Volumetric Benefits to Subbasin Groundwater System
The volumetric benefit to the groundwater system will depend on the extent to which a Conservation Practices program is implemented and will be further studied if a program is developed by the GSAs.
8.5.1.2.5.8.1.1.1.1. Implementation Criteria, Status, and Plan The implementation timeline has yet to be determined but would be provided in GSP annual reports and five-year updates when known. Any future changes in implementation would be communicated with the public and other agencies and would be documented in GSP annual reports and five-year updates.
8.5.1.2.6.8.1.1.1.1. Water Source and Reliability
This MA does not rely on the supplies from outside the Subbasin because it is a planning effort that will result in conservation benefits. It will support overall supply reliability by reducing groundwater demand in the Subbasin and moving the Subbasin towards sustainability.
8.5.1.2.7.8.1.1.1.1. Legal Authority
The Modesto Subbasin GSAs have the authority to develop a Conservation Practices program and may perform implementation and enforcement of practices via implementation of fees for noncompliance or through metering or other methods to quantify groundwater use. Mechanisms for enforcement would be outlined in the Conservation Practices program once developed and are expected to be enforced by the Modesto Subbasin GSAs and/or member agencies.
8.5.1.2.8.8.1.1.1.1. Estimated Costs and Funding Plan
Costs for UWMP and AWMP report preparation and submittals are ongoing for urban and agricultural water suppliers, respectively. Any future costs related to additional programming or program enforcement have yet to be developed. #25..
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8.5.1.2.9.8.1.1.1.1. Management of Groundwater Extractions and Recharge This MA encourages the conservation of water; this will be applicable during both wet and dry conditions.
8.5.2. Water Accounting Framework
The Water Accounting Framework consists of four-tiered MAs that would be implemented in a prioritized order as determined by the Modesto Subbasin GSAs to meet the Subbasin’s sustainability goal. Not all MAs may be needed – Subbasin conditions will be evaluated against the sustainability management criteria when considering whether an additional tiered MA is needed. The tiered order of potential Water Accounting Framework MAs implementation is:
1. Groundwater Extraction and Surface Water Accounting Reporting or Monitoring Program (Management Action 3) – see Section 8.4.2.1
2. Groundwater Allocation Program (Management Action 4) – see Section 8.4.2.2
3. Groundwater Extraction Fee (Management Action 5) – see Section 8.4.2.3
4. Groundwater Pumping Credit Market and Trading Program (Management Action 6) – see Section 8.4.2.4
The process of providing annual reports to DWR and of GSA self-reporting will allow them to update the Plan and adjust the implementation course as needed based on changing conditions.
8.5.2.1. Groundwater Extraction and Surface Water Accounting Reporting or Monitoring Program (Management Action 3)
8.1.1.2.1 Management Action Description
As required in SGMA regulations, groundwater extraction has been calculated by the GSAs for this GSP using the groundwater model (Appendix C). Presently, the GSAs intend to continue with its current data collection and groundwater extraction monitoring techniques.
This MA is provided as an alternative to allow the GSAs flexibility and additional options in the event more or alternative forms of data are needed in the future.
There are several ways that this MA could be implemented by the GSAs. For this plan, two potential components have been developed and include a voluntary program and a comprehensive program. However, these two potential components are provided only as options, and likely would be implemented in Management Areas that are determined to be net extractors. If this MA is initiated, the GSAs will further develop options before implementing.
• Voluntary program – This program is intended to provide an annual reporting of groundwater use by agricultural and private well owners and surface water transfers for in-lieu use. The Data Management System will be set up with #25..
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appropriate input data forms for voluntary reporting of groundwater use as well as other relevant information, such as irrigated acreage, crop type, and sources of water.
• Comprehensive program – This program is a more robust and elaborate strategy for reporting groundwater extraction that is intended to cover all groundwater users and surface water transfers for in-lieu use. Implementation of this program can be using satellite imagery to estimate the evapotranspiration of crops by parcel.
Additionally, this strategy can take the form of requiring the installation of meters at all agricultural wells.
The Groundwater Extraction Reporting Program would exclude de minimis extractors (domestic use of 2 AF or less per year) but may also include surface water accounting in the Subbasin due to the amount of surface water transferred from MID and OID to the NDE area used for in-lieu and direct recharge.
8.1.1.2.28.1.1.2.1 Public Noticing
Successful implementation of either component of this program would require the support and coordination of member agencies, well owners throughout the Subbasin, and other stakeholders.
The voluntary program would be noticed via public outreach and education about the logistics of participating in the program as well as the purpose and importance of doing so.
Outreach may include public notices, meetings, potential website presence and email announcements.
The comprehensive program would involve more of a robust planning process. The Modesto Subbasin GSAs anticipates that public outreach and education on the potential structure of this program would be necessary, including public notices, meetings, potential website presence and email announcements.
Permitting and Regulatory Process
The Groundwater Extraction Reporting Program is not expected to require any permitting or regulatory involvement.
Expected Benefits
Benefits to Sustainability Indicators
Direct measurement of groundwater extractions may not have direct impacts on sustainability indicators but would improve future water budget and sustainable yield refinement. The accurate and widespread collection of extraction data would provide the Modesto Subbasin GSAs with critical information to assist in management of the Subbasin, development of additional MAs, and monitoring the success of the GSP against the sustainable management criteria.
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Benefits to Disadvantaged Communities
The Groundwater Extraction Reporting Program would exclude de minimis extractors.
Volumetric Benefits to Subbasin Groundwater System
Measurement of groundwater extractions provides a vast improvement to the refinement of water budgets and basin storage calculations.
8.5.2.1.1.8.1.1.1.1. Implementation Criteria, Status, and Plan The Modesto Subbasin GSAs will develop annual reports to evaluate progress toward meeting the sustainability goal. If monitoring efforts demonstrate that the Projects and MAs being implemented are not effective in achieving stated targets, the GSAs will convene a working group to evaluate the implementation of additional supply-side and demand-side actions, such as the implementation of tiered approaches in the Pumping Management Framework.
8.1.1.2.5 Water Source and Reliability
This management action is an accounting and monitoring program and as such does not rely on water availability. The Groundwater Extraction and Surface Water Accounting Reporting or Monitoring Program is a planning effort that will support overall supply reliability by providing additional information for better management of the Subbasin and moving the Subbasin towards sustainability.
8.1.1.2.68.1.1.2.5 Legal Authority
SGMA provides GSAs with the authority to regulate the pumping of groundwater in order to stabilize the region’s water supply and recharge aquifers. As such, the GSAs have the authority to: “control groundwater extractions by regulating, limiting, or suspending extractions from individual groundwater wells or extractions from groundwater wells in the aggregate, . . . or otherwise establishing groundwater extraction allocations” (CWC, §10726.4(a)).
8.1.1.2.78.1.1.2.5 Estimated Costs and Funding Plan
The estimated costs for the Groundwater Extraction Reporting Program would vary depending on the components that are implemented:
• The costs for the voluntary component are minimal and include:
o One-time costs for initial public outreach and setup of tools and procedures to receive and compile voluntary submitted data
o Ongoing annual administrative costs to review and compile the voluntarily submitted data as well as continued outreach
• The costs for implementing the more comprehensive program would be larger as they may include:
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o One-time costs to develop a remote sensing system or a more comprehensive program to track and monitor well meters, in addition to public outreach
o Ongoing annual costs to administer the program, whether via purchase and analysis of the latest remote sensing data or to track and collect data from well meters
The Groundwater Extraction Reporting Program is in preliminary stages of discussion and possible consideration. Therefore, no costs have been estimated for its development and implementation. Such costs would be developed should the Modesto Subbasin GSAs decide to pursue a program in the future.
8.5.2.1.2.8.1.1.2.5 Management of Groundwater Extractions and Recharge This program would directly develop and expand the reporting of groundwater extractions, including during both dry and wet periods, to support better management of the Subbasin.
