Water Use

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.

As a result of climate change, heavy rainfall, as well as extended dry periods, are becoming more common in the Midwestern United States. These trends are only expected to continue. So, increasing the capacity of soil to store water has become more critical. Storing water increases availability in dry conditions. And the absorption of additional water in wet conditions reduces potential flooding...

The Owens Valley, a long, narrow valley along the east side of the Sierra Nevada in east-central California, is the main source of water for the city of Los Angeles. The city diverts most of the surface water in the valley into the Owens River-Los Angeles Aqueduct system, which transports the water more than 200 miles south to areas of distribution and use. Additionally, ground water is pumped or...

In 2014, the State of California adopted historic legislation to help manage its groundwater, the Sustainable Groundwater Management Act (SGMA) . According to the act, local Groundwater Sustainability Agencies (GSAs) must be formed for all high and medium priority basins in the state. These GSAs must develop and implement Groundwater Sustainability Plans (GSPs) for managing and using groundwater...

Project Update - 8/2/2011: Water having an arsenic concentration of 30 micrograms per liter was infiltrated from a test pond beginning in December, 2010. After water moved downward through the unsaturated zone, arsenic concentrations in Lysimeters as deep as 110 ft beneath the pond were about 2 micrograms per liter. Laboratory column experiments show similar changes in arsenic concentrations in...

The U.S. Army at Fort Irwin National Training Center (NTC) obtains all of its potable water supply from Irwin, Langford, and Bicycle Basins within the base boundaries. Groundwater pumping, since as early as 1941, has resulted in water-level declines in all of these basins and the disposal of treated wastewater in the Irwin Basin has resulted in elevated nitrate concentrations in some wells in...

The Fena Valley Reservoir, located in southern Guam, is the primary source of water for the United States Naval Base Guam and nearby village residents. At full capacity, the reservoir surface area extends approximately 0.30 mi 2, and drains a watershed area of about 5.88 mi 2. After reservoir construction, periodic bathymetric surveys, coupled with sedimentation models, can be used to produce...

The Mountains Recreation and Conservation Authority (MRCA) is considering plans for developing a new park at the confluence of the Los Angeles River and the Arroyo Seco. These plans include removing channel lining and creating a temporary lake using an inflatable rubber dam. Before implementing the plan, a wide array of scientific and engineering issues must be addressed. The U.S. Geological...

Mercury is a rare, dense metal, slightly more common than gold in the earth's crust. Mercury occurs in several different forms, the most important of which is methylmercury. Methylmercury is the form most readily incorporated into biological tissues and most toxic to humans. Methylmercury accumulates and biomagnifies in the food chain, reaching highest concentrations in predatory fish such as bass...

Groundwater pumpage for agricultural and municipal supply has resulted in water-level declines of more than 200 ft in some parts of the Antelope Valley groundwater basin and land subsidence of more than 6 ft in some areas. Future urban growth, increased agricultural demand, and limits on the supply of imported water will continue to increase the demand for 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...