Vegetative Filter Ditch Modeling
Runoff from irrigated crops can carry agrochemicals to surface water bodies. To reduce the amount of agrochemical transport, vegetated agricultural drainage ditches are used to trap the runoff and have been suggested as a best management practice.
Field studies in Yolo County, California demonstrated that vegetated ditches were able to reduce initial agrochemical concentrations by 50 percent in 22 to 169 meters, while nonvegetated ditches required 347 meters to accomplish the same task.
During this process, we also developed the Vegetative Filter Ditch Model (VFDM). This model simulates agrochemical fate and transport from fields through a vegetated ditch. It can be used as a design tool to calculate the optimum dimensions of a vegetated ditch for a particular farm system or as an evaluation tool to predict the efficacy of agrochemical reduction for a ditch of known dimensions.