000) (232,000) 2005 Wet 78,000 79,000 181,000 229,000 78,000 45,000 72,000 762,000 252,000 47,000 223,000 78,000 645,000 762,000 645,000 212,000 14,000 225,000 2006 Wet 59,000 78,000 152,000 208,000 70,000 45,000 98,000 710,000 238,000 46,000 221,000 78,000 628,000 710,000 628,000 14,000 (25,000) (11,000) 2007 Dry 23,000 66,000 218,000 171,000 50,000 45,000 48,000 621,000 431,000 57,000 217,000 127,000 877,000 621,000 876,000 (272,000) (68,000) (339,000) 2008 Dry 26,000 69,000 233,000 186,000 57,000 45,000 40,000 656,000 475,000 70,000 234,000 131,000 955,000 655,000 954,000 (321,000) (81,000) (403,000) 2009 Normal 21,000 66,000 235,000 207,000 62,000 45,000 33,000 669,000 469,000 66,000 210,000 104,000 894,000 669,000 893,000 (123,000) (28,000) (151,000) 2010 Normal 53,000 73,000 267,000 230,000 74,000 45,000 65,000 807,000 335,000 52,000 215,000 112,000 759,000 808,000 759,000 190,000 (5,000) 184,000 2011 Wet 67,000 96,000 239,000 217,000 74,000 45,000 101,000 839,000 234,000 40,000 229,000 86,000 634,000 840,000 633,000 124,000 (23,000) 100,000 2012 Dry 26,000 71,000 257,000 180,000 57,000 45,000 62,000 698,000 432,000 56,000 230,000 136,000 899,000 698,000 898,000 (162,000) (61,000) (224,000) 474
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-152
June 2022
Common Chapter August 2019June 2022
Table CC-1210: Delta-Mendota Subbasin Current Water Budget, Land Surface Budget Land Surface Budget
Water Year Water Year Type
Inflows Outflows
Precipitation Applied Wat–r - Groundwater Surface Water Inflows Total Inflows Surface Water Outflows Evapotranspiration Deep Percolation Total Outflows 2013 D 318,000 521,000 2,597,000 3,436,000 1,386,000 1,671,000 402,000 3,459,000 Land Surface Budget
Water Year Water Year Type
Inflows Outflows
Precipitation Surface Water Inflows Applied Wate–r - Groundwater Applied Wate–r - Imported Surface Water Other Direct Recharge Total Inflows Runoff Evapotranspiration Surface Water Outflows Deep Percolation Total Outflows 2013 Dry 318,000 31,000 514,000 1,428,000 17,000 2,308,000 228,000 1,685,000 30,000 385,000 2,328,000 Table CC-1311: Delta-Mendota Subbasin Current Water Budget, Groundwater System Groundwater Budget
Water Year Water Year Type
Inflows Outflows Change in Storage
Infiltration
Lateral Subsurface Flow
Total Inflows
Groundwater Extraction Lateral Subsurface Flow
Total Outflows
Estimated Annual Change in Groundwater
Storage
Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Total 2013 D 467,000 173,000 112,000 752,000 477,000 51,000 278,000 136,000 942,000 (128,000) (55,000) (183,000) Groundwater Budget
Water Year Water Year Type
Inflows Outflows Change in Storage
Deep Percolation
Subsurface
Groundwater
Inflows Seepage
through
Corcoran
Clay
Other
Direct
Recharge
Total
Inflows
Groundwater
Extraction from
Upper Aquifer
Groundwater
Extraction from
Lower Aquifer
Subsurface
Groundwater
Outflows
Total
Outflows
Estimated Annual Change in Groundwater Storage
Precipitation
Infiltration
Surface
Water
Infiltration
Applied
Water
Infiltration
Upper
Aquifer
Lower
Aquifer
Upper
Aquifer
Lower
Aquifer Inflows Outflows
Change in
Storag–e -
Upper
Aquifer
Change in
Storag–e -
Lower
Aquifer
Change in
Storag–e -
Total
2013 Dry 28,000 68,000 289,000 177,000 67,000 45,000 65,000 739,000 447,000 65,000 220,000 140,000 917,000 738,000 917,000 (123,000) (53,000) (176,000) 475
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-153
June 2022
Common Chapter August 2019June 2022
Table CC-1412: Delta-Mendota Subbasin Projected Water Budget, Land Surface Budget (containing climate change factors and projects and management actions) Land Surface Budget
Inflows Outflows
Precipitation Applied Water - Groundwater Surface Water Inflow Applied Waer - Groundwater (Project Effect–) - NCDM Only Applied Water - Imported Surface Water (Project Effect–) - NCDM Only Project Effects - All GSP Groups Total Inflows Surface Water Outflow Evapotranspiration Crop Evapotranspiration - Aliso Only Canal/Reservoir Evaporation - Aliso Only Deep Percolation Runoff (Project Effect–) - NCDM Only Project Effects - All GSP Groups Total Outflows 2014 SC 283,000 601,000 1,725,000 0 0 1,000 2,610,000 852,000 1,616,000 0 0 230,000 0 0 2,698,000 2015 SC 363,000 650,000 1,247,000 0 0 0 2,260,000 479,000 1,528,000 0 0 287,000 0 0 2,294,000 2016 D 712,000 392,000 1,605,000 0 0 0 2,709,000 631,000 1,618,000 0 0 403,000 0 0 2,652,000 2017 W 686,000 303,000 3,651,000 0 0 6,000 4,646,000 2,423,000 1,773,000 0 0 445,000 0 0 4,641,000 2018 N 527,000 389,000 2,628,000 (6,000) 0 7,000 3,545,000 1,506,000 1,660,000 0 0 403,000 0 0 3,569,000 2019 W 712,000 266,000 3,162,000 (7,000) 2,000 6,000 4,141,000 1,975,000 1,810,000 0 0 368,000 0 0 4,153,000 2020 D 434,000 394,000 2,187,000 (6,000) 9,000 7,000 3,025,000 939,000 1,726,000 0 0 343,000 0 0 3,008,000 2021 W 808,000 261,000 3,261,000 (7,000) 7,000 6,000 4,336,000 2,025,000 1,821,000 0 0 403,000 0 0 4,249,000 2022 W 1,021,000 249,000 3,266,000 (7,000) 7,000 6,000 4,542,000 2,190,000 1,834,000 0 0 449,000 0 0 4,473,000 2023 N 580,000 389,000 2,658,000 (8,000) 6,000 7,000 3,632,000 1,470,000 1,711,000 0 0 403,000 0 0 3,584,000 2024 D 573,000 387,000 2,176,000 (3,000) 6,000 6,000 3,145,000 963,000 1,726,000 0 0 374,000 0 0 3,063,000 2025 W 884,000 261,000 3,256,000 (7,000) 7,000 6,000 4,407,000 1,993,000 1,847,000 0 0 424,000 0 0 4,264,000 2026 D 575,000 483,000 2,098,000 (43,000) 52,000 9,000 3,174,000 914,000 1,785,000 0 0 412,000 0 0 3,111,000 2027 D 653,000 481,000 2,078,000 (41,000) 49,000 9,000 3,229,000 914,000 1,766,000 0 0 419,000 0 0 3,099,000 2028 D 534,000 484,000 2,115,000 (42,000) 50,000 9,000 3,150,000 934,000 1,789,000 0 0 353,000 0 0 3,076,000 2029 D 462,000 484,000 2,099,000 (46,000) 55,000 9,000 3,063,000 910,000 1,744,000 0 0 356,000 0 0 3,010,000 2030 SC 417,000 575,000 1,800,000 (47,000) 49,000 3,000 2,797,000 833,000 1,624,000 0 0 363,000 0 0 2,820,000 2031 SC 492,000 573,000 1,780,000 (48,000) 51,000 2,000 2,850,000 815,000 1,633,000 0 0 406,000 0 0 2,854,000 2032 W 832,000 269,000 3,250,000 (31,000) 46,000 6,000 4,372,000 1,963,000 1,830,000 0 0 490,000 1,000 0 4,284,000 2033 D 466,000 490,000 2,001,000 (46,000) 60,000 10,000 2,981,000 869,000 1,741,000 0 0 364,000 1,000 0 2,975,000 2034 W 851,000 252,000 3,258,000 (29,000) 47,000 7,000 4,386,000 2,003,000 1,791,000 0 0 465,000 1,000 0 4,260,000 2035 W 731,000 280,000 3,163,000 (32,000) 48,000 7,000 4,197,000 1,969,000 1,849,000 0 0 422,000 1,000 0 4,241,000 2036 W 774,000 316,000 3,268,000 (31,000) 50,000 7,000 4,384,000 2,052,000 1,867,000 0 0 494,000 1,000 0 4,414,000 2037 W 1,194,000 252,000 3,274,000 (28,000) 49,000 7,000 4,748,000 2,254,000 1,780,000 0 0 607,000 1,000 0 4,642,000 2038 N 448,000 431,000 2,689,000 (47,000) 53,000 10,000 3,584,000 1,529,000 1,660,000 0 0 381,000 0 0 3,570,000 2039 N 488,000 446,000 2,655,000 (46,000) 52,000 10,000 3,605,000 1,487,000 1,698,000 0 0 411,000 0 0 3,596,000 2040 D 534,000 423,000 2,200,000 (46,000) 66,000 9,000 3,186,000 1,001,000 1,712,000 0 0 411,000 1,000 0 3,125,000 2041 D 384,000 437,000 2,139,000 (52,000) 62,000 9,000 2,979,000 879,000 1,704,000 0 0 374,000 1,000 0 2,958,000 476
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-154
June 2022
Common Chapter August 2019June 2022
Land Surface Budget
Inflows Outflows
Precipitation Applied Water - Groundwater Surface Water Inflow Applied Waer - Groundwater (Project Effect–) - NCDM Only Applied Water - Imported Surface Water (Project Effect–) - NCDM Only Project Effects - All GSP Groups Total Inflows Surface Water Outflow Evapotranspiration Crop Evapotranspiration - Aliso Only Canal/Reservoir Evaporation - Aliso Only Deep Percolation Runoff (Project Effect–) - NCDM Only Project Effects - All GSP Groups Total Outflows 2042 N 530,000 469,000 2,730,000 (46,000) 51,000 10,000 3,744,000 1,532,000 1,795,000 0 0 400,000 0 0 3,727,000 2043 D 488,000 437,000 2,101,000 (48,000) 68,000 11,000 3,057,000 884,000 1,797,000 0 0 331,000 1,000 0 3,013,000 2044 W 875,000 286,000 3,231,000 (37,000) 53,000 11,000 4,419,000 2,141,000 1,831,000 0 0 419,000 1,000 0 4,392,000 2045 W 622,000 313,000 3,263,000 (45,000) 53,000 12,000 4,218,000 1,971,000 1,847,000 0 0 355,000 1,000 0 4,174,000 2046 D 268,000 571,000 2,149,000 (57,000) 68,000 12,000 3,011,000 893,000 1,794,000 0 0 346,000 1,000 0 3,034,000 2047 D 402,000 575,000 2,067,000 (55,000) 64,000 12,000 3,065,000 834,000 1,820,000 0 0 383,000 0 0 3,037,000 2048 N 331,000 593,000 2,696,000 (49,000) 49,000 12,000 3,632,000 1,457,000 1,893,000 0 0 358,000 0 0 3,708,000 2049 N 658,000 407,000 2,683,000 (29,000) 62,000 12,000 3,793,000 1,525,000 1,706,000 0 0 474,000 2,000 0 3,707,000 2050 W 708,000 316,000 3,145,000 (40,000) 54,000 13,000 4,196,000 1,974,000 1,878,000 0 0 376,000 1,000 0 4,229,000 2051 D 350,000 447,000 2,110,000 (51,000) 69,000 13,000 2,938,000 858,000 1,738,000 0 0 302,000 1,000 0 2,899,000 2052 D 390,000 553,000 2,103,000 (46,000) 67,000 14,000 3,081,000 873,000 1,727,000 0 0 416,000 1,000 0 3,017,000 2053 SC 306,000 634,000 1,765,000 (44,000) 47,000 8,000 2,716,000 801,000 1,699,000 0 0 304,000 0 0 2,804,000 2054 SC 340,000 632,000 1,678,000 (29,000) 34,000 7,000 2,662,000 750,000 1,657,000 0 0 354,000 0 0 2,761,000 2055 D 630,000 453,000 1,831,000 (39,000) 49,000 14,000 2,938,000 855,000 1,742,000 0 0 385,000 1,000 0 2,983,000 2056 W 745,000 351,000 3,073,000 (44,000) 46,000 12,000 4,183,000 1,935,000 1,894,000 0 0 450,000 0 0 4,279,000 2057 W 693,000 