NorthWestern Energy

The Morony Hydroelectric Development is owned and operated by NorthWestern Energy and consists of a concrete gravity dam and integral powerhouse located on the Missouri River. The project was started in 1928 and completed in 1930. The Morony Development is operated as a baseload project with outflows approximately equal to inflows into the upstream Great Falls developments. Morony is used to re-regulate releases from the upstream Cochrane and Ryan developments when the two upstream projects are operated to provide short-term reserve generation, load following generation or peaking generation.

Morony Dam is a concrete gravity dam with a length of 842-feet and a maximum height above streambed of 96 feet. The right non-overflow section is 68 feet long. An integral 390-foot-long gated spillway section extends from the right non-overflow section. The spillway section is equipped with a slide gate for handling trash and nine are equipped with 34 feet wide by 24 feet high Tainter gates. The 195 foot long gravity intake section is located between the spillway and left non-overflow section. The left non-overflow section extends 189 feet to the left abutment. A 4-ft wide and 7-ft tall inspection gallery extends through the length of the left non-overflow section, from the left side of the intake structure at floor EL. 2818 to the left abutment at floor El 2854.5.

The powerhouse is integral with the dam at the left abutment section. It is constructed with a mass concrete substructure, a structural steel frame, and reinforced concrete walls and roof slabs. Two turbine generators are installed in the powerhouse, with a total plant capacity of 49,000 kW. The amount of water taken by the plant at full load is 8,280 cfs at 82.5 feet of head.