To most anyone who can remember, the dam at the Sheboygan Broughton Marsh has been an unchanging fixture. The structure, built in 1938 was, at the time, the largest wetlands restoration project in the Wisconsin basins of Lakes Michigan and Superior. The waters that fill the 14,000 acre marsh complex are held back by the dam, and 131 square miles drain into the marsh from eastern Fond du Lac and western Sheboygan Counties. Above it is a wetlands filled with cattails, and below it, the Sheboygan River continues its course to Lake Michigan. And while the marsh itself looks like an Idyllic wetland paradise for wildlife, it has a problem that has long been in need of a cure.
Since 2017, the bypass tube installed in the 1960’s that lets water past the dam hasn’t been able to allow the marsh to draw down. Without that, the cattails become prolific and deeply rooted. And while the marsh appears to be healthy, it isn’t.
Normally the marsh would contain a mix of sedges, rushes, reeds, wild rice and grasses among other water-loving plants. Instead, a so-called “monoculture” of a hybrid cattail have supplanted most everything else in the marsh. They succeed, in large part, because of the lack of the ability to control water levels.
Sheboygan County Planning and Development Director Aaron Brault explains that the past five years – until 2021 – have been the wettest on record. When only 1 inch of rain falls on the watershed, the marsh is filled to capacity, and a continual release of water through the existing bypass has been unable to keep up with the flow. The cattails eventually release and flow to the dam, further impeding the ability to draw down the marsh.
The solution up till now has been to have the Wisconsin Department of Natural Resources to bring in a boat – which the County doesn’t have – and dig out the cattails, pushing them to a point where the County can bring in a backhoe to remove the mass, loading it into trucks for disposal in a highway reclamation pit. That happens at a cost estimated at nearly $50,000 each year. The better solution in the long run is to replace the dam and bypass tube. That project has now been put into the 5-year Capital Request of the Sheboygan County Planning and Conservation Department.
The plan, if approved, would begin this fall with design plans. Already the bypass gate that controls water flow through the tube was replaced in February of 2020. The $2.7 million project would also entail the design and construction of a new dam to replace the one installed in 1938 to better manage water levels at the Marsh, which will lead to better cattail control, and replace the 1968 bypass tube which has already surpassed its estimated 50-year lifespan. In all, the completion of the project is expected to be sometime before 2026.
Not all costs will fall upon the County itself. The local Sheboygan County Conservation Association has pledged $100,000, and the DNR has put in a request to the state budget for $1 million which looks likely to survive, as Governor Evers has also expressed approval of it. The County has requested the rest in their 5-year capital plan. Ducks Unlimited is already doing some of the preliminary engineering research, which Director Brault called a “good partnership.”
The proposal is now working its way through committees within the County Board, with approval anticipated sometime in the late summer or early fall.
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