313,000 3,150,000 (34,000) 55,000 12,000 4,189,000 1,932,000 1,893,000 0 0 401,000 1,000 0 4,227,000 2058 N 478,000 547,000 2,688,000 (49,000) 54,000 15,000 3,733,000 1,417,000 1,871,000 0 0 446,000 0 0 3,734,000 2059 W 739,000 309,000 3,154,000 (33,000) 55,000 13,000 4,237,000 1,941,000 1,888,000 0 0 425,000 1,000 0 4,255,000 2060 D 405,000 441,000 2,111,000 (52,000) 69,000 15,000 2,989,000 847,000 1,786,000 0 0 360,000 1,000 0 2,994,000 2061 W 910,000 300,000 3,276,000 (33,000) 55,000 13,000 4,521,000 2,106,000 1,896,000 0 0 512,000 1,000 0 4,515,000 2062 N 466,000 459,000 2,687,000 (50,000) 58,000 16,000 3,636,000 1,482,000 1,757,000 0 0 420,000 0 0 3,659,000 2063 N 477,000 544,000 2,674,000 (49,000) 54,000 16,000 3,716,000 1,454,000 1,861,000 0 0 397,000 0 0 3,712,000 2064 D 338,000 447,000 2,123,000 (49,000) 70,000 16,000 2,945,000 818,000 1,780,000 0 0 341,000 1,000 0 2,940,000 2065 N 725,000 443,000 2,688,000 (47,000) 58,000 17,000 3,884,000 1,502,000 1,739,000 0 0 573,000 1,000 0 3,815,000 2066 W 668,000 323,000 3,153,000 (34,000) 55,000 15,000 4,180,000 1,929,000 1,897,000 0 0 383,000 1,000 0 4,210,000 2067 W 690,000 321,000 3,262,000 (33,000) 55,000 15,000 4,310,000 1,942,000 1,898,000 0 0 394,000 1,000 0 4,235,000 2068 D 448,000 558,000 1,859,000 (52,000) 69,000 12,000 2,894,000 872,000 1,695,000 0 0 327,000 1,000 0 2,895,000 2069 D 382,000 561,000 1,824,000 (50,000) 66,000 12,000 2,795,000 788,000 1,688,000 0 0 328,000 1,000 0 2,805,000 2070 W 962,000 302,000 3,388,000 (34,000) 55,000 16,000 4,689,000 2,130,000 1,887,000 0 0 557,000 1,000 0 4,575,000 477
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-155
June 2022
Common Chapter August 2019June 2022
Land Surface Budget
Water Year Water Year Type
Inflows Outflows
Precipitation Surface Water Inflows Applied Wate–r - Groundwater Applied Wate–r - Imported Surface Water Project Effects Other Direct Recharge Total Inflows Runoff Evapotranspiration Surface Water Outflows Deep Percolation Project Effects Total Outflows 2014 Shasta Critical 283,000 26,000 556,000 1,025,000 0 7,000 1,897,000 189,000 1,605,000 5,000 200,000 0 1,999,000 2015 Shasta Critical 363,000 26,000 607,000 907,000 0 8,000 1,911,000 169,000 1,519,000 4,000 261,000 0 1,953,000 2016 Dry 712,000 39,000 355,000 1,219,000 0 9,000 2,334,000 280,000 1,598,000 32,000 367,000 0 2,277,000 2017 Wet 686,000 53,000 282,000 1,442,000 16,000 8,000 2,487,000 330,000 1,755,000 39,000 405,000 0 2,529,000 2018 Normal 527,000 39,000 356,000 1,376,000 0 6,000 2,304,000 279,000 1,625,000 33,000 363,000 (1,000) 2,300,000 2019 Wet 712,000 53,000 234,000 1,501,000 11,000 8,000 2,519,000 331,000 1,780,000 39,000 338,000 (1,000) 2,488,000 2020 Dry 434,000 39,000 353,000 1,463,000 9,000 7,000 2,305,000 236,000 1,693,000 32,000 314,000 3,000 2,275,000 2021 Wet 808,000 53,000 227,000 1,499,000 6,000 8,000 2,601,000 383,000 1,787,000 39,000 352,000 10,000 2,561,000 2022 Wet 1,021,000 53,000 216,000 1,502,000 16,000 8,000 2,816,000 440,000 1,803,000 39,000 412,000 10,000 2,694,000 2023 Normal 580,000 39,000 355,000 1,443,000 4,000 6,000 2,427,000 257,000 1,683,000 33,000 371,000 2,000 2,344,000 2024 Dry 573,000 39,000 344,000 1,466,000 8,000 7,000 2,437,000 260,000 1,695,000 32,000 347,000 3,000 2,334,000 2025 Wet 884,000 53,000 227,000 1,501,000 16,000 8,000 2,689,000 355,000 1,815,000 39,000 384,000 10,000 2,593,000 2026 Dry 575,000 39,000 440,000 1,423,000 15,000 8,000 2,500,000 248,000 1,751,000 32,000 377,000 7,000 2,408,000 2027 Dry 653,000 39,000 438,000 1,423,000 14,000 8,000 2,575,000 280,000 1,732,000 32,000 380,000 9,000 2,424,000 2028 Dry 534,000 39,000 442,000 1,424,000 14,000 8,000 2,461,000 275,000 1,758,000 32,000 312,000 9,000 2,377,000 2029 Dry 462,000 39,000 441,000 1,422,000 15,000 8,000 2,387,000 257,000 1,709,000 32,000 312,000 10,000 2,310,000 2030 Shasta Critical 417,000 26,000 531,000 1,136,000 3,000 8,000 2,121,000 209,000 1,591,000 5,000 318,000 9,000 2,123,000 2031 Shasta Critical 492,000 26,000 531,000 1,136,000 3,000 8,000 2,196,000 211,000 1,606,000 5,000 360,000 9,000 2,182,000 2032 Wet 832,000 53,000 234,000 1,503,000 21,000 8,000 2,651,000 335,000 1,802,000 39,000 420,000 23,000 2,596,000 2033 Dry 466,000 26,000 445,000 1,350,000 20,000 8,000 2,315,000 245,000 1,706,000 5,000 316,000 11,000 2,272,000 2034 Wet 851,000 53,000 215,000 1,500,000 34,000 8,000 2,661,000 365,000 1,756,000 39,000 405,000 23,000 2,565,000 2035 Wet 731,000 53,000 243,000 1,502,000 22,000 8,000 2,559,000 324,000 1,815,000 39,000 356,000 23,000 2,534,000 2036 Wet 774,000 53,000 278,000 1,508,000 35,000 8,000 2,656,000 301,000 1,842,000 39,000 441,000 23,000 2,623,000 2037 Wet 1,194,000 53,000 211,000 1,497,000 37,000 8,000 3,000,000 494,000 1,741,000 