Water Management Situation Report for Cumberland River Basin Reservoir System and Associated Waterways

J. Percy Priest

As late summer progressed, there arose an increasing concern about declining lake pool levels at some of the upstream storage projects which contribute virtually all the flows available to pass Nashville. This concern over the lack of water upstream combined with the poor condition of the tailwater area below J. Percy Priest Dam led to the start of modest spillway releases on a continuous basis from J. Percy Priest. A popular greenway passes along the left bank of the Stones River below J. Percy Priest, so any continuous flow, particularly in the warm season, helps enhance the outdoor experience on the greenway. Various amounts of water have been released via the spillway at J. Percy Priest this fall in lieu of generating with the turbine

Spillway releases at J. Percy Priest Dam are made to improve tailwater conditions and avoid the release of poor quality water through the turbine.

In general, flows gradually ramped up in response to needs in the main stem of the Cumberland River and also to begin bringing the Percy Priest pool down for winter drawdown. Regular monitoring revealed that thermal stratification continued quite strong at the dam forebay. On November 16 the turbine ran for one hour and unfortunately, the odor of rotten eggs, indicating hydrogen sulfide, was evident. This objectionable smell along with the black appearance of the water (due to dissolved manganese) meant the turbine at J. Percy Priest would remain shut down until conditions improved. Following the turbine release, flows were increased substantially up to 1900 cfs and were varied in order to adjust the pool level. Finally, on December 14 with the lake destratified, the turbine was put to use and the spillway flow was stopped.