Cascade County Commissioners approved a $25,551.50 contract to Big Sky Subsurface to continue geotechnical investigations for the Lower River Road slide area during their Oct. 24 meeting.

County public works has been working with local engineers since 2018 to collect data and help determine the cause and fixes for a section of Lower River Road to keep it from continuing to slide into the river.

In 2021 and 2022, the area began to move and slide at a fast pace than years prior, according to county public works.

County studying landslide area on Lower River Road

That led to county officials meeting with local engineers and in 2022, determining that the county needed to switch the section of asphalt back to gravel for easier maintenance and to save taxpayer money rather than continue to pave the road and have it slide and sink into the river, according to county public works.

The county is looking at a roughly 800 foot stretch of Lower River Road, north and west of White Bear Island.

County officials determined that to determine a long-term solution, they needed more research and data, including a river survey.

Earlier this year, the county and Big Sky Civil conducted the survey and passed the data to Big Sky Subsurface of Belt for further analysis, according to county public works.

Les Payne, county public works director, said that he’s asked Big Sky Subsurface to provide an engineer’s estimate for the final geotechnical investigations and long-term solutions for fixing the road.