An investigation of the relationship between spatial variability of soil hydraulic properties and overland flow formation

A sensitivity analysis is presented of the overland flow hydrograph generated by complex rainfall events to the representation of the saturated hydraulic conductivity, Ks, considered as random variable. Computation were performed through numerical solutions of a point infiltration model. For rainfall rates, r, much greater than the average value of Ks, <Ks>, the hydrograph may be appropriately derived assuming Ks=<Ks> uniform in space. On the other hand, for the range where this assumption is incorrect, evidence is given of the major role of the run-on process, which was neglected in most studies.