The Catchment Response Through A Multiple Flow Direction Approach

The runoff production in a catchment, even if produced by several phenomena, can be due to two quite distinct mechanisms: infiltration excess and saturation excess. According to the latter, the influence of topography and soil on runoff production has been incorporated in the topographic index, which reflects the tendency of water to accumulate at any point in the catchment and the tendency of gravitational forces to move that water downslope. The numerical value of such an index, based on surface flow pathway analysis using gridded elevation data, can vary according to the use of a single flow direction or a multiple flow direction approach. In this paper, by means of a spatially distributed hydrological model capable of modeling both infiltration excess and saturation excess runo