Eastern San Joaquin Groundwater
Subbasin
Groundwater
Sustainability Plan:
Executive Summary
Prepared by:
November 2019; Revised June 2022
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Acronyms
AF acre-feet
AF/year
acre-feet per year
Cal Water California Water Serv ice Company Stockton District CASGEM California Statewide Groundwater Elevation Monitoring CCWD Calaveras County Water District
CDWA Central Delta Water Agency
CSJWCD Central San Joaquin Water Conservation District
Delta Sacramento-San Joaquin River Delta
DMS data management system
DWR Department of Water Resources
Eastside GSA Eastside San Joaquin GSA
ESJGWA Eastern San Joaquin Groundwater Authority
ESJGWA Board Eastern San Joaquin Groundwater Authority Board of Directors ESJWRM Eastern San Joaquin Water Resources Model
GAMA Groundwater Ambient Monitoring and Assessment
GSA Groundwater Sustainability Agency
GSP Groundwater Sustainability Plan
LCWD Linden County Water District
LCSD Lockeford Community Services District
Letter Consultation Initiation Letter
MAF million acre-feet
mg/L mill
igrams per liter
NSJWCD North San Joaquin Water Conservation District
OID Oakd
ale Irrigation District
PMAs projects and management actions
SDWA South Delta Water Agency
SEWD Stockton East Water District
SGMA Sustainable Groundwater Management Act
SMCL secondary maximum contaminant levels
SSJID South San Joaquin Irrigation District
TDS total dissolved solids
TSS Technical Support Services
USGS United States Geological Survey
WID Woodbridge Irrigation District
Workgroup Groundwater Sustainability Workgroup
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EXECUTIVE SUMMARY
ES-1. INTRODUCTION
In 2014, the California legislature enacted the Sustainable Groundwater Management Act (SGMA) in response to continued overdraft of California’s groundwater resources. The Eastern San Joaquin Groundwater Subbasin (Eastern San Joaquin Subbasin, or Subbasin) is one of 21 basins and subbasins identified by the California Department of Water Resources (DWR) as being in a state of critical overdraft. SGMA requires preparation of a Groundwater Sustainability Plan (GSP) to address measures necessary to attain sustainable conditions in the Subbasin. Within the framework of SGMA, sustainability is generally defined as long-term reliability of the groundwater supply and the absence of undesirable results.
The Eastern San Joaquin Groundwater Authority (ESJGWA) was formed in 2017 in response to SGMA. A Joint Exercise of Powers Agreement establishes the ESJGWA, which is composed of 16 Groundwater Sustainability Agencies (GSAs): Central Delta Water Agency (CDWA), Central San Joaquin Water Conservation District (CSJWCD), City of Lodi, City of Manteca, City of Stockton, Eastside San Joaquin GSA (Eastside GSA) (compose d of Calaveras County Water District [CCWD], Stanislaus County, and Rock Creek Water District), Linden County Water District (LCWD), Lockeford Community Services District (LCSD), North San Joaquin Water Conservation District (NSJ WCD), Oakdale Irrigation District (OID), San Joaquin County No. 1, San Joaquin County No. 2 (with participation from California Water Service Company Stockton District [Cal Water]), South Delta Water Agency (SDWA), South San Joaquin GSA (com posed of South San Joaquin Irrigation District [SSJID] including Woodward Reservoir, City of Ripon, and City of E scalon), Stockton East Water District (SEWD), and Woodbridge Irrigation District (WID). The ESJGWA is governed by a 16-member Board of Directors (ESJGWA Board), with one representative from each GSA. The Board is guided by an Advisory Committee, also with one representative from each GSA, that is tasked with making recommendations to the ESJGWA Board on technical and substantive matters.
SGMA requires development of a GSP that achieves groundwa ter sustainability in the Subbasin by 2040. The GSP outlines the need to reduce overdraft conditions and has identified 23 projects for potential development that either replace groundwater use (offset) or supplement groundwater supplies (recharge) to meet current and future water demands. Although current analysis indicates that groundwater pumping offsets and/or recharge on the order of 78,37,000 acre-feet per year (AF/year) may be required to achieve sustainability, additional efforts are needed to confirm the level of pumping offsets and/or recharge required to achieve sustainability. These efforts include collecting additional data and a review of the Subbasin groundwater model, along with other efforts as outlined in the GSP.
A Public Draft GSP was prepared and made available for public review and comment on July 10, 2019 for a period of 45 days ending on August 25, 2019.
The ESJGWA received numerous comments from the public, reviewed and prepared responses to comments, and revised the Draft GSP. This Final GSP includes those edits and revisions. Comment letters and responses are included as appendices to the GSP.
On November 18, 2021, the ESJGWA received a Consultation Initiation Letter (Letter) from DWR. The Letter identified two potential deficiencies in the Subbasin GSPs which may preclude DWR’s approval, as well as potential corrective actions to address each potential deficiency. The Letter initiated consultation between DWR, the Plan Manager, the ESJGWA, and the Subbasin’s GSAs.
Critical Dates for the Eastern San Joaquin Subbasin
2020 By January 31: Submit GSP to DWR
2025 Evaluate GSP and update if warranted
2030 Evaluate GSP and update if warranted
2035 Evaluate GSP and update if warranted
2040 Achieve sustainability for the Subbasin
Figure ES-1: GSP Plan Area within
the San Joaquin Valley
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defiences and corrective actions to be addressed. In response to DWR’s comments, theisis GSP was revised in June 2022.
DWR comments have also been addressed in a series of four technical memoranda appended to this revised GSP and referenced throughout the document.
