In southeast Minnesota, swollen river threatens to reclaim cropland

THEILMAN, Minn. – It rained 10 inches here in July, twice as much as the year before, and the dike protecting Albert Carlson's farmland along the Zumbro River didn't stand a chance.

The swollen river rushed across the forested flood plain next to the cornfield, then blew a 150-foot hole in the earthen barrier, deposited sand a couple feet deep in the black dirt and submerged Carlson's fields, which he rents to a local farmer, for six weeks.

"Every year it comes up and floods, but this is the first time it tore a hole like this," said Carlson, standing atop the ruined dike, looking down into a pool of water 80 feet wide and at least 10 feet deeper than the level of his 120 acres of farmland.

The crop was destroyed. Carlson doesn't know how he can rent the land out in 2020 unless he can repair the dike, which could cost as much as $30,000. Since there is no government assistance available to repair it, and Carlson is reluctant to pay for repairs himself, a likely outcome is that the river will reclaim the land.

The Zumbro River watershed collects from the areas around Rochester, Pine Island and Zumbrota and gathers in a stream that empties into the Mississippi River south of Wabasha. Near Theilman, where the landscape is hilly and bluffs rise on either side of the river valley, farmers built dikes in the 1960s and 1970s to carve out plots of fertile cropland in the river bottom.

But heavier rainstorms in the last 10 years have made the Zumbro more volatile. The river is punching holes in berms up and down the valley, destroying crops and making the land more difficult to farm.

This year, rain gauges in Rochester, up the Zumbro from Theilman, recorded the highest total in 133 years — 20 inches more rainfall than normal. That water takes about 24 hours to reach Theilman, which saw heavy rain itself and endured a rapid meltoff from winter snow.

The Minnesota State Climatology Office said the heavier rains causing these changes in the Zumbro River Valley are a result of climate change. Since 2000, the number of rainfalls of 3 inches or more have increased 65% in Minnesota, and widespread rains of more than 6 inches are four times more likely.

"It's the bigger rain events, the larger amounts of rain in a shorter amount of time," Peters said. "Flows are increased and the water's going so fast that it's eating away at the sandy banks, especially from underneath, and then the top falls in."

Across the river from Carlson's land near Theilman, farmland owned by Bruce Wilson's family is also protected by berms. The river is eating away fast at the bank just below the levee.

"Some places since 2010 it's ate away 40 feet," Wilson said, as he looked out over a bend in the river.

He drove an all-terrain vehicle along a field of pitiful-looking corn below his home. The field was shot with winter rye, the hallmark of a field where crops were destroyed and the farmer is collecting crop insurance.

"This all was corn here, and it all was lost," Wilson said, gesturing to a field full of low, green winter rye.

He pointed to a swamp along the south side of the valley and said he suspects the river once ran through it, and may again some day in the future.

"That's just nature," Wilson said. "You can't control water."

Wilson's and Carlson's fathers cleared forest and built dikes around the land in the 1960s, helping each other. For decades, the berms worked, bringing fertile land into productivity. The river sometimes came over the top, but it was gentler in past decades. The water receded and the cropland was viable.

"It's done it four times since 1987, but it's never done this much damage before," Carlson said.

"I don't know what to do," he said. "We pay about $19,000 in taxes on the land and we can't farm it."

Peters from the Soil and Water Conservation District said she has received several calls from farmers asking for help with their dikes, but there are no government funds to repair midcentury earthen berms protecting farmland. And the view at the agency is that the river will move as the river wants.

Farmers could install riprap rock levies along the river to protect their land, but that's even more expensive. They would also speed up the river, causing problems farther downstream, and wouldn't help with rising groundwater, which is another challenge for farmland in the river bottom.

"I don't feel like there's even enough to say to some of these people that are dealing with losing their cropland," Peters said. "It's a really big challenge for us right now."