Dam malfunction leaves trout stranded

Hebgen Dam, which controls water flow in the Upper Madison River, abruptly reduced its outflow from 650 cubic feet per second (CFS) to below 200 CFS early last Tuesday, Nov. 30. The cause of the flow reduction was a dam malfunction in the flow gate. The sharp drop in flows left fish stranded and threatened serious damage to the Madison River trout fishery, a global mecca for recreational angling.

Kelly Galloup is the owner of the Slide Inn, a fly shop near Hebgen Dam named for an iconic stretch of turbulent water on the Madison known to anglers as “The Slide.” Galloup first became aware of the malfunction when a customer inquired about the low flows below Hebgen on Tuesday morning. “We started calling everybody we could,” Galloup said. Despite the urgency of the situation, Galloup and his colleagues at fly shops across the state had trouble getting through to NorthWestern Energy, which owns and operates Hebgen Dam. “It was 1 o’clock before [NorthWestern] showed up,” Galloup recalled.

At first, Galloup assumed NorthWestern would be able to quickly restore flows to the Madison once they arrived on the scene, but it soon became clear there was no immediate fix available. “Our personnel from across the company are working to restore flow to the Madison River downstream from Hebgen Dam, which dropped dramatically due to an unplanned event earlier today. Steps in place now are slowly increasing outflows at Hebgen Dam into the Madison River. However, river flows may not be fully restored for several days. The public’s safety and the health of the fishery are our priority,” NorthWestern Energy said in a series of tweets on Nov. 30.

At this point, Montana Fish Wildlife and Parks (FWP) and local fly shops began calling on volunteers to help rescue stranded fish along the Madison. “It was people that gave a damn who showed up,” Galloup said. “The number of people who are totally personally involved with this river is just staggering.”

Fall is spawning season for the Madison River’s world-famous population of wild brown trout, and low flows represent a serious threat to the survival of trout eggs deposited in the river’s gravel bottom. Before laying eggs, the trout clean a patch of gravel in the river bottom using their tails. This patch is called a redd. If the redd is deprived of flowing water for too long, the eggs could die, severely harming the future brown trout population. The Exponent spoke with Mike Duncan, a Montana FWP fisheries biologist who works in the Madison River drainage, to learn more about the effects of the dam malfunction on the fishery. “Clearly, some fish died and we probably lost some redds, but I don't think we’ll see significant population-level effects,” Duncan said, adding, “It’s probably a little too early to speculate, but it wasn’t as bad as I was expecting.” Duncan was also impressed by the volunteer turnout on Wednesday morning. “It was really encouraging to see the amount of support and the willingness of folks to come out and work together,” he said.

Among those who flocked to the river in hopes of saving fish was senior Brooklin Hunt. Hunt is a member of the MSU Fly Fishing Club and an avid angler and conservationist. “When you’re an angler around here, any damage to any river is devastating,” Hunt said. “If you’re an angler in this community it’s your personal responsibility to be as educated as possible and to make sure you’re doing what you can for conservation.”

NorthWestern Energy restored flows to the Madison River late on the night of Wednesday, Dec. 1, and the river is once again running at a healthy rate. Although disaster was largely avoided, many in the angling community are not satisfied. “Next summer when the river is perfect and we’ve got massive hatches, everybody is gonna go, ‘It’s great, the river is fine’. Well, first of all, we aren’t positive what this did, and second of all, what if this happens again?” Galloup said, “Somebody’s gotta make sure this doesn’t happen again.”