39,000 554,000 24,000 2,828,000 2038 Normal 448,000 39,000 390,000 1,440,000 12,000 6,000 2,335,000 273,000 1,626,000 33,000 335,000 15,000 2,267,000 2039 Normal 488,000 39,000 404,000 1,439,000 11,000 6,000 2,387,000 265,000 1,664,000 33,000 362,000 15,000 2,324,000 2040 Dry 534,000 39,000 373,000 1,466,000 26,000 7,000 2,445,000 263,000 1,675,000 32,000 376,000 11,000 2,346,000 2041 Dry 384,000 39,000 388,000 1,468,000 16,000 7,000 2,302,000 214,000 1,671,000 32,000 335,000 10,000 2,252,000 2042 Normal 530,000 39,000 427,000 1,484,000 12,000 6,000 2,498,000 282,000 1,759,000 34,000 344,000 15,000 2,419,000 2043 Dry 488,000 39,000 386,000 1,449,000 26,000 7,000 2,395,000 238,000 1,766,000 33,000 285,000 11,000 2,322,000 2044 Wet 875,000 53,000 244,000 1,483,000 50,000 7,000 2,712,000 400,000 1,799,000 40,000 380,000 24,000 2,619,000 2045 Wet 622,000 53,000 270,000 1,512,000 42,000 6,000 2,505,000 328,000 1,809,000 39,000 318,000 23,000 2,494,000 2046 Dry 268,000 39,000 516,000 1,477,000 17,000 7,000 2,324,000 225,000 1,765,000 33,000 301,000 11,000 2,324,000 2047 Dry 402,000 39,000 522,000 1,427,000 15,000 8,000 2,413,000 202,000 1,795,000 32,000 333,000 10,000 2,362,000 478
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-156
June 2022
Common Chapter August 2019June 2022
Land Surface Budget
Water Year Water Year Type
Inflows Outflows
Precipitation Surface Water Inflows Applied Wate–r - Groundwater Applied Wate–r - Imported Surface Water Project Effects Other Direct Recharge Total Inflows Runoff Evapotranspiration Surface Water Outflows Deep Percolation Project Effects Total Outflows 2048 Normal 331,000 39,000 548,000 1,455,000 6,000 5,000 2,384,000 212,000 1,858,000 33,000 298,000 14,000 2,401,000 2049 Normal 658,000 39,000 359,000 1,438,000 39,000 6,000 2,539,000 280,000 1,667,000 33,000 409,000 18,000 2,389,000 2050 Wet 708,000 53,000 267,000 1,505,000 48,000 7,000 2,588,000 343,000 1,840,000 39,000 336,000 23,000 2,558,000 2051 Dry 350,000 39,000 390,000 1,465,000 24,000 7,000 2,275,000 222,000 1,704,000 32,000 254,000 11,000 2,212,000 2052 Dry 390,000 39,000 496,000 1,421,000 28,000 8,000 2,382,000 210,000 1,693,000 32,000 363,000 11,000 2,298,000 2053 Shasta Critical 306,000 26,000 576,000 1,109,000 3,000 7,000 2,027,000 180,000 1,661,000 5,000 250,000 9,000 2,096,000 2054 Shasta Critical 340,000 26,000 575,000 1,045,000 5,000 8,000 1,999,000 154,000 1,627,000 4,000 300,000 8,000 2,085,000 2055 Dry 630,000 39,000 394,000 1,205,000 16,000 9,000 2,293,000 253,000 1,701,000 32,000 317,000 10,000 2,303,000 2056 Wet 745,000 53,000 300,000 1,432,000 35,000 8,000 2,573,000 311,000 1,857,000 39,000 395,000 22,000 2,602,000 2057 Wet 693,000 53,000 261,000 1,505,000 28,000 8,000 2,548,000 302,000 1,855,000 39,000 322,000 24,000 2,518,000 2058 Normal 478,000 39,000 494,000 1,459,000 11,000 5,000 2,486,000 208,000 1,836,000 33,000 380,000 15,000 2,457,000 2059 Wet 739,000 53,000 252,000 1,501,000 55,000 8,000 2,608,000 306,000 1,844,000 39,000 372,000 24,000 2,561,000 2060 Dry 405,000 39,000 377,000 1,466,000 23,000 7,000 2,317,000 200,000 1,743,000 32,000 305,000 11,000 2,280,000 2061 Wet 910,000 53,000 244,000 1,502,000 56,000 8,000 2,773,000 348,000 1,851,000 39,000 459,000 24,000 2,697,000 2062 Normal 466,000 39,000 400,000 1,441,000 14,000 6,000 2,366,000 230,000 1,716,000 33,000 352,000 15,000 2,331,000 2063 Normal 477,000 39,000 483,000 1,453,000 11,000 5,000 2,468,000 236,000 1,816,000 33,000 332,000 15,000 2,417,000 2064 Dry 338,000 39,000 379,000 1,469,000 26,000 7,000 2,258,000 168,000 1,739,000 32,000 287,000 11,000 2,226,000 2065 Normal 725,000 39,000 382,000 1,438,000 17,000 6,000 2,607,000 249,000 1,693,000 33,000 499,000 16,000 2,474,000 2066 Wet 668,000 53,000 261,000 1,503,000 28,000 8,000 2,521,000 293,000 1,853,000 39,000 300,000 24,000 2,485,000 2067 Wet 690,000 53,000 257,000 1,502,000 28,000 8,000 2,538,000 296,000 1,851,000 39,000 313,000 24,000 2,499,000 2068 Dry 448,000 26,000 484,000 1,188,000 17,000 8,000 2,171,000 222,000 1,650,000 5,000 267,000 11,000 2,144,000 2069 Dry 382,000 26,000 490,000 1,191,000 15,000 8,000 2,112,000 186,000 1,652,000 5,000 262,000 11,000 2,105,000 2070 Wet 962,000 53,000 236,000 1,498,000 55,000 8,000 2,812,000 360,000 1,838,000 39,000 490,000 24,000 2,727,000 479
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-157
June 2022
Common Chapter August 2019June 2022
Table CC-1513: Delta-Mendota Subbasin Projected Water Budget, Groundwater Budget (containing climate change factors and projects and management actions) Groundwater Budget
Inflows Outflows Change in Storage
Infiltration
Lateral Subsurface
Flow
Seepage
Through
Corcoran Clay -
SJREC Only
Applied Water
Infiltration (Project
Effect–) - NCDM
