Water Quality of Groundwater Used for Public Supply in Principal Aquifers of the Western United States

U.S. Geological Survey (USGS) | September 8th, 2020

Water Quality Science in the Sacramento-San Joaquin Delta: Chemical Contaminants and Nutrients

Delta Stewardship Council (Delta Council) | July 26th, 2018

This review focuses on contaminants and nutrients in the Sacramento-San Joaquin Delta (the Delta), and on how findings about them have been sometimes used and sometimes n

This review focuses on contaminants and nutrients in the Sacramento-San Joaquin Delta (the Delta), and on how findings about them have been sometimes used and sometimes neglected in decisions related to ecosystem health in the Delta. The review considers water quality measurements made both in support of basic research and as part of routine monitoring studies in the Delta. However, the topic of monitoring per se is not comprehensively covered in this review because the Delta ISB is in the initial stages of reviewing the extensive monitoring enterprise in the Delta. This review of water quality is based on responses to a questionnaire sent to government agencies and science programs, interviews with water quality specialists and users of water quality data, relevant scientific publications, presentations observed in workshops and conferences, and public comments received on draft versions of the review. While we sought input from a broad range of stakeholders, we do not assume that we received a complete range of perceptions about this important issue. Additionally, water quality research and monitoring efforts are constantly evolving in the Delta, and several new programs and improvements were made as this review was being researched and prepared. This review should be considered to be part of an ongoing process by the Delta ISB.

Water Right Decision 1485: Sacramento-San Joaquin Delta and Suisun Marsh

California State Water Resources Control Board (SWRCB) | August 16th, 1978

Water storage decisions will determine the distribution and persistence of imperiled river fishes

Ecological Society of America (Wiley) | December 17th, 2020

Managing the world’s freshwater supply to meet societal and environmental needs in a changing climate is one of the biggest challenges for the 21st century. Dams provid

Managing the world’s freshwater supply to meet societal and environmental needs in a changing climate is one of the biggest challenges for the 21st century. Dams provide water security; however, the allocation of dwindling water supply among reservoirs could exacerbate or ameliorate the effects of climate change on aquatic communities. Here, we show that the relative sensitivity of river thermal regimes to direct impacts of climate change and societal decisions concerning water storage vary substantially throughout a river basin. In the absence of interspecific interactions, future Colorado River temperatures would appear to benefit both endemic and nonnative fish species. However, endemic species are already declining or extirpated in locations where their ranges overlap with warmwater nonnatives and changes in water storage may lead to warming in some of the coolest portions of the river basin, facilitating further nonnative expansion. Integrating environmental considerations into ongoing water storage negotiations may lead to better resource outcomes than mitigating nonnative species impacts after the fact.

Water Temperature Modeling Platform Mid-Term Review

Delta Stewardship Council (Delta Council) | October 21st, 2021

Water Wasted to the Sea?

University of California, Davis (UC Davis) | July 15th, 2017

Watershed Action Plan Santa Ana Region - Riverside County

Riverside County | January 18th, 2017

The Watershed Action Plan (WAP) for the Santa Ana Watershed Region of Riverside County (SAR) and its Permittees is a requirement of the Riverside County Municipal Separat

The Watershed Action Plan (WAP) for the Santa Ana Watershed Region of Riverside County (SAR) and its Permittees is a requirement of the Riverside County Municipal Separate Storm Sewer System (MS4), Permit Order No. R8-2010-0033 as adopted by the Santa Ana Regional Water Quality Control Board (Regional Board) in January 29, 2010 (2010 MS4 Permit). The purpose of this requirement is to coordinate existing watershed approaches to address water quality and hydromodification impacts resulting from urbanization within the SAR. This requirement is to be achieved by evaluating existing programs relating to the integration of water quality, stream protection, stormwater management, and re-use strategies with land planning policies, ordinances, and plans within each jurisdiction to the maximum extent practicable (MEP). Throughout implementation of the 2010 MS4 Permit along with the development of this plan, the Regional Board has emphasized that the plans for each jurisdiction should address cumulative impacts of development on vulnerable streams; preserve or restore, consistent with the MEP standard, the structure and function of streams; and protect surface water and groundwater quality.

Watershed Condition, Turbidity, and Implications for Anadromous Salmonids in North Coastal California Streams

California State Water Resources Control Board (SWRCB) | May 21st, 2008

It is widely acknowledged that historically intensive human disturbances increased erosion and sediment delivery rates to extreme levels in the 1950s through the 1970s ac

