A stochastic runoff model incorporating spatial variability

Abstract

The volume of catchment discharge that reaches a stream via the overland flow path is critical for water quality prediction, because it is via this pathway that most constituents are generated and transported to the stream channel. Two of the key properties determining this runoff volume are the rainfall rate and the infiltration rate. Both these rates are variable in both space and in time, but it is common to neglect the spatial variability. In this paper we propose a stochastic runoff model that deals explicitly with spatial variability, while neglecting the temporal variability. We use an idealised model for the catchment terrain, which allows us to obtain analytical results. We consider..