From its headwaters in Sun Prairie to the final riffle before it dumps into Lake Koshkonong, every perfect storm on Koshkonong Creek seems to bring complaints of an imperfect flood of high water and pollutants.

A year after historic rains left farm fields, roads, and parks flooded throughout the creek’s 54-mile-long, 169-square-mile watershed, how to manage the water flow has become a heightened conversation.

So, too, has arisen new talk of how to fix a myriad of long-simmering other issues. Those include an EPA-flagged high concentration of phosphorus, eroding streambanks, longtime calls to clean out fallen trees and other debris that cause backups and make much of the waterway inhospitable for recreation like kayaking and canoeing, and calls to dredge out a choking layer of sediment that’s built up since the last recalled widescale cleanup 60 or 70 years ago. Farmers along the creek today say that sediment has built up to 3-feet deep in spots.

Concerns about all that — and talk of who should pay to fix the problems — have brought together officials and property owners from more than a half-dozen municipalities and unincorporated bergs within the watershed that touches Sun Prairie, Cottage Grove, Deerfield, Kroghville, Cambridge, Rockdale and Busseyville, and a variety of towns including Sun Prairie, Cottage Grove and Deerfield. A small stretch near Cambridge curves also into Jefferson County but soon returns to Dane County.

Dane County and the Wisconsin Department of Natural Resources are in on the conversation, as are federal offices like the USDA’s Natural Resource Conservation Service and a host of regional nonprofits including the Rock River Coalition. Also involved have been regional entities like the Capitol Area Regional Planning Commission and regional water trail recreation groups like Capitol Water Trails and Mad City Paddlers.

Sun Prairie water

Sun Prairie, in particular, has been called to action. It has long been the target of finger-pointing from downstream property owners, mainly farmers, many of whom blame its storm water runoff and wastewater treatment plant discharge for their flooding woes.

Ahead are coming upgrades at the city’s wastewater treatment plant, coming storm water upgrades and a historic impending agreement with the Dane County Drainage Board to help cover the cost of cleaning out the creek in two farm drainage districts that lie partially in both the town and the city of Sun Prairie.

There’s widespread recognition that the Koshkonong Creek’s troubles are not all the fault of Sun Prairie and that neither should the fixes be its sole responsibility.

Its city limits only encompass about 12 square miles of the watershed and Deerfield, Rockdale and Cambridge also send their treated sewage water into the creek (Cottage Grove is part of the Madison Metropolitan Sewage District) and have all seen their share of new development in recent decades.

Some of Sun Prairie’s storm water also flows into the Yahara River basin.

But the city has recently taken steps to acknowledge its obligation.

Next year, Sun Prairie will begin construction on a $22 million expansion of its sewer plant that sits a few hundred feet from the Koshkonong’s headwaters and contributes about 4 million gallons of treated wastewater daily into the creek. Storm water from the city amounts to another estimated 2 million gallons a day going into the creek.

And that’s just the base flow.

“In a big rain event that number goes way up,” acknowledges Sun Prairie City Engineer Adam Schleicher.

The city’s sewage treatment plant expansion is being spurred in part by an order from the U.S. Environmental Protection Agency and the Wisconsin Department of Natural Resources, that the city, which has seen a surge in development and population – up from about 20,000 residents in 2000 to nearly 30,000 today — meet its burgeoning wastewater needs.

Jim Amrhein, a stream biologist with the DNR, notes that the order isn’t unique to the Koshkonong Creek watershed.

“That’s the story of any number of streams in Wisconsin,” whose local governments are now working to meet the EPA rules for phosphorus that were tightened in the past decade, Amrhein said. Sun Prairie has until 2024 to meet the new EPA phosphorus rules.

Among the Sun Prairie plant’s planned updates are new high-tech filters that it’s hoped will help bring down the level of phosphorus contamination in the creek.


The phosphorus began building up in sediment in the creek in the mid-1900s as fertilizer use on both lawns and farm fields dramatically ramped up, said Paul Garrison, a retired research scientist with the DNR who now works as a volunteer stream monitor with the Rock River Coalition and DNR in the Cambridge area. In his time with the DNR, Garrison, who lives in Utica, helped develop the phosphorus standards now in place statewide.

In the 1960s and 70s, efforts at reducing sediment flow into waterways became effective, but “we kept adding more and more commercial fertilizers,” Garrison said.

Dane County about a decade ago banned the use of phosphorus-based fertilizers.

