BONNER, Mont. - The Montana Department of Transportation (MDT) and BNSF Railway Company (BNSF) have agreed upon a pier removal and bridge mitigation solution for the Blackfoot River near Bonner. MDT and BNSF have chosen a hybrid design option and are proceeding with both the BNSF bridge mitigation and MDT pier removal, aligned with available funding.
“We are grateful to collaborate with BNSF,” Dustin Rouse, Chief Engineer at MDT, states. “The plan is to advance bridge mitigation as quickly and efficiently as possible.”
MDT and BNSF’s agreement involves installing overlapping grout-filled bags and riprap, which will stabilize the bridge structure. This work will not change the footprint of the bridge in the Blackfoot River. Aquatic habitats will not be impacted. MDT’s primary factors when considering solutions were safety, efficiency, and environmental sensitivity.
Recreational impacts are anticipated during construction. Drivers and pedestrians will notice BNSF crews on and around the railroad bridge, south of the piers, completing mitigation efforts beginning this summer. River and access closures will begin in August and last several weeks. Impacts in 2026 will be more significant as MDT completes in-river work to remove the piers. Additional updates and information will be provided as it becomes available.
“The design alternative is a solution that allows all of us to move forward and provide a safe riverbed for recreationalists and wildlife,” said BNSF Director of External Communications, Kendall Sloan.
Scour mitigation work on the BNSF bridge is funded through a partnership agreement by MDT and BNSF.
At the end of 2019, MDT completed the reconstruction of the Interstate 90 (I-90) bridges crossing the Blackfoot River. However, the piers at the Bonner Bridges site were not removed due to additional costs that would be incurred. These include the maintenance costs for another bridge (formerly MRL, now BNSF) in the Blackfoot River that would be required if the piers were removed.
Since completing bridge stabilization on the Bonner Bridges in 2019, MDT has continued to seek opportunities and funding to remove the piers. During this time, MRL was also acquired by BNSF. A path forward is now in motion.
Public input and communication are essential components of all projects. Additional updates will be communicated as BNSF bridge mitigation begins.
If you have questions, feedback or would like to request a media interview with the project team, please email Becca MacLean at becca@bigskypublicrelations.com. Our project hotline, 406-207-4484, is also open during business hours. For more information about the project, visit mdt.mt.gov/pubinvolve/bonner.