The increases indicated in Tables 28 and 29 reflect a low flow condition which, based on gage data, has occurred only 7 percent of the time since construction of the J. Strom Thurmond Dam. In view of the existing salinity levels above U.S. 17, the minor increases in salinity predicted in this area for either a 2 or 4-foot deepening (0 - 0.68 ppt above US 17) would not be significant and would cause only minor adverse impacts on plant and animal life in the Savannah River system.

The determination that the impacts would not be significant are further supported by the information presented in Figures 20 through 22. These figures show the impacts of flow increases on salinity change predicted to result from a 4-foot deepening. As the figures indicate, in most cases, the amount of salinity change decreases as flows increase and the extent of salinity intrusion up each river system decreases substantially as flows increase. Therefore, under average flow conditions (12,000 cfs), salinity increases are much reduced.

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