Specifications include, but are not limited to: Shadow Lake Dam is an earth embankment dam with a principal spillway and auxiliary spillway. The dam is currently classified as a SIGNIFICANT hazard potential dam. According to file information, the dam is approximately 130 feet long with a structural height of 12 feet. The principal spillway is a cast-in-place concrete drop inlet- style spillway with a single stoplog section that controls lake elevation. Flow is released through a 36-inch diameter slide gate that is generally maintained in an open position. The stoplogs and slide gate are housed in a timber building. The auxiliary spillway is 33.5 feet long and 15 feet wide. The dam’s original construction dates to the 1800s and the auxiliary spillway was constructed to its current configuration in 1929. The objective of the project is to confirm the hazard potential classification, determine the Inflow Design Flood (IDF), and study alternatives to make the dam hydraulically adequate while balancing impacts both upstream and downstream
