San Joaquin River

Groundwater Quality Protection Strategy: A "Roadmap" for the Central Valley Region

Central Valley Regional Water Quality Control Board (CVRWQCB) | January 8th, 2010

The California Regional Water Quality Control Board, Central Valley Region (Central Valley Water Board) recognizes that past regulatory approaches have not protected all

The California Regional Water Quality Control Board, Central Valley Region (Central Valley Water Board) recognizes that past regulatory approaches have not protected all groundwater from historical and current practices associated with land applications of waste. For example, in some areas of the Central Valley Region groundwater produced from some aquifers that serve individual and community drinking water systems have been polluted and are unsafe to drink. In response, the Central Valley Water Board adopted Resolution R5-2008-0181 directing staff to develop a Groundwater Quality Protection Strategy (Roadmap) through an active stakeholder process. Developing a Roadmap for the Central Valley Region is not initiating a new regulatory program. This Roadmap is intended to be an overarching framework or an outline for long range planning. By presenting it to the Central Valley Water Board it allows the Board review and approval of the overarching plan as well as an opportunity to provide direction to staff. Further, it defines the regulatory programs to be enhanced, and identifies ways to expand on all partnering opportunities with other federal, state, and/or local agencies to protect groundwater quality. Following approval of the Roadmap, workplan(s) will be developed for the higher priority future actions to provide a more detailed description of tasks, timelines, and resources required to implement those actions. In order to make this Roadmap useful to the public, policy-makers, and the Central Valley Water Board, a starting point to map a course for the future had to be identified. The starting point for the Roadmap is the background (Section 3) information on agencies and organization, the Central Valley Region’s basins, and primary constituents of concern. Current Groundwater Quality Protection Programs (Section 4) being implemented by the Central Valley Water Board describe how groundwater quality is being protected now. To assist in the evaluation of existing groundwater quality protection programs and identification of future actions, Stakeholder’s Concerns and Issues (Section 5) were also considered. The final section of the Strategy is the “Roadmap” (Section 6) which focuses on future actions that can be implemented within the next five to twenty years. To illustrate the Roadmap, a description is provided of three basic elements: a) future actions; b) how the actions are prioritized; and c) resource needs to implement the actions. Implementation of future actions, are not limited to the Central Valley Water Board. Future actions may be implemented by: the Central Valley Water Board; other agencies or organization; or through a partnership between agencies.

Groundwater Quality Protection Strategy: A “Roadmap” for the Central Valley Region

California Environmental Protection Agency (CalEPA) | August 2nd, 2010

The California Regional Water Quality Control Board, Central Valley Region (Central Valley Water Board) recognizes that past regulatory approaches have not protected all

The California Regional Water Quality Control Board, Central Valley Region (Central Valley Water Board) recognizes that past regulatory approaches have not protected all groundwater from historical and current practices associated with land applications of waste. For example, in some areas of the Central Valley Region groundwater produced from some aquifers that serve individual and community drinking water systems have been polluted and are unsafe to drink. In response, the Central Valley Water Board adopted Resolution R5-2008-0181 directing staff to develop a Groundwater Quality Protection Strategy (Roadmap) through an active stakeholder process.  Developing a Roadmap for the Central Valley Region is not initiating a new regulatory program. This Roadmap is intended to be an overarching framework or an outline for long range planning. By presenting it to the Central Valley Water Board it allows the Board review and approval of the overarching plan as well as an opportunity to provide direction to staff. Further, it defines the regulatory programs to be enhanced, and identifies ways to expand on all partnering opportunities with other federal, state, and/or local agencies to protect groundwater quality. Following approval of the Roadmap, workplan(s) will be developed for the higher priority future actions to provide a more detailed description of tasks, timelines, and resources required to implement those actions.  In order to make this Roadmap useful to the public, policy-makers, and the Central Valley Water Board, a starting point to map a course for the future had to be identified. The starting point for the Roadmap is the background (Section 3) information on agencies and organization, the Central Valley Region’s basins, and primary constituents of concern. Current Groundwater Quality Protection Programs (Section 4) being implemented by the Central Valley Water Board describe how groundwater quality is being protected now. To assist in the evaluation of existing groundwater quality protection programs and identification of future actions, Stakeholder’s Concerns and Issues (Section 5) were also considered.  The final section of the Strategy is the “Roadmap” (Section 6) which focuses on future actions that can be implemented within the next five to twenty years. To illustrate the Roadmap, a description is provided of three basic elements: a) future actions; b) how the actions are prioritized; and c) resource needs to implement the actions. Implementation of future actions, are not limited to the Central Valley Water Board. Future actions may be implemented by: the Central Valley Water Board; other agencies or organization; or through a partnership between agencies.  Also: Groundwater Quality Protection Strategy for the Central Valley Region, a Roadmap - Addendum 2015/2016 Home page of Groundwater Quality Protection Strategy for the Central Valley Region, R-5