“That’s helped a lot; we know it’s made a difference,” Garrison said.

Dane County also has a “very strong,” erosion control ordinance for construction sites, which helps keep pollutants from flowing into the creek, says Sun Prairie Town Chairman Lyle Updike, who has served on the county’s Lakes and Watershed Commission.

The county “has invested a lot in green practices to reduce agriculture runoff, with the idea that if we hold the water on the land and reduce the nutrients and solids going into the watershed, it’s going to control the phosphorus across the entire watershed,” Updike added.

The city, Schleicher said, acknowledges that “the wastewater plant is a constant contributor to the stream.”


The city’s upcoming storm water initiatives include constructing a 17-acre storm water pond on its northwest side to contain storm water and, hopefully, allow some phosphorus to settle out before water runs on into the creek. Construction is slated to begin in 2020.

“We’re going to catch all that water here, clean it and then discharge it,” Schleicher said. “That’s good for the city and good for watershed.”

“We do have some flooding concerns in the city during high rain events. We’re trying to give our residents some relief and also to do the right thing for the environment,” Schleicher noted.

Part of the cost is being covered by a water quality grant from Dane County, Schleicher noted.

“They recognize the water quality impact,” Schleicher said.

New developments, Schleicher said, are required by the city to not impact the watershed by storm water runoff, more than it was impacted before the development was built.

Older neighborhoods, however, predated the ordinance and have neither had to meet those rules, nor had the infrastructure in place to do that.

“That old school philosophy was just to get (storm water) out of here,” with little treatment, reflects Schleicher. In recent decades, he said, “the DNR and cities have realized that’s not the best solution for the environment.”


Additionally, in September, the city expects to sign what some are calling a historic memorandum of understanding with the Dane County Drainage Board, a three-member countywide appointed panel that has for more than a century overseen farm drainage districts in rural areas.

Under the agreement, the city would work with the Drainage Board to cover the cost of dredging about 10 miles of the creek in two farm drainage districts and rehabbing its streambanks in an area that lies partially within its city limits and partially in the Town of Sun Prairie.

The work will specifically include dredging out the main channel from Bird Street southward to County Highway TT, as well as removing trees along the banks.

“The creek hasn’t had a large drainage project probably since the 1960s,” Schleicher said. “There are trees overgrown, it’s silted up; there are a lot of maintenance needs out there.”

“We acknowledge our responsibility for a portion of it; we contribute to the creek. In order to have the ditch available to handle our water we need it to be maintained,” Schleicher said.

As the largest land owner in one of the two drainage districts – a city park and aquatic center fall within the district’s boundaries – the city also sees a benefit in bills for work in the drainage district coming more consistently from it, rather than property owners receiving separate bills from the Drainage Board.

“The city did find some value in that,” Schleicher said.

Drainage districts were set up across Dane County in the early 1900s and are regulated by state law.

Most of the Koshkonong Creek’s drainage districts were set up in the first two decades of the 20th Century, in an era in which the once-meandering creek and its surrounding wetlands were drained into a brand new, artificially straight channel.

Over time, additional smaller ditches, some public with maintenance falling to the Drainage Board and some private, were connected into that altered main channel.

Vast stretches of former marsh were drained by networks of tiles – small pipes, originally of clay and later replaced with plastic –buried under the soil that carried water toward the creek.

A 1911 edition of the Cambridge News, talking about the push to set up drainage districts along Koshkonong Creek, noted that the natural marshes “ordinarily considered worthless… could with proper drainage be made the most valuable lands the farmer has.”

Today, those drain tile systems remain largely in place, continuing to direct water off land in the watershed that remain actively farmed. Landowners are responsible for maintaining the actual drain tiles that are buried in their fields.

Drain tiles have also been employed for civic improvement, including in the 1950s in downtown Cambridge, when the natural meandering creek there was rerouted to flow straight through what today is Westside Park.

Today, there remain 19 drainage districts scattered across Dane County, most from Madison eastward.

Within a drainage district, the Drainage Board has the power to special assess property owners for the cost of dredging, removing debris and other work to keep the water flowing.

The proposed agreement with Sun Prairie is happening as the century-old network of Dane County drainage districts is increasingly being employed to help manage storm water.

On Aug. 5, a Dane County judge agreed with a request from the Drainage Board to reactivate three drainage districts, near McFarland, Deerfield and Waunakee, to allow the board to once again special assess property owners within their boundaries for work done in the creek and along its banks.

