Scale effects in infiltration and runoff production.

Part 1 derives the expressions for the statistics of infiltration due to spatially variable soils and constant rainfall. The cumulative distribution of ponding time determines the proportion of the catchment where infiltration is soil or rainfall controlled. Part 2 extends the analysis to include both variable soil and rainfall processes. Part 3 includes the influence of topography and derives the statistical properties of infiltration and the dynamics of runoff contributing areas for a catchment with spatially variable soils and rainfall. Both infiltration excess (Horton type) and saturation excess (Dunne type) runoff production mechanisms are considered; the effect of topography is modeled through the TOPMODEL formulation of Beven and Kirkby. -from Authors