The Tennessee Valley Authority Lowers Lake Levels In Their River System At This Time Every Year, But You May Notice Boone Lake Getting Lower Much Earlier Than Normal. That’s Because TVA Is Drawing Down The Lake To Help With An Investigation Into A Sinkhole And Seepage Of Clay Particulates Into The Water At Boone Dame. Workers At The Dam Discovered The Sinkhole October 20th. TVA Vice President Of River Operations John McCormick Said TVA Employees Are Working Around The Clock To Find The Cause Of The Sinkhole.