ES-2. PLAN AREA
The ESJGWA’s jurisdictional area is defined by the boundaries of the Eastern San Joaquin Subbasin in DWR’s 2003 Bulletin 118 as updated in 2016 and 2018. The Subbasin underlies the San Joaquin Valley, as shown in Figure ES-1.
ES-3. OUTREACH EFFORTS
A stakeholder engagement strategy was developed to
enable the interests of beneficial users of groundwater in the Subbasin to be considered. The strategy
incorporated monthly Groundwater Sustainability
Workgroup (Workgroup) meetings, monthly Advisory
Committee meetings, monthly ESJGWA Board
meetings, approximately quarterly informational open
house events, outreach presentations to community
groups, and information distribution to property owners and residents in the Subbasin. Figure ES-2 shows
attendees at one of the informational open house events conducted during development of the GSP.
The Workgroup was established to encourage active
involvement from diverse social, cultural, and
economic elements of the population in the Subbasin.
The 23 Workgroup members represent large and
small landowners and growers from different
geographic locations in the Subbasin, long-time
residents, representatives from non-governmental
organizations, disadvantaged community policy
advocates, and outreach coordinators. Spanish
translation was provided at informational open house events, creating an opportunity for local Spanish-speaking individuals to engage in the GSP development process. Input from the Workgroup was presented to the ESJGWA Board and has also been incorporated into the GSP.
Public Meeting Type Number of
Meetings
ESJGWA Board Meetings 25
Advisory Committee Meetings 17
Groundwater Sustainability Workgroup Meetings 13
Informational Open House Events 4
Outreach Presentations to Community Groups 10
Figure ES-2 - Informational Open House Events
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ES-4. BASIN SETTING
The Subbasin is located to the west of the Sacramento-
San Joaquin River Delta (Delta) and is bounded by the
Sierra Nevada foothills to the east, the San Joaquin
River to the west, Dry Creek to the north, and
Stanislaus River to the south. In the eastern portion of the Subbasin, groundwater flows from east to west and
generally mirrors the eastward sloping topography of
the geologic formations. In the western portion of the
Subbasin, groundwater flows eastward toward areas
with relatively lower groundwater elevation. Surface
water generally flows from east to west, with the major river systems traversing the Subbasin being the
Calaveras, Mokelumne, and Stanislaus rivers. Multiple
smaller streams flow into the San Joaquin River, which
flows from south to north. The location of the Subbasin is shown in Figure ES-3.
ES-5. EXISTING GROUNDWATER
CONDITIONS
Groundwater levels in some portions of the Subbasin have been declining for many years, while groundwater levels in other areas of the Subbasin have remained stable or increased in recent years. The change in groundwater levels varies across the Subbasin, with the greatest declines occurring in the central por tion of the Subbasin. The western and southern portions of the Subbasin have experienced less change in groundwater levels, in part due to the minimal groundwater pumping in the Delta area to the west and the import of surface water for agricultural and urban uses.
Groundwater quality in the Subbasin varies by location. Areas along the western margin have historically had higher levels of salinity. Salinity may be naturally occurring or the result of human activity. Sources of salinity in the Subbasin include Delt a sediments, deep saline groundwater, and irrigation return wate r. Total dissolved solids (TDS), which is a measure of all inorganic and organic substances present in a liquid in molecular, ionized, or colloidal suspended form, is commonly used to measure salinity. The Groundwater Ambient Monitoring and Assessment (GAMA) Program includes numerous water quality monitoring sites in the Subbasin compiled from different sources, shown in Figure ES-4. Maximum TDS concentrations across the Subbasin have been reported as high as 2,500 milligrams per liter (mg/L) along portions of the Subbasin’s western boundary. For drinking water, California has three secondary maximum contaminant level (SMCL) standards for TDS, all based on aesthetic considerations such as taste and odor, not public health concerns. These are 500 mg/L (recommended limit), 1,000 mg/L (upper limit), and 1,500 mg/L (short-term limit ). TDS concentrations decrease significantly to the east, to typically less than 500 mg/L (the recommended limit for aesthetic considerations). Elevated concentrations of other constituents, such as nitrate, arsenic, and point-source contaminants, are generally localized and not widespread and are
Figure ES-3: Basin Setting
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generally related to natural sources or land use activities. The GSP establishes ongoing monitoring of salinity, arsenic, nitrate, and a number of other common water quality
constituents to fill data gaps and identify potential trends of concern.
While the total volume of groundwater in storage in the Subbasin has declined over time, groundwater storage
reduction has not historically been an area of concern in the Subbasin, as there are large volumes of fresh water stored in the aquifer. The total fresh groundwater in storage was estimated at over 50 million-acre-feet (MAF) in 2015. The amount of groundwater in storage has decreased by
approximately .01 percent per year between 1995 and 2015.
As such, it is highly unlikely the Subbasin will experience conditions under which the volume of stored groundwater poses a concern, although the depth to access that
groundwater does pose a concern.
Land subsidence has not historically been an area of concern in the Subbasin, and there are no records of land subsidence caused by groundwater pumping in the Subbasin.
Seawater intrusion is not present in the Subbasin. While the Delta ecosystem evolved with a natural salinity cycle that brought brackish tidal water in from the San Francisco Bay, current management practices endeavor to maintain freshwater flows through a combination of hydraulic and physical barriers and alterations to existing channels.
Surface waters can be hydraulically interconnected with the groundwater system, where the stream baseflow is either derived from the aquifer (gaining stream) or recharged to the aquifer (l osing stream). If the water table beneath the stream lowers as a result of groundwater pumping, the stream may disconnect entirely from the underlying aquifer. Major river systems in the Subbasin are highly managed to meet instr eam flow requirements for fisheries, wa ter quality standards, and water rights of users downstream.