Only
Deep Percolation
(Project Effect–) -
NCDM Only
Project
Effects
Total
Inflows
Groundwater
Extraction
Lateral Subsurface
Flow Flow to Lower AquiferGrassland Only Discharge to Surface Water/Consumptive Use by GDEs/Lateral Flow - Grassland Only Total Outflows Estimated Annual Change in Groundwater Storage Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Total 2014 SC 275,000 162,000 115,000 0 0 0 0 552,000 513,000 101,000 321,000 191,000 0 0 1,126,000 (428,000) (234,000) (662,000) 2015 SC 333,000 154,000 113,000 0 0 0 0 600,000 558,000 101,000 325,000 202,000 0 0 1,186,000 (408,000) (234,000) (642,000) 2016 D 487,000 152,000 112,000 0 0 0 0 751,000 354,000 60,000 313,000 156,000 0 0 883,000 (89,000) (130,000) (219,000) 2017 W 525,000 198,000 128,000 0 0 0 10,000 861,000 254,000 50,000 307,000 91,000 0 0 702,000 148,000 (28,000) 120,000 2018 N 465,000 190,000 115,000 0 0 0 0 770,000 347,000 59,000 264,000 101,000 0 0 771,000 105,000 44,000 149,000 2019 W 461,000 216,000 124,000 0 0 0 10,000 811,000 231,000 38,000 279,000 74,000 0 0 622,000 122,000 11,000 133,000 2020 D 385,000 153,000 106,000 0 0 3,000 0 647,000 354,000 57,000 298,000 136,000 0 0 845,000 (185,000) (142,000) (327,000) 2021 W 464,000 218,000 125,000 0 0 10,000 0 817,000 224,000 39,000 280,000 72,000 0 0 615,000 135,000 27,000 162,000 2022 W 553,000 218,000 125,000 0 0 10,000 10,000 916,000 214,000 37,000 276,000 77,000 0 0 604,000 254,000 40,000 294,000 2023 N 449,000 186,000 117,000 0 0 3,000 0 755,000 348,000 55,000 264,000 111,000 0 0 778,000 89,000 74,000 163,000 2024 D 417,000 151,000 108,000 0 0 3,000 0 679,000 349,000 58,000 301,000 134,000 0 0 842,000 (153,000) (94,000) (247,000) 2025 W 493,000 214,000 125,000 0 0 10,000 10,000 852,000 227,000 38,000 278,000 73,000 0 0 616,000 176,000 44,000 220,000 2026 D 451,000 152,000 107,000 0 0 6,000 0 716,000 413,000 51,000 302,000 137,000 0 0 903,000 (169,000) (56,000) (225,000) 2027 D 470,000 152,000 106,000 0 0 9,000 0 737,000 411,000 52,000 303,000 131,000 0 0 897,000 (148,000) (47,000) (195,000) 2028 D 390,000 153,000 104,000 0 0 9,000 0 656,000 414,000 51,000 304,000 130,000 0 0 899,000 (225,000) (55,000) (280,000) 2029 D 395,000 154,000 103,000 0 0 10,000 0 662,000 410,000 51,000 303,000 129,000 0 0 893,000 (213,000) (67,000) (280,000) 2030 SC 400,000 159,000 97,000 0 0 9,000 0 665,000 454,000 84,000 312,000 127,000 0 0 977,000 (230,000) (104,000) (334,000) 2031 SC 442,000 158,000 97,000 0 0 9,000 0 706,000 453,000 82,000 313,000 118,000 0 0 966,000 (188,000) (89,000) (277,000) 2032 W 545,000 220,000 115,000 0 0 22,000 0 902,000 213,000 35,000 279,000 68,000 0 0 595,000 258,000 61,000 319,000 2033 D 400,000 157,000 98,000 0 0 10,000 0 665,000 402,000 50,000 308,000 133,000 0 0 893,000 (201,000) (70,000) (271,000) 2034 W 547,000 220,000 118,000 0 0 22,000 10,000 917,000 203,000 29,000 273,000 70,000 0 0 575,000 275,000 57,000 332,000 2035 W 459,000 220,000 119,000 0 0 22,000 0 820,000 225,000 34,000 276,000 76,000 0 0 611,000 162,000 55,000 217,000 2036 W 552,000 221,000 119,000 0 0 22,000 10,000 924,000 243,000 51,000 275,000 76,000 0 0 645,000 275,000 65,000 340,000 2037 W 719,000 217,000 122,000 0 0 23,000 10,000 1,091,000 202,000 31,000 269,000 80,000 0 0 582,000 442,000 53,000 495,000 2038 N 415,000 185,000 114,000 0 0 15,000 0 729,000 350,000 58,000 258,000 111,000 0 0 777,000 90,000 87,000 177,000 2039 N 455,000 197,000 117,000 0 0 15,000 0 784,000 360,000 63,000 262,000 108,000 0 0 793,000 142,000 82,000 224,000 2040 D 457,000 151,000 104,000 0 0 10,000 0 722,000 348,000 53,000 299,000 136,000 0 0 836,000 (82,000) (65,000) (147,000) 2041 D 410,000 150,000 101,000 0 0 10,000 0 671,000 352,000 56,000 299,000 130,000 0 0 837,000 (123,000) (68,000) (191,000) 2042 N 448,000 197,000 111,000 0 0 15,000 0 771,000 385,000 62,000 264,000 100,000 0 0 811,000 98,000 98,000 196,000 480
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-158
June 2022
Common Chapter August 2019June 2022
Groundwater Budget
Inflows Outflows Change in Storage
Infiltration
Lateral Subsurface
Flow
Seepage
Through
Corcoran Clay -
SJREC Only
Applied Water
Infiltration (Project
Effect–) - NCDM
Only
Deep Percolation
(Project Effect–) -
NCDM Only
Project
Effects
Total
Inflows
Groundwater
Extraction
Lateral Subsurface
