Effects of Drainage and Water Table Control on Groundwater and Surface WaterQuality. Part 1. Methodology and Preliminary Results

摘要

The project addresses the effects of agricultural water management practices onpollutant movement from poorly drained soils to shallow groundwater and to surface water via both surface and subsurface runoff. The water management model DRAINMOD was coupled with the erosion and chemistry submodels of CREAMS and used to study nutrient and pesticide losses in surface runoff for a range of drain spacings and water table management scenarios. Simulated results indicated that surface drainage improvement can significantly increase chemical losses. The surface losses can be reduced with improved subsurface drainage. However, this may increase subsurface losses of mobile, non-adsorbed contaminants. Agronomic benefits can be achieved with controlled drainage and subirrigation but this will increase runoff and hence surface losses of nutrients and pesticides in some cases.