PESTIPOND

The role of ponds in pesticide transfers in agricultural catchment remains largely unexplored, with also the majority of processes involved in pesticide dissipation still of unknown contribution. This results in sub-optimal operational use of ponds. Using field survey data, a cutting-edge hydro-biogeochemical approach combined with integrative modelling at different scales, PESTIPOND aims to address a major bottleneck: new laws and concepts to implement pond impact in interlocked scales from the head-water to river catchment will only become accessible through evaluation of processes sustained by pond compartments involved in pesticide dissipation and relating them with pesticide transfer at the catchment scale. PESTIPOND is a 48-month innovative collaborative research project associating 4 partners from 4 research units, and 15 socio-economic partners with complementary areas of expertise. The innovative concept of the pond-centered PESTIPOND workflow is to constrain in situ processes of pesticide transformation in pond compartments to feed into an integrative modelling framework of risk and spatial predictions of pesticide transfer at the catchment scale, including the cumulative role of inter-connected ponds. This generic outcome will be applicable to all ponds receiving pesticides for which agro-ecological management at the catchment scale is required by environmental agencies, local cooperatives or engineering consulting offices. PESTIPOND will target processes controlling the pond capacities to degrade pesticides, far beyond their primary role of delaying pesticide transfer. PESTIPOND is organized in 3 well-defined, interconnected experimental tasks on biogeochemistry of pesticide behavior in ponds and modelling of the impact of ponds on pesticide transfer. Through its goal of identifying key parameters of pesticide dissipation in wetlands in relation to hydrological and biogeochemical cycles, but also by optimizing the synergy between natural and artificial wetlands for subsequent application by territorial stakeholders, PESTIPOND perfectly fits transversal theme B11-Axis 5 and Défi 1 (B1-Axis 1), as it may yield both new basic knowledge and technological know-how indispensable to understand and manage the resilience capacity of aquatic ecosystems to face anthropogenic inputs. The project partners have privileged access to experimental ponds, implanted in IR OZCAR and IR RZA catchments in 3 French regions with contrasted agro-climatic contexts, and excellent hydrological and biogeochemical analytical facilities. Strong and complementary consortium expertise in all aspects of the proposed work reduces potential challenges to success. Key requirements of bridging in situ processes of pesticide transformation in ponds and an integrative modelling approach at catchment scale have already been validated in preliminary studies. A thorough risk assessment was performed on all stages of the workflow, and potential issues and experimental or modelling fallback solutions were identified and described. PESTIPOND will have major scientific impact, through delivering of new laws and concepts for hydrological and biogeochemical processes in ponds and their integration in a modelling framework integrating pond and catchment scales, expected to become generally applicable to other agro-ecological contexts and territorial stakeholders. Technological impacts will also be significant due to the novelty of the approach for ecologically intensive, economically efficient and socially acceptable solutions including transition scenarios to mitigate pesticide transfers into surface waters. From a socio-economic viewpoint, PESTIPOND will facilitate the emergence of management scenarios, in particular through the involvement of 15 socio-economical partners that will evaluate different agro-environmental and transition scenarios used for predictive modelling.