WYDOT To Perform Work On US Highway 14 In Potential Landslide Area Near Steamboat Point

Photo Courtesy: WYDOT

Motorists traveling US 14 west of Dayton will notice Wyoming Department of Transportation maintenance crews working in the right of way just east of Steamboat Point beginning May 26th.

This work may require short term lane closure with flagging operations due to the need for utilizing heavy equipment in the right of way.

This work is expected to take about a week to complete.

This work is a preventative measure in the event the roadway gives way to a landslide WYDOT district four maintenance staff and geologists have been watching at mile marker 69.8 for some time.

WYDOT noticed some considerable movement in recent weeks and has concerns that the eastbound travel lane has the potential to be affected by the slide and has decided to put in place some precautionary measures.

At this time, this section of roadway is sufficient, but the boundary of the lower lip of the slide is quite close to the fence and guardrail.

Preventative measures include enlarging the westbound shoulder to accommodate westbound traffic if the landslide encroaches into the eastbound lane.

In addition, they will be placing an impermeable membrane in the ditch above the landslide to reduce infiltration of surface run-off water under the road which greatly contributes to the sliding movement.

WYDOT geologist, James Dahill and his team have been watching the Little Tongue River landslide for several years and have become quite familiar with its activity.

Dahill says the challenge with the Little Tongue River landslide is that US 14 crosses the slide at the waistline or midpoint of the slide.

This means there is just as much slide prone material above the road as there is below the roadway.

Because of the nature of this geological structure, each year’s melting snowpack, and yearly erosion results in the weak shale getting saturated over time and the blocks start sliding downhill due to gravity and the steepness of the side of the mountain.

It is a matter of time and if no action is taken, the slide will continue much like a conveyor belt and work its way up the slope and the highway will be in jeopardy, adds Dahill.

In addition to these preventative measures, WYDOT is working on some short term solutions in the event the landslide results in more severe changes to the roadway.

In the meantime, maintenance and geology will continue to monitor the landslide monthly utilizing an in-place subsurface monitoring well to track future slide movement and will be assessing the site monthly.

Maintenance will monitor slide movement daily and will notify geology should the slide encroach further into the highway surfacing.

As far as future movement, the slide is driven by moisture so movement is expected to slow down as drier conditions come about this spring and the ground dries out.

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