Water flows from Thurmond Lake into the Savannah River will be reduced further under a drought plan adopted Friday by the Army Corps of Engineers.
"This plan improves the way we respond to droughts in the Upper Savannah River Basin and balances the impacts on hydropower generation, recreation, water quality and supply, while maintaining environmental stewardship," said Col. Mark S. Held, the Savannah district commander.
The old plan, adopted in 1989, required flows from the lake into the river to be cut from an average of 9,000 cubic feet per second to 4,500 cubic feet per second when the reservoir falls 6 feet below its normal full pool.
Under the revised plan, which takes effect in a few days, the flow would be further reduced to 4,000 cubic feet per second in efforts to slow the decline of water in the lake, Col. Held said.
The lake is at 323.86, or 6.14 feet below its full level of 330 feet above sea level.
Corps projections forecast the lake dropping to about 320 feet this fall unless rain increases.
Col. Held said the frequency and severity of droughts in the southeast appears to have been increasing since the early 1980s.
"I felt it was prudent to update the 1989 Drought Contingency Plan to conserve more water in the lakes in the earlier stages of a drought while considering and balancing the needs of all the water users in the basin," he said.
Downstream users include the city of Augusta, which draws from the river for drinking water, and numerous industries.
Proper wastewater dilution also requires adequate flow in the lower river, although operations are not affected as long as flows are at least 3,600 cubic feet per second.
The drought management strategy is one tool that can be used to offset falling lake levels. Also available in the corps' efforts to balance water needs are Russell Dam's reversible hydropower turbines, which can pump water from Thurmond Lake back into Russell for reuse in hydropower generation.
The corps can use only two of the four reversible units at a time from June to September under a court order involving a lawsuit over fish kills. The two units, however, are effective in allowing the corps to meet hydropower demands without depleting water reserves as quickly.
Reach Rob Pavey at (706) 868-1222, ext. 119, or firstname.lastname@example.org.
CHANGES TO PLAN
- Level 1, triggered when Thurmond Lake falls to 326 feet above sea level, formerly required only a safety advisory and public notice. The revision would reduce flows from the dam into the river from an average of 9,000 cubic feet per second to 4,200 cubic feet per second.
- Level 2, triggered at 324 feet above sea level, formerly required flow reductions to 4,500 cubic feet per second. The revision would further reduce flows to 4,000 cubic feet per second.
- Level 3, triggered at 316 feet above sea level, formerly required flow reductions to 3,600. The revision raises that figure to 3,800.
Source: Army Corps of Engineers