Modeling Pesticide Fluxes during high flow events in an intensive agricultural catchment: the Save river (Southwestern France) case study
Modélisation des flux de pesticides pendant les fortes crues dans un bassin versant intensif : cas d'étude à celui de la rivière Save (sud-ouest de la France)
Résumé
The SWAT model was tested at a daily time step to assess the fate of pesticides of a wide range of solubility. SWAT was applied on an 1100km² intensive agricultural catchment (Save river, southwestern France). Simulated pesticide concentrations were compared to data collected at the catchment outlet from July 2009 to June 2010, with weekly measurements during low flow and daily or sub-daily measurements during flood events. SWAT was able to accurately reproduce measured pesticides concentrations during base flow and flood events, especially concentrations of pesticide in the soluble phase. During the simulation period, simulated preferred pathway for pesticide transport from land area to stream network was surface runoff. Flood events were responsible for most pesticide transfer. The SWAT model hindcasted daily pesticide concentrations back to 1998 and possible water quality policy thresholds exceeding depending on climate.