This contribution deals with a methodological framework dedicated to long-term changes modelling of the coastal environment under strong human activities influences. Our research is focused on a modeling simulation platform fitted to the analysis of interactions between human activities and environment (Cuq, 2001). It integrates the coupling of quantitative and qualitative models within a Geographic Information System (GIS). The methodology is based on the development of reality models which integrate spatio-temporal constraints (socio-economic, regulation and meteorology) in order to analyse activities progress and impact. This approach also allows to combine simulation results and analyse spatio-temporal interactions between different activities, especially in the aim to highlight strategicals or interests conflicts zones between concurentials activities.