Managing Freshwater Discharge to the San Francisco Bay/Sacramento-San Joaquin Delta Estuary―The Scientific Basis for an Estuarine Standard

San Francisco Estuary Project | October 26th, 1992

Aquatic resources of the Sacramento-San Joaquin Delta and upper portions of San Francisco Bay have undergone significant declines over the past several decades. Species c

Aquatic resources of the Sacramento-San Joaquin Delta and upper portions of San Francisco Bay have undergone significant declines over the past several decades. Species characteristic of the Delta and rivers, such as striped bass and salmon, began to decline during the late 1970s. Prolonged drought, large diversions of fresh water, and dramatic increases in populations of introduced aquatic species during the 1980s and 1990s brought a number of indigenous aquatic species to extremely low levels. Species that spend more of their lives downstream of the Delta, including Delta smelt, longfin smelt, and many zooplankton, maintained large populations through the 1970s, but declined sharply after the mid-1980s. Declines in aquatic resources have led to curtailed fishing seasons, to petitions for endangered species status, and general concern about the health of the estuarine ecosystem.

Mapping selected trace elements and major ions, 2000-2012, Mojave River and Morongo Groundwater Basins, Southwestern Mojave Desert, San Bernardino County, California

U.S. Geological Survey (USGS) | July 1st, 2015

The population of the Mojave River and Morongo groundwater basins has grown rapidly during the last several decades, increasing from an estimated population of almost 273

The population of the Mojave River and Morongo groundwater basins has grown rapidly during the last several decades, increasing from an estimated population of almost 273,000 in 1990 (Mojave Water Agency, 2004) to more than 453,000 in 2010 (Mojave Water Agency, 2014). Groundwater is the primary source of potable water in both basins (Mojave Water Agency, 2014). Previous studies noted elevated concentrations of several trace elements, nitrate, and total dissolved solids in groundwater in portions of the two basins (Christensen and Fields-Garland, 2001; Ball and Izbicki, 2004; Izbicki and others, 2008; Mathany and Belitz, 2009; Wright and Belitz, 2010; Dawson and Belitz, 2012; and Izbicki and others, 2012). Since 2000, the U.S. Geological Survey (USGS) has collected water-quality data annually from a network of wells and has provided quality-assurance for Mojave Water Agency (MWA) data that are stored in the USGS National Water Information System (NWIS) database. The new data and results from the joint State of California and USGS Groundwater Ambient Monitoring and Assessment (GAMA) program assessments of regional water quality (these data are also stored in NWIS), in combination with ongoing MWA/USGS groundwater-quality monitoring provide a timely opportunity for mapping of groundwater quality in the Mojave River and Morongo groundwater basins. The purpose of this report is to provide maps and time-series plots of concentrations of selected water-quality constituents (arsenic, boron, chromium-6, total chromium, dissolved oxygen, fluoride, iron, manganese, nitriate plus nitrite as nitrogen, total dissolved solids, uranium, and vanadium) in the Mojave River and Morongo groundwater basins using data collected by the USGS and MWA from 2000 to 2012. These maps and plots can be accessed on this website.

McMullin Area Groundwater Sustainability Agency Groundwater Sustainability Plan

McMullin Area Groundwater Sustainability Agency (MAGSA) | November 6th, 2019

Measuring Progress Toward Universal Access to Water and Sanitation in California: Defining Goals, Indicators, and Performance Measures

Pacific Institute | September 15th, 2018

In January 2018, over half a million Californians were served by water utilities that were out of compliance with the Safe Drinking Water Act (SDWA). The worst outbreak o

In January 2018, over half a million Californians were served by water utilities that were out of compliance with the Safe Drinking Water Act (SDWA). The worst outbreak of Hepatitis A in recent memory occurred in 2016-2018 due to open defecation and lack of handwashing facilities for persons experiencing homelessness. California’s tribes continue to face problems of poor housing and water and sanitation service, with two-thirds of tribal communities reporting inadequate home plumbing in 2015.1 And the cost of water has increased for many, particularly among small and medium size systems, with 39 community water systems in the state charging more than $100 a month for 12 CCF of water. In response to the problem, California enacted the Human Right to Water in 2012, declaring that “Every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes.”

