Technical note: Extending the SWAT model to transport chemicals through tile and groundwater flow

Abstract. The Soil and Water Assessment Tool (SWAT) is frequently used to simulate the transport of water-soluble chemicals in environment such as pesticides their metabolites originating from agricultural applications. However, model does not through subsurface tile drains groundwater. This limitation particularly significant lowland regions when simulating stable that can leach into accumulate To fill this gap, publicly available SWAT code was modified complement simulation by adding capabilities groundwater flow. extended tested two catchments with a typically pesticide one its metabolites. Results show mainly governed surface runoff shallow flow contributions be significant. Metabolite concentrations streamflow are, however, driven complex spatiotemporal interplay all components. highlights advantages applying catchment-scale environmental exposure studies for developing best management practices or mitigation strategies. new made an electronic supplement technical note.