Assessment of California's Water Footprint

Pacific Institute | December 11th, 2012

The Pacific Institute has released the first comprehensive assessment of California’s water footprint, providing an important perspective on the interconnections betwee

The Pacific Institute has released the first comprehensive assessment of California’s water footprint, providing an important perspective on the interconnections between everyday activities and impacts to water resources – both at home and around the world. The new report, California’s Water Footprint, analyzes the state’s water footprint – that is the amount of water required to produce the food we eat, the clothes we wear, the beverages we drink, and the other goods on which we rely. The water footprint of the average Californian is 1,500 gallons per day, slightly less than the average American but considerably more than the average resident in other developed countries or in the rest of the world.

Assessment of Interconnected Subbasins

Butte County | June 30th, 2017

The Sustainable Groundwater Management Act (SGMA) requires groundwater sustainability agencies (GSAs) to develop groundwater sustainability plans (GSPs) that achieve sust

The Sustainable Groundwater Management Act (SGMA) requires groundwater sustainability agencies (GSAs) to develop groundwater sustainability plans (GSPs) that achieve sustainable groundwater management within 20 years of adoption. All critically overdrafted basins must adopt GSPs by January 31, 2020; all other medium and high priority basins must complete GSPs by January 31, 2022. Since many subbasins are hydrologically connected to adjoining subbasins, sustainable groundwater management will require accounting for groundwater interactions with adjoining subbasins. Often, adjoining subbasins will use different analytical methods or apply different levels of technical rigor. Many GSAs are concerned that different methodologies for developing interbasin flows can lead to different results that will call into question the ability to achieve sustainability and would potentially create issues with SGMA compliance. This effort evaluated opportunities and barriers for agencies to account for interconnected basin dynamics through the collaboration of technical experts focused on a portion of the northern Sacramento Valley Integrated Regional Water Management (NSVIRWM) Plan area. As interbasin flows (i.e., groundwater flow between interconnected basins) cannot be directly measured, the project reviewed available tools to investigate how they may or may not be suitable for use in estimating interbasin flows within the region. This process highlighted areas for local agencies to consider in addressing interbasin issues, developed a framework for analysis in other areas of the state, and identified areas where the state and federal government can assist local agencies implementing SGMA. This report is developed to provide summary level information appropriate for decision makers, with more detailed technical information and examples provided in the appendices or by reference. Interbasin flow is groundwater entering or exiting a defined subbasin through its boundaries in the subsurface and may vary significantly in space and time based on the dynamics of inflow and outflow from the basins. Interbasin flows are driven by differences in groundwater levels (i.e. head gradients) across the basin boundary. Groundwater levels are, in turn, impacted by processes on the land surface. Land use and crop acreages drive water demand in a subbasin and indirectly drive groundwater pumping, which has a direct effect on groundwater levels (i.e., groundwater heads). The direction and magnitude of interbasin flow depends on the groundwater head gradient across the basin boundary and the conductivity of the aquifer materials. It is widely recognized that the groundwater subbasins in the Sacramento Valley, and throughout the Central Valley, are interconnected to varying degrees. The Sacramento Valley Groundwater Basin includes many subbasins, extends over a wide geographic area, and includes numerous established and eligible GSAs. With interconnected subbasins, management decisions and actions in one subbasin may influence one or more adjoining subbasins. Such influence may positively or negatively impact sustainability. Thus, interbasin flows become critical to both GSAs’ development of GSPs and to DWR reviewing GSPs.

Assessment of Interconnected Subbasins: Regional Collaboration and Model Selection Process

Groundwater Resources Association of California (GRA) | October 3rd, 2017

In basins with complex spatial and temporal variations in water budget components, integrated groundwater-surface water modeling is the best approach to quantify and eval

In basins with complex spatial and temporal variations in water budget components, integrated groundwater-surface water modeling is the best approach to quantify and evaluate interbasin groundwater flows.