The McFarland, Deerfield and Waunakee drainage districts had been inactive, with no assessments and no work billed out, respectively, since 1958, 1970 and 1955.

Drainage Board members say the state statutes that allowed drainage districts to be created over the past century cited the desire to drain land for farm use as the sole basis for their existence.

Board members said they see the statutes as applicable today to the need to assess property owners — including municipalities like Sun Prairie — along the creek for work that moves storm water and municipal wastewater through the watershed.

In Sun Prairie’s case, the city expanded in recent decades into one of the two drainage districts covered by its impending agreement with the Drainage Board, says longtime board member Leonard Massie

“So now those properties are in the district. They are there and the water has to be dealt with,” says Massie.

Massie further hints that the Drainage Board may just be getting restarted in the Koshkonong Creek watershed.

“We’ll get to 23 when it’s their turn,” he said, referring to the aforementioned, recently reactivated drainage district near Deerfied. It encompasses about four square miles from State Highway 73 in the village, stretching eastward to the Dane-Jefferson County line.

Farming changes

This is all in addition to efforts by Dane County and other entities to work in recent years with farmers to share the cost of planting buffer strips between their crops and the creek, where water and sediment can filter out, and farmers’ efforts to reduce and even eliminate the amount of tilling they do on their fields. The latter, called no-till farming, seeks to disturb the soil less in hopes that it will hold in place, rather than washing away toward the creek. Farmers are also experimenting with planting cover crops in the fall that stay on fields all winter, helping to stem springtime erosion.

Jerry Bradley, who farms on land in the Town of Sun Prairie that has been in his family for generations, has worked with the county and the Natural Resource Conservation Service to add buffer strips to his farm fields and to do things like virtually eliminate tilling of his soil.

“You could have waterskied in some of my fields,” Bradley says, reflecting on the floods of 2008. Since then, he said, things have improved, and he credits the city of Sun Prairie for contributing to that.

“We have not seen the creek go over the bank since then,” he said. “They’re doing a better job of holding the water back.”

Yet, Bradley estimates up to three feet of sediment covers the creek bed along some stretches of his property.

“We get that out and (the waterway) will have more capacity and our tile lines won’t be underwater,” Bradley said.

On a recent tour, he also pointed out stretches so overgrown with trees and other foliage, that the water was barely visible.

Farmers between Sun Prairie and Deerfield often point to 2008 as a year they recall for its historic floods.

Larry Dahl has spent his life on farm north of Deerfield that family has owned since 1919.

Near where he pastures his dairy cows, Koshkonong creek flows straight and shallow. The original meandering channel ran across an adjacent hillside; the family story is that the new channel was cut by steam shovel in 1911. In recent years, Dahl says, water coming from upstream has undercut the bank, causing trees along it to topple, that then have to be pulled out.

In times of heavy rain, when the creek rises, he can see it trying to reclaim its natural channel.

Dahl daily crosses the creek over a small wooden bridge built by his grandfather.

Dahl has also worked with the USDA’s Natural Resource Conservation Service to plant grass buffer strips to slow and infiltrate field runoff before it hits the creek, with some of the cost picked up by a grant.

Dahl, like many of his neighbors, says landowners need to have input on what’s done on the creek into the future, especially if they are going to be assessed for work.

“Let us make the decisions,” he said.

Dan Kelly, whose family has owned its 265-acre farm on the creek since 1948, points to one portion of his fields that haven’t been planted in several years, because they’re too wet.

“I don’t know if Sun Prairie is the only culprit, there’s a lot of houses in town and the water has go to somewhere,” says Kelly’s daughter, Dana, who grew up on the farm.

“I think this thing has gotten about 10 feet wider than I was a kid,” Dana added on a recent walk down the creek, that involved pushing through thick brush to reach the bank. “Every 10 feet there’s a log,” she added.

Private ditches

Dave Muehl, who owns Badger Farms, a popular wedding reception site on County Highway BB between Cottage Grove and Deerfield, has watched over the past couple of years as about one-fifth of the field where he grows canary grass for animal feed and erosion control cover, has remained too wet for growing.

Muehl’s farm isn’t right on the creek but rather, is on a private drainage ditch shared with neighboring farmers, cut in the 1920s and last dredged in the 1960s.It connects into the main creek channel about 500 feet downstream. For years now, Muehl contends, high water in the creek has backed up into the private ditch, and then backed up into his fields.

