Mesurer l'impact des entités linéaires paysagères sur les dynamiques spatiales du ruissellement : une approche par simulation multi-agents

Hydrosedimentary fluxes that run from agricultural plots down to the water streams are currently associated with many social, economic and environmental issues such as diffuse pollution, soil infertility, soil loss, floods, etc. While the genesis of these transfers are well-known at the scale of the agricultural plot, flow dynamics occurring on slopes remain poorly understood. This is especially the case in the small basins located in the north-western part of France, where the landscape mosaic, which includes linear networks (hedges, roads, ditches...), tends to complicate the processes. Analyzing the transfer conditions is important for a further integrated watershed management. Hence, in this paper, we propose to use a multi-agent system as a support decision tool to understand the role of anthropogenic linear networks on runoff pathways. We carried out a so-called bottom-up approach, to measure the effects of the local interactions between each linear element on the global hydrological behavior of the watershed. A first spatial analysis index, characterizing the impact of linear networks in the path of runoff, is constructed here from numerical simulations. The results of this study also tend to demonstrate the relevance of Multi-Agent Systems as diagnostic tools to the hydrosedimentary transfers and processes.