Kicking Horse Dam & Outlet Works Modification

Project overview

Kicking Horse Dam and outlet works was constructed in 1930 along with two dikes. Through an Issue Evaluation level risk analysis that was performed evaluating baseline static, hydrologic, and seismic risks posed by potential failure modes, certain risks have been identified for Kicking Horse Dam resulting in increased justification to take risk reduction action. The safety upgrades will modify and/or replace the aging infrastructure to current industry standards, including hydrology, hydraulics, structural, mechanical, geotechnical, and seismic. This includes installation of a cement bentonite cutoff wall along the entire length of the dam, removal and replacement of the existing outlet works, toe drain installation, realignment of the G-Canal Lateral, replacement of the downstream check structure, and raising low spots in the dam crest. Design is currently in a final design phase. Extensive measures have been and will continue to avoid, minimize, or mitigate impacts of construction on the wetlands and native prairies located on the site.

The project will require compensatory mitigation for unavoidable impacts to waters and wetlands that are regulated by the CSKT Shoreline Protection Program through ALCO (87A) and US Army Corps of Engineers (USACE) through the Clean Water Act, section 404. Mitigation will include at least one on-site project and two off-site projects. The on-site project includes the borrow area that will source material for reconstruction of the dam after replacement of the outlet works and converting it to a new wetland habitat. The two off-site projects may include diverting some of Lower Crow Creek water into old river oxbows reestablishing wetlands and improvements to the Agency boat launch to prevent continued degradation to the banks of Flathead River at this site.