ES-6. SUSTAINABLE MANAGEMENT CRITERIA
SGMA introduces several terms to measure sustainability, including:
Sustainability Indicators – Sustainability indicators refer to any of the effects caused by groundwater conditions occurring throughout the Subbasin that, when significant and unreasonable, cause undesirable results. The six sustainability indicators identified by DWR are the following:
Chronic lowering of groundwater levels indicating a significant and unreasonable depletion of supply if continued over the planning and implementation horizon
Significant and unreasonable reduction of groundwater storage Significant and unreasonable seawater intrusion
Significant and unreasonable degraded water quality
Significant and unreasonable land subsidence that substantially interferes with surface land uses Depletions of interconnected surface water that have significant and unreasonable adverse impacts on beneficial uses of the surface water
Figure ES-4: GAMA Water Quality
Sampling Locations
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Sustainability Goal – This goal is the culmination of conditions resulting in a sustainable condition (absence of undesirable results) within 20 years.
Undesirable Results – Undesirable results are the significant and unreasonable occurrence of conditions that adversely affect groundwater use in the Subbasin, including reduction in the long-term viability of domestic, agricultural, municipal, or environmental uses of the Subb asin’s groundwater. Categories of undesirable results ar e defined through th e sustainability indicators.
Minimum Thresholds – Minimum thresholds are numeric values for each sustainability indicator and are used to define when undesirable results occur. Undesirable results occur if minimum thresholds are exceeded in an established percentage of sites in the Subbasin’s representative monitoring network.
Measurable Objectives – Measurable objectives are a specific set of quantifiable goals for the maintenance or improvement of groundwater conditions.
The method prescribed by SGMA to measure undesirable results involves setting minimum thresholds and measurable objectives for a series of representative wells. Representative wells are identified to provide a basis for measuring groundwater conditions throughout a basin or subbasin without having to measure each well, which would be cost prohibitive. In the Eastern San Joaquin Subbasin, representative wells were selected based on history of recorded groundwater levels and potential to effectively represent the groundwater conditions.
Revisions to Sustainable Management Criteria –This revised GSP reflects changes made to the sustainable management criteria in response to the potential corrective actions suggestedrecommended by DWR. In their Consultation Initiation Letter, DWR identified the following two deficiencies:
Potential Deficiency 1 – The GSP lacks sufficient justification for determining that undesirable results for chronic lowering of groundwater levels, subsidence, and depletion of interconnected surface waters can only occur in consecutive non-dry water year types. The GSP also lacks sufficient explanation for its minimum thresholds and undesirable results for chronic lowering of groundwater levels.
Potential Deficiency 2 - The GSP does not provide enough information to support the use of the chronic lowering of groundwater level sustainable management criteria and representative monitoring network as a proxy for land subsidence.
Revisions made to sustainable management crieria, as well as additional explanation s as to how the Subbasin sustainability indicators and sustainable management criteria were determined , are described in Chapter 3: Sustainable Management Criteria.
The Letter identified two potential deficiencies with the GSP which may preclude DWR’s approval, as well as potential corrective actions to address each potential deficiency. The Letter thus initiated consultation between DWR, the Plan Manager, and the Subbasin’s GSAs regarding the amount of time needed to address the potential deficiencies and corrective actions.
A subsequent meeting with DWR was held on April 4, 2022 to discuss the Subbasin’s proposed approach to addressing the identified deficiencies. The revisions to the sustainability in dicators and sustainability management criteria represent the response to the Letter based on direction provided by the ESJGWA, the Subbasin GSAs, and DWR.
In their Letter, DWR identified the following two deficiencies:
Potential Deficiency 1 – The GSP lacks sufficient justification for determining that undesirable results for chronic lowering of groundwater levels, subsidence, and depletion of interconnected surface waters can only occur in consecutive non-dry water year types. The GSP also lacks sufficient explanation for its minimum thresholds and undesirable results for chronic lowering of groundwater levels.
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Potential Deficiency 2 - The GSP does not provide enough information to support the use of the chronic lowering of groundwater level sustainable management criteria and representative monitoring network as a proxy for land subsidence.
The Letter also provided Potential Corrective Actions. Six potential corrective actions were identified for Deficiency 1, and three potential corrective actions were identified for Deficiency 2. Revisions to this GSP reflect changes made to the Subbasin sustainability indicators and sustainable management criteria resulting from analyses and decisions made to address these deficiencies. Documentation of modifications made to Subbasin sustainability indicators and sustainable management criteria and additional explanation as to how the Subbasin sustainability indicators and sustainable management criteria were determined can be found in the appendices.
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A total of 20 representative wells were identified for measurement of groundwater levels in the Subbasin, and 10 representative wells were identified for groundwater quality monitoring. The GSP uses groundwater quality data as the basis for evaluating conditions for seawater intrusion and uses groundwater level data as the basis for evaluating conditions for groundwater storage, depletions of interconnected surface water, and land subsidence. As such, these representative wells provide the basis for measuring the six sustainability indicators across the Subbasin.
Minimum thresholds and measurable objectives
were developed for each of the representative
wells. Figure ES-5 shows a typical relationship of
the minimum thresholds, measurable objectives,
and historical groundwater level data for a sample
groundwater level representative monitoring well.
