ROADS & HIGHWAYS

Disciplines: Transportation Engineering, Hydrology & Hydraulics, Constructability Evaluation, Alternatives Analysis

The Mobridge Slide project is intended to implement landslide mitigation measures along a segment of highway in eastern Montana. Coldwater Engineering was a member of a larger team, serving as the project hydraulic engineer. The project required extensive collaboration between hydraulic, geotechnical, and transportation engineers.

Requirements: The proposed landslide mitigation would impact natural drainage patterns, requiring water to be diverted away from its natural course. The channel diversions resulted in a complicated hydraulic system which would ultimately contain retention, detention, culvert systems, and open channel flow. Due to scale of the project, a robust design of the hydraulic system was warranted in order to minimize risk of failure to hydraulic system; and, subsequently, the landslide mitigation.

Strategy / Approach: Stormwater modeling software was utilized to model design conditions and to account for nearly all hydrologic and hydraulic elements. This included: stormwater runoff, detention, retention, culvert capacity, and open channel conveyance. This advanced modeling approach provided for a deep understanding of site conditions and allowed for detailed design calculations. Due to the project’s complexity, multiple stakeholder meetings were held throughout the design process, allowing for open-discussion and brainstorming amongst the project team.