Publications

The U.S. Geological Survey began full implementation of the National Water-Quality Assessment (NAWQA) program in 1991. The long-term goals of the NAWQA program are to (1) describe current water-quality conditions for a large part of the Nation's freshwater streams, rivers, and aquifers; (2) describe how water quality is changing over time; and (3) improve understanding of the primary natural and h

Samples of the alpine and subalpine snowpack were collected in and near the headwater basins of the Yampa River in northwestern Colorado during maximum annual accumulation of snowpack in spring 1995. Sampling protocol at seven selected sites at more than 2,500 meters above sea level divided the snowpack into two distinct strata to enable separate chemical analyses of upper and lower layers of the

Surface water draining granitic bedrock in Yosemite National Park exhibits considerable variability in chemical composition, despite the relative homogeneity of bedrock chemistry. Other geological factors, including the jointing and distribution of glacial till, appear to exert strong controls on water composition.  Chemical data from three surface water surveys in the upper Merced River basin con

Salinity, or the dissolved-solids concentration, is the measure of salts such as sodium chloride, calcium bicarbonate, and calcium sulfate that are dissolved in water. About one-half of the salinity in the Colorado River Basin is from natural sources (U.S. Department of the Interior, 1995), such as thermal springs in the Glenwood-Dotsero area, located about 90 miles upstream from Grand Junction (f

As part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program, an inventory of the biological and contaminant investigations for the Upper Colorado River Basin study unit was conducted. To enhance the sampling design for the biological component of the program, previous studies about the ecology of aquatic organisms and contaminants were compiled from computerized liter

The effect of flow on release rates of solutes from soil in a 39-m2 alpine catchment in the Colorado Rockies was measured during the summers of 1990-1994. Flow rates through the soil were varied by augmenting natural rainfall with deionized irrigation water. Daily water inputs averaged between 96 and 216 1 day-1 during the five field seasons, and mean discharge (inputs minus evapotranspiration) va

The geochemical processes controlling the behavior of stable Pb, 210Pb, and 210po in seasonally anoxic Lake Sammamish, Washington were identified from water column distributions and box model calculations. Total (sum of dissolved and particulate) inventories of stable Pb, 210Pb, and 210Po increased in the whole lake during the latter part of the oxic stage of the lake and were attributed to diffus

The spatial data in geographic information system format described in this report consist of estimates for all counties in the conterminous United States of the annual use of 96 herbicides in 1989; annual sales of nitrogen fertilizer, in tons, for 1985-91; and agricultural expenses, land use, chemical use, livestock holdings, and cropping practices in 1987. The source information, originally in ta

No abstract available.

As part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) program, fish communities were sampled at five sites in the South Platte River from Denver, Colo rado, to North Platte, Nebraska. The number and composition of fish species changed from upstream to downstream in the South Platte River. The total number of fish collected at each site varied among sites and from year to

Suspended-sediment transport and its relation to water quality are important issues in the South Platte River Basin. Most sediment enters the South Platte River during snowmelt runoff from March to June. The suspended sediment varies by particle size, concentration, and load. Suspended-sediment data in the South Platte River for water years 1980-92 are limited; therefore, only generalizations can

Time‐intensive discharge and chemical data for two alpine streams in the Loch Vale watershed, Colorado, were used to identify sources of runoff, flow paths, and important biogeochemical processes during the 1992 snowmelt runoff season. In spite of the paucity of soil cover the chemical composition of the streams is regulated much as in typical forested watersheds. Soils and other shallow groundwat