ARS | Publication request: Applying SWAT for impact analysis of tile drainage on streamflow in a snow dominated watershed

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: July 1, 2011
Publication Date: August 7, 2011
Citation: Rahman, M.M., Lin, Z., Moriasi, D.N. 2011. Applying SWAT for impact analysis of tile drainage on streamflow in a snow dominated watershed. Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE) Meeting, August 7-10, 2011, Louisville, Kentucky. Paper Number: 1110866.

Interpretive Summary: Agricultural drainage systems are mainly installed to allow timely seedbed preparation, planting, harvesting, and other field operations and to protect field crops from extended periods of saturated soil conditions in the soil root zone. There has been an increase rate of the adoption of tile drainage practice in the Red River Valley watershed (RRVW) in North Dakota due to a wet weather pattern in the region since 1993. Increasing chances of snow-melt spring flooding have also been noted in recent years. In this study, the Soil and Water Assessment Tool (SWAT) model was applied to assess the impact of tile drainage on streamflow. The existing tile drained area was found about one percent of the watershed area. The model was calibrated and validated with and without tile drainage. The study results showed that SWAT simulated streamflow very well with and without tile. In both cases, the model simulated streamflow fairly well. Although tile flow consisted of about 57% of the water yield for the experimental tile drained plot within the watershed, only a slight increase on the watershed average annual water yield was observed due to inclusion of the existing tile drained area. Additional simulations are underway to improve this modeling approach in order to be used for future decision making in regional water resources management.

Technical Abstract: A rapid trend of adopting tile drainage practice to boost agricultural production has been observed in the Red River Valley watershed (RRVW) in North Dakota due to a wet weather pattern in the region since 1993. Increasing chances of snow-melt spring flooding have also been noted in recent years. In this study, the Soil and Water Assessment Tool (SWAT) model was applied to assess the impact of tile drainage on streamflow. The possible locations of the existing tile drained areas were identified using the decision tree classification method and the existing tile drained area was found about 0.75% of the basin area. The model was calibrated (1990-2000) and validated (2001-2009) with and without tile drainage. In both cases, the model simulated streamflow well as indicated by good monthly Nash-Sutcliffe efficiency (NSE) 0.83 (calibration), and 0.76 (validation). Only a slight increase in basin average annual water yield was observed due to inclusion of the existing tile drained area, while the experimental tile drained plot (20 ha) within the basin produced about 57% of its water yield as tile flow. Additional simulations are underway to improve this modeling approach and results to be used for future decision making in regional water resources management