Frequency analysis of annual runoff in peninsular Malaysia using a regional approach based on L-Moments

Abstract

Estimation of runoff is very important for flood estimation. Thus, runoff is very important in designing and managing water resources projects involving natural hazards. Region refers to a set of sites of which is expected to have data drawn in a synonymous frequency distribution. In this study, a regional frequency analysis of annual runoff in Peninsular Malaysia has been conducted and was based on the theory of L-Moments as developed by Hosking and Wallis [1] is a very reliable method for assessing exceedance probabilities of extreme environmental events when data is available from more than one site. The General Logistics (GLO) and Generalized Extreme Value (GEV) were found to be suitable for the region in peninsular Malaysia [2]. The best fit distributions of annual runoff in Malaysia are determined based on L-moment ratio diagram and statistical tests. Numerical analysis was performed on some stations in every state in Peninsular Malaysia. Thus, the analysis performed are using data from homogeneous regions established using L-moments procedure. From the analysis, probability plots and comparison between at site and regional estimation shows that most of the station are almost the same and lies on the 45o lines meaning that the site are fitted distribution.