1. EFFECTS OF THE MANAGEMENT OF AGRICULTURAL DRAINAGE ON GROUNDWATER AG & CONSERVATION PARTNER FORUM II June 15, 2011 Douglas W. Toews, P.E.

2. What are the effects of Drainage Water Management (DWM) on: the hydrologic cycle? the nitrogen cycle?

3. Water Balance

5. Nitrogen Balance

7. Benefits of DWM are achieved by: minimizing drainage flows maximizing ET maximizing N uptake by plants Increasing denitrification Increasing seepage Mitigating increased surface runoff

8. Reference Skaggs, Youssef, & Chescheir. 2011. Methods to estimate effects of drainage water management on annual nitrogen losses to surface waters. Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC.