SAVANNAH, Ga. –The three reservoirs on the Savannah River operated by the U.S. Army Corps of Engineers entered the first drought level early Sunday morning when pool elevation at
J. Strom Thurmond Lake dipped to 325.91 feet above mean sea level (ft-msl). Entering Trigger Level 1 activates the Corps’
drought management plan which limits the discharge rate from the Thurmond Dam.
Under the existing drought plan, the Corps limits outflow from Thurmond Dam to 4,200 cubic feet per second (cfs), averaged over the week. Reducing outflow decreases the amount of hydropower generated through the dams but conserves more water in the reservoirs.
The pool elevation on Aug. 31 was 656.13 ft-msl at
Hartwell Lake. Pool level at Thurmond Lake rose to 325.95 ft msl. Once either Hartwell Lake or Thurmond Lake enter drought conditions, all reservoirs remain at that level until Hartwell and Thurmond rise 2 feet above the trigger. Level 1 is 656 ft-msl for Hartwell and 326 ft-msl for Thurmond. In addition, the 28-day average flow of the Broad River into Thurmond Lake is above 10 percent of normal. Because of these conditions, the drought plan limits outflows from Thurmond Dam to 4,200 cubic feet per second (cfs) averaged over 24 hours.
Corps officials point out level 1 does not limit recreation on the reservoirs. Camping, boating, skiing, fishing and other forms of recreation continue unabated. As always they urge the public to use caution when boating, swimming or fishing. As the reservoir levels decline, underwater obstructions will be closer to the surface. This is particularly dangerous for boaters and skiers. 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 reservoirs stayed in normal operations and near or above full summer pool since the beginning of 2015,” said Stan Simpson, a hydrologist and a senior water manager for the Savannah District. The reservoirs experienced a typical late summer decline, according to Simpson. Water managers and dam operators will reduce outflows from Thurmond Dam and rely on increased pumpback operations at
Russell Dam to help meet electricity demands and to retain water in the three-reservoir system.
Pumpback 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, providing power even during drought.
The congressionally-authorized purposes of the reservoirs include water supply, water quality, recreation, flood risk management, navigation, hydropower production, and fish and wildlife management. More than 10 public water systems and industrial users draw water directly from the reservoirs and even more draw from the Savannah River downstream of Thurmond Dam. Downstream users include the cities of Augusta and Savannah in Georgia and North Augusta and Jasper County in South Carolina 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.