The city of Portage, Wis., lies between two rivers — the Fox River, which empties into Green Bay and then Lake Michigan, and the Wisconsin River, which empties into the Mississippi River and eventually into the Gulf of Mexico.
Portage also has Silver Lake within the city limits — a 70-acre lake — and last year, officials updated an aquatic plant management and lake management plan. That plan was done with the assistance and cooperation of the University of Wisconsin, Steven’s Point and the Wisconsin State Department of Natural Resources.
City Administrator Shawn Murphy said, “The impetus is to preserve and protect the water quality of the lake overall now and in the future.”
Park and Recreation Manager Toby Monogue said officials held open forums to educate the community.
Murphy said the city enlisted the help of Columbia County Land and Water Conservation to file grants and received $50,000 to conduct a survey and help develop a plan. Monogue added the plan has two parts: lake management and aquatic plant management.
Implementation is ongoing. The plan has recommended the city put in retention basins as well as sump catch basins, which allow for the settling and coagulation of solids, etc.
Murphy said there are some shoreline zoning restrictions like no one can build or have septic systems right up to the water’s edge; however, Monogue noted there should be more shoreline restrictions.
Recommendations for property owners include educating them about why they shouldn’t mow up to the water’s edge in order to leave a buffer to keep phosphorous from running off into the lake. The buffer also deters waterfowl from coming ashore.
“This plan helps residents learn best practices like putting in plants buffer strips or other material to help mitigate runoff and deter wildlife from sitting on lawns,” Monogue said.
The lake has two lobes or basins. One is shallow with naturally occurring aquatic plants, while the other is deeper by the beach and is used for water skiing, boating, etc. Monogue’s department harvests the weeds on the lake, using a cutting map the Department of Natural Resources approved for what can and cannot be cut.
He said seasonal employees harvest the weeds from mid-May through mid-September. “They’re on the lake about three days a week for seven hours a day.”
He reported in 2019, they had removed 320 tons of aquatic plants, and in 2020, they had removed 328 tons. Employees don’t remove every weed; some aquatic plants are needed, so the cutting is primarily to provide boats with better navigation of the waters.
Monogue also worked with the Fish and Wildlife Department on a goose abatement program, and the city received a permit to oil eggs in the geese nests. He reported this is the first year they’ve done this. Workers use 100% corn oil and spray the eggs, which causes them not to hatch. It tricks the geese into sitting on the eggs that will never hatch. Monogue said it takes a couple of years for the program to work because the geese are birds of habit, meaning they return to the nests year after year. After a couple of years of no hatchings, geese will supposedly change sites.
Monogue said a couple of individuals who live on the lake volunteered to oil the eggs, and they found two nests with about 15-18 eggs. There may be more nests in inaccessible areas due to thick cattails.
Restoring a historic canal
The canal in Portage connects the two rivers and was developed in the mid-1800s. It was closed up and abandoned in the early 1950s, leading it to fall into disrepair. The canal was a heavily industrialized site for manufacturing facilities, which discharged runoff into the canal.
“So it’s heavily polluted,” Murphy said.
Since it’s a state waterway, the city partnered with the Wisconsin Department of Natural Resources and the Wisconsin Department of Transportation to clean up the canal. They’ve been dredging out sections of the canal’s bottom, which are polluted with heavy metals and bacteria. Murphy described the muck as looking like chocolate pudding. Once dredged out, the muck is properly disposed of and then capped off with sand cover to dissuade aquatic plant growth. Murphy said Portage put in new sides along the canal and a trail “so it’s a more user-friendly destination.”
The canal is listed on the National Registry of Historic Places with the National Park Services. Portage improved a mile-and-a-half section last year, and this year improved another mile, cleaning out trees, plants and garbage.
“It’s been more like a swamp than a river. Cleaning up and reestablishing the channel and flowing water will keep it cleaner,” Murphy said.
Portage has also installed a path with benches and lighting, allowing it to be a recreational destination. It was an expensive endeavor, costing $9 million for the one-mile section, which the city is installing this year. Murphy said the state is picking up $7.2 million of that cost.
The total length of the canal is almost 5 miles, and the city has restored 2.5 miles. There are gates and locks in the canal prohibiting boats from using it to get from one river to another, but canoes and kayaks can access restored areas.
Murphy said, “We’re blessed to have the river within corporate boundaries, but we don’t have a lot of management or control over its use because it’s a state waterway.”
He said the city does own a boat landing, and it monitors the water levels of the river because, after snows and severe storms, the runoff impacts the community. Murphy said officials worked with the Army Corps of Engineers to construct an engineered levee in 2008 to protect the 4 miles of shoreline.
“That effectively removed 400 properties from being located in a flood zone,” he said.
For other municipalities looking to improve their waterways, Murphy said they relied heavily on experts at the University of Wisconsin Steven’s Point Center of Surface Water Education, but he suggested, “Look at the trends — how much phosphorous is in the water now compared to 20 years ago? Are the phosphorous levels creeping up?”
Monogue said the city of Portage is unique in that it doesn’t have a lake management district. “So more fell on the city’s responsibility to do a study and the harvesting.”
Murphy agreed, stating when the city did the survey early on as part of the lake management plan, there was strong support for putting in place features and structures, “but not strong support to create a lake management district to help fund some of those things.” Murphy suggested city officials “take a step back and see what you currently have and where you are.”