Willwood silt dilemma

Posted 11/17/16

Since the Willwood Irrigation District lowered the dam pool to repair the dam last month, silt has been sloughing off silt bars upstream, releasing sediment into the Shoshone River downstream. The river turned a grayish color and an unknown number …

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Willwood silt dilemma

Posted

Government officials, citizens ponder possible solutions

Close to 100 people attended a Tuesday meeting to discuss the tons of silt that have and may still flow into the Shoshone River below the Willwood Dam. But while many attendees called for action, no ultimate solution was found at the meeting.

Since the Willwood Irrigation District lowered the dam pool to repair the dam last month, silt has been sloughing off silt bars upstream, releasing sediment into the Shoshone River downstream. The river turned a grayish color and an unknown number of fish were killed.

The Wyoming Game and Fish Department notified the Wyoming Department of Environmental Quality (DEQ) of the silt on Oct. 18.

Park County commissioners called Tuesday’s informational meeting at the fairgrounds to bring all of the involved parties together.

“I know there are some raw feelings out there,” Commission Chairman Tim French said as he got things underway.

The Bureau of Reclamation owns the Willwood Dam and, under a 1949 contract, the Willwood Irrigation District is responsible for maintenance and operations, said Carlie Ronca, the bureau’s Wyoming area manager. The purpose of the dam is to raise the river’s elevation to feed the irrigation canal by gravity, Ronca said. Three sluice gates allow sediment to be sluiced out.

The DEQ issued both the district and bureau a notice of violation for the silt release, Ronca said. The district and bureau have offered to meet with the DEQ to seek a solution.

Willwood does not generate the silt, said Todd Singbeil, district manager. “It’s an upstream issue we need to address.”

A contractor is in the process of completing a two-phase project to replace two canal gates, stems on a sluice gate and pins on a penstock on the dam, Singbeil said.

Work is expected to be finished by Friday, Singbeil said. Beginning Monday, they will begin re-filling the pool above the dam. It will take seven to 10 days to bring the water back up. As the pool level rises, it will become clearer.

There are 530,000 cubic yards of silt still above the dam, Singbeil said. One price to remove it is $6 to $7 per cubic yard. A plan must also be made to dispose of the sediment too.

Floyd Derry, Powell-Clarks Fork Conservation District, said he was the third generation of his family to farm on the Willwood.

Only 2 percent of land around the Shoshone and Big Horn rivers is privately owned, Derry said. The rest is state and federal land. The “dirt” eroding from the McCullough Peaks into the Shoshone must be stopped.

“It’s time for our bureaucracies to find a common sense solution,” Derry said, earning a round of applause.

What happened

DEQ watershed protection program manager David Waterstreet said his department began meeting with the district and bureau in January to discuss the district’s planned repairs to the dam.

DEQ did authorize a turbidity waiver to Willwood, which is fairly routine, but the DEQ did not expect the huge silt release and fish kill, Waterstreet said.

There is 30 to 40 years worth of silt build up and 30 to 40 foot walls of the sediment, Waterstreet said.

While the DEQ issued a notice of violation to the bureau and district, “we’ve got the opportunity to settle this before we go to the Attorney General’s office,” Waterstreet said.

DEQ is monitoring the river for debris and metals in case there is a public health issue, but Waterstreet said he doesn’t anticipate any public health concerns.

The Wyoming Game and Fish Department does not regulate water clarity, said Jason Burckhardt, Game and Fish fisheries biologist. The department does manage the Shoshone for trout, Burckhardt said.

From Buffalo Bill Dam to the Corbett Dam, biomass is 600 pounds of trout per mile, making that stretch some of the best in Wyoming, Burckhardt said. Around the Willwood Dam, biomass is less, but it was still considered a blue ribbon trout stream, he said, adding that it may not be considered blue ribbon in the future.

There has been a fish kill, but not a complete kill below the dam, Burckhardt said. Game and Fish sampled trout below the dam on Tuesday. The department will determine the extent of the loss when the river clears.

Game and Fish has shown interest in a flushing and flow operation, Ronca said, and she indicated this might be an opportune time to consider the process. “It’s still on the table,” she said.

Flushing flow is a high release of water for a short duration to remove fine sediment. It aids trout spawning by cleaning fine sediment from spawning beds and also improves insect abundance, Burckhardt said. In this scenario, the surge of water would originate from Buffalo Bill. At this time the department is determining how much water would be needed and working to ensure it would not cause problems downstream, Burckhardt said.

Burckhardt said he did not know how much turbidity was required to kill fish, but he does know high levels of sediment are not good for fish.

‘Multiple failures’

“This is a real travesty,” said Kirk Bollinger, who lives downstream of the dam near Eaglenest Creek. “I think there’s multiple failures on multiple layers.”

Bollinger said he’s found 12 tires, toilet seats and motorcycle frames along his stretch of river.

There was no contingency plan made prior to the silt release, he said, asking if Game and Fish will hold anyone liable.

“Does anybody have a viable plan to fix the dam now that the damage is done?” Bollinger asked, suggesting that the Army Corps of Engineers might have ideas.

Bollinger said he wrote a letter to Gov. Matt Mead, asking him to find the best — not cheapest — solution.

“Our office is listening,” said Jessica Crowder, Mead’s policy adviser. “It is our priority.”

Bollinger said the DEQ did not monitor turbidity during the dam’s construction project. He earned applause when he asked if there will be any compensation to landowners for losses in property value.

Travis Conklin of Engineering Associates said he’s been involved with the dam since around 2007. The turbidity waiver was not entered into lightly, he said.

In 2015, the pool’s depth was lowered to the same level, Conklin said. The plan was to lower the pool again to install automation this year.

Conklin said he calculated that the amount of sediment now passing through was beyond the dam’s capacity. Most of the sediment is natural, he said, with some caused by humans.

‘Time to join together’

It behooves everyone involved to mine the silt before the pool level is raised, said Park County Commissioner Loren Grosskopf.

“Can we handle it right now before you fill it again?” Grosskopf asked.

It is doable, Singbeil said. However, he said Willwood does not have all the funding it needs and simply removing the silt now will only make space for more.

Plenty of the silt originates in the McCullough Peaks, French said. “A lot of heads are going to have to come together to figure out what to do with that silt.”

All entities involved with the dam should address the issue and find funding to fix it, Grosskopf said.

Tim Wade, fishing outfitter, said he did not blame Willwood. “I think the culpability started in 1929,” he said.

The bureau realized in 1949 that sediment was collecting upstream of the dam and transferred operations to the district, Wade said.

It is typical for the bureau to transfer operations to local entities, Ronca said.

Willwood has been cited three times for exceeding turbidity limits, said Dave Sweet of Trout Unlimited. “Are we simply going to walk out of this room and wait for the next one?” Sweet asked.

Burckhardt said he hopes Tuesday night’s meeting will keep the Willwood mishap in the public eye and encourage people to seek solutions so another such mishap does not occur. “To me, this is a front burner,” he said.

Commissioner Joe Tilden asked who was going to pay for the cleanup. “However you look at it, we have an ecological disaster,” Tilden said.

Bob Capron, East Yellowstone Chapter of Trout Unlimited conservation chair, suggested creating a working group to tackle the problem.

“Now is the time to join together to figure out a solution,” Capron said.

Tribune photo by Gib Mathers

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