South Coast

Economics of a State Water Resources Program

Legislative Analyst's Office (LAO) | July 9th, 1957

Effect of passive integrated transponder tag size on survival, tag loss, and growth of Santa Ana Sucker

American Fisheries Society (AFS) | December 30th, 2025

The Santa Ana Sucker Pantosteus santaanae is endemic to southern California and is listed as threatened under the U.S. Endangered Species Act. Seasonal limitations on con

The Santa Ana Sucker Pantosteus santaanae is endemic to southern California and is listed as threatened under the U.S. Endangered Species Act. Seasonal limitations on conventional sampling and inconsistencies in survey methodologies have led to an incomplete understanding of population dynamics. Alternative sampling methods have the potential to fill important knowledge gaps in biology and life history. One option is to use passive integrated transponder (PIT) tags to identify individuals and track their movements. The objective of this study was to test the effect of PIT tag size on survival, tag loss, and growth of Santa Ana Suckers.

Effective at Any Scale: Watershed-based Decision Support Tools

San Francisco Estuary Institute (SFEI) | July 1st, 2016

EcoAtlas  tools apply the USEPA’s three-level wetland monitoring and assessment framework for wetland and stream protection in a variety of California watersheds, an

EcoAtlas  tools apply the USEPA’s three-level wetland monitoring and assessment framework for wetland and stream protection in a variety of California watersheds, and it can be adjusted to more generally support natural resource planning, assessment, monitoring, and reporting. EcoAtlas operationalizes the Wetland and Riparian Area Monitoring Plan (WRAMP) by enabling users to assess the abundance, distribution, diversity, and condition of wetlands in the landscape or watershed context.

Effects of imported recharge on fluoride trends in groundwater used for public supply in California

Science of the Total Environment (Elsevier) | March 31st, 2022

Fluoride is a naturally occurring element in groundwater that supports bone and dental health at low concentrations but can cause health problems at elevated concentrati

Fluoride is a naturally occurring element in groundwater that supports bone and dental health at low concentrations but can cause health problems at elevated concentrations in drinking water. This study investigates spatial and temporal trends for fluoride concentrations in untreated groundwater from over 20,000 public supply wells in California. The presence of a significant temporal trend in fluoride concentrations in a well was assessed using the Mann-Kendall test and a spatial-weighting approach was used to identify the areal extent of the groundwater resources with significant trends. Less than 2% of the groundwater resources used for public supply in the state have concentrations above the California maximum contaminant level of 2 mg/L. Approximately 14% of the groundwater resource used for public supply show a significant recent trend (2000–2019), with decreasing trends occurring in 10%of the resource. Potential drivers for trends were evaluated in two of the areas in southern California with the greatest prevalence of trends but distinct climate and hydrogeological characteristics. Aquifers in the Mojave and Whitewater River watersheds, located in the desert region, and the Los Angeles Basin, located on the coast, have been replenished with imported and treated water over the last half century to maintain sustainable groundwater levels. The recharge of imported water with different chemistries has altered the geochemical conditions in the aquifers, driving changes in fluoride concentrations.

Effects of Sea‐Level Rise on Ground Water Flow in a Coastal Aquifer System

National Groundwater Association (NGWA) | January 29th, 2007

The effects of sea‐level rise on the depth to the fresh water/salt water interface were simulated by using a density‐dependent, three‐dimensional numerical ground w

The effects of sea‐level rise on the depth to the fresh water/salt water interface were simulated by using a density‐dependent, three‐dimensional numerical ground water flow model for a simplified hypothetical fresh water lens that is similar to shallow, coastal aquifers found along the Atlantic coast of the United States. Simulations of sea‐level rise of 2.65 mm/year from 1929 to 2050 resulted in an increase in water levels relative to a fixed datum, yet a net decrease in water levels relative to the increased sea‐level position. The net decrease in water levels was much greater near a gaining stream than farther from the stream. The difference in the change in water levels is attributed to the dampening effect of the stream on water level changes in response to sea‐level rise. In response to the decreased water level altitudes relative to local sea level, the depth to the fresh water/salt water interface decreased. This reduction in the thickness of the fresh water lens varied throughout the aquifer and was greatly affected by proximity to a ground water fed stream and whether the stream was tidally influenced. Away from the stream, the thickness of the fresh water lens decreased by about 2% from 1929 to 2050, whereas the fresh water lens thickness decreased by about 22% to 31% for the same period near the stream, depending on whether the stream was tidally influenced. The difference in the change in the fresh water/salt water interface position is controlled by the difference in the net decline in water levels relative to local sea level.

Effects of wildfire on benthic macroinvertebrate assemblages in Southern California streams and implications for bioassessment monitoring programs

California State Water Resources Control Board (SWRCB) | June 13th, 2012

Wildfires are common in arid regions of southern California, sometimes burning as much as half a million acres in a season. These fires often cause dramatic impacts to th

Wildfires are common in arid regions of southern California, sometimes burning as much as half a million acres in a season. These fires often cause dramatic impacts to the vegetation and soils of regional watersheds and, consequently, to the streams that drain them. Water quality programs that monitor and regulate these systems have to account for the influence of these factors upon water quality measurements when making monitoring and regulatory decisions. This is true for traditional water quality measures (nutrients, metals, contaminants, etc.), but is especially important for integrative ecological condition indicators like bioassessment, the use of resident biological communities to infer water quality condition.

Efficient Water Use in California: Water Rights, Water Districts, and Water Transfers

Rand Corporation (Rand) | November 13th, 1978

Elsinore Valley Subbasin Groundwater Sustainability Plan

Elsinore Valley Municipal Water District | December 23rd, 2021

The Elsinore Valley Subbasin is located within the service area of Elsinore Valley Municipal Water District (EVMWD or District). No other agencies overlap the boundaries

The Elsinore Valley Subbasin is located within the service area of Elsinore Valley Municipal Water District (EVMWD or District). No other agencies overlap the boundaries of this subbasin therefore no inter-agency coordination was required for the development of this GSP. Two outside technical experts participated as the technical advisory committee for the GSP development. EVMWD conducted public outreach throughout the development of the GSP.

Emergency Measures to Provde Water Resources in California and Improve Disaster Response in Certain Areas

The White House | January 24th, 2025

Emerging understanding of the potential role of seagrass and kelp as an ocean acidification management tool in California

California Ocean Science Trust (OST) | January 2nd, 2018

This report was produced by the OPC-SAT working group and Ocean Science Trust on behalf of the Ocean Protection Council (OPC) and the broader community of California man

This report was produced by the OPC-SAT working group and Ocean Science Trust on behalf of the Ocean Protection Council (OPC) and the broader community of California managers with the aim of: • communicating emerging scientific understanding of the ability of seagrass and macroalgae (kelps) to ameliorate ocean acidification (OA) in a California-specific context, • summarizing knowledge gaps and opportunities for filling them through research and monitoring, and • providing guidance on next steps for the State as it considers future nature-based actions to reduce the negative impacts of OA in California and beyond.