Relation among intensity, duration and frequency of rainfall in Mococa, State of São Paulo, Brazil

Abstract

The objective of this work was to perform a statistical analysis of rainfall data gathered in Mococa, State of São Paulo, from 1970 to 1990, including the relationship between intensity, duration and frequency. The studied data were registered with a rain gauge located at the Experimental Station of the Instituto Agronômico, in Mococa, São Paulo State, Brazil. The relationship were studied for the following duration intervals: 5, 10, 15, 25, 30, 45, 60, 90, and 120 minutes. The Chow-Gumbel method was applied for the study of frequency distribution of intense precipitation for recurrency times of 5, 10, 25, 50, and 100 years. Also, the method of minimum squares was applied to obtain an equation for the same relationship. Final results showed good correlation between both methods, as well as with the maximum rainfall values obtained for each duration, resulting in linear regression coefficients of 0.9990 and 0.9920, respectively. Results indicated that the equation can be utilized for cases where values of maximum rainfall intensities are needed.