Restoring Connectivity in the 

Two Hearted River Watershed

Repairing culverts, regrading roads and stabilizing river banks at 23 road crossings and man-made erosion sites along Michigan’s Two Hearted River has naturalized river flow, reduced sediment by more than 625 tons, and connected 35 miles of river. This has improved habitat for fish and wildlife and increased recreational opportunities.

Description

The Two Hearted River watershed, flowing into Lake Superior, remains relatively pristine. The area is largely forested and supports a variety of fish and wildlife species, including several fish designated as conservation priorities such as brassy minnow, brook trout, and Coho salmon. Where culverts have been installed at road crossings the flow of the river has been significantly altered, making it difficult for fish and other aquatic organisms to move throughout the river. To be effective, culverts should be wide enough to allow for the natural flow of the river to be unobstructed. The Nature Conservancy is addressing these issues thanks to grants from the Great Lakes Restoration Initiative, the Environmental Protection Agency, U.S. Fish and Wildlife Service, and the National Fish and Wildlife Foundation. The Conservancy, along with project partners, conducted an inventory of road crossings and access points within the watershed and identified 27 priority sites to restore. Old culverts that were restricting river flow were removed and replaced with new, wider culverts, or bridges. Severely eroded banks were re-graded to be less steep, using stakes, and native plantings to stabilize the new slopes. Roads crossing over the culverts were also re-graded so that water flowing onto these roads now flows into retention basins that filter out sediment before rejoining the river. At two of the fords gravel was removed to naturalize the streambeds, and the banks were stabilized. At the time of this writing, work at 19 of the sites has been completed and the remaining 8 sites will be finished by the end of this year.

Resource Challenges Addressed

  • Sedimentation
  • Erosion
  • Altered water flow of the river
  • Restricted fish migration
  • Loss of fish and wildlife habitat

TWO HEARTED RIVER CONNECTIVITY

A streambank being regraded

Eroded stream banks were regraded to be less steep, reducing sedimentation. Stairs were also constructed to provide recreational access with limited erosion. Photo credit: The Nature Conservancy.

Results and Accomplishments

The project has restored natural stream flow or stabilized banks at 19 sites along the river. Another 8 sites will be restored between June and December of 2014. This work is expected to reduce annual sedimentation of the Two Hearted River by more than 625 tons per year. Sediment reductions are exceeding expectations at 12 crossings that have been measured so far. Sedimentation degrades aquatic habitats by inundating streambeds, reducing water clarity, and increasing nutrients in the river, so this reduction in erosion will help restore fish and wildlife habitat. The project will also reconnect 35 miles of previously fragmented aquatic habitat. Road erosion and flooding will also be reduced, making the roads safer and increasing opportunities for activities such as fishing, canoeing, kayaking, and snowmobiling.

Culvert before restoration

A stream crossing in the Two Hearted River system prior to restoration efforts. The old culvert restricted stream flow. Photo credit: The Nature Conservancy.

culvert following restoration

The stream crossing following restoration efforts. A new culvert was installed to naturalize stream flow. Photo credit: the Nature Conservancy.