South Coast

National-Scale Flood Hazard Data Unfit for Urban Risk Management

American Geophysical Union (AGU) | July 19th, 2024

Navigating Transformations in 2023: The Metropolitan Water District of Southern California Year in Review

Metropolitan Water District of Southern California (MWD) | April 13th, 2024

Near-term Colorado River Operations Draft Supplemental Environmental Impact Statement

U.S. Bureau of Reclamation (USBR) | April 11th, 2023

Reclamation is proposing revising the 2007 Interim Guidelines for the near-term operation of Glen Canyon and Hoover Dams beginning in the 2024 operating year (beginning O

Reclamation is proposing revising the 2007 Interim Guidelines for the near-term operation of Glen Canyon and Hoover Dams beginning in the 2024 operating year (beginning October 1, 2023) to address the potential for continued low-runoff conditions in the Basin.

Near-term Colorado River Operations Revised Draft Supplemental Environmental Impact Statement

U.S. Bureau of Reclamation (USBR) | October 26th, 2023

Reclamation is proposing to revise the 2007 Interim Guidelines for the operation of Glen Canyon and Hoover Dams beginning in the 2024 operating year to address the potent

Reclamation is proposing to revise the 2007 Interim Guidelines for the operation of Glen Canyon and Hoover Dams beginning in the 2024 operating year to address the potential for continued low-runoff conditions in the Colorado River Basin. The potential impacts of low runoff conditions in the remainder of the interim period (prior to January 1, 2027) pose unacceptable risks to routine operations of Glen Canyon and Hoover Dams; therefore, modified operating guidelines should be expeditiously developed. Due to size, this file has been divided. Part one, Part two.

Nearly a Million Californians Lack Access to Safe Drinking Water

State of California | July 26th, 2022

Our audit of the State Water Board’s efforts to help provide Californians with safe drinking water highlighted the following: More than 370 of the State’s water

Our audit of the State Water Board’s efforts to help provide Californians with safe drinking water highlighted the following: More than 370 of the State’s water systems, serving nearly a million Californians, exceed the maximum contaminant levels for substances that are harmful to human health. More than 150 of these systems have been failing for at least five years. Hundreds of additional water systems are currently at risk of failing. The State Water Board has not prioritized the processing of water systems’ funding applications so that the systems can improve their water quality. Over the past five years, the average length of time for water systems to complete their applications and receive funding nearly doubled, from 17 months to 33 months. The State Water Board has not established performance goals or metrics related to its cumbersome application process. Although the State Water Board provides water systems with technical assistance to plan their improvements and apply for funds, it has not adequately monitored the performance of the technical assistance providers with which it contracts. The State Water Board needs to better ensure that its staff and its contracted providers do not duplicate each other’s outreach efforts.

New and Emerging Technologies for Sustainable Fisheries: A Comprehensive Landscape Analysis

Environmental Defense Fund (EDF) | April 1st, 2021

The oceans are at an inflection point. The excesses of the 20th century — over-exploitation of most of our accessible biological resources, over-pollution by plastics a

The oceans are at an inflection point. The excesses of the 20th century — over-exploitation of most of our accessible biological resources, over-pollution by plastics and other chemicals, over-crowding of coastal and marine space by unorganized and competing interests and over-capitalization of extractive industries — are being tempered by a rapidly growing realization that these excesses are having very real consequences, not just for marine life and ocean ecosystems, but for the food security and nutrition of the world’s population, the livelihoods of the communities that depend on the ocean and the very future of humanity itself. 

