The Corps operates Hartwell and the other two Savannah Lakes (Russell and Thurmond) per the Drought Contingency Plan once a drought level 1 condition is reached (656MSL for Hartwell summer pool). The purpose of the drought plan is to conserve water resources in the lakes, while providing flows necessary to protect the drinking water, commercial and environmental needs of the lower basin. A revised drought plan was put in effect several years ago with the consensus of  both states, federal agencies and Savannah Basin stakeholders. The main revision in the plan called for flow reductions at drought level 1 versus the old plan that did not call for any mitigation until level 2.

The drought plan sets flow reductions from 4200CFS down to 3800CFS through the first three drought levels. The designated flows are measured at Thurmond Dam, so typically flows from Hartwell will be in the order of 2000CFS, with the remainder provided by the other lakes’ watersheds. At drought level 4, a flow in equals flow out approach is initiated. This final level occurs when both Hartwell and Thurmond Lakes have reached the bottom of their conservation pools. The depth of the conservation pools for Hartwell, Russell and Thurmond are 35 feet, 5 feet and 20 feet respectively due to the design of each dam. As the pools of Hartwell and Thurmond are reduced during a drought, the plan calls for the level impacts to be kept essentially equal through the first 15 feet. Once at this depth, there are 20 feet of conservation pool remaining in Hartwell, but only 5 feet in Thurmond. At that point flows are regulated such that the conservation pools of each lake will simultaneously be exhausted. Thus flows from Hartwell will exceed those from Thurmond by a factor of about 4 times.

The current drought in the Savannah Basin is the most severe in the history of the lakes. In almost 50 years of operation, the Hartwell pool has never exceeded an 18-foot reduction. It is now expected that this will occur in the fall of 2008, and in a worst-case scenario, the conservation pool could be consumed by summer of 2009. This is totally uncharted territory for the management of the lakes.

Recognizing the severity of the drought, the Corps proactively reduced flows to 3600CFS in October of 2007 while still at drought level 1. This rate represents the lowest historical drought flow rate. The Corps is required to make releases per the drought plan; and any significant deviation below this rate would trigger a full environmental impact study, requiring several years for completion. The Corps and states are working on a plan to modestly reduce flows in the winter months when the river is under less stress. This program could be done under a more modest environmental assessment. LHA petitioned the Corps and states to try such an approach in winter 2007, and we continue to push for implementation in the 2008 winter season.

LHA believes that the current drought has clearly demonstrated the need for drought plan improvements. It is in the interest of all users in the basin to preserve water resources in the lakes as long as possible during a drought. It must be determined by sound science what minimum flows are absolutely required downstream, and also what mitigation can be done to operate with lower flows, e.g. lowering or relocating water intakes. We also believe that the Basin should be managed adaptively during a drought by inline, real-time monitoring of river conditions, and adjusting flows accordingly, rather than at some arbitrary constant rate. This assessment will require congressional funding for completion of the Basin Comprehensive Study, which LHA has been pushing for a number of years.  Once the current drought is past, we must continue to keep this effort in focus.