Level, sediment to be reduced at South Cobb lake

The Cobb County Board of Commissioners has agreed to pay more to the owners of Gordon & Dees Lake and Dam for flood storage volume.

That amount is $138,630 in addition to the nearly $329,567 approved in April 2010 for a total of almost $468,197, according to Cobb Water System Agency Director Steve McCullers.

The $138,630 comprises $118,630 at 17 cents per cubic foot for additional available storage, resulting from a drop in the normal pool elevation of four feet, and $20,000 for sediment removal of 16,500 tons.

The April 2010 agreement provided for the creation of additional flood storage volume by permanently lowering the normal pool level at this lake by 8.9 vertical feet to elevation 1110.

That action created about 1,938,627 cubic feet of additional flood storage volume to store flood flows and additional freeboard on this lake to enhance public safety, McCullers said, also at 17 cents per cubic foot for around $329,567.

The related repair and alterations to the dam, bringing it into compliance with applicable regulations, have been completed; but McCullers said the cost of this work substantially exceeded the funds that Cobb was able to provide to the owners under the initial agreement.

With this new agreement, the normal pool level will be lowered further to make more flood storage volume available to stop flooding in the southern part of Cobb.

The owners propose to lower the normal pool level from elevation 1110 to elevation 1106 (a drop of four feet), resulting in a total flood storage volume available for Cobb’s purposes of 2,636,451 cubic feet which is 697,824 cubic feet more than considered in the original agreement.