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.

The implications of drought and water conservation on the reuse of municipal wastewater: Recognizing impacts and identifying mitigation possibilities

Water Research, Elsevier | November 1st, 2017

As water agencies continue to investigate opportunities to increase resilience and local water supply reliability in the face of drought and rising water scarcity, wa

As water agencies continue to investigate opportunities to increase resilience and local water supply reliability in the face of drought and rising water scarcity, water conservation strategies and the reuse of treated municipal wastewater are garnering significant attention and adoption. Yet a simple water balance thought experiment illustrates that drought, and the conservation strategies that are often enacted in response to it, both likely limit the role reuse may play in improving local water supply reliability. For instance, as a particular drought progresses and agencies enact water conservation measures to cope with drought, influent flows likely decrease while influent pollution concentrations increase, particularly salinity, which adversely affects wastewater treatment plant (WWTP) costs and effluent quality and flow. Consequently, downstream uses of this effluent, whether to maintain streamflow and quality, groundwater recharge, or irrigationmay be impacted. This is unfortunate since reuse is often heralded as a drought-proof mechanism to increase resilience. The objectives of this paper are two-fold. First, we illustrate—using a case study from Southern California during its most recent drought— how drought and water conservation strategies combine to reduce influent flow and quality and, subsequently, effluent flow and quality. Second, we use a recently developed regional water reuse decision support model (RWRM) to highlight cost-effective strategies that can be implemented to mitigate the impacts of drought on effluent water quality. While the solutions we identify cannot increase the flow of influent or effluent coming into or out of a treatment plant, they can improve the value of the remaining effluent in a cost-effective manner that takes into account the characteristics of its demand, whether it be for landscaping, golf courses, agricultural irrigation, or surface water augmentation.