Open-File Report 96-483
This report is available online in pdf format (2.4 MB): USGS OFR96-483 (
)
Gregory C. Mayer
U.S. Geological Survey Open-File Report 96-483, 47 pages (Published 1997)
Drought conditions in the 1980’s focused attention on the multiple uses of the surface- and ground-water resources in the Apalachicola-Chattahoochee-Flint (ACF) and Alabama-Coosa-Tallapoosa (ACT) River basins in Georgia, Alabama, and Florida. State and Federal agencies also have proposed projects that would require additional water resources and revise operating practices within the river basins. The existing and proposed water projects create conflicting demands for water by the States and emphasize the problem of water-resource allocation. This study was initiated to describe ground-water availability in the lower-middle Chattahoochee River basin of Georgia and Alabama; and middle Flint River basin of Georgia, Subarea 3 of the ACF and ACT River basins, and to estimate the possible effects of increased ground-water use within the basin.
Subarea 3 encompasses about 6,180 square miles (mi2) of the Coastal Plain Province in southwestern Georgia and southeastern Alabama. About 55 percent of the area is drained by the Chattahoochee River, with the remainder drained by the Flint River. The drainage area of the Chattahoochee River is divided almost equally between Alabama and Georgia.
Subarea 3 is underlain by complexly interbedded sedimentary strata that dip gently to the southeast, underlying the Floridan aquifer system to the south. The strata comprise numerous porous-media aquifers and confining units that crop out in the northern part of Subarea 3 in generally northeast-trending bands.
The conceptual model described for this study qualitatively subdivides the ground-water flow system into local (shallow), intermediate, and regional (deep) flow regimes. Ground-water discharge to tributaries mainly is from local and intermediate flow regimes and varies seasonally. The regional flow regime probably approximates steady-state conditions and discharges chiefly to major drains such as the Chattahoochee River. Ground-water discharge to major drains originates from all flow regimes.
Mean-annual baseflow is about 1,618 cubic feet per second (ft3/s) in the Chattahoochee River; and about 1,812 ft3/s in the Flint River. Of the 1,618 ft3/s baseflow in the Chattahoochee, about 37 percent is discharge from Alabama and 63 percent is discharge from Georgia. Near the end of the drought of 1954, baseflow was about 579 ft3/s in the Chattahoochee River; and about 963 ft3/s in the Flint River. Of the 579 ft3/s drought baseflow in the Chattahoochee River, about 15 percent was from Alabama and 85 percent from Georgia. Baseflow in Subarea 3 during the drought of 1954 was about 45 percent of mean-annual baseflow. Near the end of the drought of 1986, baseflow was about 449 ft3/s in the Chattahoochee River and about 498 ft3/s in the Flint River. Of the 449 ft3/s baseflow in the Chattahoochee River, about 16 percent was discharge from Alabama and 84 percent was discharge from Georgia. Baseflow in Subarea 3 during the 1986 drought was about 28 percent of mean-annual baseflow.
The potential exists for the development of ground-water resources on a regional scale throughout Subarea 3. Estimated ground-water use in 1990 was about 2.2 percent of the estimated mean-annual baseflow, and ranged from about 4.9 to 8.0 percent of baseflows near the end of the droughts of 1954 and 1986, respectively. Because ground-water use in Subarea 3 represents a relatively minor percentage of ground-water recharge, even a large increase in ground-water use in Subarea 3 in one State is likely to have little effect on ground-water and surface-water occurrence in the other. Indications of long-term ground-water level declines were not observed; however, the number and distribution of observation wells having long-term water-level measurements in Subarea 3 are insufficient to draw conclusions.
Abstract
Introduction
Purpose and Scope
Physical setting of study area
Physiography
Climate
Ground-water use
Previous investigations
Surface-water station numbering system
Approach and methods of study
Mean-annual baseflow analysis
Drought-flow analysis
Conceptual model of ground-water flow and stream-aquifer relations
Hydrologic setting
Ground-water system
Geology
Aquifers
Surface-water system
Ground-water discharge to streams
Mean-annual baseflow
Baseflow in the Chattahoochee River
Baseflow in the Flint River
Drought flow for 1954 and 1986
Ground-water utilization and general development potential
Summary
Suggestions for further study
Selected references
This report is available online in pdf format (2.4 MB): USGS OFR96-483 ()
To view the PDF document, you need the Adobe Acrobat® Reader installed on your computer. (A free copy of the Acrobat® Reader may be downloaded from Adobe Systems Incorporated.)
Recent USGS publications on Georgia or Georgia Water-Resources Information
For more information, please contact webmaster-ga@usgs.gov .
U.S. Department of the Interior |
U.S. Geological Survey
URL: https://pubsdata.usgs.gov/pubs/of/1996/ofr96-483/index.html
Page Contact Information: Publications Team
Page Last Modified: Wednesday, 07-Dec-2016 16:05:38 EST
