GCRC Project Summary |
The Impact of Land Use Changes on the Salt Regimes of Georgia Estuaries
PIs: Richard Wiegert , Merryl Alber, Alice Chalmers (Dept. of Marine Sciences, Univ. of Georgia, Athens, GA, USA), and Jackson O. Blanton (Skidaway Inst. of Oceanography, Savannah, GA, USA)
Support: Georgia Coastal Incentive Grant (GA Dept of Natural Resources, Coastal Resources Division)
Timeframe: 1999-2002
Project Overview:
The research conducted for this project was a continuation of an integrated
program to examine the effects of human-induced changes on the salinity regimes
of coastal Georgia. The project had the following major objectives: 1) evaluate
changes in land use over time, 2) couple changes in land use to freshwater runoff,
3) evaluate the response of the salinity regime of the Satilla River estuary
to fluctuations in river discharge, 4) use the high and low discharge data sets
to develop a predictive 3-d finite element salinity model, and 5) begin field
efforts in the Ogeechee River.
Findings:
1) A GIS
analysis of land use in the Satilla, Ogeechee, and Altamaha watersheds was conducted
using maps from 1976, 1993, and 1998. The study found that while urban areas
have increased, they continue to be a very small portion of the watersheds;
forest, agriculture and wetlands are the largest classes of land cover/land
use in all three watersheds;
2) An analysis of precipitation and runoff records for the Satilla River watershed on the Georgia coast was conducted, and found a marked increase in the variability of yield values for winter storms. As hydrographic yield is strongly influenced by land use, this pattern suggests that seasonally changing land uses (or land uses in which the land cover changes on a seasonal basis) may significantly be affecting runoff patterns in the Satilla basin;
3) Salinity patterns in the Satilla River were analyzed during both high and low-discharge events. There was a large variation in the salinity regime of the Satilla River Estuary over the course of these observations, and they were used to demonstrate that the salinity regime of the estuary responds almost immediately to changes in discharge;
4) The Satilla data were used to assess a finite-element model developed at SkIO under State support. The study found that this model could not accurately simulate tidal and salinity conditions in the Satilla River estuary;
5) There is now
extensive field work being conducted to measure salinity, temperature, pressure,
and currents in the Ogeechee River.
Publications:
J.O. Blanton,
G. Lin and S.A. Elston. Tidal current asymmetry in shallow estuaries and tidal
creeks. Continental Shelf Research (in press).
J.O. Blanton. Are Our Estuaries Becoming Saltier? Part 1. Georgia Sound, Summer 2000.
J.O. Blanton. Are Our Estuaries Becoming Saltier? Part 2. Georgia Sound, Fall 2000.
H.E. Seim, J.O. Blanton and T.F. Gross. Direct stress measurements in a shallow, sinuous estuary. Continental Shelf Research (in press).
J. Blanton, M. Alber and J. Sheldon. Salinity responses of the Satilla River estuary to seasonal changes in freshwater discharge. In: Hatcher, K.J., editor, Proceedings of the 2001 Georgia Water Resources Conference, Athens, GA. pp. 619-622. [Summary]
Elkins, D. An analysis
of historic flows in the Satilla River using two statistical methods. In: Hatcher,
K.J., editor, Proceedings of the 2001 Georgia Water Resources Conference, Athens,
GA, pp. 787-790.
Additional Links:
http://www.ovpr.uga.edu/rcd/researchreporter/summer99/river.html