The Decline of Striped Bass in the Sacramento-San Joaquin Estuary, California

American Fisheries Society (AFS) | July 1st, 1985

The abundance of young striped bass Morone saxatilis in the Sacramento-San Joaquin Estuary has suffered an unsteady but persistent decline from population levels that wer

The abundance of young striped bass Morone saxatilis in the Sacramento-San Joaquin Estuary has suffered an unsteady but persistent decline from population levels that were high in the middle 1960s. The decline was particularly severe in 1977 and abundance of young striped bass has been low every subsequent year. The adult striped bass population also has fallen during the past 20 years, but the exact period over which the decline occurred and the rate of decline are not clear. The adult population is now about one-quarter of its former size and there is little sign of recovery. We believe the Sacramento-San Joaquin striped bass population and the fishery that it supports are in serious danger. The cause is most likely one or more of four factors. (1) The adult population is now so low that egg production may be inadequate. (2) The plankton food supply of young striped bass in the western Sacramento-San Joaquin Delta and Suisun Bay has been greatly reduced each spring. Diversion of water from the delta for agricultural purposes is a prime suspect for the decrease in food production. (3) Large numbers of young fish are lost by entrainment in water diversions. (4) The population is stressed by toxic substances such as petrochemicals and pesticides. Additional studies are underway to help determine the principal cause(s) of the striped bass decline.

The Development of Nutrient Criteria for Ecoregions within: California, Arizona, and Nevada

U.S. Environmental Protection Agency (EPA) | January 1st, 2002

Development of regional nutrient criteria is one component of a larger strategy to address water quality problems associated with nutrient over-enrichment and cul

Development of regional nutrient criteria is one component of a larger strategy to address water quality problems associated with nutrient over-enrichment and culturally-induced accelerated rates of eutrophication of waterbodies in the U.S. The U.S. Environmental Protection Agency (EPA) and Department of Agriculture have several active program initiatives to address the nutrient overenrichment problem. These programs address point and nonpoint sources of pollution, evaluate public health impacts from animal feeding operations, conduct research and monitoring to provide data and assessment techniques to better characterize the problem, and have offer nutrient management policies to provide practical support to agricultural operations to reduce the export of nutrients from their lands. The purpose of the regional nutrient criteria development process is to provide numeric targets for the various nutrient management programs that are regionally appropriate by reflecting geographic variations of waterbody response to nutrients. The current nutrient criteria development process for California and EPA Region IX (California, Nevada, Arizona, and Hawaii) started with the publication of the National Strategy for the Development of Regional Nutrient Criteria (EPA 1998) in June 1998.

The Ecological Significance of the Submarine Discharge of Groundwater

Commonwealth Scientific and Industrial Research Organisation (CSIRO Publishing) | December 15th, 1980

Discharge of groundwater into the sea is widespread. Overlooking it may lead to serious misinterpretations of ecological data in studies of coastal pollution, of benthic

Discharge of groundwater into the sea is widespread. Overlooking it may lead to serious misinterpretations of ecological data in studies of coastal pollution, of benthic zonation and productivity, and of the flux of dissolved substances within and between bottom sediments and overlying water. Data are presented indicating that in the Perth region of Western Australia, submarine groundwater discharge delivers several times as much nitrate to coastal waters as does river runoff.

The effects of artificial recharge on groundwater levels and water quality in the west hydrogeologic unit of the Warren Subbasin, San Bernardino County, California

U.S. Geological Survey (USGS) | November 4th, 2013

The effects of kaolin clay on the amphipod Eohaustorius estuarius: Part Two

San Francisco Estuary Institute (SFEI) | April 3rd, 2017

A number of lines-of-evidence suggest that the amphipod Eohaustorius estuarius has variable tolerance to clay in sediments. In Phase 1 of the current RMP special study, l

