Application of regional rainfall frequency analysis on seven sites of Sindh, Pakistan

Abstract

The paper illustrates the results of regional frequency analysis of Annual Maximum Monthly Rainfall Totals (AMMRT) of seven sites of Sindh, Pakistan. The results of run test, lag-1 correlation coefficient and Mann-Whitney test have shown that the data series at given sites is random, having no serial correlation and identically distributed. The values of discordancy measure have shown that there is no discordant site in the group of seven sites. L-moments based heterogeneity measure (H) shows that the region composed of seven sites is homogeneous. The results of L-moment ratio diagram and ZDIST statistic have shown that the three distributions: GNO, PE3 and GPA are suitable candidates for regional distribution. To obtain the rainfall quantiles at ungauged sites of the study area, a linear regression model has been developed, between the mean of AMMRT of gauged sites and their respective site’s elevation. The quality of the regression estimates has been tested using formal tests related to the assumptions of Classical Linear Regression Modeling (CLRM). The results have shown that the fitted model has satisfied various assumptions related to the estimation of CLRM. Hence, the estimates of this study will be useful for the estimation of rainfall quantiles of the study area for various return periods and can be utilized for the preventive measures of flood disasters, agricultural water management and the proposed improvement projects for the rehabilitation and modernization of major barrages of Indus River in the Sindh Province.