PRORIL - an erosion model using probability distributions for rill flow and density. I. Model development

A model, named PRORIL, was developed to account for the stochastic variability of rill networks, including both variable rill spacing and rill flow rates. PRORIL predicts an expected (statistical average) value for rill erosion rather than a purely deterministic model estimate. Physically based equations are employed to predict erosion detachment, but rill networks and flow rates are described in stochastic terms using probability density functions. Stochastic predictions of rill erosion are combined with deterministic predictions of interrill erosion to estimate total erosion. Continuity and sediment transport relationships are used to convert total erosion into sediment yield. -Authors