Flow Flow to Lower AquiferGrassland Only Discharge to Surface Water/Consumptive Use by GDEs/Lateral Flow - Grassland Only Total Outflows Estimated Annual Change in Groundwater Storage Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Upper Aquifer Lower Aquifer Total 2043 D 368,000 151,000 100,000 0 0 10,000 0 629,000 357,000 55,000 298,000 109,000 0 0 819,000 (173,000) (58,000) (231,000) 2044 W 502,000 209,000 119,000 0 0 23,000 28,000 881,000 220,000 38,000 282,000 71,000 0 0 611,000 227,000 59,000 286,000 2045 W 413,000 215,000 121,000 0 0 22,000 28,000 799,000 235,000 43,000 271,000 77,000 0 0 626,000 141,000 32,000 173,000 2046 D 382,000 151,000 101,000 0 0 10,000 0 644,000 469,000 68,000 296,000 112,000 0 0 945,000 (264,000) (85,000) (349,000) 2047 D 422,000 150,000 99,000 0 0 10,000 0 681,000 471,000 71,000 298,000 105,000 0 0 945,000 (214,000) (64,000) (278,000) 2048 N 393,000 187,000 109,000 0 0 14,000 0 703,000 475,000 92,000 263,000 100,000 0 0 930,000 (27,000) 69,000 42,000 2049 N 545,000 188,000 110,000 0 0 16,000 0 859,000 345,000 56,000 262,000 103,000 0 0 766,000 209,000 90,000 299,000 2050 W 436,000 217,000 120,000 0 0 23,000 28,000 824,000 239,000 46,000 274,000 73,000 0 0 632,000 173,000 41,000 214,000 2051 D 343,000 152,000 101,000 0 0 10,000 0 606,000 361,000 58,000 296,000 136,000 0 0 851,000 (195,000) (88,000) (283,000) 2052 D 466,000 150,000 98,000 0 0 10,000 0 724,000 463,000 66,000 296,000 105,000 0 0 930,000 (183,000) (82,000) (265,000) 2053 SC 341,000 156,000 97,000 0 0 9,000 0 603,000 499,000 99,000 312,000 104,000 0 0 1,014,000 (322,000) (95,000) (417,000) 2054 SC 392,000 156,000 96,000 0 0 8,000 0 652,000 514,000 98,000 312,000 102,000 0 0 1,026,000 (270,000) (98,000) (368,000) 2055 D 422,000 152,000 96,000 0 0 9,000 0 679,000 376,000 62,000 296,000 101,000 0 0 835,000 (138,000) (69,000) (207,000) 2056 W 511,000 222,000 115,000 0 0 22,000 28,000 898,000 258,000 58,000 278,000 67,000 0 0 661,000 244,000 48,000 292,000 2057 W 437,000 222,000 116,000 0 0 23,000 0 798,000 249,000 41,000 279,000 73,000 0 0 642,000 110,000 46,000 156,000 2058 N 479,000 205,000 108,000 0 0 15,000 0 807,000 453,000 69,000 266,000 105,000 0 0 893,000 63,000 83,000 146,000 2059 W 482,000 221,000 120,000 0 0 23,000 28,000 874,000 245,000 40,000 275,000 74,000 0 0 634,000 192,000 55,000 247,000 2060 D 395,000 150,000 101,000 0 0 10,000 0 656,000 361,000 51,000 293,000 136,000 0 0 841,000 (157,000) (76,000) (233,000) 2061 W 581,000 218,000 120,000 0 0 23,000 28,000 970,000 238,000 40,000 274,000 72,000 0 0 624,000 297,000 56,000 353,000 2062 N 454,000 198,000 113,000 0 0 15,000 0 780,000 372,000 60,000 262,000 109,000 0 0 803,000 115,000 83,000 198,000 2063 N 431,000 200,000 113,000 0 0 15,000 0 759,000 448,000 71,000 264,000 107,000 0 0 890,000 17,000 90,000 107,000 2064 D 376,000 152,000 101,000 0 0 11,000 0 640,000 368,000 52,000 299,000 134,000 0 0 853,000 (183,000) (68,000) (251,000) 2065 N 657,000 186,000 111,000 0 0 15,000 0 969,000 360,000 60,000 263,000 103,000 0 0 786,000 321,000 95,000 416,000 2066 W 419,000 218,000 120,000 0 0 23,000 0 780,000 258,000 42,000 280,000 74,000 0 0 654,000 78,000 50,000 128,000 2067 W 430,000 217,000 121,000 0 0 23,000 0 791,000 257,000 42,000 277,000 77,000 0 0 653,000 96,000 54,000 150,000 2068 D 362,000 155,000 102,000 0 0 10,000 0 629,000 451,000 64,000 311,000 113,000 0 0 939,000 (291,000) (72,000) (363,000) 2069 D 364,000 154,000 98,000 0 0 10,000 0 626,000 457,000 62,000 312,000 105,000 0 0 936,000 (297,000) (64,000) (361,000) 2070 W 638,000 211,000 118,000 0 0 23,000 28,000 1,018,000 237,000 42,000 270,000 70,000 0 0 619,000 350,000 55,000 405,000 481
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-159
June 2022
Common Chapter August 2019June 2022
Groundwater Budget
Water Year Water Year Type
Inflows Outflows Change in Storage
Deep Percolation
Subsurface
Groundwater
Inflows Seepage
through
Corcoran
Clay
Other
Direct
Recharge
Project
Effects
Total
Inflows
Groundwater
Extraction from
Upper Aquifer
Groundwater
Extraction from
Lower Aquifer
Subsurface
Groundwater
Outflows
Total
Outflows
Estimated Annual Change in Groundwater Storage
Precipitation
Infiltration
Surface
Water
Infiltration
Applied
Water
Infiltration
Upper
Aquifer
Lower
Aquifer
Upper
Aquifer
Lower
Aquifer Inflows Outflows
Change in
Storag–e -
Upper
Aquifer
Change in
Storag–e -
Lower
Aquifer
Change in
Storag–e -
Total
2014 Shasta Critical 51,000 58,000 96,000 162,000 70,000 45,000 58,000 0 540,000 500,000 97,000 281,000 186,000 1,109,000 540,000 1,110,000 (433,000) (123,000) (556,000) 2015 Shasta Critical 39,000 57,000 167,000 157,000 68,000 45,000 60,000 0 593,000 546,000 98,000 282,000 197,000 1,168,000 593,000 1,168,000 (405,000) (132,000) (537,000) 2016 Dry 98,000 75,000 235,000 154,000 67,000 45,000 70,000 0 744,000 338,000 57,000 280,000 151,000 871,000 743,000 871,000 (92,000) (49,000) (141,000) 2017 Wet 93,000 93,000 212,000 198,000 82,000 45,000 109,000 16,000 848,000 245,000 50,000 260,000 87,000 687,000 843,000 688,000 142,000 (14,000) 128,000 2018 Normal 70,000 84,000 228,000 190,000 70,000 45,000 77,000 5,000 769,000 328,000 57,000 233,000 100,000 763,000 