 Cougar Dam operates in coordination with Blue River Dam to control flooding, and since the completion of the dam, it is estimated that it prevented approximately $452 million in potential flood damages.The dam consists of a rock-fill embankment approximately long, a penstock to power two Kaplan turbines, an emergency spillway capable of a capacity of , a regulating outlet, and a diversion tunnel.The diversion tunnel was built to divert the South Fork McKenzie River during the construction of Cougar Dam, and the tunnel was later closed with a concrete plug once the construction of the dam was complete.