8.5.2.2.8.1.1.1. Groundwater Allocation Program (Management Action 4)
8.5.2.2.1.8.1.1.1.1. Management Action Description
This strategy considers the development of a Groundwater Allocation Program for the Subbasin that would result in groundwater sustainability for the Subbasin as a whole.
Outlined here is a framework for how the Modesto Subbasin GSAs might develop and implement pumping allocations in the Subbasin based on the magnitude of projected overdraft estimated by Subbasin modeling.
There are four key steps to developing pumping allocations:
1. Identify the sources of water contributing to the native yield and estimate the quantity of native yield for the subbasin annually (see Chapter 6 of this GSP)
2.1.Estimate the amount of native yield that can be used annually consistent with the Sustainable Yield
3.1.Allocate native yield to groundwater right holders based on:
a. Priority of right
b.a. Prescription
c.a. Other legal principles, such as reasonable use
4. Determine how to account for new/additional supplies
5. Develop a timeline for reducing pumping to achieve allocations over time #25..
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The Groundwater Allocation Program is only conceptual at this time. There are numerous ways to structure and implement an allocation program which will need to be further evaluated, developed, and refined by the Modesto Subbasin GSAs prior to implementation.
8.5.2.2.2.8.1.1.1.1. Public Noticing
Development of a Groundwater Allocation Program would require substantial public input to understand the potential impacts of groundwater allocations and baseline needs that should be accounted for. The Modesto Subbasin GSAs anticipates that public outreach would include multiple public workshops and meetings, potential website and/or email announcements, along with other public notices for the workshops. The Groundwater Allocation Program would be circulated for public comment before finalized, though final approval of the plan would be made by the Modesto Subbasin GSAs in partnership with their respective member agencies. Implementation of the program may be confined to specific Management Areas.
8.5.2.2.3.8.1.1.1.1. Permitting and Regulatory Process
Development of a Groundwater Allocation Program would not require any permitting but would require consideration of existing water rights and applicable permits and regulations associated with groundwater pumping in the Subbasin.
8.5.2.2.4.8.1.1.1.1. Expected Benefits
Benefits to Sustainability Indicators
Sustainability indicators benefitting from the Groundwater Allocation Program include:
• Chronic lowering of groundwater levels – By reducing groundwater demand, this MA would reduce pumping and pumping-related contributions to chronic lowering of groundwater levels.
• Reduction of groundwater in storage – Reduced pumping throughout the Subbasin contributes to a smaller rate of reduction of groundwater in storage. • Degraded water quality – This MA does not address this sustainability indicator. • Land subsidence – Reduced groundwater pumping may reduce the risk of subsidence associated with lowering of groundwater levels. • Depletion of interconnected surface water – Reduced pumping would reduce the potential for negative impacts to surface water flows associated with lowering groundwater levels.
Benefits to Disadvantaged Communities
Benefits to disadvantaged communities overlap with the benefits described above for sustainability indicators.
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Volumetric Benefits to Subbasin Groundwater System
The volumetric benefit to the groundwater system will depend on the structure of the allocation framework and will be further studied if and when the program is developed by the GSAs.
8.5.2.2.5.8.1.1.2.5 Implementation Criteria, Status, and Plan The Modesto Subbasin GSAs will develop annual reports to evaluate progress toward meeting the sustainability goal. If monitoring efforts demonstrate that the Projects and MAs being implemented are not effective in achieving stated targets, the GSAs will convene a working group to evaluate the implementation of additional supply-side and demand-side actions, such as the implementation of tiered approaches in the Water Accounting Framework.
8.5.2.2.6.8.1.1.1.1. Water Source and Reliability
This program does not rely on the supplies from outside the Subbasin because it is a planning effort that will result in conservation. It will support overall supply reliability by reducing overdraft in the Subbasin and moving the Subbasin towards sustainability.
8.5.2.2.7.8.1.1.1.1. Legal Authority
Under SGMA, GSAs have authority to establish groundwater extraction allocations.
Specifically, SGMA authorizes GSAs to control groundwater by regulating, limiting, or suspending extractions from individual wells or extractions in the aggregate.3SGMA and GSPs adopted under SGMA cannot alter water rights.
8.5.2.2.8.8.1.1.1.1. Estimated Costs and Funding Plan
Development and initiation of an allocation program is expected to include upfront costs to conduct the analysis, set up the tracking system, and conduct outreach. Costs to implement the plan would depend on the level of enforcement required to achieve allocation targets and the level of outreach required annually to remind users of their allocation for a given year. The Groundwater Allocation Program would also include an annual cost that covers ongoing enforcement and implementation. Because the Groundwater Allocation Program is in preliminary stages of discussion and possible consideration, no costs have been estimated. Such costs could be developed if the Modesto Subbasin GSAs decide to pursue a program in the future.
8.5.2.2.9.8.1.1.1. Management of Groundwater Extractions and Recharge The Groundwater Allocation Program would include provisions for the recovery of groundwater levels and groundwater in storage during non-drought periods. 3 California Water Code § 10726.4(a)(2)
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8.5.2.3. Groundwater Extraction Fee (Management Action 5)
8.5.2.3.1.8.1.1.3.1 Management Action Description
This strategy entails setting up a Groundwater Extraction Fee structure for each groundwater user. The fee structure could work in conjunction with the groundwater allocation and reporting programs, such that groundwater use above a certain allocation can be subject to a fee. This strategy could be implemented within the GSAs as needed to achieve the sustainability goals.
Revenue from these fees could then be used to pay for a variety of activities, such as the construction of water infrastructure, protection of groundwater, proper construction and destruction of wells to prevent contamination, groundwater recharge and recovery projects, purchase of imported water or other supplies to replenish the groundwater basin, and/or purchasing and permanent fallowing of marginally-productive agricultural lands dependent on groundwater. Fees could also be used to pay for administration, enforcement, and implementation of the MA.
8.5.2.3.2.8.1.1.3.1 Public Noticing
Development of a Groundwater Extraction Fee would require substantial public input to understand the potential impacts and needs that should be accounted for. The Modesto Subbasin GSAs anticipates that public outreach would include multiple public workshops and meetings, potential website and/or email announcements, along with other public notices for the workshops. The Groundwater Extraction Fee framework would be circulated for public comment before being finalized, though final approval of the plan would be made by the Modesto Subbasin GSAs in partnership with its member agencies.
Additional noticing for the public would be conducted consistent with permitting requirements in the case of the enactment of fees. GSA outreach may include public notices, meetings, website or social media presence, and email announcements. Prior to implementing any fee or assessment program, the GSAs would complete a rate assessment study or other analysis if required by the regulatory requirements.
Per Water Code §10730, prior to imposing or increasing a fee, a groundwater sustainability agency shall hold at least one public meeting, at which oral or written presentations may be made as part of the meeting. Notice of the time and place of the meeting shall include a general explanation of the matter to be considered and a statement that the data required by this section is available. The notice shall be provided by publication pursuant to §6066 of the Government Code, by posting notice on the Internet Web site of the groundwater sustainability agency, and by mail to any interested party who files a written request with the agency for mailed notice of the meeting on new or increased fees. A written request for mailed notices shall be valid for one year from the date that the request is made and may be renewed by making a written request on or before April 1 of each year. At least 20 days prior to the meeting, the groundwater sustainability agency shall make available to the #25..
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public data upon which the proposed fee is based. Any action by a groundwater sustainability agency to impose or increase a fee shall be taken only by ordinance or resolution.
8.5.2.3.3.8.1.1.3.1 Permitting and Regulatory Process
Fees imposed pursuant to Water Code §10730 shall be adopted in accordance with all applicable laws.
A fee or charge shall not be extended, imposed, or increased by any agency unless it meets all of the following requirements:
• Revenues derived from the fee or charge shall not exceed the funds required to provide the property related service.
• Revenues derived from the fee or charge shall not be used for any purpose other than that for which the fee or charge was imposed.
• The amount of a fee or charge imposed upon any parcel or person as an incident of property ownership shall not exceed the proportional cost of the service attributable to the parcel.
