‘The only tool we have:’ CDOT turns to response strategies following multiple mudslides on I-70 | PostIndependent.com
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‘The only tool we have:’ CDOT turns to response strategies following multiple mudslides on I-70

The difficulty of terrain and burn severity on the Grizzly Creek burn scar make mudslide mitigation nearly impossible

Mudslides and debris flows are expected to continue for years to come with little to no possible mitigation solutions.
CDOT/Special to the Daily

Over the past few weeks, mudslides and flash flood warnings have prompted continual closures of Interstate 70 in Glenwood Canyon. A result of the Grizzly Creek Fire burn scar, the steep slopes surrounding the interstate in the canyon have become increasingly susceptible to these large debris flows. And really, there’s not much anyone can do.

“We’ve all known that this risk of mudslides was here,” said David Boyd, public affairs officer for the White River National Forest.

Immediately following the Grizzly Creek Fire, the Forest Service sent out a Burn Area Emergency Response team, also known as a BAER team, to assess damages and risk in the area as well as provide possible mitigation solutions.



What the team — which comprises specialists like hydrologists, botanists, ecologists, soil scientists and engineers — found was that many of the drainages in Glenwood Canyon burned severely. Couple that with the steepness of the slopes in the canyon, and it equals a higher risk of debris flow.

“The problem with the high-severity burn is that it cooks the soil,” Boyd said. “Soil normally is full of all kinds of living organisms, microorganisms, roots, seeds, those sorts of things, and if the fire burns really severely, it just kills all that.”



This severe burn also, according to Boyd, makes the soil more hydrophobic, so the water isn’t absorbed into the soil — “it just comes right off.”

“The other challenge with that is reseeding isn’t going to take very well in those highly, severely burned areas,” Boyd said. “Most of Grizzly Creek, if you go up in the burned area, is recovering naturally; grasses and forbs in the area where it was brush, those are all coming back.”

In some areas of the Grizzly Creek Fire burn scar where the burn was not as severe, grass and vegetation has started to regenerate naturally.
White River National Forest/Special to the Daily

Without this regeneration, these mudslides will continue to occur with little to no vegetation to hold back the debris. This is particularly true as summer precipitation — which often dumps a lot of rain in a small area over a short period of time — continues to cause these debris flows.

“For the next few years, mudslides will be a problem,” Boyd said. “Over time, it gets better as the fire recovers more. Eventually, these severely burned areas will start coming back.”

So, what the Forest Service can, and will continue, to do, according to Boyd, is monitor the area and continue to look for opportunities to mitigate this risk.

Safety closures first

This map shows the burn severity across the Grizzly Creek Fire — 12% was marked as high severity burn, 43% as moderate, 33% was low and within the fire’s perimeter and 12% remained unburned.
White River National Forest/Special to the Daily

Instead, a lot of the mitigation efforts have been focused on these closures, which protect the safety of motorists on I-70.

“We’re talking about nature and nature’s process, that’s pretty tough to mitigate,” said Tracy Trulove, a Colorado Department of Transportation spokesperson. “CDOT is always going to put safety at the top of the list for what we’re doing in the canyon.”

Earlier this year, CDOT completed several projects related to rock and debris flow in the canyon. Spending around $1.7 million in federal funding for emergency repairs, the department constructed a number of barriers intended to mitigate smaller sloughs of rock and debris and prevent scattering of smaller rocks into the roadway areas. This also included improvements and debris removal efforts along existing fences and barriers.

Even with these fences and precautions in place, it’s incredibly challenging to predict where the debris flows will occur.

In fact, the U.S. Geological Survey created a landslide hazard map that identified areas where there was a high likelihood for these larger debris flows. So far, this map had identified the three areas where debris flows have run onto the highway as areas with a 40% to 100% chance of doing so. However, even with these models, it’s impossible to predict these occurrences.

“There’s just so many areas in that canyon that have the potential for debris flow,” Trulove said.

Not only are the flows difficult to predict, but the state of the slopes have created debris flows that would be hard for the fences to catch.

“It’s a lot of mud and water and a very soupy mix that’s coming down,” Trulove said. “So even with those barriers in place, you’re still going to get a decent amount of material that comes through.”

So far, the mudslides that have made their way onto the interstate have had minimal impacts to the road. According to Trulove, there has only been minimal damage to things like drains and some damage to the guardrail, which was already in “desperate need.” Most of the costs have been associated with cleanup operations and resources.

According to Victoria Graham, a spokesperson from Gov. Jared Polis’ office, the governor requested funds for improving I-70 in Glenwood Canyon in September 2020.

“The state has requested up to $10 million in federal funding and been approved for approximately $2.5 million in emergency repair funding, which is 100% reimbursable, and $2.8 million in permanent repairs, which is 80% reimbursable,” Graham wrote. “Additional funding to protect local community water supplies and infrastructure was passed during this last legislative session working with those communities, the state Legislature and Department of Natural Resources.”

Matthew Inzeo, CDOT’s communication director, wrote in an email that the emergency repairs funding reimbursed “funds that were spent in the immediate response to the Grizzly Creek Fire last year,” which includes the improvements mentioned above.

According to Trulove, CDOT isn’t aware of any new money earmarked for continued mitigation.