It is widely acknowledged that historically intensive human disturbances increased erosion and sediment delivery rates to extreme levels in the 1950s through the 1970s across the north coast, and are likely continuing to affect turbidity durations to some degree. A more controversial question is to what extent contemporary land use is affecting present-day erosion, sediment delivery and turbidity. Using turbidity exceedence levels to indicate watershed disturbance, we approached this question from several perspectives. Part A of this report follows up and expands on an earlier analysis (Klein, 2003) for which turbidity data sets from only eight sites were available. In the present study, annual turbidity data sets were assembled from up to 28 continuous turbidity and stage recording stations located on small streams in the northcoast region from Del Norte County in the north to Mendocino County in the south. Data spanning three water years (WY2003-2005) were processed to calculate lengths of time turbidity was higher than several thresholds. Turbidity thresholds ranged from 25 (frequently cited in the salmonid literature as causing ill effects when exceeded) to 1000 FNU. Turbidity exceedence analyses, similar to conventional flow exceedence analyses, were also performed, allowing comparison of turbidity levels at various exceedence probabilities. Part B of this report uses turbidity relationships to harvest rate to model potential effects on anadromous salmonids within a cumulative watershed effects (CWE) framework. To evaluate CWEs on anadromous salmonids and the stream ecosystem, annual turbidigraphs were produced from WY1991 through WY2005 at annual average harvest rates of 0% to 6% for an 8 mi2 old second-growth watershed in North Coastal California. The turbidigraphs were very conservative in that they used the ‘Lower Bound Lines’ to estimate turbidity from discharge, rather than a line of best fit. Turbidity thresholds established at 10, 25, and 50 FNU were applied to assess chronic background, moderate, and severe stress to stream ecosystems in each water year. A simple model of smolt growth and survival-to-adult-return (SAR), as influenced by the annual turbidigraph, indicated the minimum supportable adult steelhead population size could be more than halved at the 2% average annual timber harvest rate compared to that supported by an old second-growth watershed.

Watershed-scale Evaluation of Agricultural BMP Effectiveness in Protecting Critical Coastal Habitats: Final Report on the Status of Three Central California Estuaries

Central Coast Regional Water Quality Control Board (CCRWQCB) | April 30th, 2010

Along California's Central Coast, the Pajaro, Salinas, and Santa Maria Rivers drain to coastal estuaries that provide essential habitat for early life stages of commercia

Along California's Central Coast, the Pajaro, Salinas, and Santa Maria Rivers drain to coastal estuaries that provide essential habitat for early life stages of commercially and recreationally important marine fish species, threatened anadromous fish species, migratory birds, and other wildlife. These are the largest watersheds on the central coast and each contains year-round, intensively cultivated agricultural land that supports a $3.5 billion/year industry producing most of the nation's lettuce, artichokes, and crucifer crops. Runoff from irrigated agriculture constitutes a significant portion of river flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in these watersheds. Evidence of pesticide impacts has encouraged diverse stakeholders to begin implementing farm management practices (MPs) to reduce pesticide concentrations and toxicity in agricultural runoff. This project is designed to complement ongoing evaluations of individual MPs with measurements of pesticide concentrations throughout the estuarine environments, including the water column, sediments, and in resident biota. Biological effects were measured at the organism and community levels. Chemical analyses emphasized pesticide impacts because previous research in these watersheds has indicated these are the primary chemicals of concern impacting beneficial uses. A broad suite of pesticides were measured, including legacy organochlorines, widely-used organophosphates, increasingly-used pyrethroids, herbicides and fungicides. Sampling in the three estuaries was conducted from January 2008 until October 2009. A total of fifteen sampling events were conducted in each estuary, and these were divided between eleven irrigation season events and four storm events. Storm and irrigation monitoring included water toxicity and chemistry analyses for pesticides. Samples were collected at multiple stations in the estuaries and in key tributaries flowing to the estuaries. In addition, sediment toxicity was assessed at eight estuary stations and the tributary stations during three irrigation season sampling events. Benthic community characterizations were also conducted in May and October 2008. All sediment samples were analyzed for pesticides, as well as grain size and total organic carbon. Pesticide analyses in resident fish and sand crab tissues were conducted once in each estuary. The goal of this project was to establish a baseline of estuary conditions with respect to pesticide impacts as MPs are beginning to be implemented.

West False River Drought Salinity Barrier Project Environmental Impact Report (Draft)

California Department of Water Resources (DWR) | July 7th, 2022

The California Department of Water Resources (DWR) proposes to the install the West False River Drought Salinity Barrier Project (proposed project). During drought condit

The California Department of Water Resources (DWR) proposes to the install the West False River Drought Salinity Barrier Project (proposed project). During drought conditions, water stored in upstream reservoirs may be insufficient to repel salinity moving upstream from San Francisco Bay. Without the protection of the drought salinity barrier in West False River, saltwater intrusions could affect more than 27 million Californians who rely on the Sacramento–San Joaquin Delta (Delta) for at least a portion of their water supply; could render Delta water unusable for agricultural needs; and could reduce the value of habitat for aquatic species. DWR installed emergency drought barriers in West False River in 2015 and 2021–2022 in response to drought conditions to protect water quality in the interior Delta. Installation of a drought salinity barrier in West False River has been shown to be an effective tool for reducing the intrusion of saltwater into the Central and South Delta based on these previous installations (see Section 1.2, “Project Background,” in Chapter 1; California Department of Water Resources 2019).