Hard winters and lasting floods: Managing Minnesota’s water in a changing climate

Story by Greg Klinger, University of Minnesota Extension

In March of 2019, at the tail end of a long, hard winter in Rochester, Minnesota, I went for a walk along our local flood control reservoir.  The previous month had been challenging – we’d received close to 50 inches of snowfall without the temperature getting above freezing, and the impacts of that slowly compressing snowpack- collapsed barns, homeowners desperately trying to control the ice dams on their roofs – could be seen everywhere.  Backing our cars out of the driveway became an exercise in hopeful thinking, as the snow piled on either side was too high to see if anyone was walking or driving by.  A few days before my walk, a burst of warm, humid air blew in, bringing with it close to an inch of rain.  The result was a deluge of melting snow, and the pressure of these raging floodwaters, in turn, splintered a season’s worth of ice on our lakes and rivers, relentlessly driving chunks of ice downriver and across the valley floor.  At the reservoir on the day of my walk, the power of moving water was on ready display as I meandered among boulder-sized chunks of ice that had been pushed a hundred yards or more from the lake’s shores.

 

Sidedressing of anhydrous ammonia fertilizer on a growing corn crop

Sidedressing of anhydrous ammonia fertilizer on a growing corn crop. In broad terms, wet soil conditions in spring followed by dry soils in the summer (which is projected to be more common in Minnesota in the future) are very challenging for nitrogen management and nitrogen use efficiency. Wetter soils in May and June lead to greater losses of nitrogen while dry soils in summer can slow down the release of nitrogen from soil organic matter that is the main source of a crop’s nitrogen as it flowers and fills grain. Photo courtesy of Paul McDivitt.

Managing water – too much, or too little – is always a challenging task.  And managing it always involves decisions about what sort of risks we are willing to accept, and what costs we are willing to incur to control that water.  In the agricultural realm in which I work, I see these decisions being made every day.  Should an engineer design a farm sediment control basin to accommodate a 10 year rainfall event or a 25 year rainfall event? Does this summer’s flash drought mean I should install controlled drainage structures in my tile systems to better hold soil water in reserve for the next drought?  Looming over all these decisions is the question of how ongoing changes in climate will change the frequency and intensity of these circumstances.

In southern Minnesota, climate projections indicate that we will see increasing precipitation through the end of the century, particularly in winter and spring months, and warmer temperatures year-round, although most prominently during the winter.  This raises critical questions: how will wetter springs impact our soils’ abilities to retain critical nitrogen fertilizer?  How might warmer, drier soils in summer months impact the grain- and pod-filling of our corn and soybean crops, or the photorespiration process that robs wheat and other small grains of yield, or the release of nitrogen from soil organic matter that is the main source of fertility to crops in our region?

After that dramatic March snowmelt, the remainder of 2019 proved to be a challenging year for managing water.  Heavy rainfall that spring and summer on already saturated soils led to a late planting season with record-setting prevented plant acres across the Corn Belt.  The Upper Mississippi River had its longest-duration flood ever recorded.  In Rochester, we set a new annual precipitation record and local flash flooding made national news.  I watched as local township roads were re-graveled and re-graded only to be washed out in the next flood.  And I was fascinated to see how long lasting some of the effects of 2019 were.  In a study where I sampled local farm tiles for flow and nitrate concentrations, many sites continued to have heavy tile flow well into the summer of (locally quite dry) 2020.

It remains to be seen to what extent a year like 2019 is an anomaly versus a somewhat normal occurrence within our evolving climatic landscape.  But there are ways to better understand and prepare for the changes we can anticipate.

At the University of Minnesota Climate Adaptation Partnership, where I work, researchers are developing models to better project the range in climatic conditions we can expect between now and the end of the century.  A growing group of faculty from across the University of Minnesota are conducting research to understand and model how these climatic changes will impact agricultural and natural landscapes, our lakes and waterways, businesses, infrastructure and public health.  And those of us with specialized knowledge in areas such as agriculture or forestry are looking at the climate information we have available and asking: what does it mean to be resilient in the face of a changing climate?  And how do we help the communities whom we serve prepare?  While the answers may differ by individual and community, we know that engagement with the challenges we face today as well as the climate that is projected for the future will help us manage the impacts of our changing climate.

Greg Klinger, University of Minnesota Extension
Headshot of Greg KlingerGreg Klinger is an Extension Educator in Agricultural Climate Resilience with the University of Minnesota Climate Adaptation Partnership (MCAP). His Extension work focuses on integrating projections of future climate conditions in Minnesota into the decision-making tools and processes that agricultural stakeholders use on a regular basis. What can future climate projections tell us? What can’t they tell us? How confident are we in their predictions? And how we can we use that information to help maintain resilient and profitable farm operations?

Prior to joining MCAP, Greg worked in other capacities for the University of Minnesota Extension and Virginia Tech, conducting research and Extension programming on a diverse array of crops, including corn, apples, and grapes.

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