One year later: Groups still searching for Willwood Dam sediment solution


Emotions were running high this time last year, after repairs at the Willwood Dam caused a release of sediment into the Shoshone River and temporarily turned the popular fishery into a gray slurry. Many feared of a massive fish die-off.

Faulty sluice gates had contributed to a large amount of sediment backed up behind the dam. When repairs had to be made, the silt was carried down river along with debris — including many dozens of tires that had been illegally dumped in the river by litterers.

After news of the sediment release became public, more than 100 people attended a public meeting at the Park County Fairgrounds last November, with many calling for immediate action. Fears of a major fish kill — and frustration after the third such release since 2007 — drove much of the protests. At one point, a landowner downstream from the dam collected dozens of more than 100 tires that washed down and dumped them in the parking lot at the Willwood Irrigation District office.

“We were made out to be villains. Our manager quit because of it,” said Roger Smith, president of the Willwood Irrigation District. “We were called fish killers and destroyers of the environment.”

A year later, results from a trout population survey found that the losses from the sediment release, were not as much as originally thought, said Sam Hochhalter, Game and Fish Cody region fisheries supervisor.

“After the river cleared, we saw about a 10 percent reduction” when compared to a previous survey in 2013, he said.

The fish are measured in biomass (size of the fish) rather than population — a better metric when considering the reproductive capacity, Hochhalter said.

However, Smith said “it’s misleading to say there’s a 10 percent decrease due to the release [of silt].”

The fishery had been in decline for the past decade, Smith said, as the Game and Fish cut back on their stocking about a decade ago.

“The populations already showed a 10 percent reduction annually. I contend I have the data to back that up,” Smith said.

While name calling and finger pointing was primarily at the irrigation district, the board tried to be patient despite being irritated by the accusations, Smith said.

“We had permission from DEQ and the Game and Fish [to lower the water level]. The only other option was to not fix the dam,” Smith said.

The DEQ (the Wyoming Department of Environmental Quality) had issued a permit allowing the district to temporarily increase the turbidity of the Shoshone River during the work on the dam, but the department issued a notice of violation after so much silt was released.

DEQ spokesman Keith Guille said the notice of violation remains open.

Dave Sweet, a leader in the Trout Unlimited East Yellowstone Chapter and a member of a working group organized to look at possible solutions to the problem, said Smith at the irrigation district is “doing everything he can.”

“They don’t want this to happen again,” Sweet said of the district.

The silver lining to the public outcry concerning the sediment releases is the creation of the working groups. They were organized to have positive conversations about the issue. There are three groups. The first group addressed the immediate problem below the dam. The group sponsored a cleanup along the river in March and more than 100 volunteers showed up to help, Sweet said.

The second group was charged with looking at the dam operations in an effort to figure out how to stop the sediment releases from happening.

The third group is looking at upstream sediment sources, including erosion runoff from the McCullough Peaks, bank erosion due to development, tributaries and agricultural runoff. The group meets monthly, according to Sweet, and is assisted by two new monitoring stations  installed by the U.S. Geological Survey that provide realtime measurements of sediment in the river.

Groups involved in the talks include Trout Unlimited, the Game and Fish, DEQ, U.S. Bureau of Reclamation, Wyoming Water Development Commission and the irrigation district, according to Guille.

“It’s a long-term process. It didn’t happen overnight and it can’t be fixed overnight,” he said.

Those involved are in agreement with one thing: The working groups are a positive step for the future of the dam and the lower Shoshone River fishery.

“We have everyone sitting at the table having productive conversations on how to solve the issue,” Hochhalter said.

Even the heated public outcry was a positive for Guille.

“It’s always a positive when people are concerned,” he said. “We have strong support from the public for the resource.”

Sweet hopes to avoid heated exchanges in the future.

“Agriculture is part of our heritage as well as fishing. We just have to learn how to make them work together,” Sweet said.

Smith knows there’s no turning back the clock on the statements made about the Willwood Irrigation District, but feels positive about the current direction of discussions.

“We’re more than willing to do what is healthy for the fishery,” Smith said. “We just want to move forward in a positive direction.”

The public may notice slightly higher turbidity through Oct. 31, as the water level behind the dam is lowered in preparation for winter. Lowering the water level is necessary to prevent the dam and other infrastructure from freezing, but will be done in a manner that will minimize impacts to the downstream fishery, the DEQ says.