• No fee or charge may be imposed for a service unless that service is actually used by, or immediately available to, the owner of the property in question. Fees or charges based on potential or future use of a service are not permitted. Standby charges, whether characterized as charges or assessments, shall be classified as assessments and shall not be imposed without compliance with Section 4 (Water Code §10730).
• No fee or charge may be imposed for general governmental services including, but not limited to, police, fire, ambulance or library services, where the service is available to the public at large in substantially the same manner as it is to property owners.
8.5.2.3.4.8.1.1.3.1 Expected Benefits
Benefits to Sustainability Indicators
Collection of groundwater extraction fees incentivizes the use of supplemental or alternative water supplies where fees can also fund activities/projects that increase groundwater supplies, such as groundwater recharge, thus reducing declines in groundwater elevations and groundwater in storage. Other sustainability indicators benefitting from the Groundwater Extraction Fee program include:
• Degraded water quality – Funded activities and projects can also reduce degradation of groundwater quality (such as proper construction/destruction of wells to prevent contamination).
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• Land subsidence – Reduced groundwater pumping would reduce the risk of subsidence associated with lowering of groundwater levels. • Depletion of interconnected surface water – Reduced pumping would reduce the potential for negative impacts to surface water flows associated with lowering groundwater levels.
Benefits to Disadvantaged Communities
Any fees would comply with CWC, §10730(a) and shall exclude de minimis extractors from fees, where appropriate.
Volumetric Benefits to Subbasin Groundwater System
The volumetric benefit to the groundwater system would depend on the framework of the fee implemented and would be further studied as the Groundwater Extraction Fee framework was developed by the GSAs.
8.5.2.3.5.8.1.1.3.1 Implementation Criteria, Status, and Plan The Modesto Subbasin GSAs will develop annual reports to evaluate progress toward meeting the sustainability goal. If monitoring efforts demonstrate that the Projects and MAs being implemented are not effective in achieving stated targets, the GSAs will convene a working group to evaluate the implementation of additional supply-side and demand-side actions, such as the implementation of tiered approaches in the Water Accounting Framework.
8.5.2.3.6.8.1.1.3.1 Water Source and Reliability
The Groundwater Extraction Fee program will apply in both drought and non-drought periods.
8.5.2.3.7.8.1.1.3.1 Legal Authority
The GSAs possess the legal authority to implement special taxes, assessments, and user fees within the Project proponent service area or area of Project benefit. Fees imposed include fixed fees and fees charged on a volumetric basis, including, but not limited to, fees that increase based on the quantity of groundwater produced annually, the year in which the production of groundwater commenced from a groundwater extraction facility, and impacts to the basin.
8.5.2.3.8.8.1.1.3.1 Estimated Costs and Funding Plan
While there are certain administrative costs anticipated with the development and implementation of a Groundwater Extraction Fee, the Groundwater Extraction Fee itself is a #25..
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potential mechanism to fund the costs of groundwater management. This includes, but is not limited to, the following:
• Administration, operation, and maintenance, including a prudent reserve • Acquisition of lands or other property, facilities, and services • Supply, production, treatment, or distribution of water • Other activities necessary or convenient to implement the plan
8.5.2.3.9.8.1.1.3.1 Management of Groundwater Extractions and Recharge This program, in conjunction with the Groundwater Extraction Reporting Program (MA 3), would directly develop and expand the reporting of groundwater extractions, including during both drought and non-drought periods, to support better management of the Subbasin.
8.5.2.4.8.1.1.3 Groundwater Pumping Credit Market and Trading Program (Management Action 6)
8.5.2.4.1.8.1.1.3.1 Management Action Description
Groundwater credit markets and trading programs can be used to exchange and trade the allocation of groundwater use by each landowner within the GSAs. This strategy is contingent upon implementation of the groundwater reporting and allocation programs (MAs 1 and 2), so that the credit and trading market can monitor the exchange of groundwater allocations among the landowners and/or the GSAs. Should the Modesto Subbasin GSAs decide to pursue a program in the future, the Modesto Subbasin GSAs would seek guidance from agencies with experience in water markets to identify options for communications and outreach with stakeholders, program design, and mechanisms to ensure that non-participating stakeholders are not adversely impacted by the program.
8.5.2.4.2.8.1.1.3.1 Public Noticing
Development and implementation of a Groundwater Pumping Credit Market and Trading Program would require substantial public input to understand the potential impacts and nuances of implementing such a program. The Modesto Subbasin GSAs anticipate that public outreach would include multiple public workshops and meetings, potential website and/or email announcements, along with other public notices for the workshops. The program plan would be circulated for public comment before being finalized, though final approval of the plan would be made by the Modesto Subbasin GSAs in partnership with their member agencies.
8.5.2.4.3.8.1.1.3.1 Permitting and Regulatory Process
Permitting and other regulatory compliance issues will be identified and addressed when the program is being further explored and developed, consistent with SGMA §10726.4 (a) (3 & 4).
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8.5.2.4.4.8.1.1.3.1 Expected Benefits
Benefits to Sustainability Indicators
Sustainability indicators benefitting from the Groundwater Pumping Credit Market and Trading Program include:
• Chronic lowering of groundwater levels – By reducing groundwater demand, this MA would reduce pumping and pumping-related contributions to chronic lowering of groundwater levels.
• Reduction of groundwater in storage – Reduced pumping throughout the Subbasin contributes to a smaller rate of reduction of groundwater in storage. • Degraded water quality – This MA does not address this sustainability indicator. • Land subsidence – Reduced groundwater pumping would reduce the risk of subsidence associated with lowering of groundwater levels. • Depletion of interconnected surface water – Reduced pumping would reduce the potential for negative impacts to surface water flows associated with lowering groundwater levels.
Benefits to Disadvantaged Communities
Benefits to disadvantaged communities overlap with the benefits described above for sustainability indicators.
Volumetric Benefits to Subbasin Groundwater System
The volumetric benefit to the groundwater system will depend on the framework of the credit market and trading program implemented and would be further studied when the program was developed by the GSAs.
8.5.2.4.5.8.1.1.3.1 Implementation Criteria, Status, and Plan The Modesto Subbasin GSAs will develop annual reports to evaluate progress toward meeting the sustainability goal. If monitoring efforts demonstrate that the Projects and MAs being implemented are not effective in achieving stated targets, the GSAs will convene a working group to evaluate the implementation of additional supply-side and demand-side actions, such as the implementation of tiered approaches in the Pumping Management Framework.
8.5.2.4.6.8.1.1.3.1 Water Source and Reliability
The Subbasin area will be the source of groundwater and will be limited by the hydrology of the region.
8.5.2.4.7.8.1.1.3.1 Legal Authority
SGMA §10726.4 (a) (3 & 4) provide legal authority for groundwater transfer and accounting programs.
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8.5.2.4.8.8.1.1.3.1 Estimated Costs and Funding Plan
The Groundwater Pumping Credit Market and Trading Program is in preliminary stages of discussion and possible consideration. Therefore, no costs have been estimated for its development and implementation. Such costs would be developed should the Modesto Subbasin GSAs decide to pursue a program in the future. Costs would likely include additional staffing required to administer the program and would be borne by the participants.
8.5.2.4.9.8.1.1.3.1 Management of Groundwater Extractions and Recharge The implementation of a Groundwater Pumping Credit Market and Trading Program will include provisions for the recovery of groundwater levels and groundwater in storage during non-drought periods.
8.6.8.5. PLAN FOR ACHIEVING SUSTAINABILITY
8.6.1.8.5.1. Integrated Modeling Scenarios
To evaluate the effects of PMAs in meeting the sustainability goals of the Modesto Subbasin, Group 1 and 2 Projects have been analyzed using the C2VSimTM model.
