Publications

At Neshaminy State park, the most important aquifer is the informally named 'Trenton gravel' of Pleistocene age, which consists of poorly sorted sand and gravel. This is underlain by less permeable crystalline rock that limits the downward movement of water. Up to 5 feet of Holocene (or perhaps Pleistocene) alluvium consisting of clay and silt was deposited above the Trenton gravel, but much of th

This report updates ground-water information pertaining to the lower unit of the Chicot aquifer in the Orange County area, Texas and Louisiana. The period of data collection was from 1980 to the spring of 1985. Some data collected prior to 1980 are presented to establish long-term trends and relations. The lower unit of the Chicot aquifer, which consists of sediments of Pleistocene age, is confine

Base flow was computed to estimate discharge from regional aquifers for six large streams in the upper Coastal Plain of South Carolina and parts of North Carolina and Georgia. Aquifers that sustain the base flow of both large and small streams are stratified into shallow and deep flow systems. Base-flow during dry conditions on main stems of large streams was assumed to be the discharge from the d

Annual and summer (May 1 to September 30) low-flow frequency curves are presented for 175 continuous-record streamflow stations in Minnesota. The curves were developed for all stations with 10 or more years of continuous record. The 1-, 7-, and 30-day low-flow discharges at selected recurrence intervals obtained from these curves are listed. Low-flow characteristics can and will vary for a station

Este ' texto programado esta diseflado para ayudarle a comprender la teoria de la hidniulica de aguas subterraneas por medio de la auto-enseflanza. La instrucci6n programada es un enfoque a una materia, un metodo de aprender;que no elimina el esfuerzo mental del proceso de aprendizaje. Algunas secciones de este programa necesitan solamente ser leidas; otras tendrian que ser elaboradas con lap

No abstract available.

The National Water Commission recommended that the U.S. Geological Survey conduct intensive studies of the important regional aquifer systems in the United States, particularly those with declining water levels and deteriorating water quality.  The result has been a series of Regional Aquifer-System Analysis (RASA) studies, one of which is the West Gulf Coast RASA study (Grubb, 1984).  The West Gu

Runoff is the water in a river or stream that results from precipitation falling on the drainage basin. It is the net discharge into the stream from surface-water and ground-water sources with losses occurring from evapotranspiration and other consumptive uses. Runoff can be expressed by a variety of numerical values, but average depth of water over the drainage basin, in inches per year, probably

The Highway Division, Georgia Department of Transportation, plans the extension of Georgia Highway 400 from Interstate 285 southward to Interstate 85. As part of this extension, the Highway Division plans construction of a bridge crossing Nancy Creek near Atlanta, Georgia. The U.S. Geological Survey, in cooperation with the Highway Division, determined the flood flow characteristics of Nancy Creek

The highly productive freshwater zone of the Edwards aquifer in the San Antonio region (fig. 1) is the sole-source water supply for more than 1 million people. A transitional interface exists between the freshwater zone and the downdip, salinewater zone. A 1,000 mg/L (milligrams per liter) dissolved solids-concentration contour defines an arbitrary boundary -between the freshwater zone and the sal

A water table contour map of the lower Paleozoic and Precambrian crystalline rocks of southeastern Chester County, Pennsylvania was constructed on the basis of water levels measured in 261 wells in July and August 1986, elevations of 11 springs that were flowing in July and August 1986, and water levels measured in 15 wells. Pre-1986 measurements were incorporated on the map to provide control in

A map, constructed as a part of the Floridan Regional Aquifer-System Analysis (RASA), shows the potentiometric surface of the Upper Floridan aquifer for May 1985. It is based on measurements of water level or artesian pressure made in about 2 ,500 wells during the period May 13 to 24, 1985. Only measurements from tightly cased wells open exclusively to the Upper Floridan aquifer were used to make