Muehl said he’d support a creek impact fee were it levied on property owners and municipalities all the way down the watershed. He acknowledges the prospect of coming up with an intergovernmental agreement encompassing something like that would “be complicated with a lot of government entities. But that might be what’s required.”

Muehl also said he recognizes that the heavy rains of recent years have contributed but “there is human impact that has caused this and that has to be fixed,” he said.

Bradley agrees that “in a perfect world,” municipalities across the watershed would work together to solve its water issues.

Like Dahl, Randy Zakowski, who has owned a farm along the creek in the Town of Deerfield since the 1990s, is wary of a taxing entity ordering improvements that he might be assessed for.

“Nothing would be good if the government took over,” Zakowski said.

Zakowski has removed trees all along his stretch and planted, among other things, canary grass along the banks to stem erosion.

Zakowski said he keeps his stretch “pretty clean. I figure it’s my responsibility to do that,” he said.

I don’t like [the debris] in there. It causes problems all the way down the whole system,” Zakowski said. “I can’t change the whole creek, but I can help my neighbors out.”

Dams, wetland loss

As the creek’s waterflow is examined, others are looking at its broader health.

Other than the southernmost stretch between Rockdale and Lake Koshkonong, that still naturally meanders, it’s wildly different from what it once was.

Over the past century, for instance, it has lost almost all of its natural wetland where sport fish probably once spawned.

It has seen two dams – at Kroghville and Rockdale – go up and be removed and the resulting implications for creek life when those changes occurred.

Just below Rockdale, efforts continue today to restore the mussel population that died out when the dam there was removed in 2000, likely when their habitat was covered by large amounts of sediment swept through when the dam was breached.

Janice Redford, a member of the nonprofit group Friends of CamRock Park, has worked as a volunteer stream monitor at Rockdale since the dam came out, and has watched the mussels struggle to repopulate. The Friends group has also planted prairie seeds in the former millpond area and organized a biannual creek cleanup through CamRock County Park, removing fallen trees and other debris.

Redford said based on her records, the biotic index — the assessment of what’s living in this stretch of the creek, hasn’t changed much in 20 years.

“It isn’t as bad as some people think,” she said.

Redford, a former three-term Dane County supervisor, laughs however at the idea of municipalities across the watershed coming together in agreement on the creek’s future.

“I was a Dane County Board supervisor for three years and all they did was fight,” Redford said. “You’d be dealing with two counties, 15 municipalities.”

The fish and other small critters that live there today are mostly those classified by the DNR as tolerant of moderate pollution and okay living in a stream that mostly lacks natural bends and curves that might have once been home to more diverse array of species.

A 2016 DNR report noted that the Koshkonong is a warm water stream, not suited for popular sport fish like bass and trout that prefer colder waters.

The northernmost six miles, closest to Sun Prairie’s wastewater treatment plant, is classified as not suitable for fish.

Bottom line

Today, “the bottom line is that you have some good areas of Koshkonong Creek and you have some not so good areas,” says Amrhein.

Amrhein was part of a team that assessed the creek and issued the 2016 report on their findings.

The study noted that 42 fish were found living in the creek, most of those tolerant of low dissolved oxygen and “environmental disturbance.”

But there were also some surprises, Amrhein said, with fish found that weren’t expected.

“There are species that indicate that things aren’t, from a water quality perspective, as bad as they seem,” Amrhein said.

Amrhein said there are few historic benchmarks to show what might have naturally lived in the stream. The earliest available records, he said, are from the 1930s, after the creek was mostly already changed.

“It’s difficult to know what was there, to know what the landscape was like,” he said.

Amrhein say the creek isn’t likely to see great improvement into the future.

Although there have been small, isolated cases where individual property owners have broken drain tiles and allowed the creek through their land to return to natural meandering stream, that’s unlikely to ever happen on a watershed-wide level, Amrhein said. The cost would be prohibitive and, at least for now, the drained areas mostly remained farmed.

“To think that we are going to go back and remander the stream and break up all the tiles, that’s not going to happen,” Amrhein said.

That said, “there are certain efforts we can take to make some improvements,” Amhrein said. “But overall, especially in the parts that are upstream that are in a drainage district, they are going to be what they are going to be.”

“Is the Koshkonong Creek going to become this pristine, Canadian flowing stream? No. It’s not. Not any part of it. But that doesn’t mean it’s not valuable, that it doesn’t have valuable resources. I’m passionate about water; I believe all water resources are important,” Amrhein said.

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