C2VSimTM is a fully integrated surface and groundwater flow model capable of analyzing the effects of the PMAs on the land surface, stream, and groundwater systems of the Modesto Subbasin. The C2VSimTM model is used to develop the GSP’s water budget estimates for historical, current, and projected conditions, as well as Subbasin groundwater levels, streamflow, and interconnected surface water bodies under historical, baseline, and various Project conditions. It is understood that the projections of future groundwater conditions using the C2VSimTM model are based on the current understanding of the Subbasin, which can be further refined as more information becomes available. The 50-year projection of groundwater conditions using C2VSimTM is based on assumptions that has uncertainties in hydrologic and climatic conditions, agricultural crop mix and patterns, irrigation practices, population growth patterns and urban development trends, and land use plans, and environmental regulations. However, the C2VSimTM is currently the best available analysis tool to assist in evaluation of Project benefits and impacts, not in an absolute sense, but in a relative scale.
The analysis below evaluates the proposed projects relative to the C2VSimTM Projected Conditions Baseline. The results of this analysis are then compared to MTs to estimate the approximate amount of additional net demand reduction that will be needed to meet the sustainability goal of the Subbasin. The Projected Conditions Baseline applies the projected water supply and demand conditions under the 50-year hydrologic period of WYs 1969- 2018. A total of seven (7) Group 1 and 2 Projects were grouped into two (2) scenarios based on their use-sector and Project type. Table 8-2Table 8-10 shows a matrix of the simulated #25..
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projects and their respective scenarios. Each of these projects are described in detail in Section 8.38.2, with modeling assumptions outlined in sub-section 5 for each project.
Table 8-210: Projects Analyzed Using C2VSimTM Model
Urban and Municipal Projects Scenario 1 Scenario 2
1 Growth Realization of Surface Water Treatment Plant Phase II Baseline Baseline 2 Municipal Conservations Projects X X
3 Storm Drain Cross Connection Removal Project X X
4 Surface Water Supply Project X X
In-lieu Supply or Recharge Projects
5 MID to Out-of-District Lands In-lieu and Direct Recharge Project X 6 OID to Out-of-District Lands In-lieu and Direct Recharge Project X Flood Mitigation Projects
7 Tuolumne River Flood Mitigation Direct Recharge Project X 8 Dry Creek Flood Mitigation Direct Recharge Project X
Scenario 1: Urban and Municipal Surface Water Supply
Scenario 1 includes the three urban and municipal projects as proposed by their respective agencies. These projects, shown in Table 8-3Table 8-11 total an average net-recharge of 13,700 AFY over the 50-year simulation period. Impacts to the subbasin were simulated by reducing the urban demand in the City of Modesto, providing surface water supplies to the City of Waterford, and incorporating additional recharge facilities throughout the City of Modesto. Table 8-3Table 8-11 below summarizes the individual and cumulative impacts of each Project within this scenario.
Table 8-311: Scenario 1 Project Summary
Project Direct
Recharge
In-Lieu
Recharge
Demand
Reduction
Urban and Municipal Projects
Municipal Conservation Projects1 12,800
Storm Drain Cross Connection Removal
Project 200
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City of Waterford Surface Water Supply
Project1 700
All Urban and Municipal Projects 200 700 12,800
All Scenario 1 Projects 200 700 12,800
Notes: All Units are in acre-feet
1 The City of Modesto Conservation Projects and the City of Waterford Surface Water Supply Project include beneficiaries in both the Turlock and Modesto Subbasin. The volumes in this table represent an estimated fraction of the effective contribution to the Modesto Subbasin Scenario 1 projects are expected to reduce net groundwater pumping in the subbasin by 13,700 AFY. The net benefit to groundwater in storage is to reduce the projected average annual groundwater in storage deficit from 11,000 AFY under the Baseline conditions to 9,500 AFY with these projects, resulting in a net savings of 1,500 AFY of groundwater in storage. Details are shown in Table 8-5Table 8-13 and Error! Reference source not found.Error! Reference source not found.Figure 8-1.
Principally, Scenario 1 projects were implemented to mitigate lowering groundwater levels, depletions of interconnected surface water systems, and potential subsidence near the urban centers within the Modesto Subbasin. Section 8.5.2 presents the simulated groundwater conditions under both the projected conditions baseline and each of the PMA scenarios.
Scenario 1 is anticipated to be implemented in conjunction with multiple other agriculturally based projects to further improve and project aquifer conditions. See the descriptions of the following scenario for information on the cumulative impacts to the system.
Scenario 2: In-Lieu Supply Recharge and Flood Mitigation Projects Scenario 2 builds on the benefits of Scenario 1 to incorporate the agriculturally based in-lieu and direct recharge projects. The addition of the projects to this scenario increases the net simulated contribution to the groundwater system from an average of 13,700 AF to 71,900 AFY. The four proposed projects include
1. The MID to Out-of-District Lands In-lieu and Direct Recharge Project, providing up to 60,000 AF of in-lieu recharge in Wet and Above Normal years, or an average annual contribution of 28,800 over the 50-year simulation period.
2. The OID to Out-of-District Lands In-lieu and Direct Recharge Project, providing up to 20,000 AFY of in-lieu recharge in all non-critically dry years, providing an average of 14,400 across the planning horizon.
3. The Tuolumne River Flood Mitigation Direct Recharge Project, providing 20,000 AFY of direct recharge in Wet and Above Normal years (9,600 AFY in the 50-year simulation average),
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4. The Dry Creek Flood Mitigation Direct Recharge Project, providing 5,400 AFY of direct recharge in all year types.
The tableTable 8-4Table 8-12 below summarizes the individual and cumulative impacts of each Project within this scenario.
Table 8-412: Scenario 2 Project Summary
Project Direct
Recharge
In-Lieu
Recharge
Demand
Reduction
Urban and Municipal Projects
Municipal Conservation Projects1 12,800
Storm Drain Cross Connection Removal Project 200
City of Waterford Surface Water Supply
Project1 700
All Urban and Municipal Projects 200 700 12,800
In-lieu Supply and Direct Recharge Projects
MID to Out-of-District Lands In-lieu and Direct
Recharge Project 9,600 19,200
OID to Out-of-District Lands In-lieu and Direct
Recharge Project 1,400 13,000
All In-lieu Supply or Recharge Projects 11,000 32,200 0 Flood Mitigation Projects
Tuolumne River Flood Mitigation Direct
Recharge Project 9,600
Dry Creek Flood Mitigation Direct Recharge
Project 5,400
All In-lieu Supply or Recharge Projects 15,000 0 0
All Scenario 2 Projects 26,200 32,900 12,800
Notes: All Units are in acre-feet
1 The City of Modesto Conservation Projects and the City of Waterford Surface Water Supply Project include beneficiaries in both the Turlock and Modesto Subbasin. The volumes in this table represent an estimated fraction of the effective contribution to the Modesto Subbasin Scenario 2 projects are expected to reduce groundwater pumping in the subbasin by 44,400 AFY. The net benefit to groundwater in storage projected is to reduce the average annual groundwater in storage deficit from 11,000 AFY under the Baseline conditions to an average annual positive change in storage of 1,400 AFY with these projects, resulting in a net savings of 12,400 AFY of groundwater in storage. Details are shown in Table 8-5Table 8-13 and Error! Reference source not found.Error! Reference source not found.Figure 8-1. #25..
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Analysis of conditions under Scenario 2 show that under Project buildout, sustainability goals as defined by the Minimum Thresholds (MTs) outlined in Chapter 6, Sustainable Management Criteria, can be met without demand management. Section 8.5.2 below shows how Scenarios 1 and 2 effect groundwater levels at representative monitoring locations throughout the subbasin relative to the simulated minimum thresholds.
While simulated conditions meet sustainability metrics in the long-term, the Modesto Subbasin acknowledges that these scenarios assume immediate implementation of the projects and MAs listed above. In the near-term, sustainability of the Modesto Subbasin relies on the NDE area to actively pursue the development of these projects and understands that interim MAs, including the potential for demand reduction, may be necessary to meet SMCs.
