New seawall will help make Sheboygan resort development possible
A steel seawall will be installed along a 40-acre peninsula between the Sheboygan River and Lake Michigan in Sheboygan to contain contaminants in the river and on the property being redeveloped into a resort hotel.
The new seawall will address a unique situation the developers face: contamination on the landmass – the former C. Reiss Coal property – and in the river bottom. Exacerbating the situation is the crumbling condition of the existing seawall. Both the river and the landmass next to it have contaminated soil that needs to be removed.
The US Environmental Protection Agency (EPA) declared the Sheboygan River a Superfund site by in 2000. Deposits of silt on the river bottom are contaminated by polychlorinated bipheynls (PCBs) and heavy metals.
Dredging to remove the toxic sediment will be concentrated on the lower 14 miles of the river from the Sheboygan Falls Dam to the Inner Harbor. That means that dredging could take place adjacent to the C. Reiss Coal property.
So not only would work to replace the existing seawall have to prevent contaminants in the soil from spilling into the water, care would have to be taken to make sure the seawall would extend deep enough into the bottom silt so as not to be exposed by dredging.
According to Wisconsin Department of Natural Resources (DNR) water resources planner Stephen Galerneau, the presence of contaminants in the river silt make replacing the crumbling seawall a challenge.
"Because of two contamination sources — the C. Reiss property and the river sediment contamination — they were restricted in the kind of seawall restoration options that could be done," Galerneau said. "Something that was suggested and agreed upon by the city and EPA and DNR was to place another set of sheet piling to create a new seawall. The new wall would be placed within one foot of the existing seawall and driven into place. Once the new seawall has been constructed, there will be that small portion between the new wall and the existing wall.
"The sediment between there will be tested for contaminants. A flowable fill material (sand, fly ash, Portland cement) will be poured in there that will solidify all of that space between the two walls. Essentially, they will encapsulate those contaminants that are between the walls. Now we have a site being more thoroughly buttoned up."
According to Roger Miller of Sheboygan-based Miller Engineering, which designed the new seawall, the structure will consist of steel sheeting, each sheet being 40 feet high.
"Right at this moment, it is not known at what elevation the contaminants are," Miller said. "Out in the channel, the most contaminated sediments are now overlayed with cleaner sediments. Right along the edge, we are not sure what level the contaminants are."
Construction of the new seawall by Manitowoc-based McMullen & Pitz has started. Steel sheeting was to arrive the last week of January, according to company owner Erich Pitz.
The contractor completes similar heavy construction jobs nationwide, and Pitz seemed glad to have his men on a project so close to home. And for Pitz, the harbor and Sheboygan River are close to home for him in more ways than one — the company installed the original bulkhead as one of its first jobs in 1918.
"We did the original — and we also did the northside pier," Pitz said, referring to the Riverfront Boardwalk previously redeveloped by the City of Sheboygan. "We also did the steel sheeting across from the Coast Guard station and on the fisherman’s wharf on the opposite side."
Deadlines for grant programs and opening of the resort hotel are hanging in the balance.
Other complicating factors include the presence of a 16-inch water main, an 18-inch sanitary sewer, and fiber optic lines that exit the site and extend under the river. The steel sheeting will have to be installed around those utility lines without shattering them.
Rather than drive the steel sheeting into place, Pitz plans to vibrate it into place — the vibrations will cause the steel to sink into the bottom silt.
"It will be quieter and faster to shake it in," Pitz said. "We have a power pack and an attachment that clamps onto a piece of sheeting and shakes it down. It depends on what the soil conditions are. We also have a Vulcan air hammer if we can’t get the penetration we need."
Given long years of industrial use, the actual soils on the site are not as laden with contaminants as originally thought, according to sources involved with the project.
"We’re only looking at removing about 1,300 tons of soil," City of Sheboygan public works director Tom Holtan said. "That’s not bad for a 42-acre site."
Holtan said bids for demolition and remediation on the site will be opened Feb. 11, and the work is to be completed by March 31.
