AESI, in collaboration with Mainstream Restoration, provided alternatives analysis, design, construction documents, and construction services for two fish barriers on tributaries (Seepay Creek and Magpie Creek) of the Flathead River. The project goal was to provide a fish barrier on each creek to prevent unwanted species of fish from migrating up the tributaries over a wide range of flows. AESI served as the Engineer of Record for both projects. Specific project elements included:
- Development of a HEC-RAS hydraulic model to estimate required barrier dimensions for several species of fresh water fish;
- Design of modular fish barriers consisting of commercially available precast reinforced concrete box culverts and slabs;
- Structural design for the 100-year peak discharge;
- Design to limit upstream fish passage of rainbow trout up to 22 inches in length at flows up to the 25-year peak discharge; and
- Design of a modular fish barrier to attach to old highway bridge abutments for the Seepay Creek site.