Groundwater residence time estimates obscured by anthropogenic carbonate

American Association for the Advancement of Science (AAAS) | April 21st, 2021

Groundwater is an important source of drinking and irrigation water. Dating groundwater informs its vulnerability to contamination and aids in calibrating flow models. He

Groundwater is an important source of drinking and irrigation water. Dating groundwater informs its vulnerability to contamination and aids in calibrating flow models. Here, we report measurements of multiple age tracers (14C, 3H, 39Ar, and 85Kr) and parameters relevant to dissolved inorganic carbon (DIC) from 17 wells in California’s San Joaquin Valley (SJV), an agricultural region that is heavily reliant on groundwater. We find evidence for a major mid-20th century shift in groundwater DIC input from mostly closed- to mostly open-system carbonate dissolution, which we suggest is driven by input of anthropogenic carbonate soil amendments. Crucially, enhanced open-system dissolution, in which DIC equilibrates with soil CO2, fundamentally affects the initial 14C activity of recently recharged groundwater. Conventional 14C dating of deeper SJV groundwater, assuming an open system, substantially overestimates residence time and thereby underestimates susceptibility to modern contamination. Because carbonate soil amendments are ubiquitous, other groundwater-reliant agricultural regions may be similarly affected.

Groundwater sustainability and land subsidence in California’s Central Valley

Water (MDPI) | April 22nd, 2024

The Central Valley of California is one of the most prolific agricultural regions in the world. Agriculture is reliant on the conjunctive use of surface-water and groundw

The Central Valley of California is one of the most prolific agricultural regions in the world. Agriculture is reliant on the conjunctive use of surface-water and groundwater. The lack of available surface-water and land-use changes have led to pumping-induced groundwater-level and storage declines, land subsidence, changes to streamflow and the environment, and the degradation of water quality. As a result, in part, the Sustainable Groundwater Management Act (SGMA) was developed. An examination of the components of SGMA and contextualizing regional model applications within the SGMA framework was undertaken to better understand and quantify many of the components of SGMA. Specifically, the U.S. Geological Survey (USGS) updated the Central Valley Hydrologic Model (CVHM) to assess hydrologic system responses to climatic variation, surface-water availability, land-use changes, and groundwater pumping. MODFLOW-OWHM has been enhanced to simulate the timing of land subsidence and attribute its inelastic and elastic portions. In addition to extending CVHM through 2019, the new version, CVHM2, includes several enhancements as follows: managed aquifer recharge (MAR), pumping with multi-aquifer wells, inflows from ungauged watersheds, and more detailed water-balance subregions, streamflow network, diversions, tile drains, land use, aquifer properties, and groundwater level and land subsidence observations. Combined with historical approximations, CVHM2 estimates approximately 158 km3 of storage loss in the Central Valley from pre-development to 2019. About 15% of the total storage loss is permanent loss of storage from subsidence that has caused damage to infrastructure. Climate extremes will likely complicate the efforts of water managers to store more water in the ground. CVHM2 can provide data in the form of aggregated input datasets, simulate climatic variations and changes, land-use changes or water management scenarios, and resulting changes in groundwater levels, storage, and land subsidence to assist decision-makers in the conjunctive management of water supplies.

