MDT begins design process for Dalton Mountain Bridge replacement

Lewis and Clark County continues to work with the Montana Department of Transportation on plans to replace Dalton Mountain Road Bridge under MDT's off-system bridge program.

During the Feb.7 Lincoln Government Day meeting, Lewis and Clark County road and bridge supervisor Kevin Horne said there was a meeting last month that brought all the players involved in the project together to begin the design process. An onsite meeting followed about three weeks ago.

"It's not going to be a very quick paced project," Horne said. "I guess ... 2022, was the date they were anticipating. Our concern is the Dalton Mountain detour and maintenance and the dust control on that."

Horne said they put up additional signs to help with traffic control on the detour route. They include a yield sign at the intersection of Dalton Mountain Road and Herrin Lakes Road, and a stop sign on Herrin Lakes Road at the intersection with Stemple Pass Road.

The existing bridge, which will have to last for at least two more years, is also on the county's radar.

"The bridge ends are tough to maintain right now," Horne said. Concerns about the bridge ends which develop significant potholes that are routinely filled in, have been an ongoing concern for both user safety and constituted use of the bridge. Horne said they're working with Great West Engineering to schedule maintenance work on the bridge in the spring to ensure it remains serviceable until they begin the replacement project.

Horne said the replacement project is expected to take between 120 and 180 days, during which the old bridge will be removed, leaving the Herrin Lakes detour as the only access to the Dalton Mountain/Willow Creek area. He said there will be plenty of public notice and probably a comment period prior to that.

The Dalton Mountain Road Bridge was closed in August of 2017 due to concerns about decaying piles. Repair work shored up the east side of the structure, which re-opened as a one lane bridge that September.

During the 2019 legislative session the county received $600,000 in funding from the Treasure State Endowment Program to replace the bridge. Shortly thereafter, the county began exploring the possibility of working with MDT off-system bridge program as a way to save county taxpayer dollars. MDT accepted the bridge into their program in July, which will allow the county to use the TSEP money as a match for the MDT project funding.