Minimum thresholds for groundwater levels were
developed with reference to historical drought low
conditions and domestic well depths. Specifically,
minimum thresholds were established based on
the deeper of the historical drought low plus a
buffer of the historical fluctuation or the
10 th percentile domestic well depth, whichever is
shallower – establishing levels that are protective
of 90 percent of domestic wells. In municipalities
with ordinances requiring the use of City water
(water provided by the City’s municipal wells), the
10 th percentile municipal well depth is used in place of the 10th percentile domestic well depth criteria.
Measurable objectives were established based on the historical drought low and provide a buffer above the minimum threshold. A table summarizing minimum thresholds and measurable objectives is included in the GSP. Graphs showing the minimum threshold and measurable objective for each of the representative wells are contained in an appendix to the GSP.
Minimum thresholds for water quality were defined by considering two primary beneficial uses at risk of undesirable results related to salinity: drinking water and agriculture uses. Minimum thresholds are 1,000 mg/L for each representative monitoring well, consistent with the upper limit SMCL for TDS. Crop tolerances in the Subbasin range by crop type from 900 mg/L TDS for almonds up to 4,000 mg/L TDS for wheat, assuming a 90 percent yield.
The minimum threshold for seawater intrusion is a 2,000 mg/L chloride isocontour line established near the western edge of the Subbasin, between sentinel monitoring locations. 2,000 mg/L chloride is approximately 10 percent of seawater chloride concentrations (19,500 mg/L) and was developed as a minimum threshold based on consideration of existing management practices in other areas of the state.
For depletions of interconnected surface water, the minimum thresholds and measurable objectives for groundwater levels are used. There is significant correlation between groundwater levels and depletions, and the groundwater levels minimum thresholds are found to be protective of depletions.
Similarly, the minimum thresholds and measurable objectives for groundwater levels are used for the land subsidence and groundwater storage sustainability indicators, as both are stro ngly linked to groundwater levels. The groundwater levels minimum thresholds are found to be protective of land subsidence and groundwater storage.
Figure ES-5: Sample Relationship Between Minimum
Threshold and Measurable Objective
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Two consecutive years of minimum threshold exceedances are used to determine if an undesirable result has occurred to establish a pattern rather than an isolated event. The lowering of groundwater levels during dry or critically-dry years is not considered to be unreasonable unless the levels do not rebound to above the thresholds following wet conditions or are otherwise mitigated through adaptive management or implementation of projects and management actions. While statistically, three data points are required to establish a trend, three years of exceedances was felt to be too extreme, whereas a single exceedance was not sufficient to establish a trend. Therefore, the two consecutive years was selected as part of this definition.
At least 25 percent of representative monitoring wells used to monitor groundwater levels falling below their minimum thresholds for two consecutive years was presented to the Eastern San Joaquin Technical Advisory Committee (ESJ TAC) during the April 10, 2019 meeting and was approved by the Eastern San Joaquin Groundwater Authority (ESJGWA) Board during the May 8, 2019 meeting. The Eastern San Joaquin Water Resources Model (ESJWRM) results under the projected conditions baseline scenario were used to evaluate minimum threshold exceedances, and the model results considered in determining that a 25 percent exceedance threshold was sufficient to determine that undesirable results would occur subbasin- wide (e.g., were not a localized event).
ES-7. WATER BUDGETS
The Eastern San Joaquin Subbasin has been in an overdraft condition for many years. Overdraft occurs when the amount of groundwater extracted exceeds the long-term average
groundwater recharged.
The groundwater evaluations conducted as a part of GSP
development have provided estimates of the historical,
current, and projected groundwater budget conditions. The current analysis was prepared using the best available
information and through development of a new groundwater modeling tool, the Eastern San Joaquin Water Resources
Model (ESJWRM). It is anticipated that as additional
information becomes available, the model can be updated, and more refined estimates of annual pumping and overdraft can be developed.
Following the submittal of the Eastern San Joaquin
Subbasin GSP in January 2020, the ESJWRM was revised
to correct data relating to historical surface water deliveries and to include additional data for Water Year (WY) 2016 through WY 2020. The ESJWRM simulation period was extended to simulate Water Years 1995 through 2020 and the model recalibrated for the extended period. As a result of the model update, both the historical and projected water budgets were revised in 2021 to reflect the new data sets used in the model.
Additionally, refinements and enhancements were made to the historical data for the updated historical ESJWRM requiring an update to the projected conditions baseline ESJWRM. The updated version of the Projected Conditions Baseline (PCBL) used the extended dataset and calibration results, along with up dated data sources and assumptions for projected conditions, representing approximately water year 2040 conditions.
Based on these analyses, at projected groundwater pumping levels, the long-term groundwater pumping offset and/or recharge required for the Subbasin to achieve sustainability is approximately 7816,000 AF/year. Groundwater levels are expected to continue to decline based on projections of current land and water uses. Projects that offset groundwater pumping and/or increase recharge will help the Subbasin reach sustainability, as illustrated in Figure ES-6.
Figure ES-6: Subbasin-Wide Total Groundwater Pumping
and Offsets Required to Achieve Sustainability
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The projected Subbasin water budget was also evaluated under climate change conditions, which simulate higher demand requiring increased groundwater pumping despite more precipitation and streamflows. With the updated PCBL, the potential impact of climate change on the Subbasin in the future was also updated. The updated version of the Projected Conditions Baseline with Climate Change (PCBL-CC) largely used the same perturbation factors (2070 Central Tendency climate change conditions), but the updated PCBL-CC extends the simulation time period by two years. The climate change scenario used for the analysis was the 2070 central tendency climate change scenario prescribed by DWR. The overdraft modeled under climate change conditions is simulated to increase above projected conditions without climate change.
