NorthWestern Energy fixes Hebgen Dam, restoring flows on upper Madison River

EBS STAFF

Editor’s note: This story has been updated to reflect FWP’s announcement on the upper Madison River fishing closure.

HEBGEN LAKE – NorthWestern Energy crews successfully repaired Hebgen Dam just before midnight on Dec. 1, according to a NorthWestern Energy Facebook post, restoring flows to the Madison River.

A gate outlet on the dam malfunctioned early morning on Nov. 30, decreasing the opening for the outtake of water at the bottom of the gate. The Madison River flow dropped to nearly one third of the normal rate as a result, stranding fish and exposing spawning beds in the river called redds. 

A replacement part was fabricated overnight on Nov. 30 in Anaconda and NorthWestern Energy, operator of the dam, completed the repair last night. Associated Underwater Services provided divers who inspected and replaced the failed component underwater.

Montana Fish, Wildlife and Parks will lift the current fishing closure on Friday. FWP ordered the closure on Nov. 30 for the upper Madison River, spanning from Hebgen Dam to Ennis Lake. According to FWP, the full impact of the incident on the river’s health and the fish is still unknown.