A process based assessment of the potential to reduce flood runoff by land use change

Various runoff processes with widely varying infiltration and retention capacities, such as Hortonian overland flow, saturation overland flow and fast subsurface flow, form storm runoff in catchments. Areas can be classified according to these different runoff processes on the basis of information on soil characteristics, geology, topography, and land use. The results of such classifications can be verified with infiltration experiments combined with tracer techniques. A reduction of storm runoff by a change of land use or land use management practices is only feasible on sites, where infiltration and matrix wetting can be enhanced. In order to estimate the effects of possible land use changes on storm runoff, the spatial distribution of the dominant runoff processes and the actual land use was assessed in a meso-scale catchment in the state of Rheinland Pfalz, Germany. Based on assumptions on how changes in land use might influence the runoff processes, the potential for flood runoff reduction could be estimated.