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The final phase of restoration in Glenwood Canyon turns to debris-choked Colorado River

A July 29, 2021, storm swept debris down Devil’s Hole Canyon in Glenwood Canyon, blocking the Colorado River and threatening the retaining wall for Interstate 70. By late November, the Colorado Department of Transportation was preparing to direct contractors to remove six debris piles clogging the river in the canyon. (Hugh Carey/The Colorado Sun)
The Colorado Department of Transportation is orchestrating the removal of hundreds of thousands of tons of debris flushed down the walls of Glenwood Canyon in July deluge

GLENWOOD CANYON – Andrew Knapp leans over the railing of Interstate 70 in Glenwood Canyon and scowls at a jumble of rocks clogging the Colorado River. Those piercing piles of boulders – swept down the canyon walls in a cataclysmic rainstorm on July 29 – were rubbing against the retaining wall beneath the highway when flows were higher.

“You could hear what sounded like thunder with all those rocks just rolling downstream. That really concerned us,” said the Colorado Department of Transportation engineer.

Examination of that highway retaining wall in the Colorado River below Devil’s Hole Canyon shows it is undamaged. For now.

“But we are thinking about spring runoff,” said Knapp, who is directing CDOT’s monumental task of repairing and rebuilding Interstate 70 and the Colorado River through Glenwood Canyon after the July 29 rainstorm that swept hundreds of thousands of tons of rock, mud and trees onto the highway, recreation path and riverbed.

In a week or so, CDOT will announce it has completed repairs of Interstate 70 in Glenwood Canyon. Crews have finished rebuilding the road, thanks to a unified push by a host of federal and state agencies.

Andrew Knapp, an engineer for the Colorado Department of Transportation, crosses a debris field in the Colorado River in Glenwood Canyon on Nov. 29, 2021. (Hugh Carey, The Colorado Sun)

The impacts of the 2020 Grizzly Creek Fire that burned more than 32,000 acres in the canyon remain acute, with the scar still likely to shed rocks, timber and mud during next spring’s melt. More than 4 inches of rain on July 29 – after several days of rainstorms – shed rocks, mud and trees from atop the canyon. Six massive debris piles span a 3-mile stretch of highway and river in Glenwood Canyon. Early attempts to measure the muddy mess set it at more than 100,000 cubic yards. If it was just dry sand, that would be about 150,000 tons. CDOT estimates it has already removed about 44,000 tons of debris off the highway and recreation path.

The worst-ever debris-flow damage to the vital interstate corridor has been repaired in a little more than four months. It would probably be easier to list the federal and state agencies that were not involved in the restoration work, but CDOT led an effort with input from the Army Corps of Engineers, the U.S. Forest Service, the Federal Highway Administration, the Colorado Department of Natural Resources and just about every nearby community and Colorado River water guardians.

CDOT director Shoshana Lew said she’s never seen so many different agencies and different divisions of her own department come together so quickly and efficiently in response to a single incident.

“The surging in the moment of crisis was truly phenomenal,” she said.

With teams working on the debris-choked Hanging Lake Trail as well as seeding the burn zone to hasten growth that can prevent devastating runoff, the final stage in the restoration of the Colorado River in Glenwood Canyon begins now, with plans to clear plumes of rocks and mud blocking the Colorado River in the canyon. Crews soon will position heavy machinery in the river bed as part of a complicated plan to clear six river-jamming piles.

CDOT officials flew over the canyon this summer and mapped the river and the new debris fields using laser technology. Then a hydrology consultant created models for various runoff scenarios, looking at how the jumbles of rocks in the river might disrupt flows when the dam at Hanging Lake spills and the narrow canyon sees the river swell to 5,000, 10,000 and even 15,000 cubic feet per second next spring.

“Based on those models, we are showing the potential for catastrophic damage to eastbound 70 if the river is left in its current configuration,” Knapp said. “That is the main driver for the removal of that debris.”

Construction crews repair Glenwood Canyon’s Interstate 70 from mudslide damage inside the Colorado River bed on Nov. 29, 2021. (Hugh Carey, The Colorado Sun)

CDOT will start digging soon, chipping away at the piles until trucks have hauled away at least 60% and up to 90% of the debris choking the river and bike path in the canyon. That’s good news for downstream water users, anglers and rafters. But CDOT isn’t spending federal money to keep trout biting and rafts floating. It’s all about protecting the highway to the north and the railroad to the south of the river.

