By Kevin Brewster, Restoration Manager
The Marengo is the most erosion-prone subwatershed in the Bad River watershed, due to the amount of open agricultural land present and its erodible soils. But a lot of positive things are quietly going on across this watershed, and it's great to get little reminders once in a while just how committed some landowners are to helping improve the health of our watershed's streams. Recently, BRWA landowner contact contractor Erika Lang led a tour to visit several examples of improvements made on the landscape that help reduce sediment pollution and improve fish habitat. I was able to join the group for a visit to Ted Mika's cattle farm, where innovative streambed crossings have been installed to allow passage of farm equipment and livestock across sensitive intermittently flooded drainage features that cross grazed fields. In the past, a standard practice used to deal with intermittent stream channels on farm land was to fill the channel and install a culvert to allow water to move through during wet periods. The filled area was often added into productive acreage, decreasing vegetative buffering capacity to slow runoff to filter out nutrient pollution from livestock and reduce erosion. The relatively new approach involves leaving a vegetated channel zone in place, contouring the crossing to the approximate natural stream bed level and then creating a compacted surface consisting of a base of course rock, filter fabric, crushed gravel and a top layer of crushed or fractured granite. Eventually, the crossing will be re-colonized by streambed vegetation. The resulting hard-bottomed crossing allows cattle or heavy farm equipment to pass through the flooded channel without getting stuck or stirring up excessive sediment. A typical crossing costs about $5,000, with the landowner paying about 10% of that, and federal and county conservation incentive programs covering the rest. The Mika farm now has five of these crossings installed, virtually eliminating problems associated with wet weather operations, and greatly minimizing impacts to the intermittent stream that meanders across the property.