In northeast Michigan, habitat fragmentation due to dams and perched, undersized, and/or misaligned road- and stream-crossing structures ranks as one of the most critical natural-resource issues to address through restoration work. Huron Pines, a nonprofit organization, works with landowners and other partners to improve habitat connectivity, often by replacing culverts with larger structures.
The South Branch River, a designated trout stream, is a tributary of the Au Sable River located in the Huron National Forest in Michigan’s northeastern Lower Peninsula. At the river’s crossing of Rollway Road, a large culvert presented a barrier to aquatic organism passage during most flow conditions due to the shallow, high-velocity flow exiting the structure. The size of the existing structure and depth of fill made replacement unfeasible and called for innovative solutions to enable passage.
On behalf of Huron Pines, Barr designed a series of boulder structures to reduce flow velocity and increase water depth within the structure. The natural materials and varied flow conditions will reestablish passage for brook trout and other aquatic organisms across a wide range of river flows—especially low flows, which are common during trout spawning periods. Our services included survey, wetland evaluation, detailed design, hydraulic modeling, permitting (including evaluation of floodplain impacts), and construction observation.