Lessons gained from french R&D programs for pesticides dissipation by use of constructed wetlands | Leçons apprises des programmes de recherche sur la dissipation des pesticides par utilisation des zones humides artificielles

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU

International audience

anglais. Pesticide pollution is a major threat of surface water quality in France. To comply with the European Water Framework Directive (2000/60/EC), authorities have decided to implement a Phyto-Pharmaceutic Products or pesticide reduction plan. It targets a 50% reduction of pesticide inputs by 2018. This plan only considers actions on farming practices and does not foreseen any actions on transfers through catchments, assuming that pre-existing buffer strips are efficient. This assumption is not verified on a significant part of the territory for which complementary solutions for the control of pesticide transfer have to be found. Thanks to two R&D research programs regarding constructed wetlands, we got the opportunity to improve the state of the art, assess the performance of constructed wetlands and find economical, legal and social incentives for further nationwide extension. Two constructed wetlands were tested at both pilot and field scales. On-site wetlands were located at the outlet of sub-surface artificially drained catchments. Two contrasted regions have been chosen as well. In all cases climatic parameters water and pesticide flows in and out have been measured and monitored. We also recorded the conditions of implementation since we were very closed to real conditions. For this purpose inquiries addressing the various actors were carried out by sociologists. The results of the performance regarding pesticide dissipation are shortly given. Sociologic approaches and amenities assessments have revealed unsuspected relations of the farmers with the society and the environment, and vice versa. The implementations have resulted of a coconstruction where each actor had personal involvement. Even if co-construction should be a driving line, solutions for appropriate incentives and land reallocation tools should be fought with politics and authorities in order to facilitate further realizations.