A Method for Frequency Analysis of Rainfall and Runoff Data

Abstract

The available rainfall and runoff data from a given watershed and stream are usually of a limited number of years. The necessity and importance of extrapolating the given data for hydrological uses are obvious. In this paper, the runoff data from the Nestos River in Greece were used in order to obtain extreme values of runoff together with their corresponding frequencies and probabilities of occurence. The applied frequency analysis method is that of the normal frequency distribution method which is widely used in Statistics. It is shown that the available analytical criteria are sufficient to permit such treatment of the runoff data which show relatively small skew.