CORRELATION AND COVARIANCE OF RUNOFF

The application of objective methods for interpolation of stochastic f ields is based on the assumption of homogeneity with respect to the co rrelation function, i.e. only the relative distance between two points is of importance. This is not the case for runoff data which is demon strated in this paper. Taking into consideration the structure of the river network and the related drainage basin supporting areas theoreti cal expressions are derived for the correlation function for flow alon g a river from its outlet and upstream. The results are exact for a re ctangular drainage basin. For more complex basin geometry a grid appro ximation is suggested. The found relations are demonstrated on a real world example with a good agreement between the theoretically calculat ed correlation functions and empirical data.