Groundwater

An operational model for Salinas Valley is needed to evaluate and compare ecosystem, conservation, and water demands. This model must simulate current operations, assess benefits of and evaluate scenarios for tunnel operation and potential reservoir and spillway modifications.

The USGS seeks to increase understanding of the groundwater system in the vicinity of the Lower Colorado Water Supply Project well field and to estimate future groundwater levels and total dissolved solids concentrations in the wells and the long-term viability of the Lower Colorado Water Supply Project.

The USGS closely monitors the effects of drought through data collection and research. USGS science supports water managers in preparing for possible future drought by providing information that takes into account long-term hydrologic, climatic, and environmental changes. These studies support successful planning and science-based decision-making by water managers who must address complex issues...

The Los Angeles Coastal Plain Groundwater-flow Model (LACPGM) is a tool to help water managers better understand groundwater flow and seawater intrusion in the Los Angeles coastal plain basins. It is the culmination of years of data collection and studies in the area and builds on our understanding of the area’s geology and hydrology obtained through the geologic and groundwater flow models.

To help the U.S. Bureau of Land Management determine the long-term sustainability of the San Sebastian Marsh, and its critical role for the survival of the endangered desert pupfish (Cyprinodon macularius), the USGS is evaluating the potential interactions and relation between groundwater and surface water at the San Sebastian Marsh.

In cooperation with Air Force Civil Engineer Center (AFCEC), the U.S. Geological Survey (USGS) is evaluating the hydrogeology of the Air Force Research Laboratory (AFRL) and Site 25 areas of Edwards Air Force Base (EAFB) and the adjacent North-Muroc groundwater subbasin to help determine regional groundwater movement and the possible long-term movement and pathways of contaminated water from the...

Stakeholders in San Luis Obispo County are concerned that the increased demand for water use has, and will continue to, affect groundwater levels and availability in the Adelaida area. To address stakeholder concerns, the County of San Luis Obispo Board of Supervisors has asked the USGS to conduct a comprehensive evaluation of groundwater resources of the Adelaida area.

The MODFLOW One-Water Hydrologic Flow Model (MF-OWHM) – Conjunctive Use Simulation Software (Boyce, 2022; Boyce and others, 2020; Hanson and others, 2014) builds upon the MODFLOW-2005 framework for the simulation and analyses of conjunctive-use, water-management, and climate-crop-water scenario problems.

Groundwater is the sole source for water use to the rural community and two Native American tribes in the Cahuilla Valley and Terwilliger Valley groundwater basins, which are located approximately 35 miles southwest of Palm Springs, California. The characteristics and sustainable yield of the basins are not well understood and are threatened by increasing water use and potential changes in water...

Extensive groundwater withdrawals from aquifer systems have caused land subsidence in many California basins. Land subsidence can cause infrastructure damage, not only to buildings and roads but also to water conveyence systems. Groundwater-level and land-subsidence monitoring provide the information needed to guide mitigation efforts and management of future effects.

This is the first comprehensive geologic and hydrologic study for the San Diego area. This study will provide the integrated hydrogeologic knowledge necessary in this important and highly visible area of the United States and will serve as a role model for similar coastal settings throughout the world that have modest rainfall and small aquifers. Locally, results will help state and federal...

The Groundwater Ambient Monitoring and Assessment Program’s Priority Basin Project (GAMA-PBP) was established by the California State Water Resources Control Board (SWRCB) in response to the Ground-Water Quality Monitoring Act of 2001 (Sections 10780-10782.3 of the California Water Code). The USGS is the technical lead for the GAMA-PBP and between 2004-2012 focused on characterizing the quality of...