PARK RAPIDS, MINN. – The mating dance of the hex mayflies drew John Sorenson to the Straight River at sunset.
As the bugs floated like snowflakes in the fading summer light, he pulled on his waders and waited patiently for the distinct sound of trout breaking the dark water to feed.
"It's a treasure," he said, stepping to the edge of the grassy bank and casting his line, as he has for years.
But the Straight River is becoming warmer and more polluted as farm irrigation rigs multiply along its banks. Now Sorenson fears that the fish huddling in the cooler deep spots are a stark sign that northern Minnesota's only naturally producing trout stream is in trouble.
"In ten years the Straight River could be a big muddy stream good only for carp," he said.
And the peril is flowing downstream — into the Mississippi River and across a watershed that covers almost half of Minnesota, signaling a new and rising threat to one of the state's great natural wonders. Like many others across Minnesota, the great river is heading toward an ecological precipice.
In the last five years, the Upper Mississippi watershed has lost about 400 square miles of forests, marshes and grasslands — natural features that cleanse and refresh its water — to agriculture and urban development. That's an area bigger than Voyageurs National Park and represents the second fastest rate of land conversion in the country, according to one national study.
That breathtaking transformation is now endangering the cleanest stretch of America's greatest river with farm chemicals, depleted groundwater and urban runoff. At this rate, conservationists warn, the Upper Mississippi — a recreational jewel and the source of drinking water for millions of Minnesotans — could become just another polluted river.
Here, around Park Rapids, potato fields are replacing forests, and drinking wells show rising levels of nitrate contamination from fertilizers.
Along the western edge of the vast watershed, soaring demand for irrigation is depleting sensitive aquifers and rivers that feed the Mississippi.
And where the Upper Mississippi curves like a giant question mark through the center of Minnesota, many of its tributaries are showing signs of stress — phosphorus that breeds algae, sediment that makes the water cloudy, even bacteria in stretches farther downstream.
"What we do to our land, we do to our water," said John Linc Stine, commissioner of the Minnesota Pollution Control Agency. Yet because most land use decisions are in the hands of private property owners and local governments, Minnesota has limited power to protect the river. "We can see it coming and still not be able to do something about it," Stine said.
The battles over land use along the great sweep of brown river go beyond drinking water, to deeply held values that give the headwaters state part of its identity, said Bonnie Keeler, an environmental scientist at the University of Minnesota.
"Like clear lakes, stewardship, a sense of place and pride, and the identity of Minnesotans around clean water," she said.
Quite beyond their sheer beauty, forested lands in the watershed also provide immense economic value in purifying drinking water for millions of people, an issue that has drawn the attention of federal regulators. This past summer, the U.S. Environmental Protection Agency launched a special project to predict how changing land use around the Upper Mississippi affects water quality, part of a larger effort to understand the threats facing major drinking water systems across the country.
Keeler, who directs the Natural Capital Project at the university and studies the social value of such things as clean water and forests, said it's hard to find the right balance between protecting the Upper Mississippi and preserving economic engines such as agriculture and tourism. But, she added, the debate has thrust a new kind of environmental thinking to the forefront: Clean water, natural landscapes and wilderness have an economic value that deserves a place in the broader equation that defines a healthy economy.
In short, Keeler said, "What would a map of an ideal watershed look like?"
Running out of time
Conservation groups in Minnesota aren't waiting for the answer. Working with state agencies, they are scoping out the most ecologically valuable tracts of land and water in the Upper Mississippi's 20,000-square-mile watershed. Using public and private funds, they're buying key parcels outright or protecting them with permanent easements that prevent development.
The project has become a priority in deploying money from Minnesota's 2008 Legacy Amendment, the landmark sales tax increase for culture and nature. So far, Legacy funds have helped protect about 250 square miles in the Upper Mississippi watershed, with more in the works.
And the Nature Conservancy, which studied land use in the watershed to produce those startling numbers on lost forests and wetlands, has created a $10 million fund to protect key parts of four primary tributaries — the Crow Wing, the Pine, the Sauk and the Rum.
While they meet regularly to discuss new threats and opportunities in the watershed, conservationists and state environmental officials agree that Minnesota has no one in charge and no master plan to rescue the river. That leaves critical questions unanswered: How much land must be protected to preserve the natural infrastructure around the Upper Mississippi? Will local opposition place crucial parcels out of reach?
And they wonder whether Minnesota can move fast enough.
