New bridge restores a trout stream’s natural flow

Project Summary: Replacing a narrow culvert that restricted the Platte River, a blue ribbon trout stream in northern Michigan, restored the river’s natural flow and reduced stream bank erosion that was suffocating prime spawning areas for trout and salmon. The bridge that replaced the culvert also increased public safety by providing a safe road over the river


Project name: Platte River & Burnt Mill Bridge.

An undersized culvert at the old Burnt Mill crossing constricted the flow of the Platte Rive. (Conservation Resource Alliance photo),

Location: Benzie County, Mi., about 30 miles west of Traverse City.

Description: The Burnt Mill road crossing, located near the headwaters of the 90-mile-long Platte River, featured a culvert that restricted the river’s natural flow. Water that backed up behind the culvert caused stream-bank erosion, which caused trees to fall into the river and unleashed sediment that buried rocky spawning areas favored by trout and salmon. The river’s altered flow increased water temperatures, which threatened the trout population. Replacing the undersized culvert with a wooden bridge restored the river’s natural flow, the natural movement of sediments and aquatic life, and provided a safer river crossing for motorists.

Approximate cost of project: $328,000.

Resource challenges addressed: Altered flow of the Platte River, a blue ribbon trout stream; excessive sedimentation, which suffocated valuable fish spawning habitat; and unnatural warming of water temperatures in the river.

The new Burnt Mill Bridge restored the Platte River’s natural flow.

Key partners (public and private): Conservation Resource Alliance, Grand Traverse Band of Ottawa and Chippewa Indians, Benzie County Road Commission, Michigan Department of Natural Resources, Natural Resources Conservation Service, U.S. Fish and Wildlife Service, Platte River Watershed Council, Benzie Conservation District and McDowell Construction.

Types of jobs created: Biologists, ecologists, landscape architects, civil engineers, excavators and carpenters.

Results and accomplishments: Restored the river’s natural flow, which will help the native brook trout population; reduced the volume of sediment washing into the river by 5 tons annually; and restored the natural movement of nutrients and aquatic life above and below the road crossing.

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Originally Published: December 20, 2011