Work resumes at Hebgen Dam

Work has resumed stabilizing the intake structure, which will be anchored to the rock face behind it and rebuilt with hydraulically controlled gates, a secondary emergency shutoff gate, a large gate at the bottom for emergency flow needs and a single bay replacing the current four bays. Damage to the intake structure was caused by the failure of stoplogs in one of the intake bays in August 2008.

Work has also resumed on the cofferdam, which is expected to be completed by June. The cofferdam will create a watertight seal that will give workers access to normally submerged areas of the intake structure, allowing them to make permanent repairs.

The improvements being made at Hebgen Dam have no effect on meeting lake levels or river flows as required by PPL Montana’s federal operating license. The work has been done safely and is in keeping with PPL Montana’s goal to protect fisheries and public recreation, which are critical to the summer tourism season in the Madison Valley.

The dam itself has consistently remained safe and stable, according to engineering inspection results and on-site monitoring equipment.

PPL Montana operates the Hebgen Dam to regulate the flow of water into the Madison-Missouri system, balance the needs of recreational users of Hebgen Lake and to protect important river resources downstream on the Madison River.

Hebgen Dam creates Hebgen Reservoir near West Yellowstone, which stores water for the Madison-Missouri River system. PPL Montana owns and operates eight hydroelectric facilities on the Madison and Missouri Rivers.