The Surficial and Brunswick Aquifer Systems—Alternative Ground-Water Resources for Coastal Georgia
Clarke, John S.
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The surficial and Brunswick aquifer systems may provide a supplemental water source in coastal Georgia. The surficial aquifer system consists of two to three water-bearing zones—the water-table zone and the confined upper and lower water-bearing zones. The Brunswick aquifer system is comprised of the upper and lower Brunswick aquifers. Productivity of the aquifer systems is greatest in the vicinity of the southeast Georgia embayment and is highly variable along the outer margins of this structural feature. In the southeast Georgia embayment, transmissivity of the lower Brunswick aquifer ranges from 2,000 to 4,700 feet squared per day (ft2/d). Outside of the embayment, permeable sediments are thin or absent and the productivity is low—reported transmissivity of the Brunswick aquifer system ranges from 5 to 500 ft2/d. Withdrawal from the Brunswick aquifer system increased from about 1.5 million gallons per day (Mgal/d) during 1990 to 3.7 Mgal/d during 2000. At one site in Glynn County, average withdrawal of 0.6 Mgal/d or less since early 1999 resulted in water-level declines of about 12 feet (ft) in the upper Brunswick aquifer and about 5 ft in the lower Brunswick aquifer. This difference may reflect differences in the amount of leakage from adjacent units, the connection of the aquifer to recharge areas, or the aquifer’s hydraulic properties.