Dead River/Hoist Dam, Marquette County, Michigan
The Challenge
Upper Peninsula Power Company (UPPCO) operates the Hoist powerhouse as part of Dead River Hydroelectric Project located on the Dead River west of Marquette, Michigan. On June 30, 1997, a penstock above the powerhouse failed and released flows of up to 3,000 cfs. Sandy soils around the powerhouse and adjacent areas were eroded and carried into the Dead River. After the penstock failure, the intake structure gate was closed and the reach downstream was left dewatered and blanketed by a layer of sand that filled most of the channel. The affected river reach below the Hoist powerhouse was about 2,500 feet long and contained a popular brown trout fishery.
Steve Gough supervised the assessment of damage after this incident and directed extensive restoration efforts that included removing excess sand in the dewatered reach, planning and analysis necessary for control of reservoir levels, hydraulics and sediment transport work to flush remaining sand from the reach, and addition of woody structure and boulders to restore and maintain fish habitat.
Unfortunately, this reach was heavily impacted by the failure of an upstream reservoir dam in 2003. For information and updates, see www.superiorwatersheds.org
Clients/Cooperators:
Upper Peninsula Power Company (UPPCO), eng. firm, Michigan Departments of Environmental Quality and Natural Resources, Trout Unlimited.
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The Hoist Powerhouse shortly after a large penstock ruptured. An eight-foot diameter jet of water with a velocity of about 70 miles per hour was released behind the powerhouse. The now-bare hill behind it was forested before the accident. Roughly 10,000 cubic yards of sand and hundreds of mature trees were washed from this slope into the Dead River. Remains of the penstock lie in the foreground.
As cleanup begins, machines remove sand from the dewatered reach. The channel here was completely filled with sand.
After removal of sand, trees washed from the powerhouse slope were recovered and anchored in the streambed to restore woody debris lost during the flood. Here a crew uses an air hammer and Duckbill earth anchors to secure a tree.
The map below shows the project reach geomorphology and locations of boulders and woody structures placed to recover fish habitat. For an Adobe PDF file showing detailed notes, click here.
Steve directs boulder placement. Placement of boulders and habitat elements was carefully designed and executed to ensure that the natural appearance of this popular recreational reach would be restored.
The restored reach after all work was completed. Flow has also been restored after repair of the dam. Sand was successfully flushed from the reach and habitat elements have functioned flawlessly. The whitewater in the center of the photo is formed by boulders placed there.