This collaborative, in-depth study involved the installing and testing of the effectiveness of various forms of vegetated irrigation ditches to improve  farm runoff water quality by filtering and removing sediment, nutrients, and the common pesticides, diazinon and permethrin.  According to the Vegetated Drainage Ditches Study program manager, “a mathematical model was developed which summarizes ditch processes, and assists in predicting the length of vegetation area needed, in order to significantly improve water quality”.

The final phase involved the constructing and planting of these ditches in several local growers’ fields for testing under real-world conditions. It was completed in 2007 and field-tested in local fields planted with alfalfa and tomatoes. This system has already proven successful in the Mississippi River region of the United States, and the Yolo County RCD project focused on adjusting those techniques to work well with California’s specific cropping practices, soils, and climate.

In Phase 1, timed water sampling occurred during the field-testing of three forms of irrigation ditches.