With construction on the Jackson Mountain landslide mitigation project underway and expected to intensify as the summer progresses, the Colorado Department of Transportation is ensuring that an emergency incident management plan is in place should U.S. 160 fail during construction.
CDOT and contractor Tricon 2, LLC are completing the project, located five miles east of Pagosa Springs, with the aim of mitigating a landslide area that has been damaging the highway for decades.
The landslide is caused by sloping bedrock covered by 50 to 80 feet of earth and shale which slides due to the amount of surface and groundwater in the area and has, according to CDOT, caused the section of U.S. 160 traversing the slide to drop as much as eight vertical inches in one night, in the spring of 2005.
In the process of mitigating the landslide this summer, workers will remove portions of the toe of the slope, where the slope meets the river, in order to construct a rock buttress, said CDOT Resident Engineer Ed Archuleta.
Because of the excavation work required to install the buttress, CDOT staff members met with Colorado State Patrol and Archuleta County Sheriff’s Office Department of Emergency Management personnel Wednesday to ensure that all lines of communication are open and a plan is in place should the roadway fail during the excavation.
“Really, the concern is when the workers aren’t there,” Archuleta said, adding that the plan in place will be very similar to avalanche plans in terms of the communication between the entities.
CDOT spokesperson Nancy Shanks said the meeting was held to strengthen the lines of communications between the entities and ensure that all emergency contact information is up to date.
“We know this, we do this ... but we wanted to make sure it was in place for this particular project,” Shanks said.
Excavation work for the buttress construction is anticipated to begin in early July.
Work on the project began last fall with the installation of a surface and underground drainage system and installation of steel cable systems known as “tiebacks” to help stabilize the hillside beneath the highway.
After a winter hiatus, crews are back at work, installing more tiedowns on the slide, with Archuleta noting that last fall’s work helped to slow and, in some areas, stop the slide.
Archuleta said he’s confident that, for now, crews won’t see movement of the hillside.
Work on the tiebacks is expected to be complete by mid June, at which point crews will prepare to work in the river at the toe of the slope, Archuleta said.
CDOT is not permitted to work in the river until early July in order to protect trout during spawning, Archuleta said.
The buttress will sit on a concrete foundation and be 160 to 180 feet long; however, only 50-foot sections of the slope will be excavated at one time, with each section about 40 feet deep to allow for the buttress, Archuleta said.
Following the buttress work, likely in September, crews will begin to reconstruct the surface of U.S. 160 through the slide area with a 10-foot deep, reinforced roadway, Archuleta said.
Work on the roadway is expected to be complete in November.
As part of the preparation for any potential incident involving the landslide and highway, CDOT is urging people to sign up for free road alerts for the project.
To sign up for the alerts, visit www.coloradodot.info and click on the green phone icon in the upper right corner of the Web page.
From there, visitors have a choice of statewide or more specific alerts, as well as a choice between e-mail and text messaging alerts.
Additionally, Tricon 2 has a local project hotline for information. The number for the hotline is 264-0542.
Prior to the project, the stretch of roadway traversing the landslide required patching every few months to maintain road elevation and alignment, at a cost of $100,000-$250,000 yearly, according to CDOT, equating to millions of dollars over the years.
Money for the reconstruction project, at a cost of $5.2 million, will come from CDOT’s contingency fund, which is the entity’s emergency reserve. The decision to use contingency funds for the project was made at a Dec. 17 meeting of the Transportation Commission.