Happy Jacks Dam

Happy Jacks Dam is a major ungated concrete gravity dam across the Tumut River in the Snowy Mountains region of New South Wales, Australia. The dam's main purpose is for the generation of hydro-power and is one of the sixteen major dams that comprise the Snowy Mountains Scheme, a vast hydroelectricity and irrigation complex constructed in south-east Australia between 1949 and 1974 and now run by Snowy Hydro.

The impounded reservoir is called the Happy Jacks Pondage. The dam wall is immediately downstream of the confluence of Happy Jacks Creek and the Tumut River.

Location and features
Completed in 1959, Happy Jacks Dam is a major dam, located within the Snowy Valleys local government area. The dam was constructed by a consortium comprising Kaiser-Walsh-Perini-Raymond based on engineering plans developed by the United States Bureau of Reclamation under contract from the Snowy Mountains Hydroelectric Authority.

The dam wall comprising 8950 m3 of concrete is 29 m high and 76 m long. At 100% capacity the dam wall holds back 271 ML of water. The surface area of Happy Jacks Pondage is 5 ha. The uncontrolled spillway is capable of discharging 1827 m3/s.