“Our priority is to restore the conveyance of the river, returning it to as close as what it was … to protect the infrastructure,” Knapp said.

Who’s paying for all this?

A report by CDOT and the White River National Forest presented to the Colorado Wildlife Commission in September estimated there could be 113,500 cubic yards of debris that needs to be removed from the six piles. Early estimates pin the cost of river restoration in Glenwood Canyon around $24.2 million.

Get ready for a deluge of acronyms. The alphabet soup that follows is the only way to explain the money flowing into Interstate 70 and the Colorado River in Glenwood Canyon.

When CDOT and the Colorado Division of Homeland Security and Emergency Management, or DHSEM, first started exploring how to pay for repairs to the highway and debris removal in Glenwood Canyon, the agency assumed it would start with emergency funding from the Federal Highway Administration, or FHWA, and then move over to disaster funding from the Federal Emergency Management Agency, or FEMA.

The plan was to deplete the first wave of $11.6 million in FHWA emergency money, pronounce the area an official disaster using the federal Stafford Act Major Disaster declaration, which would pave the way, ahem, for FEMA dollars. But FEMA was busy with other disasters, so fixing I-70 would go slower under FEMA, meaning prolonged lane closures and possible not getting the river clear by 2022 spring runoff. And since CDOT had already collected from the FHWA, FEMA could only cover about 75% of the cost for debris removal. The FHWA, on the other hand, with some bureaucratic tweaking, could help pay for 90% or even 100% of the debris removal.

The FHWA, technically, deals with pavement. River restoration is not in the FHWA wheelhouse. But the highway administration has a bit of wiggle room when there is a threat of flooding that could overtake a road, which has enabled the FHWA to direct funds to clean-up in Glenwood Canyon’s Colorado River. FEMA also could only remove some of the debris – limited to the piles posing “an immediate and imminent threat” to public safety.

The FHWA is still weighing Gov. Jared Polis’ request for $116 million in federal help to pay for repairs in Glenwood Canyon, which includes $50 million for improvements to the largely unpaved county roads over the remote Cottonwood Pass, where drivers flock when the canyon closes.

The Colorado Department of Transportation is planning to hire contractors to remove six piles of debris blocking the Colorado River in Glenwood Canyon. (CDOT handout)

All this federal finagling means in late September CDOT and the DHSEM decided not to push for the disaster declaration and stuck with the FHWA, which ultimately gives the agency about $7.5 million more for debris removal than if the state went through the FEMA disaster process.

“The federal agencies decided they would streamline the process … and pushed us to work with FHWA in the river,” CDOT director Lew said. “They are testing the limits of their own authority to expedite this quickly.”

Six debris piles threatening I-70

CDOT plans to remove six debris piles by the end of April next year, before the spring runoff swells the Colorado River. Its emergency road repair contractor, Lawrence Construction Co., is on board to work the two piles that flowed from the north. The Lawrence group also plans to clear the recreation path along the river, but the priority is to clear the river before the end of April 2022.

The debris pile that poured down Blue Gulch on the north side of the highway and damaged both the westbound and eastbound lanes did the most damage to the highway and buried the largest portion of the river. That pile erased a Class IV rapid known as Barrel Springs. One mile upstream, debris from from the north side’s Wagon Gulch went beneath the westbound lanes but buried the low-lying eastbound pavement. That’s the debris pile that could most easily force the river onto the highway, Knapp said.

Those two piles – below the Blue and Wagon gulches – are more logistically straight forward, with Lawrence Construction crews able to access them both from a single closed lane on the eastbound highway. And they are in the stretch of river between the Shoshone Dam at the Hanging Lake rest area and the Shoshone Generating Station, which is regularly dewatered in the winter months as Xcel Energy diverts the Colorado River into a tunnel that feeds the hydroelectric power plant.

Construction crews repair Glenwood Canyon’s Interstate 70 from mudslide damage inside the Colorado River bed on Nov. 29, 2021. (Hugh Carey, The Colorado Sun)

The piles that came from the south, over and under the railroad, are more challenging for removal crews. CDOT will soon begin seeking contractors who can work with the Union Pacific railroad to access two of those piles above the Shoshone power plant, which are below Devil’s Hole Canyon and an unnamed gulch that CDOT has dubbed Unnamed.

(Not to be confused with the official No Name canyon downstream. And you thought those acronyms were befuddling.)

