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Nitrogen in the unsaturated soil zone in the Highland-East Highlands area of San Bernardino County, Calif., has been suspected as the source of nitrate in water from wells. Plans to recharge the local aquifers with imported surface water would raise the water table and intercept that nitrogen. This study was...

Modification of sampling programs at some water-quality stations in the Missouri River basin in Montana has eliminated the means by which solute loads have been directly obtained in past years. To compensate for this loss, water-quality and streamflow data were statistically analyzed and solute loads were simulated using computer techniques.Functional...

The Big Sioux aquifer in Brookings, Deuel, and Hamlin Counties, South Dakota, has been extensively developed and in some areas discharge, principally by wells, from the aquifer may be exceeding recharge to the aquifer.A finite-difference method digital model was used to simulate steady-state conditions of the Big Sioux aquifer. Average...

The U.S. Geological Survey is conducting a study of the Cambrian and Ordovician aquifer system of the northern Midwest as part of a national series of Regional Aquifer-Systems Analysis (RASA). An integral part of this study will be a simulation of the ground-water flow regime using the Geological Survey's three-dimensional...

Verde Valley--an area of complex geology where the crust of the North American plate changes from unstable to stable--is in central Arizona in the transition zone between the Basin and Range and the Colorado Plateaus tectonic provinces. Volcanism and tectonism have been progressing northeastward along the transition zone for about...

From October 1972 through September 1977, the effects of highway construction in the 38 square mile Blockhouse Creek basin were studied. Water discharge, suspended-sediment discharge, and stream-temperature data were collected at four stations in the basin. The 5-year period included 1 year before construction, 2 years during construction, and 2...

The Red River Waterways Project provides for the construction of five locks and dams on the Red River from the Mississippi River to Shreveport, La. The methodology used by the U.S. Geological Survey in studying the effects of the navigation pools on the ground-water-flow regime involved digital modeling of steady-...

A hydrologic reconnaissance of the southeastern part of St. Paul Island, Pribilof Islands, Alaska, was made in August 1979 to determine if sufficient freshwater is available for a proposed harbor and fish-processing facility. Only three wells were being used in 1979, two by the community of St. Paul and one...

Existing methods for measuring discharge of irrigation systems in the High Plains region are not suitable to provide the pumpage data required by the High Plains Regional Aquifer System Analysis. Three portable flowmeters that might be suitable for obtaining fast and accurate discharge measure-ments on large irrigation systems were tested...

The U.S. Geological Survey is monitoring the water quality of three major tributaries to Chesapeake Bay at their fall lines to obtain estimates of constituent inputs potentially available to the bay. The monitoring sites are: Susquehanna River at Conowingo, Md.; Potomac River at Washington, D.C.; and James River at Cartersville,...

The ground-water basin beneath the city of Thousand Oaks, Calif. , corresponds closely in area with the surface-water drainage basin of Conejo Valley. Before World War II there was little ground-water development. After World War II, urban development put a stress on the ground-water basin; many wells were drilled and...

During 1977, an average of 21,466 million gallons of water was withdrawn daily for use in Florida--an increase of 6,153 million gallons per day since 1970. The 1977 daily use was 14,812 million gallons of saline water and 6,654 million gallons of freshwater. Most of the saline water, largely surface...

Four modified nonradioactive-tracer methods and 20 predictive equations for determination of stream-reaeration coefficients in three small Wisconsin streams were compared with the radioactive-tracer method developed by Tsivoglou. Of the four modified-tracer techniques, the propane-area technique, which measures the total weight of propane gas passing stream-sampling stations, yielded the least mean absolute...

Federal and State legislation require the trophic classification of lakes and ponds in the State of Maine as part of a lake management program. In 1974, the State of Maine Department of Environmental Protection (DEP) adopted a preliminary set of procedures for establishing an index of lake trophic status. Also...

Temperature-depth profiles of six cased test holes in the Missoula and Bitterroot Valleys, west-central Montana, consist of linear segments, the intersections of which commonly correspond with lithologic boundaries. Geothermal gradients commonly decreased with depth, probably as a result of compaction and higher quartz content of the deeper sedimentary deposits. There...

Large withdrawals of ground water for irrigation are causing progressive declines of ground-water levels in some areas of Nebraska. An investigation was conducted to determine the technical feasibility of artificially recharging aquifers through wells and through surface spreading by means of impoundments, pits, and canals. Information gained from a literature...

No abstract available. ...

No abstract available. ...