The three reservoirs on the Savannah River operated by the U.S. Army Corps of Engineers reached the second drought trigger level out of four on Aug. 29, 2011 and therefore, Corps officials further reduced water discharges from the system.
“The reservoirs will likely continue to decline over the next several weeks unless a tropical system moves over the area,” said Stan Simpson, a water control manager with the Army Corps of Engineers. To slow the decline, the Corps limits outflow from Thurmond Dam to 4,000 cubic feet per second, averaged over the week at drought level 2. Reducing outflows from the level 1 rate of 4,200 cfs decreases the amount of hydropower generated through the dams but conserves more water in the reservoirs.
Users will find ample opportunities for fishing, boating, using personal watercraft, and water skiing, especially during the busy Labor Day weekend. However, with lower water levels, Corps officials continue to urge the public to use caution when on the reservoirs. As the reservoir levels decline, underwater obstructions are closer to the surface. This is particularly dangerous for boaters and skiers. Swimming or wading outside designated swimming areas can pose special dangers due to uneven and unpredictable slopes and underwater obstructions. All visitors should wear a life jacket when swimming, boating or fishing. Dock owners may need to move their docks to remain in adequately deep water.
The pool elevation on Aug. 29 was 654.5 feet above mean sea level (ft-msl) at Hartwell Lake, and 323.8 ft-msl at Thurmond Lake. Under the drought plan the Drought Level 2 trigger is 654 ft-msl for Hartwell and 324 ft-msl for Thurmond. Currently, Hartwell averages only five percent of normal amount of water entering the reservoir from rainfall, rivers, and streams. Thurmond’s water inflow is about 35 percent of normal. Precipitation forecasts show little rain for the region in upcoming weeks. Hydrologists with the Savannah District note that current declining reservoir conditions follow a typical summer pattern.
Earlier in the summer, to conserve more water in the three-reservoir system but still meet hydropower demands, workers increased the pump-back operation of the Russell Dam. Pump-back allows the Corps to generate electricity at the Russell Dam during peak afternoon demand times then reverse turbine direction at night to return the water for reuse the next day. This helps meet summer power needs even during drought. The recent addition of an oxygen-injection system in Lake Thurmond allowed the Corps to increase pump-back operations.
The Corps’ water management plan, which sets the downstream water releases, included input from the public plus state and federal natural resource agencies. Representatives from these agencies have indicated that further flow reductions can have a detrimental effect on critical habitat downstream of the reservoirs.
The Corps strives to meet the congressionally-set purposes of the reservoirs. Besides recreation and hydropower production, other congressionally-authorized purposes of the reservoirs include water supply, water quality, flood risk management, navigation, and fish and wildlife management. During drought, the Savannah District only generates hydropower as a byproduct of passing water through the dams to meet downstream needs, according to Jason Ward, a water manager for the Savannah District.
Augusta and Savannah in Georgia and North Augusta and Jasper County in South Carolina withdraw drinking water from the river. Industries and utilities use river water, Ward said. Threatened and endangered species and the Savannah National Wildlife Refuge also depend on the river.
For more information on current lake levels and projections, contact the Savannah District Corporate Communications Office at 912-652-5014, or visit the District’s lake-level website at http://water.sas.usace.army.mil