Groundwater Sustainability Assessments: A Review of the Department of Water Resources’ Determinations on Groundwater Sustainability Plans in Critically Overdrafted Basins

Groundwater Leadership Forum (GLF) | August 31st, 2022

Of the 46 GSPs submitted in January 2020, the Department of Water Resources (DWR) determined eight GSPs to be adequate and 34 GSPs to be incomplete. In this paper we eval

Of the 46 GSPs submitted in January 2020, the Department of Water Resources (DWR) determined eight GSPs to be adequate and 34 GSPs to be incomplete. In this paper we evaluate to what extent DWR’s determinations provide oversight on the key issues of drinking water, disadvantaged communities, the environment, stakeholder involvement,and climate change. We summarize the corrective actions that DWR is recommending or requiring, as well as compare DWR’s determinations to the assessment of 31 GSPs that we conducted in 2020. We also reviewed the 11 comment letters submitted by the State Water Resources Control Board (SWRCB), 25 comment letters submitted by the California Department of Fish and Wildlife (CDFW), and seven comment letters submitted by the National Oceanic and Atmospheric Administration’s National Marine Fisheries Service (NMFS) to compare deficiencies identified in GSPs across agencies.

Groundwater Sustainability Plan for the Cosumnes Subbasin

Cosumnes Groundwater Authority | December 15th, 2021

Seven GSAs have been established within the Basin, each acting as the exclusive GSA in their respective areas. The seven GSAs form the Cosumnes Subbasin SGMA Working Gro

Seven GSAs have been established within the Basin, each acting as the exclusive GSA in their respective areas. The seven GSAs form the Cosumnes Subbasin SGMA Working Group (Working Group): Amador County Groundwater Management Authority (ACGMA), City of Galt, Clay Water District, Galt Irrigation District (GID), Omochumne-Hartnell Water District (OHWD), Sacramento County, and Sloughhouse Resource Conservation District (SRCD). The Working Group developed this single coordinated GSP to meet SGMA regulatory requirements, reflect stakeholder values, and preserve local control over management of the groundwater resource.

Groundwater Sustainability Plan for the Delta-Mendota Subbasin

Delta-Mendota Subbasin Coordination Committee | July 31st, 2024

1. Table of Contents 2. Executive Summary 3. Introduction 4. Plan Area 5. Basin Setting 6. Groundwater Conditions 7. Water Budget 8. Sustainability Criteria 9

1. Table of Contents 2. Executive Summary 3. Introduction 4. Plan Area 5. Basin Setting 6. Groundwater Conditions 7. Water Budget 8. Sustainability Criteria 9. Monitoring 10. Projects and Management 11. Plan Implementation 12. References 13. Appendices For a full history of basin GSPs, go to the Department of Water Resources Sustainable Groundwater Management Act portal.

Groundwater Sustainability Plan for the Northern and Central Delta-Mendota Regions

San Luis & Delta-Mendota Water Authority (SLDMWA) | November 30th, 2019

Table of Contents Executive Summary Introduction Plan Area Governance and Administration Outreach and Communication Basin Setting Sustainable M

Table of Contents Executive Summary Introduction Plan Area Governance and Administration Outreach and Communication Basin Setting Sustainable Management Criteria Sustainability Implementation Plan Implementation Technical Studies Appendices A. Coordination Agreements B. Common Chapter C. Outreach Documentation D. Water Budget Model Documentation E. Hydrographs for Sustainable Management Criteria F. Quality Assurance Program G. Noticing and Adoption Implementation H. Elements Guide

Groundwater Sustainability Plan for the San Joaquin River Exchange Contractors Groundwater Sustainability Plan (GSP) Group in the Delta-Mendota Subbasin

San Joaquin River Exchange Contractors GSA (SJREC GSA) | December 13th, 2019

Groundwater Sustainability Plan for the San Joaquin River Exchange Contractors GSP Group in the Delta-Mendota Subbasin (5-022.07)

San Joaquin River Exchange Contractors Water Authority (SJRECWA) | June 30th, 2022

The GSP was adopted by the SJREC GSA on December 13, 2019. The GSP has been amended in response to the January 21, 2022 DWR Determination letter to Delta-Mendota Subbasin

The GSP was adopted by the SJREC GSA on December 13, 2019. The GSP has been amended in response to the January 21, 2022 DWR Determination letter to Delta-Mendota Subbasin’s Point of Contact that included evaluation of the San Joaquin River GSA’s Groundwater Sustainability Plan (GSP). The amended plan was adopted by the SJRECGSA Board on July 5, 2022. On March 2nd, 2023, the Department of Water Resources announced decisions for Groundwater Sustainability Plans (GSPs), finding that numerous subbasins were found to be inadequate. One of these subbasins—the Delta-Mendota Subbasin in San Joaquin, Stanislaus, Merced, Fresno, Madera, and San Benito counties—includes a region for which the Exchange Contractors are responsible for developing the GSP. Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8