New bridge unleashes

a northern Michigan trout stream

Replacing two dysfunctional culverts with a bridge over the Black River reconnected 18 miles of free-flowing trout stream to Lake Huron in northern Michigan and created miles of prime spawning habitat for lake-run coaster brook trout, steelhead and salmon.


The Black River in northeast Michigan is known for coaster brook trout and steelhead that migrate up the river from Lake Huron. In 2007, a study by the conservation group Huron Pines identified a problem with twin culverts that allows the river to flow beneath Sucker Creek Road. The culverts, each of which was 5-feet in diameter and 50-feet long, created a bottleneck in the river, which increased the river’s velocity. The increased velocity created a plunge pool on the downstream side of the culvert, effectively leaving the culverts perched above the river channel. The perched culvert block fish passage and created a biological disconnect between the lower Black River and 18 miles of the river and tributaries upstream of the road crossing. Soil erosion from steep banks near the bridge crossing sent about 80 tons of sediment into the stream each year, covering rocky areas where trout spawn. During high-flow events, the river flowed over the road, creating safety hazards for motorists. Working with the Alcona County Road Commission and the U.S. Forest Service and Fish and Wildlife Service, the conservation group Huron Pines coordinated plans to replace the perched culverts with a 30-foot long timber bridge. The bridge restored the river’s natural flow, reconnected 18 miles of free-flowing Black River to Lake Huron and created miles of spawning habitat for lake-run coaster brook trout, steelhead and salmon.

Resource Challenges Addressed

  • Fragmentation of a river
  • Disruption of fish passage
  • Soil erosion
  • Damaged trout habitat


culvert being removed by a backhoe.

Removing culverts like the one pictured above, allows for a natural stream flow and for fish migration upstream. Credit: Cuyahoga Soil and Water Conservation District.

Results and Accomplishments

Reconnected 18 miles of a free-flowing section of the Black River to Lake Huron, which created new habitat for migratory fish species. The project also reduced by about 80 tons annually the amount of sediment washing into the stream near the bridge.