This dam has a bypass spillway near the bottom of the dam which spills a certain amount of water through almost the whole year. Being near the bottom of the dam the water comes out under considerable pressure, creating an almost horizontal waterfall. It looks much like a really big fire hose.
The dam is on the South Fork of the Flathead River and creates the Hungry Horse Reservoir Recreation Area. The reservoir contains a maximum of 3,468,000 acre-feet of water when full.
Hungry Horse Dam is 564-feet-high and has a variable-thickness concrete arch structure with a crest length of 2,115 ft. The dam and appurtenant works contain 3,086,200 cubic yards of concrete. The spillway is the highest morning-glory structure in the world. Water cascading over the spillway rim drops a maximum distance of 490 feet. The capacity of the spillway is 50,000 cubic feet per second, and the reservoir has a total capacity of 3,468,000 acre-feet.
The above ground powerplant building at the base of the dam houses four 107,000 kW hydroelectric generation units. The four steel penstocks are 13.5 feet in diameter and 450 feet long. Maximum operating head is 477 feet with a maximum turbine discharge of 3,150 cubic feet per second for each turbine. A selective withdrawal system is installed in each penstock trash rack to control the temperature of water released for downstream fishery enhancement.
The generating units were uprated and overhauled during the period 1990-1993. Capacity of each unit went from 71,250 kW to 107,000 kW. Conversion work for remote operation began in 1994. The switchyard was rebuilt in 1995 and a penstock selective withdrawal system was also installed in 1995.
From the Department of the Interior