Publications

The U.S. Geological Survey (USGS) was established by an act of Congress on March 3, 1879, to provide a permanent Federal agency to conduct the systematic and scientific classification of the public lands and to examine the geological structure, mineral resources, and products of national domain. An integral part of that original mission includes publishing and disseminating the earth...

The Edwards-Trinity aquifer system is a sequence of near-surface, hydraulically connected, Cretaceous carbonate and quartzose clastic rocks that underlie about 42,000 mi2 of west-central Texas (fig. 1). The aquifer system is currently (1991) being studied as a part of the U.S. Geological Survey's Regional Aquifer-System Analysis (RASA) program, which is intended to describe the regional

The Edwards-Trinity Regional Aquifer-System Analysis (RASA) is one of 25 completed or ongoing studies conducted by the U.S. Geological Survey on regional aquifer systems that individually provide essential quantities of ground water to large parts of the country. Underlying about 42,000 mi2 of west-central Texas, the Edwards-Trinity aquifer system extends approximately from Atascosa...

No abstract available.

This report was prepared in cooperation with the Fort Bend Subsidence District and presents data on water-level changes in wells during 1990-93 and 1992-93 in the Chicot and Evangeline aquifers (figs. 1-4) in Fort Bend County. Water-level changes maps were prepared previously by Locke (1990), and Locke and Santos (1992) for both aquifers, and by Wesselman (1972) for the Chicot aquifers.

National Water Summary 1990-91 Hydrologic Events and Stream Water Quality was planned to complement existing Federal-State water-quality reporting to the U.S. Congress that is required by the Clean Water Act of 1972. This act, formally known as the Federal Water Pollution Control Act Amendments of 1972 (Public Law 92-500), and its amendments in 1977,1979,1980,1981,1983, and 1987, is the...

This report is one in a series of reports that annually depict altitudes of water levels since 1977, the most recent of which (Barbie and others, 1991) presented maps of the altitudes of water levels for 1990. This report was prepared in cooperation with the City of Houston and the Harris-Galveston Coastal Subsidence District, and preents approximate altitudes of water levels in wells in...

This report is one in a series of reports that depict water-level changes since 1977 and compaction of subsurface material since 1973. The report was prepared in cooperation with the Harris-Galveston Coastal Subsidence District and the City of Houston, and presents maps showing the approximate changes in water levels in wells completed in the Chicot and Evangeline aquifers, 1977-93 and...

This report was prepared in cooperation with the Fort Bend Subsidence District, and presents maps of the approximate altitude of water levels in wells completed in the Chicot and Evangeline aquifers (figs. -2) during January-February 1991 in Fort Bend County and adjacent areas, Texas. These approximate altitudes of water levels give an approximate depth to potable ground water within...

No abstract available.

Remote-sensing data were used to estimate that 190,000 acre-feet of water was pumped from the Edwards aquifer in 1989 to irrigate crops in Uvalde and Medina Counties. Landsat digital satellite images for March and July 1989 were combined and classified to identify the areas of crops irrigated with water from the Edwards aquifer in the two counties. Normalized difference, the difference...

This report was prepared in cooperation with the Fort Bend Subsidence District, and presents data on water-level changes during 1991-92 in the Chicot and Evangeline aquifer (fig. 1-2) in Fort Bend County. Water-level change maps were prepared previously by Locke (1990),and Locke and Barbie (1991), for both aquifers, and by Wesselman (1972) for the Chicot aquifer.