National Program of Inspection of Non-Federal Dams, Tennessee. Grand Valley Dam Number 2 (Inventory Number TN 06925), Hatchie River Basin, Near Hickory Valley, Hardeman County, Tennessee. Phase I Investigation Report

摘要

Grand Valley Dam No. 2 is located in Hardeman County, Tennessee seven miles east of Hickory Valley, Tennessee and is an earth fill embankment 16 feet high and 560 feet long with a crest width of 22 feet. Facilities for discharge for the reservoir are located in the left abutment and include a 24 inch corrugated metal pipe culvert through the dam, and an emergency spillway cut into the right abutment. This spillway is trapezoidal shaped with a bottom width of 50 feet. A paved road fill crosses the spillway at approximately the location of the control section and effectively cuts off the spillway from use. The embankment slopes are 1 vertical on 3 horizontal from the water line to the top of the dam on the upstream slope. The downstream slope averages 1 vertical on 3 horizontal. The upstream slope is free of undesirable growth and debris but the downstream slope is covered with high grass and small saplings. On the basis of hydraulic analysis, flood storage (95 acre-feet) and spillways are insufficient to safely pass the 1/2 Probable Maximum Flood (PMF) which the Office of the Chief of Engineers (OCE) Guidelines specify to be the design flood for a dam in the small size and high hazard categories. The dam is in the small size category and has a downstream hazard potential classification of high by the USCE and '1' by the State of Tennessee.