The practice of designating green space, especially for dogs to romp freely, have become more and more popular. But one dog park in Milwaukee's Riverwest neighborhood has some questioning the safety of the ground where their dogs frolic.
What's under the grass at the Roverwest dog park in Riverwest? Some say it was a poisonous dumping ground. Are our dogs safe there?
James Bruss submitted those questions to Bubbler Talk — our series that answers your questions about Milwaukee and the region. And it turns he isn't the only person unsure of the parcel's past.
Annie McSherry, who lives a couple of blocks from Roverwest, was recently walking her golden retriever near the park.
"I don't know what was here, but I have heard that the groundwater is contaminated and that they can't build on it, and that's why the dog park is here," she says.
It turns out the site has had multiple lives. From 1910 to the 1990s, the parcel, which was owned by Johnson Controls, was filled with a manufacturing and storage facility. Over time it was home to everything from box manufacturing to lead-acid battery production.
Sarah Toomsen, with Milwaukee County Parks, says in 2010 Johnson Controls donated the land to Milwaukee County. The company wanted it to be a green space for recreational use, but the county had to be mindful of contaminated soil and groundwater.
"The appropriate thing there would be a dog park where you wouldn't have that much contact with the contamination beneath the cap but it would be actively used by the neighborhood, which is fairly dense residential and a lot of dog owners would like a place to play with their dogs," she explains.
It would be four years before Roverwest welcomed its first visitors.
Toomsen calls the final design of the park a protective layer cake.
"The soil cap is 2 feet in depth, but there is a 4 inch layer at the top that is stone aggregate. And that stops dogs digging or people digging into that cap layer — for their own protection to keep them from the contaminated soil beneath," she says.
That's one reason you don't see any trees in the park. The protective cap needs to remain intact – any deep digging could migrate contamination upward, Toomsen says.
"We're not able to plant trees. We've had questions about shade structures, which would have concrete footings that would go deep into the ground. And so again, we have to be very careful that everything we're doing is just really on the surface because we need to keep the contamination capped," she says.
Mark Drews knows a lot about the parcel's past and present. He's a hydrogeologist with the Wisconsin Department of the Natural Resources.
Drews says the parcel's multiple industrial lives left contaminated soils and groundwater in their wake.
"Various metal compounds detected — lead is a primary one. Actually, the main contamination that was found here – the reason they had to do much of the work was for chlorinate solvent contamination. Usually, the solvent materials are used for cleaning … Many businesses use, it's a very common material that's used, drycleaners use it, that's what's used to clean your clothes," he explains.
Drews says step one was getting rid of the most highly contaminated soil.
"A number of areas on the parcel were excavated and soils removed and taken to a landfill," he says.
While excavation was underway, Drews says crews laid underground piping that made additional remediation easier. One treatment involves a molasses solution.
"It's really a carbon. If you add carbon to the groundwater, the chemicals — the chlorinated solvents — in our groundwater will use that carbon and start to decrease, so it's a natural process," he explains.
So, is Roverwest safe for dogs? Drews says while groundwater continues to be tested four times a year, the remediated parcel is safe for dogs and their owners – as long as they don't dig deep into the ground.
Riverwest resident Annie McSherrry, who you met earlier, says she rarely takes her dog to Roverwest. But not because she's worried about its environmental safety.
"We don't go because my dogs not the friendliest dog … I would love to go more, we just have to train her better," she says.
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