Publications

Estimates of nonpoint and point sources of nitrogen were made for 107 watersheds located in the U.S. Geological Survey's National Water-Quality Assessment Program study units throughout the conterminous United States. The proportions of nitrogen originating from fertilizer, manure, atmospheric deposition, sewage, and industrial sources were found to vary with climate, hydrologic conditions, land u

Thick unsaturated zones in arid regions increasingly are being sought for the burial of radioactive and other hazardous wastes. Estimating percolation rates of water from precipitation at proposed burial sites is important for site assessment. Chloride profiles in unsaturated sediments are used to show differences and similarities in the rates of percolation at two sites in the Mojave Desert of so

The Minnesota River, 10 major tributaries, and 21 springs were sampled to determine the sources and transport of sediment, nutrients, and oxygen- demanding substances. The study was part of a four-year assessment of non-point source pollution in the Minnesota River Basin. Runoff from tributary watersheds was identified as the primary source of suspended sediment and nutrients in the Minnesota Rive

Historical scour data were collected by means of geophysical techniques and used to evaluate the scour-computation procedures recommended by the U.S. Federal Highway Administration and 12 other pub- lished pier-scour equations. Geophysical data were collected at 10 bridges in Indiana. For this evaluation it was assumed that the historical scour measured by use of geophysical techniques was associa

The Navy Ships Parts Control Center near Mechanicsburg, Pa., occupies an area of 824 acres, of which 358 are covered by impervious surfaces. Most of the impervious area is drained by stormwater systems that discharge to an open channel that extends about 7,900 feet from its headwaters to its confluence with Trindle Spring Run. The channel drains an area of 992 acres, of which 435 are covered by im

In this study, turbidity is used to help explain spatial and temporal patterns of erosion and sediment transport.Automated turbidity sampling in streams in the Bull Run watershed during water years 1989 and 1990, showed turbidity levels, in general, are remarkably low, with levels below 1 NTU (nephelometric turbidity unit) about 90 percent of the time. However, ephemeral increases in turbidity in

Discharge and water-quality data collected in two adjacent karst-spring basins in Cumberland County, Pa., from May 1990 through April 1991 were used to (1) describe the hydrogeology of the area; (2) determine the concentrations of selected herbicides, herbicide-soil metabolites, and nutrients in water from wells and discharges from springs, (3) determine herbicide and nutrient discharges from spri

The effects of flood-detention reservoirs on peak discharges along downstream reaches in six urban drainage basins in Gwinnett County, Georgia, were studied during 1986-93 using the U.S. Geological Survey's Distributed Routing Rainfall-Runoff Model (DR3M). Short-term rainfall-runoff data were collected at selected stations in six urban drainage basins in Gwinnett County. The basins range in size f

Operation of the Garrison Diversion Unit may have some affect on the hydrology of the James River in North Dakota and South Dakota. The Garrison Diversion Unit Monthly Operations Model was developed to analyze a wide range of streamflow conditions that could occur in the James River Basin. The purpose of this study was to compute monthly streamflows that are required as input to the model.Historic

Johnson Creek flows through a basin of approximately 51 square miles with mixed land uses over a reach of approximately 24 river miles from southeast of Gresham, Oregon, to its confluence with the Willamette River in Milwaukie, Oregon. Land uses within the basin include forested and agricultural lands, suburban residential, urban, and light industrial. Surface runoff and ground-water flow from the

Changes in water levels in the High Plains aquifet underlying parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming result from the variability of precipitation, land use, and ground-water withdrawals. From the beginning of development of the High Plains aquifer to 1980, water levels declined throughout much of the area; the declines exceeded 100 feet in parts

Water and streambed-sediment samples were collected on March 9 and 10,1987 from one site upstream and three sites downstream of the discharge from a municipal wastewater-treatment plant on Rowlett Creek near Dallas, Texas. To extract and separate organic compounds, purgeand-trap, closed-loop stripping, and pH-adjusted solvent extraction methods were used for water samples; and a Soxhlet-solvent ex