26.-Estimation of maximum1-day point rainfall for the Krishna basin using Nomogram method

Abstract

A quick and simple procedure has been developed for evaluating maximum point rainfall for different return periods for any station in the Krishna catchment. Maximum one-day rainfall for different return periods of 2 to 100 years have been worked out using Gumbel's statistical method for all the stations in the Krishna basin. With the help of this data 2 and 100-year generalized rainfall charts for 1-day duration, frequency interpolation nomogram have been prepared.

Knowing the 2-year and 100 year rainfall values of any station in this catchment and with the help of this nomogram, rainfall magnitudes for intermediate return periods viz. 5, 10, 25 and 50 years can be obtained directly. Maximum 1-day rainfall obtained by this method for different return periods have been found to agree within the limits of ± 4% of the results obtained by Gumbel's statistical method.