USGS Scientific Investigations Report 2008-5170
Prepared in cooperation with the National Park Service, Congaree National Park
By Paul A. Conrads, Toby D. Feaster, and Larry G. Harrelson
U.S. Geological Survey Scientific Investigations Report 2008-5170, 58 pages (Published online, October 2008)
This report is available online in PDF format:
SIR 2008-5170 (
) (6.1 MB)
The Congaree National Park was established "… to
preserve and protect for the education, inspiration, and
enjoyment of present and future generations an outstanding
example of a near-virgin, southern hardwood forest situated
in the Congaree River flood plain in Richland County, South
Carolina" (Public Law 94–545). The resource managers at
Congaree National Park are concerned about the timing,
frequency, magnitude, and duration of flood-plain inundation
of the Congaree River. The dynamics of the Congaree River
directly affect ground-water levels in the flood plain, and
the delivery of sediments and nutrients is constrained by the
duration, extent, and frequency of flooding from the Congaree
River. The Congaree River is the southern boundary of the
Congaree National Park and is formed by the convergence of
the Saluda and Broad Rivers 24 river miles upstream from the
park. The streamflow of the Saluda River has been regulated
since 1929 by the operation of the Saluda Dam at Lake
Murray. The U.S. Geological Survey, in cooperation with the
National Park Service, Congaree National Park, studied the
interaction between surface water in the Congaree River and
ground water in the flood plain to determine the effect Saluda
Dam operations have on water levels in the Congaree National
Park flood plain.
Analysis of peak flows showed the reduction in peak flows after the construction of Lake Murray was more a result of climate variability and the absence of large floods after 1930 than the operation of the Lake Murray dam. Dam operations reduced the recurrence interval of the 2-year to 100-year peak flows by 6.1 to 17.6 percent, respectively. Analysis of the daily gage height of the Congaree River showed that the dam has had the effect of lowering high gage heights (95th percentile) in the first half of the year (December to May) and raising low gage heights (5th percentile) in the second half of the year (June to November). The dam has also had the effect of increasing the 1-, 3-, 7-, 30-, and 90-day minimum gage heights by as much as 23.9 percent and decreasing the 1-, 3-, 7-, 30-, and 90-day maximum gage heights by as much as 7.2 percent. Analysis of the ground-water elevations in the Congaree National Park flood plain shows similar results as the gage-height analysis--the dam has had the effect of lowering high ground-water elevations and increasing low ground-water elevations. Overall, the operation of the dam has had a greater effect on the gage heights within the river banks than gage heights in the flood plain. This result may have a greater effect on the subsurface water levels of the surficial flood-plain aquifer than the frequency and magnitude of inundation of the flood plain.
Abstract
Introduction
Purpose and Scope
Previous Investigations
Approach
Description of Study Area
Data-Collection Networks
Characterization of Surface Water and Ground Water
Surface Water
Ground Water
Analysis of Surface-Water and Ground-Water Dynamics
Analysis of Surface-Water Peak Flows and Potential Effects of Climatic Variability
Analysis of Surface-Water Daily Gage Heights
Analysis of Ground-Water Dynamics
Summary
Acknowledgments
Selected References
Appendix 1. Generalizied lithologic description of sediment samples examined during the installation of observation wells RIC-341, RIC-345, RIC-346, RIC-699, RIC-700, RIC-701, RIC-702, RIC-703, RIC-704 and RIC-705 in the Congaree National Park, South Carolina
Appendix 2. Description of Artificical Neural Network Models
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Suggested citation: Conrads, P.A., Feaster, T.D., and Harrelson, L.G., 2008, The effects of the Saluda Dam on the surface-water and ground-water hydrology of the Congaree National Park flood plain, South Carolina: U.S. Geological Survey Scientific Investigations Report 2008–5170, 58 p. (online at http://pubs.water.usgs.gov/sir2008-5170)
For more information, please contact Paul A. Conrads.
U.S. Department of the Interior |
U.S. Geological Survey
Persistent URL: http://pubs.water.usgs.gov/sir2008-5170
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