Minnesota’s floods have human fingerprints

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Matt Doll, Minnesota Environmental Partnership

Right now, large areas of Minnesota – basements, roads, fields – are underwater. From the Minnesota Valley, to northern St. Louis County, to areas of the Twin Cities including Saint Paul and Hastings, communities have faced some of the most severe floods they’ve seen in recent memory. After recent droughts parched the state, we’re getting more than what we wished for.

Like the drought, however, this flooding has human fingerprints.

Climate change is paradoxically making both problems worse, creating a “feast or famine” situation for precipitation. Hotter average temperatures cause more evaporation, reducing the amount of water on the ground – hence drought. But that evaporation and higher storm-causing energy due to heat waves can also cause clusters of torrential rain like we’ve seen throughout June. If we don’t get our climate pollution under control, the cycle will only get worse and worse, ever more threatening Minnesota communities

But it’s not just what we put into the air that’s making these floods so historic. It’s also what we put into the ground: the drain tile used to carry water away from farm fields.

Drain tile can be quite useful for farms, especially those growing the dominant row crops: corn and soybeans. It makes fields less vulnerable to oversaturation of water. Its advocates credit it with stabilizing and increasing yields of these commodity crops, and thus helping farmer income.

The problem is, all that water has to go somewhere, and Minnesota’s lands and waters aren’t what they used to be. Wetlands have been filled in and prairies plowed over for farmland. Small, meandering streams have been straightened or otherwise modified. The natural topography of most of Minnesota has been altered in a big way.

That means that when it rains cats and dogs, water surges through the soil, into the drain tile, and then hits streams and larger and larger rivers, all at a pace more rapid than it would have been even a few decades ago. The result is what we saw earlier this week, as the Blue Earth River carved out a new channel next to the Rapidan Dam, as dozens of communities were deluged.

Minnesota’s landscape is simply not as flood-resistant as it should be, and we can expect more floods as climate change continues. Like climate change, this problem is a complicated one, but that doesn’t mean we can’t improve.

One good first step relates to state legislation passed during this year’s session that requires a full inventory to be made of all the state’s public waters to ensure they’re protected under the law. That effort can help protect further streams from changes that could make them less able to handle heavy rains. It won’t make our floods any easier, but we can’t start climbing out of the hole unless we first stop digging it.

The other big step we can take in the near term is to invest heavily in putting cover crops on farmland to help replicate some of the benefits of a prairie. That includes both perennials that cover the soil continuously and annual crops that can complement corn and soybeans. These crops’ root systems can help the soil absorb a lot more water than if it lies exposed and unplanted for most of the year, as it does in the usual row cropping system. This also helps prevent nutrient pollution, which contributes to health problems and causes the annual dead zone in the Gulf of Mexico.

In the long term, it’s worth considering how Minnesota farmland is used and what crops win state and federal support. Minnesota devotes about 5% of our land area just to grow corn for ethanol, for example. Ethanol isn’t a true climate solution, and it’s likely to scale back rapidly as vehicle electrification advances.

Finally, these floods make it clear how much water infrastructure matters, and what can happen when it fails. Our rural communities are especially vulnerable to continued effects of floods, and Minnesota’s Legislature should make every effort to build on its water infrastructure investments of recent years.

We hope policymakers see these floods as not simply a senseless natural disaster, but a recurring problem shaped by our choices. If we don’t change course, many more of our communities will be up the creek without a paddle.

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