763,000 762,000 105,000 18,000 122,000 2019 Wet 106,000 92,000 145,000 215,000 79,000 45,000 105,000 15,000 802,000 226,000 37,000 233,000 73,000 614,000 798,000 614,000 116,000 13,000 128,000 2020 Dry 58,000 78,000 179,000 152,000 62,000 45,000 68,000 9,000 651,000 336,000 52,000 266,000 134,000 833,000 645,000 833,000 (184,000) (43,000) (227,000) 2021 Wet 108,000 93,000 166,000 218,000 80,000 45,000 85,000 16,000 811,000 219,000 37,000 235,000 71,000 607,000 805,000 608,000 128,000 15,000 144,000 2022 Wet 126,000 88,000 221,000 216,000 80,000 45,000 107,000 26,000 909,000 209,000 35,000 231,000 75,000 595,000 904,000 596,000 246,000 21,000 267,000 2023 Normal 81,000 78,000 212,000 188,000 72,000 45,000 75,000 9,000 760,000 329,000 52,000 234,000 108,000 768,000 753,000 768,000 91,000 28,000 119,000 2024 Dry 75,000 74,000 194,000 153,000 62,000 45,000 70,000 9,000 682,000 331,000 51,000 270,000 132,000 829,000 676,000 829,000 (152,000) (13,000) (164,000) 2025 Wet 111,000 91,000 173,000 214,000 81,000 45,000 107,000 26,000 848,000 220,000 36,000 234,000 71,000 606,000 841,000 606,000 170,000 27,000 197,000 2026 Dry 75,000 76,000 223,000 153,000 62,000 45,000 70,000 13,000 717,000 391,000 46,000 269,000 135,000 886,000 711,000 885,000 (165,000) (7,000) (172,000) 2027 Dry 82,000 80,000 233,000 153,000 60,000 45,000 68,000 15,000 736,000 390,000 47,000 270,000 128,000 880,000 731,000 879,000 (144,000) 0 (144,000) 2028 Dry 72,000 81,000 161,000 156,000 59,000 45,000 68,000 15,000 657,000 391,000 47,000 269,000 127,000 879,000 651,000 879,000 (216,000) (5,000) (222,000) 2029 Dry 60,000 84,000 175,000 155,000 58,000 45,000 68,000 16,000 661,000 387,000 46,000 269,000 127,000 874,000 654,000 875,000 (208,000) (13,000) (221,000) 2030 Shasta Critical 59,000 65,000 204,000 162,000 57,000 40,000 65,000 9,000 661,000 440,000 78,000 277,000 125,000 960,000 660,000 960,000 (225,000) (33,000) (257,000) 2031 Shasta Critical 66,000 66,000 240,000 162,000 57,000 40,000 65,000 9,000 705,000 439,000 77,000 276,000 116,000 948,000 703,000 947,000 (180,000) (22,000) (201,000) 2032 Wet 112,000 97,000 236,000 222,000 75,000 40,000 86,000 29,000 897,000 205,000 32,000 240,000 68,000 585,000 891,000 584,000 253,000 17,000 271,000 2033 Dry 61,000 69,000 195,000 161,000 57,000 40,000 65,000 17,000 665,000 386,000 45,000 273,000 130,000 874,000 659,000 874,000 (195,000) (18,000) (213,000) 2034 Wet 114,000 96,000 214,000 219,000 77,000 40,000 107,000 39,000 906,000 194,000 26,000 233,000 69,000 562,000 901,000 562,000 269,000 15,000 285,000 2035 Wet 100,000 93,000 165,000 220,000 78,000 40,000 86,000 29,000 811,000 215,000 30,000 237,000 74,000 596,000 806,000 596,000 157,000 14,000 171,000 2036 Wet 105,000 89,000 236,000 219,000 78,000 40,000 105,000 39,000 911,000 234,000 48,000 236,000 74,000 632,000 905,000 633,000 266,000 19,000 285,000 2037 Wet 149,000 86,000 359,000 214,000 83,000 40,000 107,000 40,000 1,078,000 192,000 27,000 230,000 77,000 566,000 1,072,000 566,000 431,000 14,000 445,000 2038 Normal 80,000 75,000 175,000 187,000 74,000 40,000 75,000 21,000 727,000 323,000 54,000 232,000 107,000 756,000 722,000 756,000 95,000 20,000 115,000 2039 Normal 72,000 75,000 219,000 195,000 76,000 40,000 77,000 21,000 775,000 332,000 60,000 236,000 105,000 773,000 769,000 773,000 143,000 20,000 163,000 2040 Dry 76,000 70,000 232,000 154,000 63,000 40,000 70,000 18,000 723,000 324,000 46,000 271,000 133,000 814,000 717,000 814,000 (75,000) (11,000) (87,000) 2041 Dry 61,000 75,000 197,000 153,000 60,000 40,000 68,000 16,000 670,000 328,000 49,000 269,000 128,000 814,000 665,000 814,000 (115,000) (12,000) (127,000) 2042 Normal 80,000 82,000 198,000 197,000 72,000 40,000 75,000 21,000 765,000 357,000 58,000 238,000 99,000 792,000 758,000 791,000 98,000 27,000 125,000 2043 Dry 72,000 77,000 136,000 152,000 60,000 40,000 70,000 18,000 625,000 329,000 49,000 271,000 106,000 795,000 617,000 796,000 (171,000) (10,000) (180,000) 2044 Wet 117,000 91,000 172,000 209,000 80,000 40,000 107,000 57,000 873,000 203,000 35,000 242,000 70,000 590,000 867,000 590,000 230,000 17,000 247,000 482
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-160
June 2022
Common Chapter August 2019June 2022
Groundwater Budget
Water Year Water Year Type
Inflows Outflows Change in Storage
Deep Percolation
Subsurface
Groundwater
Inflows Seepage
through
Corcoran
Clay
Other
Direct
Recharge
Project
Effects
Total
Inflows
Groundwater
Extraction from
Upper Aquifer
Groundwater
Extraction from
Lower Aquifer
Subsurface
Groundwater
Outflows
Total
Outflows
Estimated Annual Change in Groundwater Storage
Precipitation
Infiltration
Surface
Water
Infiltration
Applied
Water
Infiltration
Upper
Aquifer
Lower
Aquifer
Upper
Aquifer
Lower
