Private reservoirs support Corps public ones

Senior Public Affairs Specialist
Published Dec. 11, 2014
Editor’s note: This installment of a continuing series of articles explaining the operations of the Savannah River basin, looks at the support upstream, privately-owned reservoirs contribute to keeping the basin in balance. Savannah District officials often get asked why Lake Keowee, owned by Duke Energy, seems to remain full while the Corps’ reservoirs, particularly Hartwell Lake seems to drop. Read below on how the far-upper basin supports the central basin.

Georgia’s Tugaloo River and South Carolina’s Seneca River meet underneath the waters of Hartwell Lake to form the Savannah. Both rivers host privately-owned reservoirs used to produce electricity for the region. Those reservoirs also provide water for Hartwell, Russell and Thurmond lakes – and therefore the rest of the basin.

Stakeholders in the basin occasionally ask why Keowee seems to remain full while Hartwell Lake and Thurmond Lake drop, especially during drought. In reality, Duke Power in South Carolina, owner of Lake Keowee, Lake Jocasee and the Bad Creek reservoir, provide significant amounts of water to the basin, according to Stanley Simpson, a Savannah District water manager. Duke provides water to the Corps based on a storage balance agreement established in 1968.

Under the agreement Duke Energy provides water to Hartwell Lake based on the percentage of remaining conservation storage in Hartwell. As Hartwell declines during drought, the total conservation storage of Duke’s reservoir system must decline by the same percentage, Simpson said. The agreement uses percentages rather than elevation because of the difference in size between Hartwell and any one of Duke’s reservoirs.

Another important issue requires a more stable water level at Lake Keowee – the Oconee Nuclear Station. In order to operate and to operate safely, a nuclear power plant requires a large, reliable and instantly-available water supply. The Nuclear Regulatory Commission requires Duke to maintain Lake Keowee within a specified range by not allowing the reservoir to decline more than six feet. This range limits the available conservation storage at Keowee. To fulfill its agreement with the Corps, Duke Energy occasionally must pass water from Jocasee at a greater rate.

Meeting their obligation to the Corps also requires close coordination with Savannah District water managers. “We have a minimum of weekly discussions with Duke Power,” Jason Lavecchia, another Savannah District water manager, said.

“We tell Duke how much they must release to meet their agreement,” Simpson added. “They are limited on how much they can send to us and still operate their nuclear power plant. We keep that in mind whenever we discuss discharges from their system.”

Like at Hartwell Lake, many people live along Keowee Lake. With its multiple access points and active recreation support, Keowee attracts many of the same people who enjoy Hartwell Lake. This leads to the complaint that Keowee does not support the basin as Hartwell and Thurmond lakes do. While it may seem that way, Duke Energy supports the well-being of Hartwell Lake, lives up to its agreement with the Corps and contributes to balancing the basin.


Stan Simpson and Jason Lavecchia, Savannah District’s water managers, expect a leveling off of the district’s reservoirs by the end of 2014. According to long-range outlooks by the National Weather Service, an anticipated milder winter, with the annual, natural reduction in evaporation and transpiration, will lead to the reservoirs stabilizing. Weather predictions continue to call for an equal chance of normal, wet or dry conditions.