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- Data supporting the Georgia Water Plan
USGS IN YOUR STATE
USGS Water Science Centers are located in each state.
Assessment of Ground-Water Flow near the Savannah River Site,Georgia and South Carolina
Progress and Significant Results, 2002—2003
- Collected water-level measurements from 282 wells in
Georgia and South Carolina during September 9 –13, 2002,
and constructed potentiometric-surface maps for four major
aquifers. The potentiometric-surface maps were integrated
into a Geographic Information System to determine the
horizontal and vertical hydraulic gradients for the aquifers
along with any interaction with streams and rivers. The
water-level measurements were used to adjust boundary
conditions and determine if any additional calibration is
required to the model under 2002 hydrologic conditions.
- Updated ground-water use estimates within the eight-county
study area to reflect the changes that have occurred since the
previous study (Clarke and West, 1998). The major increase
in ground-water use between 1995 and 2000 is evident for
Burke, Jefferson, and Screven Counties, Ga.; and Allendale
and Barnwell Counties, S.C. In these counties, ground-water
use for irrigation increased from 16.7 million gallons per
day (Mgal/d) during 1995 to 53.1 Mgal/d during 2000 and
irrigated acreage increased from 61,690 acres during 1995
to 97,690 acres during 2000 (Fanning, 2003).
- Converted existing regional groundwater model to Graphical User Interface (GUI) environment to generate current model input for MODFLOW-2000 simulations. The new MODFLOW GUI incorporates the hydrogeologic framework
(Falls and others, 1997) into the various model layers and is essential when performing three-dimensional particle-tracking analysis.
- Adjusted specified heads in the source-sink layer (A1) of the model to conform with the 2002 potentiometric-surface
map of the Upper Three Runs aquifer, and lowered the specified heads along the lateral boundaries of the model in
layers A2–A7 based on observation points in each aquifer. The specified heads in the source-sink layer were lowered
to reflect the decline in water levels that resulted from the drought that occurred from 1998 to 2002.
- Evaluated ground-water model under steady-state conditions for 2002 to determine if additional calibration is
necessary. The model simulations conducted using updated pumping estimates, observed aquifer heads, and recharge
rates from the source-sink layer (A1), indicated that no additional calibration was required.