Publications

Ground-water samples were collected from four shallow water-table aquifer observation wells beneath the Small-Arms Firing Range study area at Shaw Air Force Base. Water-chemistry analyses indicated that total lead concentrations in shallow ground water beneath the study area do not exceed the U.S. Environmental Protection Agency maximum contaminant level established for lead in drinking water (0.0

The Edwards-Trinity aquifer system is currently (1993) being studied as part of the Regional Aquifer-Systems Analysis program. A major goal of the project is to understand and describe the regional ground-water flow system. A finite-element model for simulating two-dimensional steady-state ground-water flow was applied to the major aquifers of the Edwards-Trinity aquifer system and contiguous hydr

Many researchers have studied the downdip limit of freshwater in the Edwards aquifer or various aspects of the saline-water zone and its relation to the freshwater zone. These studies were summarized and used to synthesize a consistent hydrologic and geochemical framework from which to interpret data from field studies. The concept derived from the previous work on the downdip limit of the freshwa

Water-level change in the High Plains aquifer underlying parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming results from differences in recharge from precipitation and ground-water withdrawals for irrigation. From the beginning of irrigation development (1940) to 1980, water levels declined in several areas, and exceeded 100 feet in parts of the Central and

Water resources of the Menominee Indian Reservation, Wisconsin, were investigated during the period October 1981 through September 1987. The report presents baseline data and some interpretation of ground- and surface-water hydrology and quality of the Reservation. The area stratigraphy consists of basal Precambrian crystalline bedrock and overlying till and sand and gravel deposits. In the Reserv

Valley-fill aquifers in Pennsylvania are the source of drinking water for many wells in the glaciated parts of the State and along major river valleys. These aquifers area subject to contamination because of their shallow water-table depth and highly transmissive sediments. The possibility for contamination of water-supply wells in valley-fill aquifers can be minimized by excluding activities that

The effects of changing patterns of ground-water pumping and aquifer recharge on the surface-water and ground-water hydrologic systems were determined for the Cape Cod, Martha's Vineyard, and Nantucket Island Basins. Three-dimensional, transient, ground-water-flow modelS that simulate both freshwater and saltwater flow were developed for the f1ow cells of Cape Cod which currently have large-capaci

The Sacramento/San Joaquin Delta was once tidal marshland and was formed by the confluence of the Sacramento and the San Joaquin Rivers. The delta covers more than 1,000 square miles and is bordered by the major population centers of the San Francisco Bay area, Sacramento, and Stockton (fig. 1). The delta took its current form by the 1930's when drainage of 100 islands and tracts and construction

In 1991, the U.S. Geological Survey (USGS), Department of the Interior, began a National Water-Quality Assessment (NAWQA) Program. The long-term goals of the NAWQA Program are to describe the status of and trends in the quality of a large, representative part of the Nation's surface- and ground-water resources and to identify the major natural and human factors that affect the quality of these res

No abstract available.

Annual ground-water withdrawals in Arizona were 2.9, 3.3, 3.6, and 3.4 million acre-feet for calendar years 1987. 1988, 1989, and 1990. The average annual ground-water withdrawal for Arizona from 1980-89 was 3.7 million acre-feet, which was the lowest average annual withdrawal for any decade since the 1940' s. Since 1947, annual ground-water withdrawals in Arizona were at the lowest rate in 1983 a

A map showing ground-water levels in Buckingham and Wrightstown Townships, Bucks County, Pennsylvania, was constructed from water levels measured in 251 wells and from 3 reported elevations of quarry sumps from June 1992 through January 1993. Observed water-level altitudes range from 459 feet above sea level along Burnt House Hill Road, south- west of Mechanicsville, to 10 feet above sea level alo