Publications

The delta smelt (Hypomesus transpacificus) is listed as a threatened species under both the Federal Endangered Species Act (FESA) and the California Endangered Species Act. Through formal consultation under Section 7 of the FESA, USBR and DWR received a Biological Opinion from the USFWS, which allows for the incidental take of delta smelt arising through operation of the Central Valley Project and

Water samples from 27 wells completed in and near the Shell Valley aquifer were analyzed for benzene, toluene, ethylbenzene, and xylene (BTEX), polynuclear aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), and pentachlorophenol (PCP) using the enzyme-linked immunoassay method. The analyses indicated the presence of PAH, PCB, and PCP in the study area. However, an individual compound at

In practical terms, water use is divided into two basic types: instream use and offstream use. Instream use is water used in its natural channel, basin, or behind a dam and includes activities such as fishing, boating, and other recreational activities. Instream use also includes hydroelectric power generation. Off-stream use is water pumped or diverted from its natural channel, basin, or aquifer.

No abstract available.

An integrated assessment of the water quality in streams and aquifers in the Wapsipinicon, Iowa, Cedar, and Skunk River basins was conducted in 1996 through 1998 as part of the Eastern Iowa Basins (EIWA) study unit of the U.S. Geological Survey's National Water-Quality Assessment Program (NAWQA). The EIWA study unit is one of 59 study units across the Nation designed to assess the status and trend

During the first cycle of the National Water Quality Assessment (1992–1996), ground water in 20 of the nation's major hydro-logic basins was analyzed for 90 pesticide compounds (pesticides and degradates). One or more of the pesticide compounds examined were detected at 48.4% of the 2485 ground water sites sampled. However, approximately 70% of the sites where pesticides were detected, two or more

This special issue is devoted to recent and ongoing research relating to the fate and transport of agricultural chemicals in the Mississippi River Basin by the US Geological Survey Toxic Substances Hydrology (Toxics) Program. The Mississippi River Basin drains approximately 3 200 000 km2 representing 41% of the United States. This is the largest river in the United States and the third largest in

Analyses of water samples collected from the Mississippi River at Baton Rouge, Louisiana, during 1991–1997 indicate that hundreds of metric tons of herbicides and herbicide metabolites are being discharged annually to the Gulf of Mexico. Atrazine, metolachlor, and the ethane-sulfonic acid metabolite of alachlor (alachlor ESA) were the most frequently detected herbicides and, in general, were prese

Analysis of in-bottle digestate by using the inductively coupled plasma?mass spectrometric (ICP?MS) method has been expanded to include arsenic, boron, and vanadium. Whole-water samples are digested by using either the hydrochloric acid in-bottle digestion procedure or the nitric acid in-bottle digestion procedure. When the hydrochloric acid in-bottle digestion procedure is used, chloride

The role of the tropics in global climate change during glacial cycles is hotly debated in paleoclimate cycles today. Records from South America have not provided a clear picture of tropical climate change. In his Perspective, Betancourt highlights the study by Maslin and Burns, who have deduced the outflow of the Amazon over the past 14,000 years. This may serve as a proxy that integrates hydrolo

Annual State reporting requirements yield data on public water-supply use in Kansas. data is essential for responsible and effective use of the information by various State agencies. This fact sheet describes water-use data evaluation, illustrates variations in public-supply water use from 1987 through 1997, and documents improvements in water conservation efforts among Kansas public water supplie

Analyses of water samples collected over a 5-year period (1993-98) in the Mill Creek and Muddy Run Basins during implementation of agricultural best-management practices (BMP’s) indicate statistically significant trends in the concentrations of several nutrient species and in nonfilterable residue (suspended solids). The strongest trends identified were those indicated by a more than 50- percent d