Dam Safety Assurance Study for Dover Dam, Tuscarawas County, Ohio

The Huntington District of the US Army Corps of Engineers operates and maintains seventeen flood control reservoirs in the Muskingum River Basin located in the east central and southeastern region of Ohio. The fourteen original projects were constructed during the mid to late 1930's. Since that time, nearly seven decades of hydrologic data and stream flows have been recorded. Also, hydrologic and hydraulic design criteria for dams have evolved, and the sensitivity and awareness for public safety in the downstream areas has elevated significantly. The Corps of Engineers Dam Safety Assurance (DSA) program provides for upgrading existing dams which have hydrologic or seismic deficiencies to allow them to function safely, and as originally intended. Project specific downstream hazards are determined in terms of population at risk, loss of life, and economic damages for the base condition and for an array of alternatives for correction of the deficiencies. The extent to which any individual project is upgraded is determined by the reduction of the downstream hazard that is provided by the recommended plan. One of the original fourteen Muskingum River projects is the Dover Dam. This project is a concrete gravity structure located approximately 3.5 miles northeast of New Philadelphia, Ohio on the Tuscarawas River. The Corps of Engineers has initiated the DSA program studies for Dover Dam, which involves extensive analysis to determine the deficiencies of the existing dam as compared to modern day design criteria. The dam has no seismic deficiencies. However, the project does have hydrologic deficiencies. Based on present day design criteria, the Probable Maximum Flood (PMF) would exceed the top of the existing dam by six feet, assuming the dam to be raised in place. In addition, geotechnical and structural stability computations demonstrate that the dam could fail at flood pool levels approaching the spillway crest of the existing dam (elevation 916), or approximately 36% of the PMF. Therefore, Dover Dam must be upgraded to meet present day design criteria provided by ER 1110-2-1155. Major features of the recommended plan for correction of the hydrologic deficiencies include raising the top of the dam 8.6 feet to elevation 940.0, and stabilizing the existing dam monoliths with high strength, multi-strand steel anchors. This paper will provide an introduction to the Dover Dam, describe the DSA study process, and present the recommended plan. The selection of the level of the proposed upgrade will be provided. (Proceedings includes full paper) 20 pp.