With the updated PCBL, the potential impact of climate change on the Subbasin in the future was also updated. The updated version of the Projected Conditions Baseline with Climate Change (PCBL-CC) largely used the same perturbation factors (2070 Central Tendency climate change conditions) as the original simulation , but the updated PCBL-CC extend eds the simulation time period by two years. TheThe overdraft modeled under climate change conditions is simulated to increase above projected conditions without climate change, requiring long-term groundwater pumping offset and/or recharge required for the Subbasin to achieve sustainability of approximately 38,000 AF/year.
Finally, as part of the revisions to this GSP to address DWR-identified deficiencies, projects and management actions (PMAs) likely to be implemented over the next five years were simulated in the projected water budget, both with and without climate change. The projected water budget with PMAs demonstrated that with implementation of the identified subset of projects, the Subbasin could achieve and maintain sustainability. However, when climate change impacts are added to the scenario, the Subbasin remains in overdraft conditions, indicating that additional PMAs will be required in the future to address climate change impacts on the groundwater basin.
ES-8. MONITORING NETWORKS
The GSP outlines the monitoring networks for the six sustainability indicators. The objective of these monitoring networks is to monitor conditions across the Subbasin and to detect trends toward undesirable results. Specifically, the monitoring network was developed to do the following:
Monitor impacts to the beneficial uses or users of groundwater Monitor changes in groundwater conditions relative to measurable objectives and minimum thresholds Demonstrate progress toward achieving measurable objectives described in the GSP DRAFT EXHIBIT 1
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There are four monitoring networks in the Eastern San Joaquin Subbasin: a representative network for water levels, a broad network for water levels, a representative network for water quality, and a broad network for water quality. Representative networks are used to determine compliance with the minimum thresholds, while the broad networks collect data for informational purposes to identify trends and fill data gaps. The two monitoring networks for water quality will additionally b e used to develop a chloride isocontour to monitor for
potential seawater intrusion and water levels data will inform depletions of interconnected surface water.
The monitoring networks were designed by evaluating data from the DWR’s California Statewide Groundwater
Elevation Monitoring (CASGEM) Program, the United
States Geological Survey (USGS), and participating GSAs.
The monitoring network consists largely of wells that are already being used for monitoring in the Subbasin.
Additional wells are being added, including two new deep, multi-completion monitoring wells awarded under DWR’s
Technical Support Services (TSS) program. Figure ES-7
shows the location of existing groundwater monitoring
wells in both the representative and broad monitoring
networks.
Wells in the monitoring networks will be measured on a
semi-annual schedule. Historical measurements have
been entered into the Subbasin Data Management System
(DMS), and future data will also be stored in the DMS.
A summary of the wells in the monitoring networks is shown in the table below.
Summary of Monitoring Network Wells
Representative Networks Well Count
Groundwater Level 20
Groundwater Quality 10
Broad Networks
CASGEM (Groundwater Levels) 76
Nested or Clustered Wells (Groundwater Levels & Quality) 16 Agency Wells (Groundwater Levels & Quality) 5
Figure ES-7: Groundwater Monitoring Wells
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ES-9. DATA MANAGEMENT SYSTEM
The Eastern San Joaquin DMS was built on a flexible, open software platform that uses familiar Google maps and charting tools for analysis and visualization. The DMS serves as a data-sharing portal that enables use of the same data and tools for visualization and analysis. These tools support sustainable groundwater management and create transparent reporting about collected data and analysis results.
The DMS is web-based; the public can easily
access this portal using common web
browsers such as Google Chrome, Firefox,
and Microsoft Edge. The DMS is currently
populated with available historical data.
Future data will also be entered into the
system as it is collected.
The DMS portal provides easy access and
the ability to query information stored in the
system. Groundwater data can be plotted for
any of the available data points, providing a
pictorial view of historical and current data.
The DMS can be accessed at this link using
the Guest Login:
https://opti.woodardcurran.com/esj/
Figure ES-8: Opti DMS Screenshot
Figure ES-9: Typical DMS Data Display
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ES-10. PROJECTS AND MANAGEMENT ACTIONS
Achieving sustainability in the Subbasin requires implementation of projects and management actions. The Subbasin will achieve sustainability by implementing water supply projects that either replace groundwater use or supplement groundwater supplies to attain the current estimated pumping offset and/or recharge need of 7816,000 AF/year. It should be noted that this number will be reevaluated in the future after additional data are collected and analyzed. In addition, three projects have been identified that support demand conservation activities, including water use efficiency upgrades. Currently, no pumping restrictions have been proposed for the Subbasin; however, GSAs maintain the flexibility to implement such demand-side management actions in the future if need is determined.
Although the ESJGWA does not have direct authority to re quire GSAs to implement projects, the ESJGWA will coordinate analysis of GSA-level demands and will compile annual or biannual reports to evaluate progress. If projects do not progress, or if monitoring efforts demonstrate that the projects are not e ffective in achieving stated recharge and/or offset targets, th e GWA will convene a working group to evaluate supply-side and demand-side management actions such as the implementation of groundwater pumping curtailments, land fallowing, etc.
