The failure of a solid metal shaft that dropped a gate on Hebgen Lake Dam was responsible for cutting off water to the Madison. Although the failure resulted in significant dewatering of an upper Madison River the lower flows farther downstream violated NorthWestern Energy’s requirements with the Federal Energy Regulatory Commission.
The company also violated its license because it is required to limit changes in outflows from Hebgen Lake Dam to no more than 10% a day.
LINK (via Montana Standard)
