Manure Down the Rat Hole

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I was talking to a hydrologist the other day when he mentioned he was investigating the development of a sinkhole adjacent to a large dairy manure lagoon in Winona County. Southeast Minnesota’s fractured limestone geology, otherwise known as karst, has always offered a handy way for pollutants such as liquid manure to find their way into our groundwater. Sinkholes can appear literally overnight in that part of the country under even normal meteorological conditions. And when you have an unprecedented flooding event like the one that occurred in August, the combination of fast-moving water, liquid crap-fueled hydraulics and Swiss cheese-like rock formations has the makings of a manure meltdown. Well, the Aug. 31 Minnesota Department of Public Safety’s Southeastern Minnesota Flash Flooding Situation Report confirms that in localized areas, this is exactly what happened. Read it and weep:

“Feedlots: Winona County reported 12 known basin overflows and numerous other structures within inches of overflowing. Many facilities are transferring manure to other structures with available space. As available cropland dries out, manure will be land applied to make space for more rainfall. One operator was required to recover manure and clean out 1+ miles of dry run stream bed as the result of a pumped discharge from a barn pit. One basin was 4-5 feet underwater and appears to have had 5 sinkholes form next to the basin. This basin is to be pumped and repaired. Fillmore County had one report of a basin in danger of discharging and Houston County had one report of a basin in danger of discharging.”

To be sure, the August flooding devastated all types of farming in that region, and no manure lagoon in the world could be built to withstand 17 inches of rain at one shot. These facilities probably held up as best they could, given the extreme circumstances. But there’s one sentence in that situation report I find particularly troubling:

“One basin was 4-5 feet underwater and appears to have had 5 sinkholes form next to the basin.”

Five sinkholes? Good gravy! Now, I do understand that it’s a tricky endeavor to predict where the next sinkhole will yawn open, giving us a surpise peek into our collective basement. Sinkholes (trivia lesson of the day: sinkholes are called “cockpits” in Jamaica) are the geologic equivalent of a morel mushroom: they can pop up in places that the day before showed no sign this fully formed freak of nature was lurking beneath decks all along. But the science of hydrogeology does have ways of tracking which parts of southeast Minnesota have a high probability of sinkhole development. In fact, some cutting-edge sinkhole mapping has been done in Winona and Fillmore counties. I am willing to venture a guess that a farm that develops five of these bad boys in a matter of hours—even under extreme weather conditions—was in a “high probability” area. It’s Sinkhole City out there, and now it’s lakefront property.

So here’s the question of the hour: What local or state environmental officials in their right minds ever allowed that lagoon to be built in that particular location? It’s doubtful anyone will be made to answer for such a lapse in judgment—weather events of Biblical proportions tend to offer excuses for forgiving past sins.

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