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RESEARCH PRODUCT

Sensitivity of water quality of three contrasted north-eastern French watersheds to climate change (2006-2100) using SWAT model

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description

International audience; The SWAT model has been chosen to assess climate change impacts on water quality of three subbassins ofnorth-eastern France: located on headwaters of three major rivers of France (Loire, Seine and Rhône riversrespectively). These watersheds have a size less than 3000km² and present different hydrogeological andgeological characteristics. Land-use as well as their agricultural practices being also diversified, the threewatersheds studied constitute a relevant experimentation area. The goal of this study is to assess local vulnerability of surface water quality (sediments, nutrients,dissolved oxygen loads) to climate change (2006-2100) following the Representative ConcentrationPathways (RCP) 8.5. To this purpose, a database (soil, land-use and daily climate data) has been built.Climate change is provided at 12 km-resolution by a dynamical downscaling of a General CirculationModel (GCM) using a Regional Climate Model (RCM). Changes in exports from watersheds (totalsuspended sediments, N-NO) and evolution of biotic conditions in the mainstream (dissolved oxygen andchlorophyll a levels) are analyzed. Further analysis will provide results for many other concerns:agronomy (study of the evolution of available soil water quantity) or watershed management (sensitivitystudies of land-cover and fertilization change impacts) and will allow concrete decision-making at localscale