Assessment of Interim Flow Water-Quality Data of the San Joaquin River Restoration Program and Implications for Fishes, California, 2009–11

U.S. Geological Survey (USGS) | June 29th, 2015

After more than 50 years of extensive water diversion for urban and agriculture use, a major settlement was reached among the U.S. Departments of the Interior and Commerc

After more than 50 years of extensive water diversion for urban and agriculture use, a major settlement was reached among the U.S. Departments of the Interior and Commerce, the Natural Resources Defense Council, and the Friant Water Users Authority in an effort to restore the San Joaquin River. The settlement received Federal court approval in October 2006 and established the San Joaquin River Restoration Program, a multi-agency collaboration between State and Federal agencies to restore and maintain fish populations, including Chinook salmon, in the main stem of the river between Friant Dam and the confluence with the Merced River. This is to be done while avoiding or minimizing adverse water supply effects to all of the Friant Division contractors that could result from restoration flows required by the settlement. The settlement stipulates that water- and sediment-quality data be collected to help assess the restoration goals. This report summarizes and evaluates water-quality data collected in the main stem of the San Joaquin River between Friant Dam and the Merced River by the U.S. Bureau of Reclamation for the San Joaquin River Restoration Program during 2009–11. This summary and assessment consider sampling frequency for adequate characterization of variability, sampling locations for sufficient characterization of the San Joaquin River Restoration Program restoration reach, sampling methods for appropriate media (water and sediment), and constituent reporting limits. After reviewing the water- and sediment-quality results for the San Joaquin River Restoration Program, several suggestions were made to the Fisheries Management Work Group, a division of the San Joaquin River Restoration Program that focuses solely on the reintroduction strategies and health of salmon and other native fishes in the river. Water-quality results for lead and total organic carbon exceeded the Surface Water Ambient Monitoring Program Basin Plan Objectives for the San Joaquin Basin, and results for copper exceeded the U.S. Environmental Protection Agency Office of Pesticide Programs’ aquatic-life chronic and acute benchmarks for invertebrates. One sediment sample contained detections of pyrethroid pesticides bifenthrin, lambda-cyhalothrin, and total permethrin at concentrations above published chronic toxicity thresholds.

Assessment of Nutrient Status and Trends in the Delta in 2001–2016: Effects of drought on ambient concentrations and trends

San Francisco Estuary Institute (SFEI) | March 1st, 2018

Nutrients and the effects of nutrients on water quality in the Sacramento-San Joaquin Delta is a priority focus area for the Delta Regional Monitoring Program (Delta RMP)

Nutrients and the effects of nutrients on water quality in the Sacramento-San Joaquin Delta is a priority focus area for the Delta Regional Monitoring Program (Delta RMP). The Program’s first assessment question regarding nutrients is: “How do concentrations of nutrients (and nutrient-associated parameters) vary spatially and temporally?” In this analysis, we confirmed previously reported declining trends in the San Joaquin River for nutrient concentrations at Vernalis and chlorophyll-a concentrations at Buckley Cove and Disappointment Slough. A slight increasing trend for dissolved oxygen at Buckley Cove was also detected which could be confirmation that management actions for the San Joaquin River Dissolved Control Program are having the desired effect. Finally, at stations in Suisun Bay, the Confluence region, and Franks Tract, chlorophyll-a showed modest increasing trends, which were not evident in previous analyses. The new analyses presented in this report and the findings from earlier reports constitute encouraging early progress toward answering the Delta RMP’s assessment questions. Specifically, due to the existence of long-term data sets and synthesis efforts, spatial and temporal trends in the concentrations of nutrients and nutrient-related parameters are reasonably well understood and so are the magnitudes of the most important sources of nutrients from outside the Delta. However, additional synthesis work could be done to understand the factors behind these trends. Large knowledge gaps remain about nutrient sinks, sources, and processes within the Delta. The mechanistic, water quality-hydrodynamic models being developed for the Delta may be able to address these questions in the future.

Assessment of the condition of San Francisco Bay Area depressional wetlands

California State Water Resources Control Board (SWRCB) | March 23rd, 2017

Depressional wetlands are the most abundant, yet most threatened wetland type in California. Despite their relatively ubiquitous nature, they are poorly characterized, an

Depressional wetlands are the most abundant, yet most threatened wetland type in California. Despite their relatively ubiquitous nature, they are poorly characterized, and unlike streams, they are not subject to any systematic ambient monitoring and assessment in California. Consequently, decisions regarding protection, restoration, and management, such as issuance of Section 401 water quality certifications or prioritization of projects for wetland restoration grant funding, are usually made without the benefit of any regional context of condition, knowledge of predominant stressors, or rigorous documentation of reference conditions. The goals of this study were to apply tools for ambient monitoring of depressional wetlands in the San Francisco Bay region to accomplish the following: 1) To evaluate the regional condition of depressional wetlands in this portion of northern California, and 2) To evaluate the relationship between condition and stress by sampling both local stressors (intensity of direct wetland use, water chemistry, and sediment chemistry) and landscape stressors (adjacent land use, flow diversions, and road density). Once achieved, these goals should establish the foundation for developing a robust ambient depressional wetland monitoring program. This study included perennial (have surface water year round) and seasonal (lack surface water for part of the year) depressional wetlands as defined by Brinson (1993) located within the boundaries of the San Francisco Bay Regional Water Quality Control Board. Depressional wetlands in this study includes both natural water bodies such as sag ponds and small lakes, as well as created wetlands such as abandoned or active stock ponds, aesthetic ponds, and irrigation/treatment ponds. Wetlands were not considered for this study if they were concrete lined, marine influenced, wastewater treatment ponds, livestock wastewater ponds, riverine (i.e., dominated by riverine hydrology), dry, or vernal pools. It is likely that a majority of wetlands sampled in this study would be considered waters of the State of California; the field teams did not perform a regulatory-based delineation of a wetland as part of this study. Thirty wetlands in the San Francisco Bay area were sampled during the spring of 2014, including both perennial and seasonal wetlands. The proportion of wetlands in the region considered “likely intact” (scores in the upper 50th percentile of the range found at reference sites) varied by indicator.