In terms of the long-term revegetation work, that will fall under federal funding for the Forest Service. “In a recent call with President Biden, Vice President Harris and key cabinet officials, Gov. Polis underscored the post-fire watershed and mudslide impacts,” Graham wrote.

Just this week, the Colorado Transportation Commission approved $238 million via Senate Bill 260 to address “critical statewide multimodal needs,” according to the press release. However, no improvements to I-70 in the canyon made the list. This is because, according to Trulove, transportation funding has been a challenge statewide, and there are many roadways, including Glenwood Canyon before the fire, that require rockfall mitigation and resources.

“The Grizzly Creek burn scar has added another layer of complexity,” she said, adding that it also doesn’t help that “this burn scar is right over one of the major arteries in Colorado.”

‘The only tool we have’

CDOT crews make progress cleaning up the lower eastbound decks of Interstate 70 on June 28, near mile marker 120 after a mudslide swept down the cliffs in Glenwood Canyon in the area of the Grizzly Creek burn scar the day before.
Chelsea Self/Post Independent

Instead of mitigating risks, CDOT has been concerned with merely responding to these risks as they occur. Just this week, two separate flash flood warnings prompted the closure of the interstate through the canyon.

CDOT starts preparing once it receives a flash flood watch from the National Weather Service, sending out maintenance teams on standby at several closure locations along the highway.

And then, once the watch is upgraded to a warning, “When we get a warning, we’re moving to a safety closure for the canyon in an effort to not have vehicles in there when a potential debris flow happens,” Trulove said.

Of this response, Trulove said, “Right now that is really the only tool we have.”

In Eagle County, the Sheriff’s office is also watching for these warnings and closures, prompting its own response on Cottonwood Pass.

Alternative routes

One common alternative route when Glenwood Canyon closes is Cottonwood Pass, which has seen its fair share of accidents and delays over the years.
Adrian Hughes/Daily File Photo

Over the past few years, Cottonwood Pass, a local and scenic roadway, has become inundated with traffic as closures in Glenwood Canyon continue to increase. The roadway has seen its fair share of crashes, including a truck rollover earlier this summer.

Matt Koch, who has been an Eagle County resident for 15 years, drives Cottonwood Pass every day in the summer to get to his job in Garfield County. However, over the past few years, closures on I-70 have led to an influx of “weekend warriors and tourists,” on the roadway, Koch said.

“Basically, as soon as the EC Alert goes out that there’s flash flood watch, I basically have to leave work and jump in my car and head home,” Koch said. “I’m in the very fortunate position that my boss is very understanding, and they let me leave. I think about the guy or gal who doesn’t have that luxury; they have to be there until the job is done.”

This can often lead to locals being stranded and unable to get home from work.

“Many locals work and live on both sides of Cottonwood Pass, making it a very important route for them to utilize when the Canyon is closed,” wrote John Harris, from the Eagle County Road and Bridge department, in an email. “We are concerned about the viability of the route and passenger safety with increased traffic. Cottonwood Pass is not designed to handle a large volume of traffic.”

This situation has led the Eagle County Sheriff’s Office — in partnership with the town of Gypsum and Eagle County Road and Bridge — to create an incident management plan. In the event that CDOT closes I-70, the Sheriff’s Office will send out deputies to both sides of the pass where they will manage traffic until Eagle County Road and Bridge arrives and takes over management. In managing traffic, those stationed are slowing traffic and making sure those commercial vehicles and others over 35-feet in length are not driving over the pass.

“Narrow sections, steep grades and sharp curves make it difficult to handle the traffic during closures without the boots-on-the-ground traffic control the county and its partners have been providing,” Harris wrote.

The incident plan also includes investing in a number of warning and educational signs for out-of-state visitors and drivers that take on the pass.

It’s worth noting that CDOT specifically asks motorists not to use Cottonwood Pass as well as Hagerman Pass, Eagle/Thomasville Road or other county or Forest Service roads in Eagle, Garfield and Pitkin counties as a detour — although GPS routing systems will tell drivers to use those roads. Instead, the department recommends a northern alternate route using Colorado Highway 9, US Highway 40 and Colorado Highway 13. Really, there’s no good way around the closures.

Koch has noted these interventions and said that while they are helping — “I haven’t gotten stuck yet” — it’s not enough. In a letter to the Vail Daily, Koch referred to the road as “ill-prepared and ill-equipped.”

On the phone, Koch noted that guardrails and metering could help improve the drive and prevent accidents. “I don’t think that Cottonwood should be a viable alternative route. I think it should remain quiet and sleepy for the ranchers as a scenic byway,” he said.

According to Harris, the county has made some road surface improvements and has “been in discussions on different levels of improvements and costs associated with them.” However, at this time, there is no planned funding to help aid the project.

Koch has been reaching out to local and state representatives to try and raise some noise about the pass, and it’s need — as well as I-70’s need — for repairs and financial investments.

“I know it’s an astronomical amount of money, but when you start stacking that against all the commerce that gets stopped and the trickle down of having 70 closed for a day or a couple of hours. The supply chain just gets incredibly disrupted, and it’s not just Coloradans, it’s everywhere, it’s national,” he said. “I would encourage the other travelers to speak up and contact their representatives, and if we unify and make our voices heard, action will hopefully be taken.”


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