GIS for EAPs: Preparation and training applications

O ’Shaughnessy Dam was built on the Scioto River in 1925,18 miles upstream of Columbus, Ohio and four miles upstream of Dublin, which was a small village at that time. The dam was constructed to create a large water supply reservoir for Columbus, supplementing the earlier Griggs Reservoir formed by Griggs Dam 10 miles downstream. O ’Shaughnessy Dam is comprised mainly of a concrete spillway section 880 feet long, which creates a normal pool 70 feet above the streambed. The dam also has earthen embankments at each end that are 18 feet higher than the spillway. A highway is located on top of the embankments that crosses the spillway on a 12-span bridge.O ’Shaughnessy Dam impounds 16,300-acre-feet of water at normal pool level. Griggs Dam is of total concrete construction, its spillway is 35 feet high and the crest of the dam is 20 feet higher. It impounds 4,300-acre-feet of water at normal pool level. A 5-megawatt hydroelectric power plant was constructed in 1986 at O ’Shaughnessy Dam. The primary purpose of the dam remains water supply storage; the hydro plant usually generates power only when there is excess streamflow from the 980 square mile drainage area tributary to the dam. The hydro plant was constructed in compliance with requirements of the Federal Energy Regulatory Commission. It also has to be operated in compliance with FERC requirements, which includes having an Emergency Action Plan. 5 pp.