Some of you may have noticed that over the past few weeks Lake Hartwell has gradually become out of balance with Thurmond Lake. In fact, as of this writing the disparity is almost 4.5 feet in Hartwell’s favor: Hartwell’s elevation is 652.87 (7.13 feet below full) and Thurmond’s elevation is 318.52 (11.48 feet below full).
There are two contributing factors to this disparity:
1. Location of January rainfall – As our earlier post stated, January brought above-average rainfall to the Hartwell sub-basin. In fact, Hartwell’s rainfall was the second highest recorded in January since we built the dam. In contrast, Thurmond’s sub-basin experienced below-average rainfall. The following image demonstrates this point best. This plot shows data on January rainfall. Notice the sharp contrast in color at the southern boundary of Hartwell sub-basin:
2. Re-balancing takes time. During drought operations, water is only released from the Hartwell project when it is required to maintain a balanced pool with Thurmond. When Hartwell rises out of balance with Thurmond, we will move water from Hartwell through Russell down to Thurmond in a managed approach not to exceed the needs of the local electric cooperatives. This helps to keep electric rates in your area as low as possible rather than wasting the water at times when the power is not needed. This process of rebalancing can take from several days to possibly months. And if it keeps raining predominantly in the Hartwell basin, this will appear to exacerbate the imbalance. We understand these actions contribute to the levels going out of balance for a brief time, but we’re confident this decision is the best for all stakeholders – even those at Thurmond who will eventually benefit from the extra water. This approach is better than wasting water in a time of drought just to ensure the lakes are balanced especially while we are in the refill period.
We hope this helps explain the temporary difference in reservoir levels, and of course we welcome your questions and comments.
~ Russell Wicke, Savannah District Corporate Communications