Figure 8-1: Scenario 1-2 Cumulative Change in Storage
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Figure 8-2: Scenario 2 Groundwater Budget
Table 8-513: Scenarios 1-2 Groundwater Budgets
Baseline Scenario 1
Urban & Municipal
Scenario 2
In-lieu and Direct
Recharge Projects
Deep Percolation 234,900 230,100 235,800
Canal, Res., & Direct
Recharge 47,300 47,500 73,500
Net Stream Seepage 24,300 18,800 -4,100
Inflow from Foothills 9,300 9,300 9,300
Net Subsurface Flow -5,900 -7,600 -36,500
Groundwater Pumping 321,000 307,600 276,600
Groundwater in Storage
Deficit 11,000 9,500 -1,400
8.6.2.8.5.2. Representative Hydrographs Scenarios 1-2
Figure 8-3Figure 8-3 shows the location of the representative monitoring wells that were used in the development and calibration of the Modesto Subbasin in C2VSimTM. As representative wells of simulated conditions, these wells were used to evaluate the performance of the PMAs in each of the different scenarios. #25..
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Figure 8-3: Modesto Subbasin Representative Wells
Chapter 6: Sustainable Management Criteria describes thresholds for representative monitoring network wells that protect the Subbasin from experiencing Undesirable Results from the chronic lowering of groundwater levels (SMC1), and depletions of interconnected surface water systems (SMC6). Chapter 6 defines Undesirable Results such that at no more than 33% of the representative monitoring wells shall exceed the 2015-low for a period longer than 3 consecutive years. Under Scenario 2, SGMA compliance was predicted to be met throughout the simulation period. As shown in the figures below, simulated groundwater levels occasionally drop below the MT, but do not exceed the combination of drought-time spatial and temporal limitations.
Note, the twelve wells listed below (Figure 8-5Figure 8-5 though Figure 8-14Figure 8-14) are not inclusive of all monitoring locations, rather this subset was included as they are considered representative of RMS throughout the Subbasin. Locations of these example representative hydrographs are shown in the following figureFigure 8-4Figure 8-4 below. #25..
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Figure 8-4: SMC1 Example Hydrographs
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Figure 8-5: SMC1 Hydrograph C2VSimTM 01
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Figure 8-6: SMC1 Hydrograph C2VSimTM 07
Figure 8-7: SMC1 Hydrograph C2VSimTM 11
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Figure 8-8: SMC1 Hydrograph C2VSimTM 19
Figure 8-9: SMC1 Hydrograph C2VSimTM 24
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Figure 8-10: SMC1 Hydrograph C2VSimTM 34
Figure 8-11: SMC1 Hydrograph C2VSimTM 45
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Figure 8-12: SMC1 Hydrograph C2VSimTM 48
Figure 8-13: SMC1 Hydrograph C2VSimTM 52
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Figure 8-14: SMC1 Hydrograph C2VSimTM 54
Figure 8-15: SMC1 Hydrograph C2VSimTM 64
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Figure 8-16: SMC1 Hydrograph C2VSimTM 65
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9. IMPLEMENTATION PLAN
9.1. PLAN IMPLEMENTATION
Implementation of this GSP includes implementation of the projects and MAs included in Chapter 8, as well as the following:
• Modesto Subbasin GSAs administration and management
• Implementing the monitoring program
• Implementation of Projects and MAsManagement Actions
• Developing annual reportsAnnual Reports
• Developing required five-year GSP updatesPeriodic Evaluations This chapter also describes the contents of both the annual and five-year reportsperiodic evaluations that must be provided to the California Department of Water Resources (DWR) as required by Sustainable Groundwater Management Act (SGMA) regulations.
9.1.1. Implementation Schedule
Figure 9-1Figure 9-1 illustrates the GSP’s implementation schedule. Included in the chart are activities necessary for ongoing GSP monitoring and updates, as well as tentative schedules for projects and MAs.
Additional details about the activities included in the schedule are provided in these activities’ respective sections of this GSP. Adaptive management would only be implemented if triggering events are reached, as described in Chapter 8, and are shown as ongoing in the schedule. #25..
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Figure 9-1: Implementation Estimated Schedule1,2
# Project/Management Action Name
202220232024202520262027202820292030203120322033203420352036203720382039204020412042 Beyond
Urban and Municipal Projects
1 Growth Realization of Surface Water Treatment Plant Phase II
2 Advanced Metering Infrastructure (AMI) Project
3 Storm Drain Cross Connection Removal Project2Project3 4 Surface Water Supply Project
In-Lieu & Direct Recharge Projects
5 MID to Out-of-District Lands In-lieu and Direct Recharge Project
6 OID to Out-of-District Lands In-lieu and Direct Recharge Project
Flood Mitigation Projects
7 Tuolumne River Flood Mitigation Direct Recharge Project 8 Dry Creek Flood Mitigation Direct Recharge Project
Management Actions
1 Project development and design periodGroundwater
Allocation and Pumping Management Program
Project
Constr
uction
Project
operati
on
2 Groundwater Extraction and Surface Water Reporting
Program
3 Groundwater Extraction Fee
4 Groundwater Pumping Credit Market and Trading Program 5 Voluntary Conservation and/or Land Fallowing
6 Conservation Practices
7 Dry Well Mitigation Program
PMA development and design period Project construction PMA operation 1 Potential futureSupplemental projects (Projects 9 through 13) and are not included because they will be implemented by the GSAs as needed and do not currently have a planneddefinite schedule at this time.. 2 This2
In accordance with the resolution, a schedule for management actions 1 through 6 will be developed no later than January 31, 2026, and implemented no later than January 31, 2027. The dry well mitigation program (management action 7) will be developed and implemented no later than January 31, 2026.
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3 The Storm Drain Cross Connection Removal Project has multiple phases and components that will be developed over time and therefore portions are in development/design, construction, or are completed simultaneously. #25..
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9.2. IMPLEMENTATION COSTS BUDGETS AND FUNDING SOURCES
The operation of the Modesto Subbasin GSAs and GSP implementation will incur costs, which will require funding. The five primary activities that will incur costs are listed here.
Table 9-1Table 9-1 summarizes these activities and their estimated costs. These estimates will be refined during GSP implementation as more information becomes available. • Implementing the GSP
• Implementing GSP-related projectsProjects and MAsManagement Actions • Operations of the GSAs
• Developing annual reportsAnnual Reports
• Developing five-year evaluation reportsPeriodic Evaluations
9.2.1. GSP Implementation and Funding
Costs associated with GSP implementation and operation of the GSAs could include the following:
• Modesto Subbasin GSAs administration and legal support: Overall program management and coordination activities, and legal services • Stakeholder Engagement: GSAs board meetings, Technical Advisory (TAC) meetings, general GSA meetings, and public workshops as needed.
