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A numerical model of ground-water flow in the Twin Cities metropolitan area was converted from the TrescottLarson computer code to the McDonald-Harbaugh computer code to facilitate current and future use of the model using up-to-date computer software and hardware. Differences exist between the two computer codes in how headdependent source-sink...

Chemical manufacturing, munitions filling, and other military-support activities have resulted in the contamination of ground water, surface water, and soil in the Canal Creek area of Aberdeen Proving Ground, Maryland. Chlorinated volatile organic compounds, including 1,1,2,2-tetrachloroethane and trichloroethylene, are widespread ground-water contaminants in two aquifers that are composed of unconsolidated...

North Fish Creek is underused as a trout and salmon hatchery despite its excellent water quality. The shifting-sand streambed in the lower 9 miles of the stream inhibits successful spawning and is a poor habitat for macroinvertebrates, the primary food for juvenile trout and salmon. To provide data necessary for...

Foster Creek, a freshwater tidal creek in Berkeley County, South Carolina, is located in an area of potential contaminant sources from residential, commercial, light industrial, and military activities. The creek is used as a secondary source of drinking water for the surrounding Charleston area. Foster Creek meets most of the...

In the winter of 1811-12, three of the largest historic earthquakes in the United States occurred near New Madrid, Mo. Seismicity continues to the present day throughout a tightly clustered pattern of epicenters centered on the bootheel of Missouri, including parts of northeastern Arkansas, northwestern Tennessee, western Kentucky, and southern...

A field experiment was conducted at the Levee 4 canal site below control structure G-88 in the Everglades agricultural area in northwestern Broward County, Florida, to study the relation of acoustic attenuation to suspended-solids concentrations. Acoustic velocity meter and temperature data were obtained with concurrent water samples analyzed for suspended-solids...

A one-dimensional model of unsteady discharge waves was applied to research flowr that were released from Glen Canyon Dam in support of the Glen Canyon Environmental Studies. These research flows extended over periods of 11 days during which the discharge followed specific, regular patterns repeated on a daily cycle that...

Natural monthly streamflows were synthesized for the years 1928-89 for 43 sites in the upper Missouri River Basin upstream from Fort Peck Lake in Montana. The sites are represented as nodes in a streamflow accounting model being developed by the Bureau of Reclamation. Recorded and historical flows at most sites...

Urban areas in Perris Valley, California, have more than tripled during the last 20 years. To quantify the effects of increased urbanization on storm runoff volumes and peak discharges, rainfall-runoff models of the basin were developed to simulate runoff for 1970-75 and 1990-93 conditions. Hourly rainfall data for 1949-93 were...

Upper Klamath Lake is a large (140 square-mile), shallow (mean depth about 8 ft) lake in south-central Oregon that the historical record indicates has been eutrophic since its discovery by non-Native Americans. In recent decades, however, the lake has had annual occurrences of near- monoculture blooms of the blue-green alga...

This report presents the estimated short-term yields and quality of ground water in stratifieddrift aquifer areas in the Neponset River Basin, Massachusetts. Stratified glacial drift forms the major aquifer areas in the basin. These thin valley-fill aquifer areas of sand and gravel have saturated thicknesses of as much as 130...

The potential for subsurface storage and recovery of treated effluent into the uppermost producing zone (zone A) of the Upper Floridan aquifer in St. Petersburg, Florida, is being studied by the U.S. Geological Survey, in cooperation with the city of St. Petersburg and the Southwest Florida Water Management District. A...

The physical and chemical characteristics of Lake Powell have a direct effect on the quality of water below Glen Canyon Dam. Understanding the physical and chemical characteristics of the lake and outflows from the dam is essential in order to effectively manage the operation of the dam. During August 1990...

The U.S. Geological Survey's Distributed Routing Rainfall-Runoff Model [DR3M] was applied to a 2.27-square-mile portion of Bear Branch watershed at Murfreesboro, Tennessee, to demonstrate the application of this model to small urban watersheds in central Tennessee. Kinematic wave theory was used to route excess rainfall overland and through a branched...

Rain-on-snow events are common on mountain slopes within the transient-snow zone of the Pacific Northwest. These events make more water available for runoff than does precipitation alone by melting the snowpack and by adding a small amount of condensate to the snowpack. In forest openings (such as those resulting from...

The alluvial aquifer at Louisville, Ky., lies in a valley eroded by glacial meltwater that was later partly filled with outwash sand and gravel deposits. The aquifer is primarily unconfined, and the direction of flow is from the adjacent limestone and shale valley wall toward the Ohio River and major...

The City of Columbus, Ohio, operates four radial collector wells in southern Franklin County. The 'South Well Field' is completed in permeable outwash and ice-contact deposits, upon which flow the Scioto River and Big Walnut Creek. The wells are designed to yield approximately 42 million gallons per day; part of...

Water samples from four springs and five wells in basalt aquifers near Spring Creek National Fish Hatchery in Skamania County, Washington, were collected and analyzed for selected inorganic ions and stable isotopes. Eight samples were analyzed for carbon-14 (14C), carbon-13 ([3C), and either chlorofluorocarbons (CFCs) or tritium. This work was...

In inland areas of northwest central Florida, sulfate concentrations in the Upper Floridan aquifer are extremely variable and sometimes exceed drinking water standards (250 milligrams per liter). This is unusual because the aquifer is unconfined and near the surface, allowing for active recharge. The sources of sulfate and geochemical processes...

Earthquakes at three localities in eastern North America have been attributed on geological and seismological grounds to compressional reactivation of some of the late Proterozoic or early Paleozoic normal faults in the northeast-trending Iapetan passive margin. Assessment of seismic hazard can be aided by identifying the boundaries of the area...

Ground-water and surface-water flow models traditionally have been developed separately, with interaction between subsurface flow and streamflow either not simulated at all or accounted for by simple formulations. In areas with dynamic and hydraulically well-connected ground-water and surface-water systems, stream-aquifer interaction should be simulated using deterministic responses of both systems...

The South Florida wetlands ecosystem is an environment of great size and ecological diversity (figs. 1 and 2). The landscape diversity and subtropical setting of this ecosystem provide a habitat for an abundance of plants and wildlife, some of which are unique to South Florida. South Florida wetlands are currently...