SPATIAL MODELING WITH GEOGRAPHIC INFORMATION-SYSTEMS FOR DETERMINATION OF WATER-RESOURCES VULNERABILITY APPLICATION TO AN AREA IN MASSIF-CENTRAL (FRANCE)

A method for water resources protection based on spatial variability o f vulnerability is proposed. The vulnerability of a water resource is defined as the risk that the resource will become contaminated if a po llutant is placed on the surface at one point as compared to another. A spatial modelling method is defined in this paper to estimate a trav el time between any point of a catchment and a resource (river or well ). This method is based on spatial analysis tools integrated in Geogra phical Information Systems (GIS). The method is illustrated by an appl ication to an area of Massif Central (France) where three different ty pes of flow appear: surface flow, shallow subsurface flow, and permane nt ground water flow (baseflow). The proposed method gives results sim ilar to classical methods of estimation of travel time. The contributi on of GIS is to improve the mapping of vulnerability by taking the spa tial variability of physical phenomena into account.