A Geographic Information System (GIS)-based project consisting of designing and applying a simulation model of flood levels was set up in order better spatially identify the areas most at risk for riverside populations and to infrastructure during important floods. This simulation model uses flows and levels data, within a GIS, and a highly precise digital elevation model (DEM), to create a simulation and a visualization of different levels reached by the Saint-François River. Results obtained from this model are presented visually in the form of maps to observe and identify the limits regarding bodies of water during high flows or major floods.