Abstract
Generally, it is well known that rainfall-runoff phenomena belong to a random process. So, the runoff system is described by random differential equations. In this paper, I adopted Kinematic Wave model for tow slopes and a river channel and derived differential equations whose solutions provided the average and variance of discharge output from the runoff system under the condition of mutually independent rainfall input. The validity of proposed theoretical equations was cross-checked by a simulation. By using similar way, it is possible to estimate the higher order moments of discharge output and its probability density function which change with time.
The results of this study can be applied to the evaluation method of models based on its stochastic response characteristics.