Projects to increase water supply availability in the Subbasin were identified by individual GSAs. The initial set of projects was reviewed with the ESJGWA Board, Advisory Committee, and Workgroup. A final list of 23 potential projects are included in the GSP, representing a variety of project types including direct and in-lieu 1 recharge, intra-basin water transfers, demand conservation, water recycling, an d stormwater reuse. Projects are classified into three categories based on project status:
Planned, Potential, and Longer-term/Conceptual. Planned projects are anticipated to be completed and implemented prior to 2040. Near-term PPlanned projects are anticipated to provide enough water to meet the 78,000 AFY ofrequired groundwater pumping offset and/or recharge needed to reach sustainability without climate change; however, additional projects will be required in the future to address climate change impacts . Potential projects provide a menu of options for additional water supply projects that can be implemented in the Subbasin. These projects require further analysis and permitting to determine feasibility and cost effectiveness. Longer-t erm/Conceptual projects are in the early conceptual planning stages and would require significant additional work to move forward. Projects are summarized in the table below.
Additionally, a study has been proposed by NSJWCD to evaluate reaches of the Mokelumne River downstream of Camanche Reservoir to support model refinement and validation and to inform SGMA basin accounting. These projects are summarized below.
1 In-lieu recharge refers to the use of surface water or recycled water supplies for applications where groundwater is currently used.
This “in-lieu” use reduces groundwater pumping and allows groundwater to remain in the aquifer.
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Project Description Project Type Project Proponent
Estimated
Demand
Reduction
(AF/year)
Planned Projects:
Lake Grupe In-lieu Recharge In-lieu Recharge Stockton East Water District 10,000 SEWD Surface Water Implementation Expansion In-lieu Recharge Stockton East Water District 19,000 City of Manteca Advanced Metering Infrastructure Conservation City of Manteca 272 City of Lodi Surface Water Facility Expansion &
Delivery Pipeline
In-lieu Recharge City of Lodi 4,750
White Slough Water Pollution Control Facility
Expansion
Recycling/In-lieu
Recharge
City of Lodi 115
CSJWCD Capital Improvement Program In-lieu Recharge Central San Joaquin Water Conservation District 5,000
NSJWCD South System Modernization In-lieu Recharge North San Joaquin Water Conservation District 4,500
Long-term Water Transfer to SEWD and CSJWCD Transfers/In-lieu Recharge
South San Joaquin GSA 45,000
Potential Projects
BNSF Railway Company Intermodal Facility
Recharge Pond
Direct Recharge Central San Joaquin Water Conservation
District 1,000
City of Stockton Advanced Metering Infrastructure Conservation City of Stockton 2,000 South System Groundwater Banking with EBMUD In-lieu Recharge North San Joaquin Water Conservation District 4,000
NSJWCD North System Modernization/Lakso
Recharge
In-Lieu
Recharge/Direct
Recharge
North San Joaquin Water Conservation
District 2,600
Manassero Recharge Project Direct Recharge North San Joaquin Water Conservation District 8,000
Tecklenburg Recharge Project Direct Recharge North San Joaquin Water Conservation District 8,000
City of Escalon Wastewater Reuse Recycling/In-lieu
Recharge/Transfers
South San Joaquin GSA 672
City of Ripon Surface Water Supply In-lieu Recharge South San Joaquin GSA 6,000 City of Escalon Connection to Nick DeGroot Water
Treatment Plant
In-lieu Recharge South San Joaquin GSA 2,015
Longer-term/Conceptual Projects
Farmington Dam Repurpose Project Direct Recharge Stockton East Water District 30,000 Recycled Water Transfer to Agriculture Recycling/Transfers/ In-lieu Recharge
City of Manteca 5,193
Mobilizing Recharge Opportunities Direct Recharge San Joaquin County Not determined NSJWCD Winery Recycled Water
Recycling/In-Lieu
Recharge/Direct
Recharge
North San Joaquin Water Conservation
District 750
Pressurization of SSJID Facilities Conservation South San Joaquin GSA 30,000 SSJID Storm Water Reuse
Stormwater/In-lieu
Recharge/Direct
Recharge
South San Joaquin GSA
1,100
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Groundwater Sustainability Plan ES-14
Executive Summary November 2019; Revised June 2022
As previously noted, The ESJGWA received the Letter from DWR ’s Consultation Initiation Letter that that identified two potential deficiencies with the Subbasin GSP which may preclude DWR’s approval, as well as potential corrective actions to address each potential deficiency. Potential Deficiency 1 related to the GSP’s requirement of two consecutive non-dry (i.e., below normal, above normal, or wet) water year types and the exclusion of dry and critically dry water-year types in the identification of undesirable results. (Please see Chapter 3, Su stainable Management Criteria, for revisions that address this deficiency). Potential Deficiency 1 also rrequesteds additional detail on how projects and management actions, in conjunction with the proposed chronic lowering of groundwater levels sustainable management criteria, will offset drought related groundwater reductionshelp the subbasin achieve sustainability and avoid significant and unreasonable impacts. Specifically, Potential Correction Action 1(b) stated that the GSP "fails to identify specific extraction and groundwater recharge management actions the GSAs wo uld implement or other wise describe how the Subbasin would be mana ged to offset...dry year reductions of groundwater storage”. As a Potential Corrective Action, the following is suggested: “The GSP should be revised to include specific projects and management actions t he GSAs would implement to offset drought year groundwater level declines.”
As part of the process to respond to DWR, the ESJGWA worked with each GSA individually to update GSP project descriptions with new information that has become available in the past two years since the GSP was first adopted in 2020. These revised projects were then divided into two categories: Category A projects (projects that are likely to advance in the next five years and have existing water rights or agreements) and Category B projects (projects that are not anticipated to advance in the next five years, but could be leveraged in the future, particularly if Category A projects do not fully achieve stated recharge and/or offset targets). Category A projects and Category B projects are shown in Table 6-2 and Table 6-3, respectively, along with project assumptions; please see Chapter 2, Basin Setting, for information as to how the Category A projects were simulated in the projected water budget to evaluate their effectiveness on achieving Subbasin sustainabilityand for a description of their effectiveness on addressing overdraft in the Subbasin. Category B projects may be elevated to a Category A project should feasibility studies demonstrate a viable project, if water rights or contracts are firmly identified, if partnerships are formed, and if economic evaluation demonstrate that the projects are cost effective, and remain part of the overall adaptive management strategy that the Subbasin is utilizing in GSP implementation to achieve and maintain Subbasin sustainability..
