Geohydrologic units of the coastal lowlands aquifer system, south-central United States

Abstract

The Regional Aquifer-System Analysis (RASA) Program was started in 1978 following a congressional mandate to develop quantitative appraisals of the major groundwater systems of the United States. The RASA Program represents a systematic effort to study a number of the Nation's most important aquifer systems, which in aggregate underlie much of the country and which represent an important component of the Nation's total water supply. In general, the boundaries of these studies are identified by the hydrologic extent of each system and accordingly transcend the political subdivisions to which investigations have often arbitrarily been limited in the past. The broad objective for each study is to assemble geologic, hydrologic, and geochemical information, to analyze and develop an understanding of the system, and to develop predictive capabilities that will contribute to the effective management of the system. The use of computer simulation is an important element of the RASA studies, both to develop an understanding of the natural, undisturbed hydrologic system and the changes brought about in it by human activities, and to provide a means of predicting the regional effects of future pumping or other stresses. The final interpretive results of the RASA Program are presented in a series of U.S. Geological Survey Professional Papers that describe the geology, hydrology, and geochemistry of each regional aquifer system. Each study within the RASA Program is assigned a single Professional Paper number, and where the volume of interpretive material warrants, separate topical chapters that consider the principal elements of the investigation may be published. The series of RASA interpretive reports begins with Professional Paper 1400 and thereafter will continue in numerical sequence as the interpretive products of subsequent studies become available.

Groundwater availability of the Mississippi embayment

“…The Mississippi embayment aquifer system was analyzed as part of the GCRASA study. The GCRASA study produced several USGS Professional Papers (Grubb, 1998;Hosman and Weiss, 1991;Weiss, 1992;Ackerman, 1996;Ryder and Ardis, 2002;Williams, 2001;Hosman, 1996;Martin and Whiteman, 1999;Arthur and Taylor, 1998) from several authors. The GCRASA compiled data and simulated groundwater flow using groundwater-flow models in three main parts: the Mississippi River Valley alluvial aquifer, the Mississippi embayment aquifer system, and the Gulf Coastal lowland aquifer system (U.S. Geological Survey, 2008a).…”

Hydrogeological modeling of submarine groundwater discharge on the continental shelf of Louisiana

“…Individual confining beds are present throughout the system; however, they are not regionally extensive. The hydrostratigraphic model proposed by the United States Geological Survey is adopted here, which represents the system in terms of five permeable zones (Permeable Zones A -E) on the basis of sediment age and patterns of water levels in wells completed at different depths [Weiss, 1992]. Two regional confining units, Confining Units D and E, have also been defined, although only Unit E is present within the study region.…”

“…[8] Hydrogeologic units in the study region belong to the Coastal Lowlands Aquifer System (Figure 3), which encompasses all the sedimentary units that overlie the Vicksburg-Jackson regional confining unit [Weiss, 1992]. Sediments were deposited as complexly interbedded sands, silts, and clays.…”

Gulf Coast Regional Aquifer-System Analysis — A Kentucky perspective

“…Hosman and Weiss (1988) present detailed maps of aquifer thickness, percentage and aggregate sand thickness, and altitude of top for each regional geohydrologic unit in the Mississippi embayment and Texas coastal uplands aquifer systems. Detailed maps of the geohydrologic units of the coastal lowlands aquifer system are presented by Weiss (1990). Maps of dissolved-solids concentrations and water temperature for all the aquifers in the three aquifer systems are presented in Pettijohn and others (1988).…”