Megapluvials in Southwestern North America

American Geophysical Union (AGU) | March 25th, 2025

Droughts over the last century in Southwestern North America (SWNA) have had severe consequences for people and ecosystems across the region, most recently during the ear

Droughts over the last century in Southwestern North America (SWNA) have had severe consequences for people and ecosystems across the region, most recently during the early 21st-century megadrought (2000–2022). The 20thcentury, however, was bracketed by two extended pluvials that also had significant impacts in the region. We use a 1,224 years (800–2023 CE) record of observed and reconstructed soil moisture, in concert with a paleoclimate reanalysis product, to place the 20th-century pluvials in a longer-term context and investigate the occurrence and dynamics of similar events in the Common Era.

Memorandum Report on the Floods of January and February 1969 in the Southern District of the Department of Water Resources

California Department of Water Resources (DWR) | February 27th, 1970

Merced Groundwater Subbasin Groundwater Sustainability Plan (Revised)

Merced Subbasin Groundwater Sustainability Agency (MSGSA) | July 6th, 2022

Due to size, this file has been divided into six part. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6

Due to size, this file has been divided into six part. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6

Mid-Kaweah Groundwater Sustainability Agency 2022 First Amended Groundwater Sustainability Plan

Mid-Kaweah Groundwater Sustainability Agency (MKGSA) | July 27th, 2022

Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9

Due to size, this file has been divided. Part 1, Part 2, Part 3, Part 4, Part 5, Part 6, Part 7, Part 8, Part 9

Midcoast Groundwater Study Phase III, San Mateo County, California

San Mateo County | June 4th, 2010

San Mateo County ‘Midcoast’ extends from northern Half Moon Bay to Devils Slide along Highway 1. It encompasses the communities of Montara, Moss Beach, Seal Cove, Pri

San Mateo County ‘Midcoast’ extends from northern Half Moon Bay to Devils Slide along Highway 1. It encompasses the communities of Montara, Moss Beach, Seal Cove, Princeton, El Granada, and Miramar. Domestic water is supplied to the southern part of the region by Coastside County Water District (CCWD), providing services from Half Moon Bay to Princeton, and by Montara Water and Sanitary District (MWSD) on the north, servicing Montara and Moss Beach. Private wells are scattered through both service districts and outlying areas. With the exception of CCWD, which meets much of its demand through long-term contractual agreements with San Francisco Public Utilities Commission, the source of domestic water is from local surface water and groundwater resources. The carrying capacity of the local resources may be considered as the population that can be sustained using conservation measures during an extended drought without undue stress to valued natural habitats.

Mojave Region Functionally Equivalent Storm Water Resources Plan

Mojave Water Agency (MWA) | October 4th, 2017

The State of California now recognizes the importance of incorporating storm water as a potential resource in a region’s water portfolio. Historically, storm water was

The State of California now recognizes the importance of incorporating storm water as a potential resource in a region’s water portfolio. Historically, storm water was thought of as a public risk (e.g., flooding) and a source of water quality impairment. Traditional approaches for storm water focused on diverting storm water into the storm drain system which ultimately and efficiently moved said water away from populated areas; the State is now supporting watershed-based approaches where storm water and dry weather runoff can yield benefits beyond flood control, such as water supply, water quality improvement, and habitat enhancement. To incentivize use of storm water, the State of California has linked storm water resources planning to state funding. Storm water and dry weather runoff capture projects seeking funding from any California bond act approved by voters after January 1, 2014 must be included in a Storm Water Resources Plan, which meets California Water Code. Regional water planning has a long history in the Mojave region. In 2005, agencies in the Mojave service area, that share a common concern for the area’s water resources, met and agreed to develop an Integrated Regional Water Management Plan (IRWMP). The Region’s first IRWMP identified, defined, and established strategies to capitalize on all water management opportunities that were present at that time or would become possible in the Mojave Region in the future. Since that time the IRWMP has acted as a forum for regular collaboration. The IRWMP is a living document and the regional objectives as well as strategies to improvement water management are regularly updated. The IRWMP was last updated in 2014. This Mojave Region Storm Water Resource Plan (SWRP) is an extension of the IRWMP process and is meant to bring an integrated and watershed-based approach to managing and creating benefits from storm water. This SWRP is regional and multi-agency. This SWRP includes all components required by the Water Code and will be submitted to the IRWM group. This SWRP will help entities in the Mojave Region identify, prioritize, and implement storm water projects.