Conservation Minnesota

Mega-rain Events Test Our Waterways

Both cattle grazing pastures and corn fields were heavily affected by the September flooding. Those with buffers fared better than those without.

Both cattle grazing pastures and corn fields were heavily affected by the September flooding. Those with buffers fared better than those without.

Last winter, I wrote a blog in response to some renewed attention that summer 2015’s Whitewater River fish kill was getting in the Star Tribune. At the time, I talked about the landscape and the potential for future rain events to result in another mass die-off of trout and other aquatic species. Most likely, the devastation was due to the timing of the storm and the large amounts of fungicide and fertilizer that had just been applied to the summer’s crops. Fortunately, this was not the case with the early fall storms of September 20th, though I was still anxious when over eight inches of rain fell in the region in a single day.

As I drove from Rochester to Winona for a meeting the day after, the cattle grazing pastures through which the Whitewater typically trickles clearly and slowly were completely flooded over and the current was evident in the murky water. While I often see the cattle  standing in the stream and cringe, the image of all of the manure being picked up by the current and rushed downstream turned my stomach.

I also passed corn fields–some with buffers along the ditches, some without–and I was struck by the differences. Those without buffers looked more like ponds, and you could see the soil washout from the base of the corn to the water running through the ditches. Those with buffers were protected and the vegetation in the ditches seemed to be slowing the current and protecting both the fields and the roadway.

Two days later, I drove the same stretch of Highway 14. While the water had receded somewhat by that point, the differences were still evident. The grazing pasture had a stream again, but the banks were undercut and the ground too saturated to bring the cattle back to graze. In the fields where there was little or no buffer, the water was still standing and was clear that it was unlikely the submerged corn would be harvestable. Where there were buffers, the ditch looked less like a canal and the water was back to a slow trickle; the corn on the edges of those fields looked no different from the rest of the crop.

These recent mega-rain events are supposed to happen once every hundred years or so. In the last 10 years, we’ve had several just in southern Minnesota. As I go around talking about the need for conscientious water management, there are still those who want to talk about regulations as though the previous assumptions of 100, 500 or even 1,000-year flood projections are accurate; we know they aren’t. This is all the more reason to be planning our urban and agricultural landscapes in such a way that these rainfalls don’t become devastating events.

As far as we know, these late September storms didn’t produce the kind of horrific fish kill that the storms of last summer did. We do know that the usually clean streams are running full with sediment, manure, and chemicals from roads, lawns and farms. A member of the Hiawatha Chapter of Trout Unlimited recently informed me that rain events like this damage the riparian efforts that have been made in the watershed to improve the streams and fix the impaired areas.

I think it’s time we treat our streams and rivers with more respect. We can no longer assume that without our help they will be capable of handling these mega-rains without causing significant damage to property and crops. It was upsetting to see some of the beautiful landscape I’ve become familiar with entirely changed in a 24-hour period. I imagine it was upsetting for so many farmers to lose, in some cases, acres of their yield just weeks before harvesting time. These are things that could be prevented if we work together to respect our streams and ditches and allow for them to manage water the way they were intended to do.

About Anna Richey

Anna Richey
Anna Richey joins the team after a decade spent in the trenches on political campaigns around the state.  She will be serving as the community coordinator for Southern Minnesota, which means she will be working with community leaders and people who want to protect Minnesota’s Great Outdoors throughout the region.
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