• Outreach: Email communications, newsletters, and website management • GSP implementation program management: Program management and oversight of project and management action implementation, including coordination among GSAs Boards, staff and stakeholders, coordination of GSAs implementation technical activities, oversight and management of the GSAs consultants and subconsultants, budget tracking, schedule management, and quality assurance/quality control of project implementation activities, and integrating and maintaining a live projects and management actions list
• Monitoring: Data collection, filling data gaps, improvements and/or enhancements to DMS
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Table 9-1: Modesto Subbasin GSAs and GSP Implementation Budgets Activity Estimated Annualized Budget a
GSP Implementation and GSA Management
Administration and Legal Support for the GSAs $35,000
Stakeholder and Board Engagement $3,000
Outreach $5,000
GSP Implementation Program Management $25,000
Monitoring Program, including Data Management $15,000
Annual Reporting $100,000
Five-Year GSP UpdatesPeriodic Evaluations (total cost estimated to be $500,000, $100,000 annually) $100,000 Data Gap Analysis TBD
Projects and Management Actions
Project 1: Growth Realization of Surface Water Treatment Plant Phase II $93,190,000 Project 2: Advanced Metering Infrastructure Project (AMI) $20,000,000 Project 3: Storm Drain Cross Connection Removal Project $40,000,000 Project 4: Waterford/Hickman Surface Water Pump Station and Storage Tank $8,500,000 Project 5: Modesto Irrigation District In-lieu and Direct Recharge Project $53,340,000 - $75,000,000 Project 6: Oakdale Irrigation District In-lieu and Direct Recharge Project $17,780,000 - $25,000,000 Project 7: Tuolumne River Flood Mitigation and Direct Recharge Project See Project 5 above b Project 8: Dry Creek Flood Mitigation and Direct Recharge Project $4,800,600 - $6,750,000 Project 9: Stanislaus River Flood Mitigation and Direct Recharge Project To be developed if
implementation is neededduring
evaluation
Project 10: Detention Basin Standards Specifications Update To be developed if
implementation is neededduring
evaluation
Project 11: Recharge Ponds
To be developed if
implementation is neededduring
evaluation
Project 12: OID Irrigation and Recharge to Benefit City of Oakdale To be developed if
implementation is neededduring
evaluation
Project 13: Modesto Irrigation District FloodMARFlood-MAR Projects To be developed if
implementation is neededduring
evaluation
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Activity Estimated Annualized Budget a
MA 1: MA 1: Groundwater Allocation ProgramVoluntary Conservation and/or Land Fallowing To be developed if
implementation is
neededdetermined during
evaluation
MA 2:
Conservation
Practices To be developed if implementation is needed
MA 3:2: Groundwater Extraction and Surface Water Accounting Reporting Program To be developed if
implementation is
neededdetermined during
evaluation
MA 4:
Groundwater
Allocation
Program To be developed if implementation is needed
MA 53: Groundwater Extraction Fee
To be developed if
implementation is
neededdetermined during
evaluation
MA 6:4: Groundwater Pumping Credit Market and Trading Program To be developed if
implementation is
neededdetermined during
evaluation
MA 5: Voluntary Conservation and/or Land Fallowing To be determined during evaluation
MA 6: Conservation Practices To be determined during
evaluation
MA 7: Dry Well Mitigation Program Baseline fund: $300,000 a Estimates are rounded and based on full implementation years (FY 2023 through FY 2042). Different costs may be incurred in FY 2022 as GSP implementation begins and during each 5-year update cycle.
b Projects 5 and 7 use the same infrastructure for surface water conveyance.
9.2.1.9.1.1. GSP Implementation and Funding
Costs associated with GSP implementation and operation of the GSAs could include the following:
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• Modesto Subbasin GSAs administration and legal support: Overall program management and coordination activities, and legal services
• Stakeholder Engagement: GSAs board meetings, Technical Advisory (TAC) meetings, general GSA meetings, and public workshops as needed.
• Outreach: Email communications, newsletters, and website management • GSP implementation program management: Program management and oversight of project and management action implementation, including coordination among GSAs Boards, staff and stakeholders, coordination of GSAs implementation technical activities, oversight and management of the GSAs consultants and subconsultants, budget tracking, schedule management, and quality assurance/quality control of project implementation activities, and integrating and maintaining a live projects and management actions list
• Monitoring: Data collection, filling data gaps, improvements and/or enhancements to DMS #25..
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Implementation of this GSP is projected to run between $250,000 and $350,000 per year, and projects and MAs totaling between $237,610,600 - $268,440,000. The GSAs have adopted a resolution committing to the development of MAs and a Well Mitigation Program. The GSAs anticipate having the policies and regulations, estimated future costs and funding sources for MAs and the Well Mitigation Program identified by January 31, 2026. Development of this GSP was funded through a Proposition 1 Sustainable Groundwater Planning Grant. Operation of the GSAs is fully funded through contributions from GSAs member agencies. Although ongoing operation of the GSAs is anticipated to include contributions from its member agencies, which are ultimately funded through customer fees or other public funds, additional funding may be required to implement the GSP. Of the implementation activities in the GSP, only project implementation is likely to be eligible for grant or loan funding; funding through grants or loans have varying levels of certainty. As such, the GSAs will develop a financing plan that may include one or more of the following financing approaches:
• Pumping Fees: Pumping fees would implement a charge for pumping that would be used to fund GSP implementation activities. In the absence of other sources of funding (i.e., grants, loans, or combined with assessments) fees could range between $10 and $100 per AF per year. To meet the funding needs of the GSP, fees would be lower when pumping is higher, such as current pumping levels, and higher when pumping is lower, such as when sustainable pumping levels are achieved.
Although this funding approach would meet the financial needs of the GSP and GSAs, it may discourage pumping reductions due to cost. The financing plan developed by the GSAs would evaluate how to balance the need for funding with encouraging pumpers to commit to compliance with desired groundwater pumping reduction goals.
• Assessments: Assessments would charge a fee based on land areas. There are two methods for implementing an assessment based on acreage. The first option would assess a fee for all acres in the Subbasin outside of those in federal lands, which would cost approximately $5 to $10 per acre per year. This option would not distinguish between land use types. The second option would be to assess a fee only on irrigated acres. Based on current irrigated acreage, the assessment would be $10 to $50 per acre per year. Similar to the pumping fee approach, assessment based on irrigated acreage could affect agricultural operations and contribute to land use conversions, which could affect the assessment amount or ability to fully fund GSP implementation.
• Combination of fees and assessments: This approach would combine pumping fees and assessments to moderate the effects of either approach on the economy in the Basin. This approach would likely include an assessment that would apply to all acres in the Basin, rather than just to irrigated acreage. It would be coupled with a pumping fee to account for those properties that use more water than others. #25..
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During development of a financing plan, the GSAs would also determine whether to apply fees across the Subbasin as a whole or just within certain Management Areas. Prior to implementing any fee or assessment program, the GSAs would complete a rate assessment study and other analysis consistent with the requirements of Proposition 218.
The GSAs member agencies will pursue grants and loans to help pay for project costs to the extent possible. If grants or loans are secured for project implementation, potential pumping fees and assessments may be adjusted to align with operating costs of the GSAs and ongoing GSP implementation activities. A potential hurdle to the utilization of state grant funding is that delays in payment by the state can cause hardships for disadvantaged communities. Therefore, it would be appropriate to expedite payments associated with grant funding by DWR.
9.2.2. Projects and Management Actions
Costs for the Projects and MAs are described in Chapter Error! Reference source not found.8: Projects and Management Actions of this GSP. Financing of the projects and MAs would vary depending on the activity. Potential financing options for projects and MAs are provided in Table 9-2Table 9-2, though other financing may be pursued as opportunities arise or as appropriate.
