The focus of this study is on analysis of existing hydrologic, chemical, and microbiological data; collection of surface-water and shallow ground-water hydrologic, chemical, and microbiological data; and characterization of dissolved organic carbon composition.
At the request of the U.S. Agency for International Development, USGS is helping regional partners manage scarce groundwater resources, and improve water supply, using artificial recharge methods.
Developing a Dynamic SPARROW Model to Evaluate Nutrient Loads, Sources, and Transport to the Upper Klamath Lake, USA
Phosphorous (P) and Nitrogen (N) loading from various sources of water to the Upper Klamath Lake (UKL) are important and potentially controllable factors for the hyper eutrophication of the lake. A total maximum daily load plan (TMDL) has been in place for over a decade to reduce the level of eutrophication and...
The potential impacts of suction dredging on water quality remain largely undetermined, especially with regard to trace metals including Hg. Several State of California regulatory agencies have expressed concerns that suction dredging may cause deleterious impacts with regard to turbidity and Hg contamination in downstream areas.
Determination of Mercury Loads for Cache Creek Settling Basin Inflow and Outflows and Related Investigations
Mercury (Hg), a legacy pollutant from mining of mercury deposits in the Coast Ranges as well as gold deposits in the Sierra Nevada, has contaminated surface waters throughout northern . Methylmercury (MeHg) is an organic form of Hg that bioaccumulates in food webs to elevated concentrations that threaten ecological health and human health through consumption of sport fish.
Statistical Evaluation of Factors Affecting Occurrence of Organic Constituents from Fuels in Public-Supply Wells in Southern California
Biofuels, including ethanol, are expected to provide a greater contribution to the fuel supply in the United States. Research in the past decade has shown that ethanol in gasoline can cause plumes of benzene in groundwater to be larger than they would otherwise be.
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 U.S. Army Corps of Engineers (USACE) is conducting a hydrologic analysis of floodplain areas protected by the federal-state levee system within the San Joaquin-Sacramento drainage basins.
The State Water Resources Control Board (SWRCB) of California has initiated a process to develop biological objectives for wadeable freshwater streams and rivers for the entire state.
The CALFED Science Program funded a multi-party effort that worked from 2003-2005 to collect field data at six wetland sites spanning the estuarine salinity gradient from the western Delta to the North Bay. The project sought to address the question of how tidal marsh restoration efforts through the bay and delta affect ecosystem processes at different scales.
Historical water-chemistry data will be used in conjunction with data collected as part of this study. Water chemistry samples will be collected from monitoring wells installed as part of this study, including two multiple-well monitoring sites (monitoring different depths in the aquifer) and eight shallow monitoring wells. Samples will also be collected from about 15 existing wells (locations...
Groundwater is the main source of water in the San Antonio Creek Valley. Demand for groundwater in the predominantly rural valley has increased significantly because of the establishment of extensive irrigated agriculture on formerly non-irrigated land. Groundwater withdrawals have resulted in measured water-level declines ranging from 35 to more than 100 feet since the 1950s. There is concern...