Field Notes
U.S. Fish & Wildlife Service
Field Notes Entry   
Engineered Log Jams Installed in Whittlesey Creek to Stabilize Creek and Improve Fish Habitat
Midwest Region, December 6, 2004
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Engineered log jams were placed in Whittlesey Creek, upstream of the Whittlesey Creek National Wildlife Refuge, on private land in early December. These log jams incorporate large woody debris, and simulate conditions found historically in the forested streams of northern Wisconsin. Large woody debris jams create habitat for wildlife, macroinvertebrates and fish by providing nesting and attachment sites, stabilizing spawning substrate, creating more complex pool and riffle habitat, providing refuge for juvenile fish, and providing overhead cover for all life stages of fish. The debris also adds hydraulic roughness to streams, thereby reducing local stream power. If properly designed, jams can attenuate erosion problems, cause selected sediment deposition and reduce sediment input into streams.

Large woody debris is created naturally when large, old trees or branches fall into the stream due to decay or blow-down. Other debris that is carried downstream becomes caught in the tangle of fallen trees, creating larger debris jams. Since most of northern Wisconsin's forests were cut in the late 1800s and early 1900s, the amount of old wood recruited into streams such as Whittlesey Creek is now minimal. Continual timber harvest to present day results in young riparian forests and inadequate recruitment of large woody debris into northern streams, limiting potential fish habitat in some areas. In addition to the loss of old trees, streams were used to transport logs during the early logging era, so natural woody debris was flushed downstream along with harvested logs. The result is that most streams today have very few large woody debris jams.

Engineered log jams have been widely used in successful restoration of salmon habitat in the Pacific Northwest, and to some degree in other parts of the country including Wisconsin. Logs are sized for the width of the stream, expected flow conditions and desired restoration outcome. Typically, the first logs placed in the stream are excavated into the bed or adjacent bank. Additional logs are placed on top of these or placed on the adjoining banks. Logs are cabled to one another and to live trees on adjacent banks to ensure they remain in place during flood flows. All are carefully placed by engineers or river geomorphologists to obtain desired flow patterns during floods.

The Whittlesey Creek Engineered Log Jam Project is designed to monitor the effect of various types of log jams on habitat creation, bank erosion, channel bed adjustment, sediment stability, stream power and bluff erosion in the sand bed and bank channels typical of northern Wisconsin. A site was chosen that, although has low base flow and limited fish habitat, provides ideal conditions for monitoring such changes. Construction was completed Dec. 3, 2004, and included the installation of seven engineered log jams comprised of 120 total logs over a 1,200 foot stretch of stream. Three types of jams were featured: 1) to reduce bank erosion; 2) to treat a bluff erosion; and, 3) for investigation of bank erosion, channel scour and fish habitat creation. This project is yet another step in continued efforts to reduce damaging flood effects, reduce sediment loads into the National Wildlife Refuge and aid in the restoration of coaster brook trout. This project featured engineered log jam design and monitoring plan by Inter-Fluve, volunteer help and use of local contractors. Draft horses were used to transport logs to the site and help reduce impacts to the riparian area. The local chapter of Trout Unlimited was also extremely helpful by providing about 60 hours of volunteer time to cable logs into place.

This project was initiated by the Wisconsin Chapter of Trout Unlimited. They received a National Fish and Wildlife Foundation grant to improve trout habitat on Lake Superior streams in Wisconsin. The Wisconsin Department of Natural Resources also provided funding and technical assistance. The U.S. Fish and Wildlife Service was a partner by providing funding through a Cooperative Conservation Initiative grant and our Coastal Program. The Whittlesey Creek National Wildlife Refuge and Ashland Fishery Resources offices helped with project coordination, technical assistance, and labor. Both offices will be involved in monitoring the effect of the log jams on habitat and invertebrates of the stream.

Contact Info: Larry Dean, 612-713-5312, Larry_Dean@fws.gov
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