Seasonal biological technician Brian Allen inspecting a water control structure at Moosehorn NWR, October 26, 2006. Maintenance staff had unplugged the structure, however beavers re-dammed the structure with sticks and mud within one day. (Photo by Andy Weik)

(L to R) Seasonal biological technician Brian Allen, maintenance mechanic Mike Krug, and heavy equipment operator Bill Jones pause after installing beaver fence at a water control structure on MacDougall Flowage, Moosehorn NWR, on October 26, 2006. (Photo by Andy Weik, USFWS)

Fence and pipes installed to exclude beavers from plugging the water control structure at MacDougal Flowage, Moosehorn NWR, October 31, 2006. (Photo by Andy Weik, USFWS)

Staff at Moosehorn National Wildlife Refuge installed fencing and piping at a water control structure that had a history of being plugged by beavers.  The beavers' activity at the outlet of MacDougall Flowage had raised the water to a level that greatly reduced the stand of wild rice in the wetland, and threatened the stability of a downstream refuge road.  Wild rice provides high quality food and habitat for waterfowl, rails, and other migratory birds.  By installing beaver fencing to exclude beavers from the water control structure at the wetland outlet yet allow outflow through the installed pipes, and by allowing regulated trapping, we hope to reduce maintenance costs and to provide high quality habitat for migratory birds, beavers, and other wildlife.

The fencing project was accomplished in two hours on October 26, 2006 by heavy equipment operator Bill Jones, maintenance mechanic Mike Krug, biologist Andy Weik and seasonal biological technician Brian Allen.  Observations over the next few weeks indicated the beavers had not been able to affect the function of the half circle riser water control structure, and we have been able to maintain the wetland at our objective water level.   To date, the water control structure has required no maintenance.  For comparison, a similar water control structure on another nearby wetland was plugged by beavers within one day of being cleared of debris.