San Joaquin River

Towards sharing water better with near real-time maps on evaporative water use by crops and natural vegetation

Nature Portfolio (Springer Nature) | January 15th, 2024

The combination of advancements in evapotranspiration theory, eddy covariance flux measurements of water vapour and satellite remote sensing are putting technology on the

The combination of advancements in evapotranspiration theory, eddy covariance flux measurements of water vapour and satellite remote sensing are putting technology on the verge of producing information on evapotranspiration with unprecedented coverage and resolution. The OpenET project provides this information to farmers and land and water managers for better water practice.

Towards the Protection, Restoration, and Enhancement of the Delta Ecosystem: A Synthesis

Delta Stewardship Council (Delta Council) | March 15th, 2018

Towards the Protection, Restoration, and Enhancement of the Delta Ecosystem: A Synthesis. Appendix A: Summary of Existing Habitat and Species-Specific Plans, Strategies, and Management Approaches

Delta Stewardship Council (Delta Council) | March 15th, 2018

Toxicological assessment of potable reuse and conventional drinking waters

Nature Portfolio (Springer Nature) | October 27th, 2022

Potable reuse, the process of treating wastewater to drinkable standards, offers a reliable and sustainable solution to cities and regions facing shortages of clean water

Potable reuse, the process of treating wastewater to drinkable standards, offers a reliable and sustainable solution to cities and regions facing shortages of clean water. However, implementation is hindered by perceptions of poor water quality and potential health threats. Herein, we compare water samples from potable reuse systems with conventional drinking waters based on the analysis of Chinese hamster ovary cell cytotoxicity contributed by disinfection by-products (DBPs) and sewage-derived anthropogenic contaminants. In all cases, the cytotoxicity of potable reuse waters is lower than that of drinking waters derived from surface waters. The median contribution to total cytotoxicity was 0.2% for regulated DBPs and 16% for the unregulated DBPs of current research interest. Nonvolatile, uncharacterized DBPs and anthropogenic contaminants accounted for 83% of total cytotoxicity. Potable reuse waters treated by reverse osmosis are not more cytotoxic than groundwaters. Even in the absence of reverse osmosis, reuse waters are less cytotoxic than surface drinking waters. Our results suggest that potable reuse can provide a safe, energy-efficient and cost-effective alternative water supply.

Tracking California’s striking water storage gains attributed to intensive atmospheric rivers

Journal of Hydrology (Elsevier) | February 5th, 2025

California is highly vulnerable to extreme precipitation events due to the dense landfall of atmospheric rivers (ARs) during the winter months, often resulting in catastr

California is highly vulnerable to extreme precipitation events due to the dense landfall of atmospheric rivers (ARs) during the winter months, often resulting in catastrophic consequences such as widespread floods, mudslides, and landslides. This study focuses on the recovery of daily variations in AR-driven terrestrial water storage (TWS), which produces geodetically detectable ground subsidence. We invert GNSS vertical positions to obtain daily estimates of equivalent water height (EWH) through a variational Bayesian principal component analysis (vbPCA) based inversion scheme and track significant water gains during record-setting winter months in four water years (WYs) 2011, 2017, 2019, and 2023. These precipitation extremes have resulted in a substantial short-term increase in water storage, as evidenced by the multi-source EWH datasets (GNSS, GRACE, and NLDAS). Notably, WY 2023 experienced the highest snowfall due to the landfalls of high-density, high-category ARs, while WY 2017 recorded the highest precipitation totals, driven by the most frequent occurrence of hazardous ARs. Our findings further highlight that GNSS can accurately detect exceptionally wet hydrological events on short time scales, benefiting from an improved signal-to-noise ratio due to substantial increase in water storage. The results also indicate that while these extreme water years can help alleviate surface subsidence in the Central Valley caused by groundwater overexploitation, it is insufficient to alter California’s heavy reliance on groundwater for its intensive agricultural activities. Our findings demonstrate that GNSS is successful in tracking prodigious water increases from short-term precipitation extremes that are weaker than powerful hurricanes, illuminating the prospect of GNSS in supporting water management and flood preparedness.

Tracking Organic Matter in Delta Drinking Water

CALFED | April 1st, 2008

Tracking Where Water Goes in a Changing Sacramento–San Joaquin Delta

Public Policy Institute of California (PPIC) | May 26th, 2022

Click here for the accompanying Technical Appendix.

Click here for the accompanying Technical Appendix.

Tracking Where Water Goes in a Changing Sacramento–San Joaquin Delta Technical Appendix: Methods and Detailed Results for 1980–2021

Public Policy Institute of California (PPIC) | May 26th, 2022

Our goal is to provide water policymakers, managers, and regulators with information that will be helpful in managing the Delta and its watershed for multiple objectives

Our goal is to provide water policymakers, managers, and regulators with information that will be helpful in managing the Delta and its watershed for multiple objectives as warming conditions increase water demand, reduce snowpack, and make it harder to balance these objectives. An accompanying policy brief summarizes the findings presented here and highlights the major policy recommendations. This appendix provides details and evidence to support those recommendations and is intended for both a technical and policy audience. In the following sections we first review our approach for categorizing water flows in the watershed, and we review the caveats and limitations of the analysis. We next present key results and discuss several important watershed trends. We then review the management challenges of changing conditions in the Delta in wet and dry years through the lens of detailed water accounting. We conclude with implications for policy and management, including recommendations to improve watershed accounting and adapt the regulatory and management framework to the changing conditions in the watershed. All data assembled for this study, along with the sources and methods used, are detailed in the accompanying PPIC Delta Water Accounting spreadsheets.

Tracy Subbasin Groundwater Sustainability Plan

County of San Joaquin GSA | November 1st, 2021

The Tracy Subbasin boundaries follow the Old River on the northwest, the Coastal Range on the southwest and south, and the San Joaquin River on the east. The southeast bo

The Tracy Subbasin boundaries follow the Old River on the northwest, the Coastal Range on the southwest and south, and the San Joaquin River on the east. The southeast boundary of the Subbasin, along the San Joaquin-Stanislaus county line, follows irregular water district boundaries. The Subbasin is almost entirely with San Joaquin County but includes a small triangular portion of Alameda County. About one-half of the Subbasin is a mix of Delta islands (mostly agriculture) and waterways while the other half is comprised of urban and agricultural communities (Non-Delta areas).

Trading Sustainably: Critical Considerations for Local Groundwater Markets Under the Sustainable Groundwater Management Act

University of California, Berkeley (UC Berkeley) | June 1st, 2017

The Sustainable Groundwater Management Act (SGMA), passed in 2014, is changing the way California manages its groundwater resources. SGMA calls for the creation of loc

The Sustainable Groundwater Management Act (SGMA), passed in 2014, is changing the way California manages its groundwater resources. SGMA calls for the creation of local Groundwater Sustainability Agencies (GSAs) and tasks them with developing and implementing Groundwater Sustainability Plans (GSPs) to achieve sustainable groundwater management. SGMA offers GSAs a broad palette of tools to choose from and significant flexibility to tailor their management activities to local conditions and needs. Because it allows GSAs to assign groundwater extraction allocations to pumpers and to authorize transfers of these allocations under certain circumstances, SGMA potentially opens the door for the development of local groundwater markets. In such a market, a willing seller might trade a portion of their groundwater extraction allocation to a willing buyer, allowing the buyer to pump groundwater in the seller’s stead.