Priorities for California’s Water

Public Policy Institute of California (PPIC) | November 14th, 2022

This report considers the state of water in California: What changes are we seeing now, and what should we expect in the near future? Then it examines how these climate s

This report considers the state of water in California: What changes are we seeing now, and what should we expect in the near future? Then it examines how these climate shifts will impact urban and rural communities, agriculture, and the environment. Finally, it explores wet-year strategies that will help Californians get through the dry years.

Priorities for California’s Water -- Stewarding the Wet Years

Public Policy Institute of California (PPIC) | November 2nd, 2023

The 2023 water year provided a case study of California’s increasingly volatile climate, with large swings between wet and dry conditions both within and between years.

The 2023 water year provided a case study of California’s increasingly volatile climate, with large swings between wet and dry conditions both within and between years. It highlighted our need to better navigate multiple imperatives: storing more water during intense wet periods to build water supply reliability, protecting communities and infrastructure against the threat of increasingly damaging floods, and taking better advantage of wet years to improve the health of freshwater ecosystems and native fish and wildlife.

Priorities for California’s Water: Advancing Research During Uncertain Times

Public Policy Institute of California (PPIC) | November 12th, 2025

In California, research underpins all water-related activity. It is vital for coping with too much water, too little water, and rapid changes in hydrology. Whether you ar

In California, research underpins all water-related activity. It is vital for coping with too much water, too little water, and rapid changes in hydrology. Whether you are a farmer managing the precise application of water to your crops, a utility providing clean drinking water supplies to your community, or a restorationist trying to heal a damaged wetland, your actions rely upon decades of applied research that guides your actions and measures your success.  The same reliance on research applies if you are developing policies to reduce the price of water, increase its reliability, regulate its usage, and reduce hazards from floods. None of this works without a vast research enterprise that is regularly updating the science and technology we use to manage water, prepare for the future, inform the public, and address new problems as they arise. 

Priorities for California’s Water: Are We Ready for Climate Change?

Public Policy Institute of California (PPIC) | November 12th, 2024

California faces many immediate challenges around water management, but as the record-breaking heat of 2024 makes clear, temperatures are rising—and Californians are co

California faces many immediate challenges around water management, but as the record-breaking heat of 2024 makes clear, temperatures are rising—and Californians are contending with the consequences. In a PPIC poll earlier this year, residents named climate change, forest fires and wildfires, and water supply and drought as the most important environmental issues facing the state. 

Prioritization of Oil and Gas Fields for Regional Groundwater Monitoring Based on a Preliminary Assessment of Petroleum Resource Development and Proximity to California’s Groundwater Resources

U.S. Geological Survey (USGS) | July 20th, 2018

The California State Water Resources Control Board initiated a regional monitoring program in July 2015 to determine where and to what degree groundwater quality may be a

The California State Water Resources Control Board initiated a regional monitoring program in July 2015 to determine where and to what degree groundwater quality may be adversely impacted by oil and gas development activities. A key issue in the implementation of the regional groundwater monitoring program is that each year, detailed characterization work can be done in only a few of California’s 487 onshore oil and gas fields. The first step in monitoring groundwater near petroleum development is to prioritize oil and gas fields using consistent statewide analysis of available data that indicate potential risk of groundwater to oil and gas development. The U.S. Geological Survey compiled data for four factors that characterize the intensity of petroleum resource development and proximity to groundwater resources: petroleum-well density, volume of water injected in oil fields, vertical proximity of groundwater resources to oil and gas resource development, and water-well density. An overall priority ranking for each field was determined by computing summary metrics, analyzing statewide distributions of summary metrics for all oil and gas fields, using those distributions to define relative categories of potential risk for each factor, and combining relative risk rankings for different factors into an overall priority ranking. This preliminary assessment does not represent an evaluation of groundwater risk to oil and gas development, which needs to be based on detailed analysis and data related to development activities including well stimulation, well integrity issues, produced water ponds, and underground injection. Based on the prioritization analysis, 22 percent (107 fields) of the total number of oil and gas fields in California were ranked as high priority, 23 percent (114 fields) as moderate priority, and 55 percent (266 fields) as low priority. These results indicate that between 100 and 200 oil fields are principal candidates for the next steps in the regional monitoring program. The land area of fields that ranked high priority accounted for 41 percent of the total field area (3,392 square miles). More than half of the high priority fields were in the southern San Joaquin Valley and the Los Angeles Basin. Some of the larger fields tended to have higher rankings because of greater intensity of petroleum development, sometimes coupled with proximity to groundwater resources. The U.S. Geological Survey, in collaboration with the California State Water Resources Control Board and other agencies, has begun regional groundwater monitoring near oil and gas fields selected for study through the California Oil, Gas, and Groundwater cooperative program. Groundwater monitoring includes compiling, analyzing, and developing three-dimensional visualizations of existing data, including geological frameworks, salinity mapping, identification of surface features that could potentially affect groundwater quality, locations and depths of oil/gas and water wells, cataloging well-construction integrity issues, and evaluating the directions of groundwater flow. These analyses are required to determine where existing wells should be monitored and where new monitoring wells may need to be drilled.

