2024 GROUNDWATER SUSTAINABILITY PLAN ADOPTIONStockton City CouncilCity of Stockton Groundwater Sustainability AgencyMarch 18, 2025Agenda Item No. 16.3 Municipal Utilities Department (MUD)Department DescriptionWater Utility• Treat and deliver high-quality drinking water to the communityWastewater Utility• Collect, treat, recover and reuse wastewater for the greater Stockton areaStormwater Utility• Collect and discharge surface runoff in City to rivers, sloughs, and local flood basins City of Stockton Water Service Areas•MUDserves North and South Stockton•California Water Service Company serves Central Stockton Drinking Water - Surface Water Sources•San Joaquin and Mokelumne Rivers•Treated at City’s Delta Water Treatment Plant•Calaveras and Stanislaus Rivers•Treated at Stockton East Water District Water Treatment Plant 4 Drinking Water - Groundwater Supplies•Groundwater wells ensure continued water supply, quality, reliability, and drought resiliency for the City. •Used conjunctively with surface water supplies•North Stockton - 6 active wells •South Stockton - 3 active wells
Drinking Water - Groundwater ProductionTotal Well Production (Acre Feet)South Wells (Acre Feet)North Wells (Acre Feet)Year8,635148,62120207,0892016,88820211,547731,47420222,4322412,19120231,06614092620244,1541344,020Average Sustainable GroundwaterManagement Act•California State law passed in 2014•Sustainable Groundwater Management Act, or SGMA, is statewide legislation that establishes a path for the sustainable local management of groundwater•Includes Urban, Agricultural and Environmental Interests
Groundwater Basin Setting
•The Eastern San Joaquin Groundwater Subbasin(Subbasin) is one of 21 basins identified by the California Department of Water Resources (DWR) as being in a state of critical overdraft•SGMA requires formation of Groundwater Sustainability Agencies and preparation of a Groundwater Sustainability Plan (GSP) Eastern San Joaquin Groundwater Authority•Joint Powers Authority of 16 Groundwater Sustainability Agencies•Includes Cities, County, Irrigation Districts & Water Agencies•One GSP for Basin
What Does SGMA Require?•Groundwater Sustainability Agencies (GSAs) must prepare and submit Groundwater Sustainability Plans (GSPs)•First GSP adopted by GWA and submitted to DWR in 2020•GSPs must include measurable objectives and milestones to achieve sustainability within 20 years of adoption•GSAs must assess progress after initial GSP submittal through Periodic Evaluations (PEs)•GSP development must be open and transparent•GSP updates every 5 years The 2024 GSP – What’s In It?1. Agency Information, Plan Area, & Communication2. Basin Setting3. Sustainable Management Criteria4. Monitoring Networks5. Data Management System6. Projects & Management Actions7. Plan Implementation8. References
Statewide Basin Sustainability Indicators•Chronic Lowering of Groundwater Levels•Reduction in Groundwater Storage•Seawater Intrusion•Degraded Water Quality•Land Subsidence•Depletion of Inter-connected Surface Water
GSP Projects – South Stockton Well No. 8
•Project- Well Rehabilitation•Location– Ernie Shropshire Park, District 6•Project Cost - $4.8M•Project Completion - 2024•Capacity – 1,500 gpm; 7,200 homes per day GSP Projects – Stockton Delta Water Supply Groundwater Recharge Project •Type – Direct Recharge (70 ac)•Status– Eng. Design @ 35%•Benefit– est. 20,000 ac ft annually•Facilities – 3 ponds w/wildlife habitat, visitor center, viewing area and walking trail•Cost– $12.2M; $2.9M Grants•Completion– 2027
GSP Projects – Stockton Automated Metering Infrastructure (AMI)•Project– Automated Metering Infrastructure (AMI)•Location– North and South Stockton Service Areas•Project Cost - $17.2M; Grant $4.3M•Project Completion - 2029•Meters and Radios – 50,000 radio installations and an estimated 12,000 water meter changeouts.•Project Benefits • Hourly meter readings• Reduces billing discrepancies caused by human error• Reduce groundwater demand - 2,000 ac feet per year • Reduces water loss• Customer portal
GWA – Actions Completed for 5-Year UpdateAddressed 8 recommended corrective actionsPrepared 2024 GSP AmendmentPrepared Subbasin’s first Periodic EvaluationHeld public open house & public review periodGSA adoption of GSP Amendment & approval of Periodic EvaluationSubmittal of all documentation
2024 GSP Amendment& Periodic EvaluationGWA continues to make significant progress toward achieving sustainability goals including:•Most monitoring wells show groundwater levels at or above their measurable objectives with interim milestones being met throughout the subbasin•Groundwater quality in the subbasin remains suitable to support beneficial uses and is expected to surpass measurable objectives with no exceedances of minimum thresholds observed •Groundwater quality should meet measurable objectives or minimum thresholds over the next five years•GSP and other documents published on GWA: esjgroundwater.org Recommendations•2024 GSP recommended by Water Advisory Group and Council Water Committee - October 2024•Public Hearing Notices – March 5 & 12, 2025•City Council, acting as the GSA, adopt the ESJ Subbasin 2024 Groundwater Sustainability Plan Amendment and all other recommended actions