Kevin Willibey, who grows corn, soybeans and wheat near Angola, IN, says that the two-stage ditch behind him has stopped the ditch-bank erosion as expected. “There’s quite a bit of interest in it here.” The shallower, wider ditch mimics a natural floodplain, which dissipates the energy of the larger flows and reduces its destructive forces on ditch sides. The stream-bottom microbes filter out up to 500% more N than conventional ditches.
Photo: Beth Warner
As we change the landscape to accommodate straight property lines, farming, roads and parking lots, we change how water moves across our landscape and ask a lot of our ditches, says one conservationist. These natural and ditch streams in Mower County, MN, contrast a stream meandering about a floodplain (right or left) and a straight-line ditch without room for a floodplain. As a natural stream slows down when it makes a bend, gets pushed up on that grassy floodplain and slows down further, the vegetation removes nutrients. A ditch just keeps the water moving, without slowing down or reaching much vegetation. This additional water force erodes ditch banks. A new two-stage ditch design mimics the floodplain’s contours and benefits by widening the stream channel to spread water more slowly during floods. Photos: FSA and Rich Biske, Nature Conservancy