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Table 9-2: Financing Options for Proposed Projects, Management Actions, and Adaptive Management Strategies Project/Activity Responsible Entity Potential Financing Options Projects
Project 1: Growth Realization of Surface Water Treatment Plant Phase II City of Modesto/MID City of Modesto Operating CostsGrants and Loans Project 2: Advanced Metering Infrastructure Project (AMI) City of Modesto City of Modesto Operating Costs Grants and Loans
Project 3: Storm Drain Cross Connection Removal Project City of Modesto City of Modesto Operating Costs Grants and Loans
Project 4: Waterford/Hickman Surface Water Pump
Station and Storage Tank City of Waterford City of Waterford Operating Costs Project 5: Modesto Irrigation District In-lieu and Direct Recharge Project NDE Areas Grants and LoansParticipating NDE landowners Project 6: Oakdale Irrigation District In-lieu and Direct Recharge Project NDE Areas Grants and LoansParticipating NDE landowners Project 7: Tuolumne River Flood Mitigation and Direct
Recharge Project NDE Areas Grants and Loans Participating NDE landowners Project 8: Dry Creek Flood Mitigation and Direct Recharge Project Stanislaus County/NDE Areas Grants and LoansParticipating NDE landowners Project 9: Stanislaus River Flood Mitigation and Direct Recharge Project NDE Areas Grants and LoansParticipating NDE landowners Project 10: Retention Basin Standards Specifications
Update City of Modesto Grants and LoansCity of Modesto Operating Costs Project 11: Recharge Ponds NDE Areas Grants and Loans
Participating NDE landowners
Project 12: OID Irrigation and Recharge to Benefit City of Oakdale OID/City of Oakdale Grants and LoansCity of Oakdale Operating Costs Project 13: Modesto Irrigation District Flood-MAR Projects MID Grants and Loans MID Operating Costs
Management Actions
MA 1: Groundwater Allocation ProgramMA 1: Voluntary
Conservation and/or Land Fallowing GSAs
Grants and Loans
GSA Operating Funds
GSA Member Agencies
MA 2: Groundwater Extraction and Surface Water
Accounting Reporting ProgramMA 2: Conservation
Practices
GSAs
Grants and Loans
GSA Operating Funds
GSA Member Agencies
MA 3: Groundwater Extraction FeeMA 3: Groundwater
Extraction and Surface Water Accounting Reporting
Program
GSAs
Grants and Loans
GSA Operating Funds
GSA Member Agencies
MA 4: Groundwater Pumping Credit Market and Trading
ProgramMA 4: Groundwater Allocation Program GSAs
Grants and Loans
GSA Operating Funds
GSA Member Agencies
MA 5: Voluntary Conservation and/or Land FallowingMA
5: Groundwater Extraction Fee GSAs
Grants and Loans
GSA Operating Funds
GSA Member Agencies
MA 6: Conservation PracticesMA 6: Groundwater Pumping
Credit Market and Trading Program GSAs
Grants and Loans
GSA Operating Funds
GSA Member Agencies
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9.3. ANNUAL REPORTS
Annual reports must be submitted by April 1 of each year following GSP adoption per California Code of Regulations. Annual reports must include three key sections as follows:
• General Information
• Basin Conditions
• Plan Implementation Progress
An outline of what information will be provided in each of these sections in the annual report is included below. Annual reporting will be completed in a manner and format consistent with Section 356.2 of the SGMA regulations. As annual reporting continues, it is possible that this outline will change to reflect Subbasin conditions, priorities of the GSAs, and applicable requirements.
9.3.1. General Information
General information will include an executive summary that highlights the key content of the annual report. As part of the executive summary, this section will include a description of the sustainability goals, provide a description of GSP projects and their progress as well as an annually updated implementation schedule and map of the Subbasin. Key components as required by SGMA regulations include:
• Executive Summary
• Map of the Basin
9.3.2. Basin Conditions
Basin conditions will describe the current groundwater conditions and monitoring results.
This section will include an evaluation of how conditions have changed in the Subbasin over the previous year and compare groundwater data for the year to historical groundwater data. Pumping data, effects of project implementation (e.g., recharge data, conservation, if applicable), surface water flows, total water use, and groundwater in storage will be included. Key components as required by SGMA regulations include:
• Groundwater elevation data from the monitoring network • Hydrographs of elevation data
• Groundwater extraction data
• Surface water supply data
• Total water use data
• Change in groundwater in storage, including maps
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9.3.3. Plan Implementation Progress
Progress toward successful plan implementation would be included in the annual report.
This section of the annual report would describe the progress made toward achieving interim milestones as well as implementation of projects and MAs. Key components as required by SGMA regulations include:
• Plan implementation progress
• Sustainability progress
This section may include updates to the projects and management actions list, as new project ideas are presented or existing projects are phased out, completed, or found not to be feasible.
9.4. FIVE-YEARPERIODIC EVALUATION REPORT
SGMA requires evaluation GSPs regarding their progress toward meeting approved sustainability goals at least every five years. SGMA also requires developing a written assessment and submitting this assessment to DWR. An evaluation must also be made whenever the GSP is amended. A description of the information that will be included in the five-year reportperiodic evaluation is provided below and would be prepared in a manner consistent with Section 356.4 of the SGMA regulations.
9.4.1. Sustainability Evaluation
This section will contain a description of current groundwater conditions for each applicable sustainability indicator and will include a discussion of overall Subbasin sustainability.
Progress toward achieving interim milestones and measurable objectives will be included, along with an evaluation of groundwater elevations (i.e., those being used as direct or proxy measures for the sustainability indicators) in relation to minimum thresholds. If any of the adaptative management triggers are found to be met during this evaluation, a plan for implementing adaptive management described in the GSP would be included.
9.4.2. Plan Implementation Progress
This section will describe the status of project and MAmanagement action implementation, and report on whether any adaptive MAmanagement action triggers had been activated since the previous five-year reportperiodic evaluation. An updated project implementation schedule will be included, along with any new projects that were developed to support the goals of the GSP and a description of any projects that are no longer included in the GSP.
The benefits of projects that have been implemented will be included, and updates on projects and MAs that are underway at the time of the five-year reportperiodic evaluation will be reported.
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9.4.3. Reconsideration of GSP Elements
Part of the five-year reportperiodic evaluation will include a reconsideration of GSP elements. As additional monitoring data are collected during GSP implementation, land uses and community characteristics change over time, and GSP projects and MAsmanagement actions are implemented, it may become necessary to revise the GSP. This section of the five-year reportperiodic evaluation will reconsider the Basin setting, management areas, undesirable results, minimum thresholds, and measurable objectives. If appropriate, the five-year reportperiodic evaluation will recommend revisions to the GSP. Revisions would be informed by the outcomes of the monitoring network, and changes in the Basin, including changes to groundwater uses or supplies and outcomes of project implementation.
9.4.4. Monitoring Network Description
A description of the monitoring network will be provided in the five-year report.periodic evaluation. Data gaps, or areas of the Subbasin that are not monitored in a manner commensurate with the requirements of Sections 352.4 and 354.34(c) of the SGMA regulations will be identified. An assessment of the monitoring network’s function will also be provided, along with an analysis of data collected to date. If data gaps are identified, the GSP will be revised to include a program for addressing these data gaps, along with an implementation schedule for addressing gaps and how the GSAs will incorporate updated data into the GSP.
9.4.5. New Information
New information that becomes available after the last five-yearprevious evaluation or GSP amendment would be described and evaluated. If the new information warrants a change to the GSP, this would also be included.
9.4.6. Regulations or Ordinances
The five-year reportperiodic evaluation will include a summary of the regulations or ordinances related to the GSP that have been implemented by DWR since the previous report, and address how these may require updates to the GSP.
9.4.7. Legal or Enforcement Actions
Enforcement or legal actions taken by the GSAs or its member agencies in relation to the GSP will be summarized in this section along with how such actions support sustainability in the Subbasin.
9.4.8. Plan Amendments
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updates, and amendments that are underway during development of the five-year reportperiodic evaluation.
9.4.9. Coordination
The Modesto Subbasin GSAs will continue to work collaboratively to ensure implementation of the GSP to reach sustainability in the Subbasin by 2042. The GSAs will also coordinate with neighboring Subbasins including Eastern San Joaquin, Turlock, Delta-Mendota, and Tracy as needed, or any other land use agencies or entities for project implementation. This section of the five-year reportperiodic evaluation will describe coordination activities between these entities, such as meetings, joint projects, or data collection efforts.
9.5. DATA GAP ANALYSIS
As documented in Table 3-7, data gaps have been identified that would support sustainable groundwater management. Those data gaps include improved monitoring and analysis for the Western Lower Principal Aquifer, Eastern Principal Aquifer, interconnected surface water, and GDEs. In addition, the analysis in Section 2.3.3 identified data gaps for domestic wells. Each of these data gaps are described in the sections below.
9.5.1. Improvements to Monitoring Network
The current GSP monitoring network described in Chapter 7 meets monitoring objectives for initial tracking and evaluation of sustainable groundwater management criteria in each principal aquifer across the Subbasin. Nonetheless, there are data and knowledge gaps that could improve local monitoring and management. Monitoring improvements targeted for early GSP implementation are summarized below. These improvements will be made over time based on priorities and funding. As mentioned above, a comprehensive assessment of the monitoring network will be conducted as part of the five-year GSPperiodic evaluation.