Assessment of the condition of Southern California depressional wetlands

California State Water Resources Control Board (SWRCB) | April 18th, 2016

Application of Macroinvertebrate, Diatom and Overall Condition Indices for Assessing Southern California Depressional Wetlands Depressional wetlands are the most abund

Application of Macroinvertebrate, Diatom and Overall Condition Indices for Assessing Southern California Depressional Wetlands Depressional wetlands are the most abundant, yet most threatened wetland type in California. Despite their relatively ubiquitous nature, they are poorly characterized, and unlike streams, they are not subject to any systematic monitoring and assessment. Consequently, decisions regarding protection, restoration, and management are usually made without the benefit of any regional context of condition, knowledge of predominant stressors, or rigorous documentation of reference conditions. Ambient monitoring of depressional wetlands can be a critical tool to inform management decisions. However, before such a program can be implemented, biological assessment tools must be evaluated, validated, and modified (if necessary). Once these steps are completed, preliminary assessments can begin to provide answers to critical questions regarding wetland condition and key stressors. The goals of this study were 1) to adapt three readily available bioassessment tools for assessing depressional wetland condition in southern California. This included a statewide rapid assessment method that had been calibrated and validated for depressional wetlands (CRAM) but had no prior use in a regional assessment program, a macroinvertebrate index developed for depressional wetlands from a different geography (northern California), and a benthic diatom index which had been developed for a different habitat type (wadeable streams). 2) To evaluate the regional condition of depressional wetlands in southern California using the adapted tools. 3) To evaluate the relationship between condition and stress by sampling both local stressors (intensity of direct wetland use, water chemistry and sediment toxicity) and landscape stressors (adjacent land use, flow diversions, road density). Once achieved, these goals should establish the foundation for developing a robust and ongoing depressional wetland ambient monitoring program. This study included perennial or seasonal depressional wetlands as defined by Brinson (1993) located within the boundaries of the Los Angeles, Santa Ana, and San Diego Regional Water Quality Control Boards. Wetlands were not considered for this study if they were concrete-lined, marine-influenced, treatment ponds, livestock wastewater ponds, riverine (i.e. dominated by riverine hydrology), dry (i.e. not seasonal), or on-military bases (due to access issues). Vernal pools were also excluded; while these are considered a subclass of depressional wetlands, they represent a distinct wetland habitat that is typically evaluated with specific methods. Furthermore, given their rarity and ecological sensitivity they are often assessed through focused studies.

Assessment of the Economic Impacts of California's Drought on Urban Areas

Rand Corporation (Rand) | September 6th, 1993

Associations between per-and polyfluoroalkyl substances (PFAS) and county-level cancer incidence between 2016 and 2021 and incident cancer burden attributable to PFAS in drinking water in the United States

Nature Portfolio (Springer Nature) | January 9th, 2025

Associations between PFAS in public water system drinking water and serum among Southern California adults

Nature Portfolio (Springer Nature) | October 30th, 2025

The CARE (California Regional Exposure) biomonitoring study measured PFAS in serum of Southern and Eastern California adults between 2018 and 2020. Participant addresses

The CARE (California Regional Exposure) biomonitoring study measured PFAS in serum of Southern and Eastern California adults between 2018 and 2020. Participant addresses were geocoded and geographically assigned to public water systems (PWS). Between 2019 and 2022, the California State Water Resources Control Board issued investigative PFAS monitoring orders to potentially impacted PWS, focusing primarily on source wells. PFAS detections above the required reporting limit (4 ng/L for PFAS included in the final analysis) were used to assess associations with serum PFAS levels.