Prioritization of State Investments in Delta Levees and Risk Reduction - Initial Statement of Reasons

Delta Stewardship Council (Delta Council) | August 26th, 2022

Prioritization of State Investments in Delta Levees and Risk Reduction Amendment to Existing Regulation

Delta Stewardship Council (Delta Council) | September 21st, 2023

Prioritizing Candidate Green Infrastructure Sites within the City of Ukiah: A Demonstration of the Site Locator Tool of GreenPlan-IT. Report prepared for the City of Ukiah Department of Public Works under Supplemental Environmental Project # R1-018-0024

San Francisco Estuary Institute (SFEI) | April 1st, 2019

Green infrastructure (GI), also known as Low Impact Development (LID), has emerged as an integral aspect of multi-benefit, watershed approaches to address concerns about

Green infrastructure (GI), also known as Low Impact Development (LID), has emerged as an integral aspect of multi-benefit, watershed approaches to address concerns about stormwater quality and quantity in an urban environment. When carefully applied, GI installations, such as rain gardens, tree-well planters, and permeable pavement, can be cost-effective, resilient ways to manage storm water at its source with measurable, cumulative environmental and community benefits. 

Priority Margin Unit Stormwater Monitoring to Support Load Estimates of PCBs into San Leandro Bay and the Emeryville Crescent

San Francisco Estuary Institute (SFEI) | July 15th, 2022

The Priority Margin Unit Studies: The 2014 update of the RMP PCB Strategy called for a multi-year effort to implement the recommendations of the  PCB Synthesis Report (D

The Priority Margin Unit Studies: The 2014 update of the RMP PCB Strategy called for a multi-year effort to implement the recommendations of the  PCB Synthesis Report (Davis et al., 2014) including: 1. identifying margin units that are high priorities for management and monitoring, 2. developing conceptual models and mass budgets for margin units downstream of watersheds where management actions will occur, and 3. monitoring in these units as a performance measure. The goal of the effort was to inform the review and possible revision of the PCB TMDL and the reissuance of the Municipal Regional Permit for Stormwater (MRP).

Probabilistic Assessment of the Biotic Condition of Perennial Streams and Rivers in California

Central Valley Regional Water Quality Control Board (CVRWQCB) | August 22nd, 2006

States are required under the Clean Water Act §305(b) to report annually to Congress on the condition of their waterbodies, but satisfaction of this requirement has been

States are required under the Clean Water Act §305(b) to report annually to Congress on the condition of their waterbodies, but satisfaction of this requirement has been confounded by the lack of resources (both technical and financial) to adequately assess these waterbodies. Partly because of this limitation, most regions of the nation have been unable to answer the most basic questions about their water quality, even 35 years after the passage of the act. To address these constraints, the U.S. EPA established its Environmental Monitoring and Assessment Program (EMAP), a long term research program designed to develop the tools and techniques needed for cost-effectively answering the fundamental status and trends questions in the Clean Water Act. The EMAP studies are based on a probabilistic survey design in which each sampling location represents a known length of stream with known statistical confidence. This design permits the inference of stream conditions for large geographic regions with a relatively small investment in sampling. After completing an assessment of the condition of wadeable streams in the Middle-Atlantic states, the EPA initiated a similar assessment of streams in the western states (WEMAP), which included a high density of sites in California. Now that the first round of WEMAP studies has been completed, California has the ability to include the first statistically defensible condition assessments in its 305b reports. Because they provide a direct measure of the biotic integrity, bioassessment data are a key component of EMAP water quality monitoring. Bioassessment, the science of describing the ecological condition of waterbodies from the assemblages of organisms they contain, is well established as a valuable tool for water resource management (Karr 1981, Yoder and Rankin 1995, Barbour et al. 1996, Wright et al. 2000, Bailey et al. 2004). Because assemblages of aquatic organisms (e.g., fish, benthic macroinvertebrates (BMIs) and algae) are comprised of taxa that are differentially responsive to different environmental stressors, bioassessments provide a direct means of measuring compliance with the goal of biotic integrity stipulated under the Clean Water Act. Although comprehensive condition assessments will ultimately include assessments of the physical and chemical conditions of waterbodies, condition assessments based on bioassessment data can stand alone as effective measures of the ecological condition of the state’s waterbodies. There are many different approaches to translating a list of organisms present at a site into an assessment of its ecological condition (Wright et al. 1984, Kerans and Karr 1994, Hawkins et al. 2000, Van Sickle et al. 2005, Ode et al. 2005). We have demonstrated elsewhere (Rehn and Ode 2004, Rehn and Ode 2005) the use of BMI data to produce regional 305(b)-type stream condition assessments using multimetric techniques to calculate site condition scores. These regional assessments were possible because we had previously developed benthic indices of biotic integrity (B-IBIs) for northern and southern coastal California; statewide assessments require a tool for scoring sites that can be applied statewide. We present here a statewide condition assessment using predictive models based on the River Invertebrate Prediction and Classification System (RIVPACS, Wright 1984). Like multimetric approaches (Kerans and Karr 1994, Ode et al. 2005, Rehn and Ode 2005), predictive modeling techniques establish thresholds of ecological impairment based on a characterization of the biotic assemblages expected to occur under minimal human disturbance (Wright et al. 1984, 1989, 2000). However, predictive models compare assemblages at test sites to an expected taxonomic composition rather than expected metric values. Taxon-based models have seen widespread use since the first BMI models were created in Great Britain in the late 1970s (Norris and Georges 1993, Hawkins et al. 2000, Van Sickle et al. 2005) and have been promoted in the US (Hawkins et al. 2000, Hawkins and Carlisle 2001) as an alternative to the multimetric approach initially endorsed by the EPA (Barbour et al. 1999). For this analysis, we employed newly developed California RIVPACS models (C. Hawkins unpublished) that can be used to score sites throughout the state.