Traffic experiences delays for project near Lake Alva

LAKE ALVA - Motorists should expect traffic disruptions on Highway 83 along Lake Alva due to a Montana Department of Transportation project. The project is intended to re-establish roadway slope stability as well as evaluate a nearby culvert which may need to be repaired or replaced. 

Between mile markers 24.9 to 25 on Highway 83, work began the week of Oct. 12 with traffic diverted into a single lane. Travelers should expect 15 minute delays, 12 foot width restrictions and reduced speeds to 35 miles per hour for the duration of the work which is expected to end Nov. 25.

Slope instability in the Highway 83 embankment occurred in the spring of 2018 as a result of snowmelt and precipitation which reduced soil strength. Soil mass sliding occurred below the roadway creating concern that additional movement would damage the roadway. In August 2018, the Geotechnical Bureau sent a memo to the District recommending nominating a project to repair the problem.

Bret Boundy is a geotechnical manager for the Geotechnical Bureau of Montana who had to establish a workable concept that would meet established engineering standards and requirements.

"As the slope instability that precipitated this project is of a geotechnical nature, it fell to me to put together a viable, efficient solution to the problem," Boundy said. "The solution I created was assembled into plans by the Road Design Section with input from the Environmental Bureau, Hydraulic Section, Right-of Way Section and other disciplines."

Workers are re-establishing slope stability by building a tie-back sheet pile wall along the failure and tension crack area and re-grading the slope below the wall to a shallower shape. Repairing the existing culvert inlet includes installing drains below the wall as well as lining the inside ditch of the highway above the failure area and along the inside ditch of the Lake Alva campground road at the base of the Highway embankment. An optional grade raise of up to four feet for the campground road could improve stability and provide better drainage.

The engineer's estimated cost for the project is $1,336,594. This covers all elements of construction including mobilization, traffic control and contingency, plus conditions of engagement and interest during construction. A July Montana Transportation Commission report stated that Bullock Contracting, LLC out of Boulder put out a bid for the project for $1,412,820.53.

Boundy said he was proud to contribute to the project with his coworkers.

"It is easy to take our good highway system for granted but there are many dedicated people who work hard to keep the roads open - across embankments, over bridges and culverts, and through road cuts, all of which will degrade due to the ceaseless erosion and corrosion by the elements without constant work," Boundy said. "The personnel in our Maintenance Division particularly are our eyes and ears on the highway system and we work closely with them to identify potential problems or conditions before they could potentially impact the traveling public."

For additional information about the project call (406) 444-6372 or email Boundy at bboundy@mt.gov.