ABSTRACT
The history of drainage and ditches to decrease water logging and promote sustainable agriculture was discussed. Two-stage ditches can be stable, viable options for drainage ditches if designed and installed properly. Straight, trapezoidal-shaped surface drainage channels efficiently drain soils, but their deviations from natural fluvial conditions drive frequent maintenance. We developed a two-stage ditch design that is more consistent with fluvial form and process. We applied the design and studied geomorphic change of the inset channel, benches, and banks of seven two-stage ditches in Ohio, Indiana, and Michigan. Three to ten years after construction, inset channel changes reflected natural adjustments, but not all ditches had reached their quasi-equilibrium state. Ditches had experienced both degradation and aggradation on the benches at a rate of 0.5–13 mm/year. Aggradation on the benches was not likely to threaten tile drain outlets. Localized scour was observed on the banks at some sites, but at all but one site changes were not statistically significant. Except for the removal of woody vegetation, none of the ditches required routine maintenance since construction. The approach has potential to enhance ecological services while meeting drainage needs essential for agricultural production.
US Environmental Protection Agency