Later this winter, the transportation department will hire contractors to help remove the two piles downstream of the power plant, which are below Deadman Gulch and above the Maneater rapid. (Those last two will be trickier, because the river is flowing there and crews will likely be unable to access the highway to remove debris.)

CDOT has a unique plan for the Devil’s Hole and Unnamed piles. The rocks and mud that flowed down Devil’s Hole Canyon funneled beneath the railroad tracks and slammed into the eastbound highway retaining wall, completely blocking the river. CDOT hopes a contractor can work with the railroad to deliver equipment to the debris piles but then build a temporary debris bridge across the river so earthmovers can load trucks on the highway. The plan for a debris bridge is the same for the Unnamed pile. That way no debris would be removed via the railroad.

But downstream, in the heavily rafted Shoshone stretch of the Colorado River, the two piles at Deadman and Maneater will require more coordination with Union Pacific. The railroad has given CDOT a four-hour midday window between its passing trains to load and remove train cars with debris. CDOT’s yet-to-be-issued request for contractors is hoping to find a company that can speedily fill train cars while working on the edge of the moving Colorado River.

“Those two piles, they are going to be more complicated,” Knapp said.

Union Pacific spokeswoman Robynn Tysver said the railroad understands the risks posed by the debris piles in Glenwood Canyon and is “proud and grateful” to be working with CDOT in removing them.

“Our goal is to have these piles removed by spring, and our team is working diligently to accomplish this goal,” she said.

What about those rafters?

The Shoshone stretch of whitewater is one of the most consistent stretches of Class III whitewater in the state. It starts flowing early and rafting companies can keep floating boats deep into the fall, offering one of the longest rafting seasons in the state.

A vibrant commercial rafting industry in Glenwood Springs hosts anywhere from 50,000 to 65,000 commercial rafters every season. Those rafters stir a $20 million annual impact for the region, according to annual reports from the Colorado River Outfitters Association. That’s the second biggest boost from rafting in Colorado, behind the Arkansas River, which ranks as the most rafted stretch of whitewater in the country. And that rafting economy flowing out Glenwood Canyon has had a rough couple years, with closures in 2020 during the Grizzly Creek Fire and then again in 2021 with the debris and closed highway.

The Forest Service and CDOT, recognizing the critical role rafting plays in the local economy, opened early access to the river for several owners of rafting companies.

It was quite a scene, said Ken Murphy, the owner of the Glenwood Adventure Co. Nine or so competitors, working together in the middle of rapids with ropes, chainsaws and winches to clear dense walls of timber clogging the rapids above Glenwood Springs.

“We just had to get it open,” Murphy said, “and get our businesses back up and running. The river is an important economic driver for our community. There is huge support to get that cleaned up and ready.”

After two days of sawing and yanking, they cleared a path for rafts. Then the owners brought in their guides, who had to learn how to navigate a completely different river. The jagged piles of rock at Deadman and Maneater have changed how rafts and kayaks descend the rapids.

That’s not necessarily new. After exceptionally snowy seasons in Colorado, the Shoshone stretch can see flows reach 15,000 or even 18,000 cubic-feet-per-second in the spring. (For comparison, the stretch typically runs around 1,200 cfs.)

Those rowdy runoff flows shift rocks and reorient rapids. Murphy said commercial and private whitewater paddlers are closely watching how the debris removal might change rapids.

“We understand that the first priority is the road, then the river and protecting the railway,” Murphy said. “What’s important for our company and all the companies that run Shoshone is that it still maintains its family-oriented feel as a Class III stretch.”

CDOT’s Knapp is a kayaker. He lived in Glenwood Springs. He’s confident that removing debris from the side of the river channel will not alter the rapids. When the project is wrapped, he expects the river to look and paddle a lot like it did before the summer rockfall. He knows he’s not spending millions in taxpayer dollars so whitewater paddlers can still enjoy the river. But recreation is an important consideration and one of the resources the Forest Service wants to protect in Glenwood Canyon.

“There is great support from the White River National Forest and the governor and CDOT to get recreation back open in this canyon,” said Murphy, who also handles bookings for the Hanging Lake Trail, where teams are scrambling to clear debris and open access by next spring. “The fact that recreation is at the table at all shows the economic value of recreation in this area and an understanding of how valuable this is to us all here.”

Read more at The Colorado Sun

The Colorado Sun is a reader-supported, nonpartisan news organization dedicated to covering Colorado issues. To learn more, go to coloradosun.com.