Channel runs between Mirror, Shadow lakes
By Angie Landsverk
Dredging the channel between Waupaca’s Mirror and Shadow lakes, and managing the channel from a wetland into Shadow Lake are both being examined.
The two areas were discussed June 15 during a Friends of Mirror Shadow Lakes meeting, at South Park.
The last time there was a dredging project involving the channel between the two lakes was in 2003.
The outlet to Shadow Lake was included.
“Dredging is certainly something that can be done,” said Scott Koehnke. “Everything is possible. Typically, it’s cost.”
Koehnke, a Wisconsin Department of Natural Resources water management specialist, explained the process to the group.
He said it begins with a simple request.
The group would need to describe the project’s location, how much material would be dredged, the dredging method and type of equipment that would be used, where it would dispose the sediment and information about any previous sediment samples.
The sediment review team would then decide if a sediment analysis was needed, Koehnke said.
If an analysis was required, a consultant would need to be hired.
Discovering any hazardous materials in the sediment would change the disposal method.
“It doesn’t cost anything to ask about dredging,” Koehnke said.
He also said dredging is not a permanent solution.
If people use the channel, it helps keep an open pathway through it.
When projects are approved to apply for a permit, a $603 fee has to be filed with the application.
That is followed by a public notice of the project and comments from the DNR’s fisheries, aquatic and wildlife “folks,” Koehnke said.
“So there’s quite a few logistics,” he said.
How to manage the channel from a wetland into Shadow Lake is also an issue.
“We have been talking about that area,” said Aaron Jenson, the city’s parks and recreation director.
Discussions have included rerouting the channel and planting native species of plants to filter out phosphorous before it reaches the lake.
“We reached out to some consultants, construction companies,” he said. “We thought it could be done for $50,000. Now we’re looking at $80,000 to $90,000.”
He wonders if spending that amount is worthwhile when there are still other sources affecting the lake.
The water in the channel is being tested through September, and Jenson said native plants could be planted for more less than $90,000 and filter out the phosphorous.
“We want to make that area attractive,” he said.
Paul McGinley told the group to think of the wetland as an extension of the shoreline.
He is a professor of water resources at the University of Wisconsin-Stevens Point and a UW-Extension water quality specialist.
“If you can get the water to go into the ground and not run across a surface, that is where you want to be,” McGinley said.
Koehnke said there are number of factors to consider.
“You have to find the sources of what’s coming in,” he said. “Stormwater is a big contributor to the system.”
The beach affects the lake.
Any time a street is redone or a driveway is changed or a lawn mowed in the city, it becomes a contributing factor, Koehnke said.
“I think educating and understanding is a huge part of it,” he said. “I don’t think it’s your fault that you had elevated phosphorous at that site.”
Koehnke described Shadow Lake as a “giant salad bowl” and said everything slides into the lake.
“The more people who get involved and think about what they’re doing, the more of an effect,” he said.