Hydrogeology and predevelopment flow in the Texas Gulf Coast aquifer systems

Water-Resources Investigations Report 87-4248




A multilayered groundwater flow system exists in the Coastal Plain sediments of Texas. The Tertiary and Quaternary deposits have an areal extent of 128,000 sq mi. Two distinct aquifer systems are recognized. The older Texas coastal uplands aquifer system consists of four aquifers and two confining units in the Wilcox and Claiborne Groups. It is bounded from below by the practically impermeable Midway confining unit or by the top of the geopressured zone. It is bounded from above by the poorly permeable Vicksburg-Jackson confining unit, which separates it from the overlying system. The overlying coastal lowlands aquifer system consists of five aquifers and two confining units that range in age from Oligocene to Holocene. The hydrogeologic units of both systems crop out in bands that parallel the coastline. The units dip and thicken toward the Gulf. Quality of water in the aquifer systems varies greatly, with dissolved solids ranging from a few hundred to more than 200,000 mg/L. A three-dimensional, variable-density digital model was calibrated to simulate predevelopment flow. Horizontal hydraulic conductivities of the aquifers range from 15 to 170 ft/d. Vertical hydraulic conductivities of all units range from 0.00001 to 0.01 ft/d. Simulated recharge rates in the outcrop areas do not exceed 6 inches/year. The high rates exist in small , local topographically high areas. The average recharge rate in the outcrop areas is 0.74 inch/year. Total simulated recharge in the outcrop areas is 269 million cu ft/d. (USGS)

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USGS Numbered Series
Hydrogeology and predevelopment flow in the Texas Gulf Coast aquifer systems
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Water-Resources Investigations Report
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U.S. Geological Survey,
vii, 109 p. :ill., maps ;28 cm.