Drainage Water Management Awareness

Presented by Patrick H. Willey, P.E., Wetland and Drainage Engineer, USDA NRCS West National Technology Support Center; Hamid Farahani, Ph.D., Water Management Engineer, USDA NRCS East National Technology Support Center; Ruth Book, Ph.D., P.E., State Conservation Engineer, USDA NRCS Illinois; and Jerry Walker, P.E., Agricultural Engineer, USDA NRCS Central National Technology Support Center
Unrestricted agricultural drainage systems contribute to increased loss of nitrates and other soluble constituents that end up in nearby water bodies. This creates economic, environmental, and human health concerns downstream. A prime example is evident in the Mississippi River Basin, within which the nitrate carried in drainage water is contributing to hypoxia in the Gulf of Mexico. Drainage research and extension programs are exploring ways to reduce the potential environmental impacts of agricultural drainage while retaining its agronomic benefits. Some practices that can reduce nitrate loads on drained soils include: growing winter forage or cover crops, nutrient management, bioreactors, constructed wetlands, and drainage water management (DWM) or controlled drainage. Controlled drainage is an effective practice for reducing nitrate losses from drainage systems, yet its adoption has not been widespread. This presentation explores the importance of DWM via control structures and its impact on drainage water quantity and quality. Basic DWM planning and implementation information is presented so NRCS conservation planners can begin to add DWM to their toolbox of practices for water quality improvement.