Assessment of risks of pesticides transfer by surface runoffs

This work presents a method for assessing pesticides transfer risks to the surface water by erosion and runoff. It was developed in a part of the watershed of the Boiron de Morges (Vaud, Switzerland). This method combines observations in the field with the use of Geographic Information Systems (GIS). It considers timeless and timely factors. An evaluation grid permits to classify the different factors by the risk severity they generate. Their combination then allows to produce a synthetic map showing the transfer risks of pesticides in the whole zone examined. This method makes not only possible to identify the plots with an inherent risk of high transfer, but also the factors responsible for it. Once the plots have been identified, targeted measures can be envisaged to limit the soil loss and the pesticides transfer.