NPDES Stormwater Cost Survey

California State Water Resources Control Board (SWRCB) | January 4th, 2005

Task A – Documenting Stormwater Program Costs  Five California municipalities and one metropolitan area with stormwater programs that are demonstrating meaningful

Task A – Documenting Stormwater Program Costs  Five California municipalities and one metropolitan area with stormwater programs that are demonstrating meaningful progress toward maximum extent practicable (MEP) compliance as identified by Regional Water Quality Control Board (RWQCB) staff were surveyed for the most recent stormwater compliance costs. Demonstrating meaningful progress is defined in this report as implementing activities specifically presented in the Storm Water Management Plans (SWMPs). Because permits use an iterative approach that increases requirements until water quality objectives are met, current levels of implementation may not be the ultimate MEP standard. This report does not address the benefits of permit compliance activities. Some scenarios addressing ultimate compliance cost are addressed in Task B. Task A was accomplished by the Office of Water Programs (OWP) at California State University, Sacramento (CSUS). Task B – Alternative Approaches to Stormwater Quality Control Task B is an assessment of regulatory policy to determine the intent of stormwater regulation regarding advanced treatment. Alternatives for stormwater quality control that are believed to comply with the intent of the regulations are described. Costs were estimated for the Los Angeles Regional Water Quality Control Board (LARWQCB) area. Task B was accomplished by the University of Southern California (USC) and the University of California at Los Angeles (UCLA).

Numerical Simulation of Ground-Water Flow and Assessment of the Effects of Artificial Recharge in the Rialto–Colton Basin, San Bernardino County, California

U.S. Geological Survey (USGS) | July 1st, 2001

Oases of the future? Springs as potential hydrologic refugia in drying climates

Ecological Society of America (Wiley) | June 1st, 2020

Natural springs in water‐limited landscapes are biodiversity hotspots and keystone ecosystems that have a disproportionate influence on surrounding landscapes despite t

Natural springs in water‐limited landscapes are biodiversity hotspots and keystone ecosystems that have a disproportionate influence on surrounding landscapes despite their usually small size. Some springs served as evolutionary refugia during previous climate drying, supporting relict species in isolated habitats. Understanding whether springs will provide hydrologic refugia from future climate change is important to biodiversity conservation but is complicated by hydrologic variability among springs, data limitations, and multiple non‐climate threats to groundwater‐dependent ecosystems. We present a conceptual framework for categorizing springs as potentially stable, relative, or transient hydrologic refugia in a drying climate. Clues about the refugial capacity of springs can be assembled from various approaches, including citizen‐science‐powered ecohydrologic monitoring, remote sensing, landowner interviews, and environmental tracer analysis. Managers can integrate multiple lines of evidence to predict which springs may become future refugia for species of concern, strengthening the long‐term effectiveness of their conservation and restoration, and informing climate adaptation for terrestrial and freshwater species.

Observed and projected changes in snow accumulation and snowline in California’s snowy mountains

Climate Dynamics (Springer) | May 25th, 2023

The Sierra Nevada and Southern Cascades—California’s snowy mountains—are primary freshwater sources and natural reservoirs for the states of California and Nevada.

The Sierra Nevada and Southern Cascades—California’s snowy mountains—are primary freshwater sources and natural reservoirs for the states of California and Nevada. These mountains receive precipitation overwhelmingly from wintertime storms including atmospheric rivers (ARs), much of it falling as snow at the higher elevations. Using a seven-decade record of daily observed temperature and precipitation as well as a snow reanalysis and downscaled climate projections, we documented historical and future changes in snow accumulation and snowlines. In four key subregions of California’s snowy mountains, we quantified the progressing contribution of ARs and non-AR storms to the evolving and projected snow accumulation and snowlines (elevation of the snow-to-rain transition), exploring their climatology, variability and trends. Historically, snow makes up roughly a third of the precipitation affecting California’s mountains. While ARs make up only a quarter of all precipitating days and, due to their relative warmth, produce snowlines higher than do other storms, they contribute over 40% of the total seasonal snow. Under projected unabated warming, snow accumulation would decline to less than half of historical by the late twenty-first century, with the greatest snow loss at mid elevations (from 1500 to 3300 m by the mountain sub-regions) during fall and spring. Central and Southern Sierra Nevada peaks above 3400 m might see occasionally extreme snow accumulations in January–February resulting entirely from wetter ARs. AR-related snowlines are projected to increase by more than 700 m, compared to about 500 m for other storms. We discuss likely impacts of the changing climate for water resources as well as for winter recreation.