Cass County committee approves KLJ for preliminary design of County Road 31 Cheyenne River bridge

A Cass County roads committee approved moving forward with KLJ Engineering to provide preliminary and design engineering for the County Road 31 (Cheyenne River) bridge project, with the work to be presented for potential approval at the April 7 commission meeting.

The vote followed a presentation describing why the existing bridge was closed in June 2024 because of severe substructure movement and a noted slip plane in the soils. County staff said inclinometers installed along the alignment confirmed continuing movement and that piers were visibly leaning; one presenter described the current piers as appearing “at about a 30 degree angle.”

The county’s presentation summarized engineering history at the site: recorded rotation beginning in the 1950s, extensions in 1957 and a replacement in 1976, and accelerating movement that prompted the 2024 closure. Staff said the county engaged Houston Engineering and Braun Intertech for preliminary engineering and soil analysis and later solicited proposals; three firms responded to the request for proposals (Houston, KLJ and SRF). Committee members said KLJ’s proposal stood out for its combined technical approach and its experience pursuing grant funding.

The county estimated a new bridge could cost between $8 million and $12 million; staff said they had already approved a budget carryover (approved in July) of $5,500,000 to help accommodate the anticipated construction in 2026. Staff also said the county will pursue federal funding (including a possible flex‑fund opportunity) and that securing roughly $4 million in federal aid would be significant enough to accept a roughly six‑month shift to the project timeline. With that funding path, staff described a possible bidding window in mid‑2026 and construction spanning late 2026 into 2027.

Committee discussion covered alternatives to rebuilding on the existing alignment, noting the slide depth and the risk that additional pile driving could aggravate instability. Staff said KLJ would also examine alternative alignments and continue soil monitoring while pursuing grants. A representative of the Rush River Water Resources board recommended inviting a diversion‑authority representative to answer hydraulic questions at a future meeting.

A motion to advance KLJ for the preliminary and design engineering for the C‑31 Cheyenne River bridge to be considered at the April 7 commission meeting was made and seconded; the committee recorded all in favor and the chair ruled the motion carried. Staff said the approval allows negotiations on scope and price with KLJ before the commission meeting.

The committee did not finalize construction contracts at this meeting; members and staff emphasized that geotechnical analyses and grant outcomes will shape the final design, alignment and schedule.