9.5.1.1. Western Lower Principal Aquifer
As noted in Table 3-7, an insufficient number of monitoring wells are screened solely in the Western Lower Principal Aquifer to monitor groundwater levels and flow. Figure 7-2 shows the five existing monitoring sites for this aquifer and illustrates the need for additional wells in the west. As noted on the figure, these wells support monitoring for chronic lowering of groundwater levels, reduction of groundwater in storage, and land subsidence. Additional wells would provide better coverage for development and tracking of sustainable management criteria and development of groundwater elevation contour maps. In turn, these improvements would allow better protection against future land subsidence, assist with water budgets and model calibration, and provide a better understanding of groundwater quality data in the Subbasin.
As part of this process, the GSAs will prioritize unmonitored areas of the aquifer and identify district-owned or other available lands where new monitoring wells might be sited in the future. To expedite collection of key data in the short-term, GSAs will explore the use of #25..
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existing, properly- screened wells from cooperative private well owners. If available, the GSAs would use grant funding for additional monitoring well installations in the future. Two of the existing five monitoring sites were recently installed with a Sustainable Groundwater Management grant funded by Proposition 68.
9.5.1.2. Eastern Principal Aquifer
As noted in Table 3-7 and described in Section 7.1.1, the Eastern Principal Aquifer in the Non-District East Management Area represents a critical data gap for both historical and current data on groundwater levels and flow. As documented throughout the technical analyses in Chapters 3, 5, and 6, groundwater in this area has had the largest rates of decline and continuing overdraft – conditions that have the greatest potential to lead to undesirable results.
Proposition 68 provided an opportunity to install additional monitoring wells in this area to provide more information on local groundwater conditions. However, existing wells are insufficient for development and tracking of sustainable management criteria in key areas of the Non-District East Management Area. It is anticipated that new wells will be installed as part of project implementation by the Non-District East Management Area. Grant funding will be used for these new wells, as available.
In addition to new monitoring wells, there are data gaps with respect to the existing agricultural wells that need to be better understood. Construction and extraction data from active irrigation wells in this area are unknown. Using available well records and working directly with Non-District East Management Area landowners, the GSAs will work to fill these data gaps, providing more accurate assessments of groundwater conditions in the future. These new data will be incorporated into the water budget analyses as available, which will be provided in annual reports (see Section 9.3).
9.5.1.3. Interconnected Surface Water
As indicated in Table 3-7 and illustrated on Figure 7-5, data gaps exist for monitoring and management of interconnected surface water along the Subbasin river boundaries. The Proposition 68 grant provided the opportunity to install five new wells along the Tuolumne and Stanislaus rivers to support GSP monitoring of interconnected surface water. However, given the long river boundaries and other priorities for monitoring, the current network is incomplete. Since the GSP was submitted in 2022, the GSAs have completed an analysis and have identified potential locations of new monitoring wells along the rivers. The GSAs may seek future grant opportunities to provide funding for the additional wells. Additional wells would also assist with monitoring GDEs.
GSAs in the neighboring subbasins, including the Eastern San Joaquin, Turlock and DeltaMendota subbasins, are currently planning additional wells along the shared river boundaries of the Stanislaus, Tuolumne, and San Joaquin rivers. Consistent with the Modesto Subbasin Sustainability Goal, the GSAs will coordinate with neighboring GSAs to site and install wells that are capable of generating useful data for the shared surface water resources.
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9.5.2. Analyses of Groundwater Dependent Ecosystems
The dataset of Natural Communities Commonly Associated with Groundwater (NCCAG) provided by DWR were published after the GSP work plan and grant application had been completed. As such, it was difficult to include anything more than a high-level screening of potential GDEs in the initial GSP using periods of high and low groundwater elevations (Section 3.2.8). Following this screening, more than 70 percent of the original NCCAG polygons were retained as potential GDEs for future analyses.
As explained in Section 3.2.8, Moore Biological Consultants reviewed the potential GDEs within Mapes Ranch, a private property near the San Joaquin River. Using both a desktop study and field survey, Moore Biological Consultants concluded that 56 potential GDE polygons within Mapes Ranch are not GDEs. Given this, there may be more potential GDEs in the Subbasin that are not actually GDEs.
Because of the large number of potential GDE polygons, it was unreasonable to incorporate field surveys for all of these areas in the initial GSP assessment. As noted in Section 6.8, MTs were set at 2015 levels along the interconnected surface water to be protective of the GDEs along the rivers (where most of the potential GDE polygons occur). Monitoring data will be used to consider potential impacts on GDEs and shared publicly in annual reports.
In addition, the GSAs will continue to investigate potential GDEs and conduct additional analyses going forward. As an initial step, the GSAs will seek technical consultants with expertise to assist in developing a plan for additional GDE analyses.
9.5.3. Domestic Well Data
During the analysis of impacts to domestic wells, it was determined that significant data gaps exist. As noted in Table 6-2 (Section 6.3.1.1), 159 domestic wells failed during 2015- 2017 drought conditions (see also Figures 2-15 and 6-1). However, recent records of well permits also indicate that many of the failed wells appear to have since been replaced.
Although more than 3,000 domestic wells are included in the DWR Well Completion Report database, hundreds of those lack either completion date, construction data or complete location information and there is no indication of which wells have since been destroyed or taken offline. In addition, the well use is not documented for many additional wells in the DWR database, which could represent unknown domestic wells.
The technical team worked with the GSA representative from the City of Modesto to test the DWR database in a rural neighborhood outside of the city where domestic wells are known to be located. Even in that small area, many wells could not be correlated to DWR data and/or did not have construction or other key data in the DWR dataset.
Although production from these wells is likely to be de minimis (less than 2 AFY/well) as defined by SGMA, it would be helpful to better understand the number, location, and status of active domestic wells. As part of GSP implementation, GSAs will consider how best to #25..
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improve domestic well datasets. Areas where domestic wells are concentrated or vulnerable to declining water levels will be prioritized (see Figures 2-14, 2-17, and 6-1). An additional resource for domestic well data includes the Nitrate Control Program (NCP), where ongoing monitoring for nitrate and other constituents is focused on domestic wells (see Sections
2.4.4, 6.6.2.1.1, 6.6.2.2, and 7.1.4); access to well data will be coordinated through the Valley Water Collaborative, which is implementing the NCP in the Modesto Subbasin.
Outreach and well registration activities being applied in other subbasins will also be considered for the Modesto Subbasin.
9.6. CLOSING
The GSP implementation activities are designed to identify and document steps for successful implementation. Collectively, the sustainable management criteria, monitoring networks, and projects and management actions are anticipated to achieve the Modesto Subbasin sustainability goal. Although it is recognized that more information and actions will be needed over time, the GSAs will incorporate an adaptive management approach to prioritize activities based on best available information and document those activities and data through continued outreach and annual reporting.
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4/23/2024 5:00:00 PM
OFFICE OF THE CITY CLERK
NOTICE OF SPECIAL MEETING
Please take notice that a special Closed Session meeting of the Council of the City of Modesto has been called pursuant to Section 2-1.02 of the Modesto Municipal Code to be convened on
TUESDAY, JULY 9, 2024 AT 4:45 PM
and after the regularly scheduled meeting in the Tenth Street Place, Chambers Conference Room, Basement Level, 1010 Tenth Street, Modesto, California.
Any and all of the following agenda items are subject to action being taken by the Modesto City Council.
The business to be considered at said City Council meeting shall consist of a Closed Session concerning the following:
CLOSED SESSION
CONFERENCE WITH LEGAL COUNSEL – EXISTING LITIGATION
One Case (Pursuant to Section 54956.9(d)(1) of the Government Code) Name of Case: Magda Abraham v. City of Modesto, et al.
Superior Court of California, County of Stanislaus
Case No.: CV-18-003342
BY ORDER OF THE CHAIR
/S
Diane Nayares-Perez, City Clerk
Posted pursuant to Government Code Section 54956 on the bulletin board at Tenth Street Place on at by
date time signature
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