COSMOS, Minn. — Carrie Jennings flits around the South Fork Crow River like a water bug in the old single-seater canoe she bought years ago for $100, then stops in the middle of the river to gaze at the brown water.
“This is very cloudy,” he murmurs.
She has come to see this upper reaches of the Crow River as it begins its journey through central Minnesota farmland to the Mississippi River, showing how a small river can do so much damage.
The paddle comes as work gets underway on a major new multi-county water quality plan for the South Fork Crow watershed under the state’s “One Watershed, One Plan” framework.
The stakes are high.
The state’s prized Mississippi River is clean as it emerges in northern Minnesota and heads south. It then meets the Crow River, the first major agricultural river to flow into it, and its nutrient pollution doubles, state pollution officials say, adding phosphorous, nitrogen and sediment. You can see the water change at the intersection, some rowers say.
The Minnesota Pollution Control Agency placed a large exclamation point at the location, near Dayton, north of the Twin Cities, on its map of Upper Mississippi.
Jennings, director of research and policy at the nonprofit Freshwater Society in St. Paul, points out with her oar some of the key reasons.
Large black plastic pipes protrude from the banks of the South Fork Crow River near Cosmos in Meeker County, dumping water around almost every bend. It’s tile drainage water, which comes from fields that are filled mostly with corn and soybeans here, about 80 miles west of where the Raven meets the Mississippi.
The nearly invisible network of pipes is like a vast underground road system, draining water to maximize crop yields. The shingle line drainage carries agricultural chemicals: state pollution regulators say it is the largest source of nitrate in the Mississippi, delivering 43% of it.
Along with surface runoff, shingle drainage also increases the volume of the Raven. High flows scrape against its shores, a dynamic that is only made worse by more intense rains from climate change.
The scrubbing exposes the roots of mighty cottonwoods and other trees on the banks, many of which have collapsed into the river. There should be a mix of sand and gravel on the banks and bed of the Crow River, Jennings said. Instead, there is a thick black mud, like quicksand, that sucks the shoes.
Scrubbed riverbanks, unlike fields, have been a growing source of sediment in the Mississippi River, he said. The topsoil carried away by the fields is still significant, she said, “it’s just that the big increase has been from non-field sources.”
Jennings said he expects to see water that brown in the Minnesota River, the state’s notoriously dirty agricultural river to the south, but not in the Crow. And this is just the beginning of the Raven. It only picks up more as it moves downstream through heavy farming areas like Renville County before joining the main Crow River at Rockford.
From there, the Raven races down the Mississippi, bringing its share of the pollution that drives the large and growing oxygen-depleted “dead zone” in the Gulf of Mexico.
“If our farming system does this to rivers that far up the Mississippi River basin, imagine the cumulative damage by the time it reaches the Gulf,” Jennings said. “This is not a mystery that needs to be solved. We know why these rivers are damaged and we know how to fix them.”
Agriculture is not the only source of Crow contamination, but it is important. The city’s sewage treatment plants and stormwater runoff take into account. The bottom line is that most of the land in the Crow River watersheds is devoted to agriculture, as row crops make their way further north into Minnesota.
The problem is problematic farming practices, such as over-application of nitrogenous fertilizers and manure, overuse of drainage tiles with pipes discharging directly into ditches and streams, and over-tillage of the soil. East of Cosmos, where Jennings paddled, the South Fork Crow meanders naturally; upstream is an abnormally straight agricultural drainage channel.
Since the Clean Water Act exempts agricultural drainage and runoff, environmental regulators are hoping to convince farmers to voluntarily adopt best management practices: apply fertilizers more precisely, plant cover crops to capture more nitrogen in the floor and disturb tile drainage outlets. One solution is to drain the water from the tiles first into a wetland or basin.
Such practices are not yet mainstream. Change has been slow. It could all take decades, said MPCA watershed project manager Scott Lucas: “So many different things have to change.”
Large sections of the two main crow forks remain impaired for aquatic recreation or fish consumption, and for aquatic life such as insects. While there has been progress over the years in reducing phosphorus in the Mississippi River, there has been almost no progress in reducing nitrate, pollution officials say.
Local farmers say they are aware of the problems and want to be good stewards of the land. But weighing conservation against production can be difficult when farm profit margins are thin. And changing entrenched farming practices is hard, said Joe Norman, district technician for the Meeker County Soil and Water Conservation District.
However, slowly, practices are evolving. For example, government programs have funded 81 wetland restorations in the South Fork Crow River watershed since 2004, state data shows. However, while they may benefit water quality, most are not the type designed to collect and treat tile drainage runoff, said David Wall, an environmental research scientist with the Minnesota Pollution Control Agency.
Doug Adams, who farms 1,500 acres with his family near Cosmos, including land in South Fork Crow, said he switched to strip tillage, which disturbs the soil less and leaves plant debris on the surface for better ground cover. He reduced his use of fertilizers by 40%, he said. It also keeps topsoil in place and reduces runoff into the river, with no change to your crop yield.
But trimming your tile drainage system? It is not an option. This spring was rainy and late, she said. The fields were waterlogged.
“I don’t know when we would have been able to plant without the tile,” Adams said.
Adams said he doesn’t think the water in his tiles is contaminated and he wouldn’t be afraid to drink it.
Cities are also making changes. Nearby, Hutchinson is embarking on a multimillion-dollar project to address the sediment and pollution that the South Fork Crow carries into Otter and Campbell lakes, two shallow lakes in the city. That means working with local landowners, shoring up crumbling creek banks, restoring wetlands and adding native buffer plantings, among other things.
The Crow River’s impact on the Mississippi River is well known in the watershed world, but it’s hard to make people care, said John Paulson, environmental regulation manager for the Hutchinson project. Communities need to address the problem locally, where they can see it.
That is what Kandiyohi County did. He just finished a decades-long project to restore a large drained prairie wetland in the South Fork Crow headwaters area near Willmar. More than a dozen families sold the state’s permanent conservation easements to rebuild Grass Lake. It now retains and filters farm drainage and stormwater from Willmar, said Loren Engelby, Kandiyohi County drainage manager. A large gate valve allows them to manage the water levels.
Frogs, turtles and birds are already coming back, Engelby said. Grass Lake’s water flows into Lake Wakanda and Little Kandiyohi Lake, impaired lakes that are the official headwaters of the South Fork Crow River.
But it could be argued that the real source of the river is the old Kandi Mall parking lot in Willmar, said DNR wildlife supervisor Cory Netland, who works in the area. The mall was built on a cow pasture made from drained wetland, and the parking lot empties into a large ditch that runs down to Grass Lake.
Engelby calls Grass Lake “a big kidney” that he hopes will significantly reduce nitrate, phosphorous and sediment leaching into South Fork Crow.
“This is a big piece of the puzzle,” he said, “but it’s a very big puzzle.”