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Groundwater Sustainability Plan ES-0
Executive Summary November 2019; Revised June 2022
Project Submitting
GSA
Project
Type Water Source
Baseline
Water Year
Type
Annual
Volume
(AFY)
Notes
1. Lake Grupe In-Lieu
Recharge
Stockton East
Water District
In-Lieu
Recharge
The surface water source of this project is from
SEWD’s existing contract with the U.S. Bureau of
Reclamation (USBR) for the New Hogan Reservoir.
Surface water is diverted from the Calaveras River.
This is an existing surface water right.
Drought 2,000 Range of 0-2,000 AFY in
multiple dry years
Dry 4,900
Normal 4,900
Wet 4,900
2. SEWD Surface Water
Implementation
Expansion
Stockton East
Water District
In Lieu
Recharge
This project relies on water from New Hogan
Reservoir (Calaveras River water) and New Melones
Reservoir (Stanislaus River water). This is an existing surface water right. SEWD has long-term water supply
contracts with USBR for both New Hogan Reservoir
and New Melones Reservoir.
Drought 4,000 Range of 0-4,000 AFY in
multiple drought years
Dry 8,000
Normal 19,000
Wet 19,000
3. West Groundwater
Recharge Basin
Stockton East
Water District
Direct
Recharge
This project relies on water from New Hogan Reservoir
(Calaveras River water) and New Melones Reservoir
(Stanislaus River water). Th is is an existing surface
water right. SEWD has long-term water supply
contracts with USBR for both New Hogan Reservoir
and New Melones Reservoir. In addition to Calaveras
River and Stanislaus River water, stormwater runoff will also contribute to the volume of water available for
recharge.
Drought 1,500
Dry 4,000
Normal 16,000
Wet 16,000
4. CSJWCD Capital
Improvement Program
Central San
Joaquin
Water
Conservation
District
In-Lieu
Recharge
This project relies on water from New Melones
Reservoir. This is an existing surface water right.
CSJWCD has long-term water supply contracts with
USBR for the New Melones Unit Central Valley Project.
Drought 0
Dry 12,000
Normal 24,000
Wet 24,000
Drought 20,000
Table ES-810: Category A Projects
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Groundwater Sustainability Plan ES-1
Executive Summary November 2019; Revised June 2022
Project Submitting
GSA
Project
Type Water Source
Baseline
Water Year
Type
Annual
Volume
(AFY)
Notes
5. Long-Term Water
Transfer to SEWD and
CSJWCD
South San
Joaquin GSA
Transfers/In
-Lieu
Recharge
This project relies on water from New Melones
Reservoir (Stanislaus River water). This is an existing surface water right (pre-1914) held by Oakdale
Irrigation District (OID) and South San Joaquin
Irrigation District (SSJID).
Dry 5,000
This project currently only
covers the transfer of water
from OID and SSJID to
SEWD urban customers.
Normal 0
Wet 0
6. White Slough
Pollution Control
Facility Expansion
City of Lodi
Recycled
Water/In-
Lieu
Recharge
Treated wastewater effluent from White Slough Water
Pollution Control Facility.
Drought 3,729
Dry 3,729
Normal 3,729
Wet 3,729
7. NSJWCD South
System Modernization
North San
Joaquin
Water
Conservation
District
In-Lieu
Recharge/D
irect
Recharge
This project relies on water from the Mokelumne River.
This is an existing water right held by NSJWCD
(Permit 10477).
Drought 0
Dry 0
Normal 4,800
Wet 6,000
8. NSJWCD
Tecklenburg Recharge
Project
North San
Joaquin
Water
Conservation
District
Direct
Recharge
This project relies on water from the Mokelumne River.
This is an existing surface water right held by
NSJWCD (Permit 10477).
Drought 0
Dry 1,000
Normal 4,800
Wet 6,000
9. NSJWCD South
System Groundwater
Banking with EBMUD
North San
Joaquin
Water
Conservation
District
In-Lieu
Recharge
This project relies on water from the Mokelumne River.
This is an existing water right held by East Bay
Municipal Utility District (EBMUD) (Permit 10478) as
per Protest Dismissal Agreement from 11/25/2014.
Drought 0
Dry 1,500
Normal 6,400 80% of wet year supply
Wet 8,000
10. NSJWCD North
System
Modernization/Lakso
Recharge
North San
Joaquin
Water
Conservation
District
In-Lieu
Recharge/D
irect
Recharge
This project relies on water from the Mokelumne River.
This is an existing surface water right held by
NSJWCD (Permit 10477).
Drought 0
Dry 1,000
Normal 3,200
Wet 4,000
11. Delta Water
Treatment Plant
Groundwater Recharge
Improvements Project
City of
Stockton
Direct
Recharge
This project relies on raw water from the Delta Water
Treatment Plant.
