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This report presents water-quality data for ground-water and surface-water samples and water-level data collected by the U.S. Geological Survey from October 1998 through September 1999 at West Branch Canal Creek, Aberdeen Proving Ground, Maryland. The report also provides a description of the sampling and analytical methods that were used to...

Mature, synrift lacustrine shales of Eocene to Oligocene age and mature, late-rift coals and coaly shales of Oligocene to Miocene age are source rocks for oil and gas in two important petroleum systems of the onshore and offshore areas of the Northwest Java Basin. Biogenic gas and carbonate-sourced gas...

The U.S. Geological Survey has completed an integrated geologic and geophysical study of the Texas Springs syncline for the National Park Service with the intention of locating a new production water well near existing water-collection and distribution facilities. Subsurface information was required to determine which, if any, sites within the...

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Most of the Christian quadrangle is in the Porcupine Plateau; the northwestern part is in the southern Brooks Range, and the southern quarter is in the Yukon Flats. Outcrops of bedrock are poor or lacking, except in the Brooks Range. Although large valley glaciers have moved through the Porcupine Plateau,...

The 2nd Interface Between Ecology and Land Development Conference was held in association with Earth Day 1997, five years after the first Interface Conference. Rapid population growth in California has intensified the inevitable conflict between land development and preservation of natural ecosystems. Sustainable development requires wise use of diminishing natural...

Macroinvertebrate and algal community samples were collected during a 3-year period at sites located near Guanella Pass, Colorado, to provide baseline characterization data. Water-quality sampling and habitat evaluations were used to aid in the interpretation of the biological data. The study was part of an environmental investigation for a proposed...

During July, 1997, twenty four Schlumberger dc resistivity soundings were made in the Boulder watershed and adjacent areas (fig. 1). The objective of geophysical studies in the watershed is to map subsurface lithologic, structural and hydrologic features important in controlling possible ground water contamination from mining activities and for design...

This report presents a proposal for conducting a water-quality modeling study at drought streamflow, a detailed comprehensive plan for collecting the data, and an annual drought-formation monitoring plan. A 30.8 mile reach of the Red River of the North receives treated wastewater from plants at Fargo, North Dakota, and Moorhead,...

Analytical methods using high-performance liquid chromatography-diode array detection (HPLC-DAD) and high-performance liquid chromatography/mass spectrometry (HPLC/MS) were developed for the analysis of the following chloroacetanilide herbicide metabolites in water: acetochlor ethanesulfonic acid (ESA), acetochlor oxanilic acid (OXA), alachlor ESA, alachlor OXA, metolachlor ESA, and metolachlor OXA. Good precision and accuracy were...

Flow-velocity and depth data were collected from July 1996 through December 1998 during peak discharge events at 21 bridge crossings that are adjacent to U.S. Geological Survey streamgaging stations in North Carolina. These data were collected during measurements of peak discharges that had recurrence intervals ranging from less than 2...

In 1996-1998 the U.S. Geological Survey (USGS) conducted a geochemical study of the Bureau of Land Management’s (BLM) 5.5 million-acre Northern and Eastern Colorado Desert Resource Area (usually referred to as the NECD in this report), Imperial, Riverside, and San Bernardino Counties, southeastern California (figure 1). This study was done...

Ground water in Triassic-age sedimentary fractured-rock aquifers in the area of Gettysburg, Pa., is used as drinking water and for industrial and commercial supply. In 1983, ground water at the Gettysburg Elevator Plant was found by the Pennsylvania Department of Environmental Resources to be contaminated with trichloroethene, 1,1,1-trichloroethane, and other...

The National Water Quality Laboratory (NWQL) determined ammonium plus organic nitrogen (Kjeldahl nitrogen) by using semiautomated, block digester methods for filtered and whole-water samples from 1986 until October 1, 1991. During that time, phosphorus was determined by a persulfate digestion method. In 1991, projected increases in demand for both tests by the U.S. Geological Survey?s National Water-Quality Assessment Program led...

Environmental Quality and Preservation-Bedrock Beneath Reefs: the Importance of Geology in Understanding Biological Decline in a Modern Ecosystem' is a four-page and one-plate full-color discussion of the geologic framework and evolutionary history of the coral reef ecosystem that lines the outer shelf off the Florida Keys....

This report documents the Observation, Sensitivity, and Parameter-Estimation Processes of the ground-water modeling computer program MODFLOW-2000. The Observation Process generates model-calculated values for comparison with measured, or observed, quantities. A variety of statistics is calculated to quantify this comparison, including a weighted least-squares objective function. In addition, a number of...

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