Groundwater

The Central and West Coast groundwater basins provide nearly a third of the water supply to 43 cities in southern Los Angeles County. Over 250,000 afy are pumped from the basins for municipal and industrial use. To properly manage the ground-water resource and to ensure its future availability, it is necessary to identify and manage threats to the drinking water aquifers from surface contamination...

Two key hydrologic issues in all coastal aquifer systems are the delineation and the management of the renewable water resources. The proper development and management of the renewable resources helps to minimize ground-water mining of the lower aquifer systems, and minimizes overdraft and seawater intrusion of the upper aquifer system while maximizing the sustainable yield of the renewable water...

The USGS California Water Science Center is working in partnership with state and federal agencies to answer the following questions about oil and gas development and groundwater resources:

Strategies for managing local water supplies and ground-water quality are being formulated and evaluated by the Stanislaus-Tuolumne River Groundwater Basin Association (STRGBA).

Prior to 1997, local surface water and groundwater supplied all of the water supply for the city of Santa Barbara (about 120 miles northwest of Los Angeles). Excess pumping of groundwater during times of drought resulted in saltwater intrusion in Storage Unit I of the Santa Barbara groundwater basin.

Our objective is to determine the effectiveness of coagulation and adsorption techniques in removing mercury from contaminated surface waters of the Cache Creek watershed.

The USGS partners with local, state, and other federal agencies through cooperative agreements for a variety of reasons. The USGS and partners jointly plan the scientific work conducted under cooperative agreements resulting in science that has broad relevance to address current water issues. Partners choose to work with the USGS because of the agency's broad technical expertise, its long-standing...

Land subsidence has been ongoing in the dry lake beds throughout the Mojave and Morongo groundwater basins since the 1960s. In a study conducted from 2004 - 2009, continuous GPS stations were added to interferometric synthetic aperture radar (InSAR) methods to measure changes in land surface altitude.

Groundwater is an important water-supply source in the Coachella Valley. The demand for water has exceeded the deliveries of imported surface water, and groundwater levels have been declining as a result of increased pumping. A network of GPS stations has been set up in the valley to monitor subsidence resulting from declining groundwater levels.

A numerical modeling approach was used to quantify groundwater conditions and land subsidence spatially along the Delta-Mendota Canal. In addition, selected management alternatives for controlling land subsidence were evaluated.

The objective of this study is to provide downscaled ensemble projections of climate and hydrology for the next century for the state of California with specific application to the San Francisco Bay Area.

In areas adjacent to the Delta-Mendota Canal (DMC), extensive groundwater withdrawal from the San Joaquin Valley aquifer system has caused areas of the ground to sink as much as 10 feet, a process known as land subsidence. This could result in serious operational and structural issues for the Delta-Mendota Canal (DMC). In response, the USGS is studying and providing information on groundwater...