Floods, Destructive? Or Something Else?

Photo credit: Dan Fleming.

No doubt about it, floods sure can be a pain. The recent high waters from Clifty Creek, plus the East fork of the White, Driftwood, Flatrock, and Blue rivers, made for plenty of inconvenience. No doubt, anyone reading this of driving age has a story to tell of the struggles suffered in just finding a route that would take them to town. And folks who suddenly found themselves with waterfront property had a mess to clean up after the water level dropped.

For those of us whose property actually borders a river, there can be a certain amount of dreaded anticipation of giant drifts and damaged fences. As a boy, downed fences happened to be my biggest concern. Checking and fixing damaged fence was my given job growing up.

However, roaming the banks of the Driftwood, I knew that periodic high water would sometimes produce more exciting finds. After all, Huckleberry Finn found a canoe! The best thing I ever found though was a homemade rowboat that leaked profusely despite my best efforts to restore it.

More serious consequences from periodic high water in our area and state are surely a major concern of those who make their living off the land. It is a disheartening sight for a crop producer to see his or her fields turned into a “Lake Monroe” only a few days before optimum planting time.

In addition to the poor timing of an early April flood, there can be serious consequences to consider when fields are under water. Soil under water is void of oxygen, oxygen that is needed for the survival of the multitude of living organisms that play an important role in soil health. These in-soil organisms, be they bacteria or fungi, are chiefly responsible for converting various organic matter present in soil into usable nutrients needed by plants. This process is called soil respiration.

According to soil scientists at Purdue University, it was fortunate that the recent early April flooding in Indiana happened this year before soils warmed. The microbes that make soil respiration possible had yet to come out of their protective dormancy. In addition, earthworms so important for drainage and the movement of moisture through the soil were still in hibernation in early April this year.

Agronomists at Purdue make the point that floodplain soils in Indiana flood nearly every winter and are some of our most productive. When flooded, unprotected soils, rich in organic matter are carried downstream, the silt left when the water recedes benefits the receiving area with a new dose of nutrients and useful minerals. Historically, the same principal made ancient Egypt the breadbasket of northeastern Africa. High country snow melt and spring rains flooded the Nile valley annually. These high-water events brought nutrients like nitrogen, phosphorus, and organic material to the land, improving soil quality and plant growth. These repeated deposits of rich nutrients indirectly made Egypt a wealthy and powerful empire in BC times.

Nitrogen loss via leaching of nitrate below the root zone or into tile drainage always is a concern for farmers, especially when urea-based nitrogen was applied to fields in the fall. Fortunately, in most situations, soil scientists at Purdue have found that little nitrate- nitrogen is present in the soil during winter. This is because the majority of nitrogen applied as anhydrous ammonia or manure in late fall and early winter will likely remain in the ammonium or organic forms during cold temperatures, and not subject to leaching. Bottom line, nutrient loss in late winter flooded soils is probably not worth worrying about.

Still, life during a flood sure can be a pain, or at least very inconvenient for most adults. However, for young boys living close to a river, a flood can mean adventure and the possibility of treasure. After all, a simple exploratory walk along a riverbank could produce a slightly damaged cooler, a perfectly good but soiled boat cushion, or even a canoe!