Aquifer Inflows Outflows
Change in
Storag–e -
Upper
Aquifer
Change in
Storag–e -
Lower
Aquifer
Change in
Storag–e -
Total
2045 Wet 89,000 87,000 113,000 215,000 81,000 40,000 107,000 56,000 788,000 217,000 40,000 230,000 75,000 602,000 782,000 603,000 143,000 9,000 151,000 2046 Dry 44,000 75,000 179,000 154,000 61,000 40,000 68,000 17,000 638,000 439,000 62,000 268,000 109,000 918,000 632,000 919,000 (259,000) (19,000) (278,000) 2047 Dry 52,000 80,000 206,000 152,000 59,000 40,000 68,000 16,000 673,000 440,000 65,000 270,000 103,000 918,000 667,000 919,000 (210,000) (10,000) (220,000) 2048 Normal 52,000 84,000 168,000 188,000 68,000 40,000 75,000 20,000 695,000 446,000 85,000 237,000 98,000 906,000 690,000 907,000 (26,000) 19,000 (7,000) 2049 Normal 94,000 84,000 271,000 188,000 70,000 40,000 77,000 24,000 848,000 312,000 51,000 238,000 101,000 742,000 842,000 742,000 210,000 24,000 234,000 2050 Wet 87,000 90,000 133,000 216,000 80,000 40,000 107,000 57,000 810,000 219,000 41,000 235,000 72,000 607,000 803,000 608,000 172,000 11,000 183,000 2051 Dry 48,000 76,000 134,000 152,000 61,000 40,000 68,000 17,000 596,000 329,000 51,000 269,000 133,000 822,000 591,000 822,000 (192,000) (20,000) (212,000) 2052 Dry 49,000 81,000 249,000 154,000 58,000 40,000 68,000 17,000 716,000 430,000 60,000 268,000 103,000 901,000 711,000 901,000 (175,000) (14,000) (189,000) 2053 Shasta Critical 49,000 63,000 148,000 160,000 57,000 40,000 63,000 9,000 589,000 474,000 91,000 276,000 101,000 982,000 588,000 982,000 (316,000) (14,000) (330,000) 2054 Shasta Critical 37,000 65,000 208,000 161,000 55,000 40,000 63,000 8,000 637,000 488,000 91,000 277,000 101,000 997,000 638,000 996,000 (262,000) (18,000) (280,000) 2055 Dry 85,000 86,000 152,000 156,000 55,000 40,000 70,000 16,000 660,000 340,000 54,000 268,000 100,000 802,000 654,000 801,000 (139,000) (6,000) (145,000) 2056 Wet 95,000 97,000 185,000 220,000 75,000 40,000 107,000 55,000 874,000 237,000 52,000 238,000 66,000 633,000 869,000 633,000 236,000 17,000 253,000 2057 Wet 97,000 95,000 133,000 223,000 76,000 40,000 85,000 30,000 779,000 228,000 34,000 240,000 72,000 614,000 772,000 613,000 105,000 14,000 119,000 2058 Normal 66,000 82,000 236,000 205,000 68,000 40,000 75,000 21,000 793,000 416,000 61,000 239,000 103,000 859,000 786,000 860,000 65,000 20,000 85,000 2059 Wet 101,000 92,000 152,000 222,000 79,000 40,000 107,000 58,000 851,000 222,000 33,000 235,000 72,000 602,000 845,000 602,000 187,000 18,000 205,000 2060 Dry 59,000 76,000 168,000 151,000 61,000 40,000 70,000 17,000 642,000 325,000 42,000 265,000 133,000 805,000 635,000 805,000 (155,000) (13,000) (167,000) 2061 Wet 108,000 91,000 243,000 217,000 80,000 40,000 107,000 58,000 944,000 214,000 33,000 235,000 70,000 592,000 938,000 592,000 289,000 20,000 309,000 2062 Normal 73,000 79,000 199,000 199,000 73,000 40,000 77,000 22,000 762,000 330,000 53,000 236,000 106,000 765,000 756,000 765,000 119,000 21,000 140,000 2063 Normal 71,000 77,000 183,000 201,000 73,000 40,000 75,000 21,000 741,000 408,000 61,000 237,000 104,000 850,000 735,000 850,000 20,000 25,000 45,000 2064 Dry 50,000 74,000 159,000 153,000 61,000 40,000 68,000 18,000 623,000 328,000 42,000 271,000 131,000 812,000 616,000 813,000 (180,000) (9,000) (190,000) 2065 Normal 81,000 82,000 388,000 187,000 71,000 40,000 77,000 22,000 948,000 315,000 53,000 238,000 100,000 746,000 941,000 745,000 323,000 26,000 349,000 2066 Wet 94,000 90,000 114,000 219,000 80,000 40,000 85,000 30,000 752,000 229,000 34,000 240,000 72,000 615,000 745,000 615,000 74,000 17,000 91,000 2067 Wet 97,000 89,000 126,000 216,000 80,000 40,000 85,000 30,000 763,000 227,000 33,000 236,000 75,000 611,000 756,000 611,000 92,000 16,000 108,000 2068 Dry 65,000 58,000 146,000 157,000 62,000 40,000 63,000 11,000 602,000 415,000 53,000 274,000 110,000 892,000 603,000 892,000 (284,000) (12,000) (296,000) 2069 Dry 57,000 64,000 150,000 156,000 58,000 40,000 63,000 11,000 599,000 421,000 53,000 274,000 103,000 891,000 598,000 890,000 (290,000) (8,000) (298,000) 2070 Wet 119,000 100,000 274,000 211,000 77,000 40,000 107,000 57,000 985,000 204,000 33,000 227,000 69,000 573,000 980,000 573,000 350,000 19,000 369,000 483
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-161
June 2022
Common Chapter August 2019June 2022
484
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-162
June 2022
Common Chapter August 2019June 2022
Figure CC-64: Change in Storage, Delta-Mendota Subbasin Projected Water Budget 485
Draft Delta-Mendota Subbasin Groundwater Sustainability Plan Groundwater Sustainability PlanRevised Common Chapter
CC-163
June 2022
Common Chapter August 2019June 2022

Los Banos City CouncilJuly 6, 2022

Los Banos City Council
July 6, 2022