Contribution of a geographical information system for the localisation of areas at risk of pollution by pesticides

Abstract

The contamination of surface and underground water by phytosanitary substances used in farming induces the administrators of aquatic resources to implement policies for restoring the quality of water. In cooperation with the AQUALIS engineering office, the Loire-Bretagne Water Board has developed a method, which provides help in determining preventive strategies for the qualitative management of surface and underground water. This consists of setting up a territorial area in order to localize the sectors responsible for a pollution risk. Zoning is carried out using a Geographic Information System, by crossing factors, which lead to sensitivity to the mobilization and entrainment of phytosanitary molecules used in crop management. With respect to surface water management, the zoning maps are completed by an approach, which identifies the land-area controlled by runoff barriers. This second part enables one to assess the consequences on the runoff transfer of pollution, which is generated in risk-prone areas.