Accept'Hydro: a tool for evaluating potential wetland areas at floodplain scale.

Abstract

Alluvial wetlands have the functions of hydrological regulation and water purification, but are also of interest for preventing flooding and improving the water quality of the natural environment that serves as a reserve for drinking water and biodiversity. Delimiting these areas is often difficult because it involves both the physical characteristics (topography, river morphology etc.) and hydrodynamic characteristics of the porous medium (permeability etc.) The proposed tool, Accept'Hydro, includes a hydrodynamic simulation of the river, the alluvial aquifer and their interaction, and produces maps of alluvial wetlands with using hydrological criteria. The tool's primary step consists of selecting the studied area using Google Maps, which automatically triggers the generation of a non-uniform mesh covering this area, as well as all the inputs needed for the hydrodynamic simulation to run. The hydrodynamic model based on the equations of Peyrard et al. (2008) allows water levels and flow rates in the river and the alluvial aquifer to be simulated with a non-uniform mesh (cells from 1 to 200 metres per side), combined with a good performance in CPU calculation time. The software program allows the impacts of climate change (changes in hydrology and temperature) and/or anthropogenic change on the hydrodynamic functioning of wetlands to be assessed, and the impact of infrastructure and hydropower facilities on the river to be tested.