In other parts of the country, communities have discovered the cost of waiting too long. In 2014, the city of Toledo warned residents not to drink their tap water after pollution from farms and sewage treatment plants created toxic algae blooms in Lake Erie. Last year, the city of Des Moines took the extraordinary step of filing suit against upstream drainage district managers for allowing high concentrations of nitrates from farmland to flow into the city's drinking water.
Other states have had more foresight. Around the Quabbin Reservoir that supplies much of Boston's water, for example, Massachusetts placed protections on 182 square miles and allows only extremely limited hiking, biking and boating — and no swimming. Though state officials denied it, a recent plan to reintroduce an endangered timber rattlesnake to the area was seen by some as an indirect way to deter visitors.
"We know what happened where we lost [clean-water] infrastructure — and the cost of getting it back," said Richard Biske of the Nature Conservancy. "It's either pay a little bit now or a lot later."
One of the key battlegrounds in protecting the Upper Mississippi will be the Pineland Sands Aquifer, a 770-square-mile water formation that lies beneath the Straight River and the central-Minnesota town of Park Rapids.
In 2014, Fargo-based R.D. Offutt, the nation's largest potato grower, stunned state regulators by applying for a whopping 54 irrigation permits, each of which would allow Offutt to pump as much as 1 million gallons of water per year from the aquifer.
Offutt's plan represented just the latest in a burst of demand for agricultural irrigation in an area known for sandy soils that can become perfect for growing corn, soybeans and potatoes — given sufficient water. Irrigation has increased by an average of 77 million gallons per year since 1988, or 85 percent, according to the Minnesota Department of Natural Resources (DNR).
Nitrate contamination of local drinking water has climbed in lockstep. The city of Park Rapids had to dig deeper wells at a cost of $3 million, and in some areas above the aquifer more than 10 percent of private drinking wells have nitrate concentrations above the level considered safe for infants and pregnant women.
Excess nitrates, bacteria and sediment have also turned up in the nearby Crow Wing River, which provides one-fifth of the water volume in the Mississippi after they merge near Brainerd.
"This is the headwaters of the Mississippi," said Randy Wenthold, who lives near Park Rapids. "If we are polluting this area, it's floating downstream … to the people of the Twin Cities. It's coming at you, baby. Whether you like it or not."
For decades, much of the aquifer was covered — and protected — by forests managed by the Potlach Corp., once the largest private land holder in Minnesota. But now Potlach is moving most of its tree-growing operations elsewhere. Above the sensitive Pineland Sands Aquifer, about 10,000 acres have been or soon will be deforested for farming, and another 20,000 could be, DNR officials said.
The expansion of agriculture has slowed for now, in part because of a drop in corn prices. Ironically, Offutt embarked on the expansion of its potato fields in large part to reduce pollution to local drinking water. Adding more fields meant it could rotate potatoes more often with other crops that require fewer chemicals. Last year it reduced its request for permits to five, and the DNR and other state agencies are trying to gauge the scope of the problem.
The Minnesota Department of Agriculture is studying how nitrates move from soil to groundwater in land that's never been cultivated. And the DNR is planning a $1.5 million project to study the movement of water to and through the aquifer — and just how much irrigation it can tolerate.
Sorenson, the Straight River trout angler, said he's glad the state is stepping in. Even so, he worries about the rising demand for water and the next big drought. What will happen to the trout, he wondered, if all the groundwater goes to corn and potatoes?
"If it was for national defense, if it was for hungry people, I'd be all for that," he said. "But for French fries for an already overweight country? That triggers my ire."
In addition to studying the aquifer, state agencies and conservation groups are taking advantage of the lull in land conversion to acquire prime pieces of the Potlatch properties.
But that can go only so far, said Richard Peterson, who manages a forest easement program for the DNR. Peterson estimates that the state will be able to protect only 10 percent of the forested land over the Pineland Sands aquifer. A key reason: local governments object when easements or public ownership halt the progress of private development and reduce local tax revenue.
"We are putting this price on conservation," said Matthew Hilgart, policy analyst for the Association of Minnesota Counties. "But at the cost of what? Property tax increases? Service reductions? Is that fair to the local population?"
Hilgart says the Legacy Amendment, though well intentioned, has spawned local animosity toward state government and conservation groups. Half of Itasca County, for example, is now in public hands, he noted.
"We have not reached this huge anti-government … atmosphere. But I don't want us to," he said.
North of Brainerd, where the Mississippi starts to curl south, there's another kind of deforestation underway. But this one — exemplified by the tree stumps alongside the new four-lane Highway 371 — is driven by the growing number of people seeking the quintessential Minnesota getaway.
