The U.S. Army Corps of Engineers Savannah District will reduce outflows from the three reservoirs it operates on the upper Savannah River Basin in response to water levels reaching drought level 3. Water managers will gradually reduce outflows from 3,800 cubic feet per second (cfs) to 3,100 cfs, based on a maximum daily average.
The process of flow reduction to 3,100 cfs will take place over the next several days. By Nov. 2, the Corps has a targeted outflow of 3,600 cfs. Outflows are scheduled to be reduced to 3,400 cfs by Nov. 6 and 3,200 cfs by Nov. 9. Beginning Nov. 10, the target will be 3,100 cfs through January.
A gradual reduction in flow allows the U.S. Department of Fish and Wildlife to monitor the progress of the freshwater mussels adjusting to the shifting water level on the river banks.
The lower Savannah River will see effects of flow reductions about a week after the outflow reduction.
Corps officials remind the public extensive recreation opportunities remain available on the reservoirs and surrounding areas.
“The large size of the reservoirs affords the public many reasons to visit, including boating, fishing, camping, and hiking,” said Melissa Wolf, Chief of the Natural Resources section for the Savannah District. “However, we encourage people to exercise caution when boating and swimming – and to wear life jackets when in, on, or near the water.”
Due to the lower reservoir levels, hazards such as tree stumps and other obstructions, normally far underwater are near or above the surface, according to Wolf. “There are too many hazards to mark so we encourage boaters to be safe and maintain low speeds on the lakes. The centerline of the reservoir channel is the safest place to operate,” she said.
The Corps of Engineers updates the status of boat ramps at the reservoirs weekly on the Savannah District website.
DETERMINING DROUGHT LEVELS
The reservoirs enter drought level 3 when water levels for either Hartwell or Thurmond reservoir fall 14 feet below full pool. Full pool at Hartwell is 660 feet above mean sea level (ft-msl) and 330 ft-msl for Thurmond.
The flow reduction was authorized in the Corps 2012 update to its drought plan, which established wintertime flow reductions from November through January. The wintertime flow reduction is 3,600 cfs if the reservoirs are in drought level 2; and 3,100 cfs if the reservoirs are in drought level 3. Flows can be reduced in the winter months because the cooler water can hold more oxygen for fish.
The reservoirs entered drought level 2 in August 2011. The Corps has held a flow rate of 3,800 cfs since October 2011.
DROUGHT RECOVERY ACTIONS
In addition to flow reductions, the Corps plans to make an exception to the conventional refill rates. Typically, the Corps increases outflows as the reservoirs refill. However, based on recent developing trend s of decreasing winter rains, Savannah District Commander Col. Jeff Hall has authorized the water manager to maintain the level 3 release (3,800 cfs) until the reservoirs return to full summer pool.
The Corps manages the Hartwell, Russell and Thurmond reservoirs as one balanced system, using water from the reservoirs for seven Congressionally-authorized purposes: water quality, water supply, recreation, fish and wildlife, flood risk management, navigation, and hydropower. During moderate to severe drought, priority is given to water quality (diluting downstream municipal and industrial discharges) and water supply (drinking water). Hydropower is only generated as a byproduct of releasing water for downstream purposes.
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.