Increased nutrients in the Chesapeake Bay region is partly linked to agricultural activities. In the Choptank River basin, one way of nutrient transport from agricultural fields is through extensive drainage open ditches. Studies have shown that annually an average of 6% of nitrate applied to agricultural fields can be transported in drainage water to receiving surface waters. One of the best management practices (BMPs) being used in the open ditches has been the installation of a water control structure at a drainage outlet. These control structures can be placed in field ditch to control water levels from agricultural fields to not only reduce water flow, but nutrient, mainly N due to denitrifications. A typical management schedule is to increase water elevation at the outlet elevation to just below the root zone during the growing season and lower to or near the bottom of the drainage ditch at the outlet (free drainage) during planting and harvesting operations. Our preliminary studies have shown that this schedule can reduce nitrate losses up to 40%. Elevating the drainage outlet to just below the root zone during the growing season can potentially reduce nitrate losses in drainage water from 15% to 30%. A more detailed results will be presented and discussed.