SAF Upper Peninsula Chapter Field Day
Dead River Flood Damage, Bridges, and Wetland Crossings
On 14 May, 2003 over four inches of rain fell in Marquette County. The next day a Silver Lake earthen dike broke, sending a flood of water down the Dead River and spilled into Lake Superior. About nine billion gallons of water scoured 25 miles through the river system leaving a wake of damage.
On 22 August, Dean Wilson, Gordy Mouw, and Matt Rintamaki arranged a tour of the Dead River watershed for the Upper Peninsula Chapter of the Michigan SAF. In addition to the flood damage, the group inspected a newly emplaced bridge structure over creek on Longyear property and examined emergency road repair from the flood, including a wetland crossing. The Michigan Department of Environmental Quality was present to address construction issues, permitting, and emergency measures.
Three square mile Silver Lake drained in about nine hours. The aftermath of the flooding was impressive. Much of the river riparian zone was scoured. Up to 15 feet of sand was deposited in some areas, resulting in blockage of several Dead River tributaries. In many areas, crews were actively stabilizing banks and had returned the river to its original channel.
The Dead River has four impoundments; Silver Lake, Dead River Basin, McClure dam, and Tourist Park. The Hoist dam holds back the largest impoundment, Dead River Basin. Had that structure failed, much of the north side of the City of Marquette would have been flooded.
The Presque Isle power plant supplies over 600 megawatts to the area grid and is the sole supplier of 300 megawatts needed to run the Tilden and Empire iron mines. Mining operations were shut down and incrementally resumed over the next month as power plant units were brought back on-line.
Damages were grouped in three categories: infrastructure loss, economic loss, and environmental impact. Roads, bridges, and dams accounted for only about $4.2 million. The other losses are more difficult to assess. The impact to the river may never be put into dollar figures.
Click on one of the thumbnail images for a larger picture.
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Last update of this page was 30 September, 2005
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