A number of lines-of-evidence suggest that the amphipod Eohaustorius estuarius has variable tolerance to clay in sediments. In Phase 1 of the current RMP special study, laboratory dose-response experiments were conducted in 2014 with kaolin clay to evaluate whether clay effects varied with amphipod size. The results indicated that smaller amphipods were more tolerant of clay than larger individuals. Average survival was 81%, 79%, and 65% for small, medium and large amphipods, respectively, in concentrations > 50% clay. As part of Phase 2 confirmation studies conducted in 2015-2016, the original kaolin dose-response experiments were repeated. Results of this experiment showed that average amphipod survival was 88%, 63%, and 41% for small, medium and large amphipods, respectively, in concentrations > 50% clay. Standard 96-hour reference toxicant tests with cadmium chloride (CdCl2) were conducted to determine whether there were size-specific differences in response to this metal reference toxicant. The CdCl2 median lethal concentrations (LC50s) for small, medium and large amphipods were 6.78, 5.13, and 4.63 mg/L, respectively. Responses of all three size classes to cadmium were within historic confidence intervals for this reference metal, and were not significantly different from one another based on overlapping confidence intervals. Additional experiments with high clay reference site sediments from San Francisco Bay were conducted to confirm the size related response with field sediments. The results confirm that use of smaller amphipods in routine monitoring of high clay sediments will reduce the influence of this factor on test results. 

The evolution of dam induced river fragmentation in the United States

Nature Portfolio (Springer Nature) | June 28th, 2023

The frontiers of water and sanitation

Nature Portfolio (Springer Nature) | January 19th, 2023

The way in which human society uses water is continuously evolving. The present challenges related to clean water availability require the development of sustainable tech

The way in which human society uses water is continuously evolving. The present challenges related to clean water availability require the development of sustainable technologies and infrastructure. Furthermore, a stronger and wider appreciation of water inequalities and injustice demand an adequate transformation of water governance at local and global scale. We have asked nine experts in various sectors of water-related research to share their views on how water and sanitation science, technology and governance must evolve to meet the requirements of a healthier relationship between water and society.

The Green Visions Plan for 21st Century Southern California: 21. Hydrology and Water Quality Modeling of the Calleguas Creek Watershed

University of Southern California (USC) | November 2nd, 2009

The hydrology and water quality simulation presented in this report is a part of the Green Visions Plan for 21st Century Southern California project. The primary

The hydrology and water quality simulation presented in this report is a part of the Green Visions Plan for 21st Century Southern California project. The primary focus of the Calleguas Creek Watershed water quality modeling is to determine the pollutant concentration and loads entering the stream network and to what degree surface waters are subject to water quality impairments.

The Human Right To Water In Poor Communities Of Color

University of California, Los Angeles (UCLA) | January 19th, 2021

Since the state enacted the Human Right to Water Legislation (AB 685) eight years ago, California has added more regulatory authority and more funding to help small disa

Since the state enacted the Human Right to Water Legislation (AB 685) eight years ago, California has added more regulatory authority and more funding to help small disadvantaged or severely disadvantaged community water systems. The California Water Resources Control Board (State Water Board) can order mandatory consolidation to merge failing community systems with another, higher-functioning water system. The State Water Board is authorized to issue an enforcement order to mandate that water systems meet water quality standards. Other recent legislation authorizes the State Water Board to designate an Interim Administrator to manage the system, improve it, or consolidate the water system with another. The newly enacted Safer and Affordable Funding for Equity and Resilience (SAFER) drinking water program calls for annual appropriation of $130 million dollars for ten years to address the problems of disadvantaged community water systems. This report identifies the 64 community water systems in Los Angeles County serving disadvantaged or severely disadvantaged populations.

The impacts of climate change on coastal groundwater

Nature Portfolio (Springer Nature) | January 11th, 2024

Coastal groundwater (CGW) is a critical water resource for many communities and can be a key part of coastal ecosystems. Owing to its location, CGW faces both terrestrial

Coastal groundwater (CGW) is a critical water resource for many communities and can be a key part of coastal ecosystems. Owing to its location, CGW faces both terrestrial and marine effects of climate change while simultaneously being impacted by anthropogenic activities. In this Review, we discuss the expected impacts of climate change on CGW and CGW-dependent ecosystems. Sea-level rise, coastal flooding increases and precipitation and aridity changes will drive alterations in the amount, chemistry and fluxes of CGW. Impacts could also arise from changes in storm and cyclone activity, land and ocean temperature rises, cryosphere melt, ocean chemistry and coastal erosion, but the overall effect is understudied. Human-induced stressors, such as groundwater extraction, will interact with climate change impacts to alter CGW at different temporal and spatial scales. CGW-associated ecosystems are expected to respond to changes in an ecosystem and site-specific manner — for example, some coastal temperate and tropical ecosystems might be more impacted by seawater intrusion owing to sea-level rise and coastal flooding, whereas others, such as coastal polar ecosystems, could be more affected by increases in cryosphere melt. A comprehensive and global CGW observatory programme is needed to better understand baseline CGW conditions, track change and support resource management.