The population around Minnesota's lake country is growing rapidly, and is expected to accelerate as baby boomers retire. The population of Crow Wing County has risen 15 percent since 2000 — faster than the state as a whole — and is projected to rise another 13 percent in the next two decades. And that doesn't include the seasonal vacationers who clog the roads every summer weekend, driving the expansion of Highway 371.
"This is just a darn nice place to live," said Rod Osterloh, who's been working as a real estate agent in the Brainerd area for 30 years. "There's high quality water, fishing, hunting, lots of recreation and proximity to the Twin Cities." As a result, he added, "There's traffic all the time."
At the same time, grandparents are dividing their lake home properties to help pay taxes or hand them down to their kids and grandkids, said Jeff Forester, executive director of the Minnesota Lakes & Rivers Advocates. "It's the largest intergenerational transfer of forested land in history," he said. "And you can't put it back together."
Taken together, these trends mean more roofs, lawns, docks, driveways and boats — all of which can drive water pollution.
Starting a few years ago, Crow Wing County began requiring stormwater management systems for any property that has 15 percent or more hard surfaces. That's the point where "you start seeing problems" in water quality, said county land manager Chris Pence.
But local governments are already facing hard choices.
This year the Crow Wing County Board of Commissioners created a tempest when it voted overwhelmingly to allow ATV and snowmobile trails in a protected forest it owns along the Mississippi near the Brainerd airport.
The land, once slated for development, was purchased from Potlatch with $11 million in Legacy funds as a major forest conservation area. But motorized trails are not good for wildlife or habitat, said outraged members of the state's Lessard-Sams Outdoor Heritage Council, a body that advises the Legislature on the use of Legacy funds. Giving it to ATVs and snowmobiles, they said, violated the spirit of the Legacy Amendment.
Crow Wing County Administrator Tim Houle says the county was always clear in its intentions. But the larger problem, he said, is that other counties saw Crow Wing take a lashing and are now wary of conservation partnerships with the state.
"We have been mistreated by the Lessard-Sams folks," he said.
'God awful insult'
One day this past summer, some of the farmers around Rice, Minn., left their fields to attend a meeting in town with state pollution officials. For two hours they listened to experts from the DNR, the Agriculture Department and the Health Department explain the hydrology of aquifers and the risk of high nitrates in drinking water.
"A baby can drink three bottles of it and die," said Rich Soule, a hydrologist with the Health Department. "We lose sleep about it."
The farmers were hearing quite a different message: That their way of life was at risk. Collectively, they have invested millions of dollars in the chemicals and massive irrigation systems that, over the last few decades, have transformed the sandy soils of Benton and Morrison Counties near St. Cloud into an extraordinarily rich region for corn, soybeans and potatoes.
Water from the aquifer, in short, is what built their lives, their families and their community.
Now these government officials were suggesting that the state might restrict their use of water — all to protect a modest stream called Little Rock Creek that carries a rising load of agricultural pollution into the powerful sweep of the Mississippi River flowing serenely past them just 2 miles away.
"It's a god awful insult on us," said farmer Dean Zimmerman.
Conflicts like this one are intensifying up and down the lower part of the river's watershed, between Little Falls and St. Cloud. Here the forests give way to farms and cities, and most of the tributaries that flow to the Mississippi are in trouble.
To Wally Parkins, that's just the way it's got to be, as long as people need food and a place to live. Parkins, who raises corn, soybeans and potatoes, farms 5,300 irrigated acres around Royalton, north of St. Cloud.
"That's more important than a little disruption to the planet," he said.
Driving his pickup truck past iridescent green rows of corn in midsummer, Parkins pointed to the massive irrigation pivots that arched over his fields. Each one assures that the soil will produce the perfect oblong potatoes that consumers expect. He sells his crop to Michael Foods, a Minnetonka company that turns them into French fries and hash browns under the brand Simply Potatoes.
Farming, he said, paid for the recent county school referendum. Without it, he said, "kids, schools, everything would shrink dramatically in rural areas. We are big drivers of the local economy."
But irrigation around Little Rock Creek as increased 180 percent in the last 25 years, and shows no sign of slowing down, according to DNR officials. Nitrate levels are rising in the Rice community drinking water system and in private wells.
Ken Nodo has lived next to Little Rock Creek all his life, and he used to fish for trout there as a boy. He pointed out a deep wide spot where he could once see straight down to the sandy bottom.
"This was my little hole," he said. "But it's all mud."
Nodo doesn't blame local farmers for fighting to hang onto their investments and their way of life. "Naturally they are upset," he said, because their days of unlimited water use are probably over.
It's just too bad, he said, that the state didn't step in 25 years ago — before it was too late for Little Rock Creek.