National Program of Inspection of Non-Federal Dams, Tennessee. Lever Lake Dam (Inventory Number TN 18708), Harpeth River Basin, near Kingston Springs, Williamson County, Tennessee. Phase I Investigation Report

摘要

The dam is a linear earthen structure 163 feet long and 26.4 feet high with a crest width of 11 feet. The upstream and downstream slopes are both 1.4H:1V. The surface area of the lake is 3.7 acres at normal pool and 5.8 acres at the top of the dam. The 104 acre drainage area of the reservoir is predominantly woodland and meadow with an average ground slope of approximately 14%. Reportedly, water seeps slowly through fissures in the natural ground into a 0.4 acre lake 200 feet right of Lever. This dam was built for the purpose of maintaining pressure on the seeps and thereby maintaining the pool level of the larger lake. OCE guidelines recommend that small, high hazard dams such as Lever pass the one-half Probable Maximum Flood (1/2 PMF) to the full PMF. Analysis reveals that the dam will be overtopped by 0.6 feet for 0.6 hours under the 1/2 PMF. The reservoir contains the 100-year frequency storm maintaining 3 feet of freeboard. The dam is given a condition classification of 'unsafe - nonemergency' because of its spillway limitations and because the steepness of its downstream slope constitutes a stability concern. It is recommended that a qualified engineer be retained to study the embankment stability and the hydraulic limitations of the spillway and make recommendations for their correction.