Drought 5,040
Dry 5,040
Normal 5,040
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Groundwater Sustainability Plan ES-2
Executive Summary November 2019; Revised June 2022
Project Submitting
GSA
Project
Type Water Source
Baseline
Water Year
Type
Annual
Volume
(AFY)
Notes
Geotechnical
Investigation Wet 5,040
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Groundwater Sustainability Plan ES-0
Executive Summary November 2019; Revised June 2022
Project Name Project Type Submitting
GSA Current Status
Time-table
(initiation and
completion)
Annual
Volume (AFY)
Perfecting Mokelumne River Water Right In-lieu Recharge San Joaquin County Planning phase 2022-2025 20,000 to
50,000
City of Manteca Advanced Metering Infrastructure Conservation City of Manteca Currently underway 2019-2021 272 City of Lodi Surface Water Facility Expansion &
Delivery Pipeline In-lieu Recharge City of Lodi Planning phase 2030-2033 4,750 BNSF Railway Company Intermodal Facility Recharge
Pond Direct Recharge CSJWCD Planning phase 2020-2023 1,000 City of Stockton Advanced Metering Infrastructure Conservation City of Stockton Initial study completed in 2011 2020/25-2025/28 2,000
Manaserro Recharge Project Direct Recharge NSJWCD Planning phase 2019-2022* 8,000 City of Escalon Wastewater Reuse
Recycling/
In-lieu Recharge/
Transfers
SSJ GSA Planning phase 2020-2028 672
City of Ripon Surface Water Supply In-lieu Recharge SSJ GSA Design complete;
environmental
permitting underway
2020-2024 6,000
City of Escalon Connection to Nick DeGroot Water
Treatment Plant In-lieu Recharge SSJ GSA
Conceptual design
phase;
environmental review
complete
2020-2023 2,015
Farmington Dam Repurpose Project Direct Recharge SEWD
Preplanning phase
with reconnaissance
study complete
2030-2050 30,000
Recycled Water Transfer to Agriculture Recycling/Transfers/ In-lieu Recharge City of Manteca
Planning phase with
evaluation completed
in Draft Reclaimed
Water Facilities
Master Plan
Not determined 5,193
Mobilizing Recharge Opportunities Direct Recharge San Joaquin County
Early conceptual
planning phase Not determined Not determined
NSJWCD Winery Recycled Water
Recycling/
In-Lieu Recharge/
Direct Recharge
NSJWCD Conceptual planning
and discussion 2025-2027 750
Table ES-810: Category B Projects
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Groundwater Sustainability Plan ES-1
Executive Summary November 2019; Revised June 2022
Project Name Project Type Submitting
GSA Current Status
Time-table
(initiation and
completion)
Annual
Volume (AFY)
Pressurization of SSJID Facilities Conservation SSJ GSA Feasibility study complete 2019-2030 30,000
SSJID Storm Water Reuse
Storm Water/
In-lieu Recharge/
Direct Recharge
SSJ GSA Planning phase 2027-2030 1,100
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Groundwater Sustainability Plan ES-0
Executive Summary November 2019; Revised June 2022
ES-11. GSP IMPLEMENTATION
The overdraft condition in the Subbasin requires projects to offset groundwater pumping and/or increase recharge. The exact amount of required offset/recharge will be reevaluated after additional data are collected and analyzed.
Projects will be administered by the GSA project proponents. GSAs may elect to implement projects individually or jointly with one or more GSAs or with the ESJGWA.
Implementing the GSP will require numerous management activities that will be undertaken by the ESJGWA, including the following:
Monitoring and recording of groundwater levels and groundwater quality data Maintaining and updating the Subbasin DMS with newly collected data Annual monitoring of progress toward sustainability
Annual reporting of Subbasin conditions to DWR as required by SGMA Refining Subbasin model and water budget planning estimates Evaluating the GSP once every 5 years and updating if warranted The ESJGWA Board adopted a preliminary schedule for project implementation. Project implementation is scheduled to begin in 2020, with full implementation by 2040. This approach provides adequate time to put in place methods necessary to refine model estimates and verify project cost effectiveness.
Implementation of the eight identified Planned Projects will begin prior to 2030 and will continue through 2040. Evaluation and possible implementation of the nine Potential Projects and six Longer-term/Conceptual Projec ts will be based on long-term management or changing needs of the GSA or Subbasin. Further evaluation is necessary to determine technical, economic, and institutional feasibility.
ES-12. FUNDING
Implementation of the GSP requires funding sources. To the degree they become available, outside grants will be sought to assist in reducing cost of implementation to participating agencies, residents, and landowners of the Subbasin. However, there will be a need to collect funds to support implementation.
The areas associated with ESJGWA-wide management and GSP implementation will be borne by the ESJGWA through contributions from the member GSAs, under a cost-sharing arrangement to be developed following GSP adoption. These costs include:
ESJGWA administration
Groundwater level monitoring and reporting
Groundwater quality monitoring and reporting
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Groundwater Sustainability Plan ES-1
Executive Summary November 2019; Revised June 2022
Water use estimation
Data management
Stakeholder engagement
Annual report preparation and submittal to DWR
Developing and implementing a funding mechanism
Grant applications
GSP evaluation and updates, if warranted (every 5 years) For budgetary purposes, the estimated initial cost of these activities is on the order of $600,000 to $1 million per year excluding projects and management actions costs and costs associated with the installation of new monitoring wells and grant writing.
Additional one-time costs, such as model refinement, are estimated to be on the order of $315,000.
GSAs will individually fund implementation of projects in their respective areas. Options for GSA funding include fees based on groundwater pumping, acreage, or combinations of these, and pursuit of any available grant funds. The GSAs will evaluate options for securing the needed funding on an individual basis.
The estimated initial costs of projects range from on the order of $50,000 to $328 million, depending on the project. Annual project costs range from $3,000 to $9 million per year to provide funds for operations and maintenance.
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