Regional flood frequency analysis for Southwest Peninsular Malaysia by LQ-moments

• Published in: Journal of flood risk management Vol. 6; no. 4; pp. 360 - 371
• Main Authors: Shabri, A., Jemain, A.A.
• Format: Journal Article
• Language: English
• Published: London Blackwell Publishing Ltd 01.12.2013; John Wiley & Sons, Inc
• Subjects: Comparative studies; Freshwater; L-moments; LQ-moments; Mean square errors; regional frequency analysis; Stream flow; Malaysia
• ISSN: 1753-318X; 1753-318X
• DOI: 10.1111/jfr3.12023

A regional flood frequency analysis based on the L‐moments procedure has been applied successfully for modelling floods. In this study, we propose an alternative regional frequency analysis by using LQ‐moments. Annual maximum stream flow data observed at 12 sites in Southwest Peninsular Malaysia are investigated. Three probability distributions, the generalised extreme value (GEV), generalised Pareto (GPA) and generalised logistic (GLO) distributions, were derived and used to develop the regional frequency analysis procedure. The moment ratio diagram and Z‐test were developed using LQ‐moments to determine the best fitting distribution. A comparative study was performed between LQ‐moments and L‐moments for the study area. Analyses showed that the GLO and GEV distributions were suitable for a homogeneous region based on L‐moments and LQ‐moments. The robustness of the designated regional frequency distributions was further investigated by assessing the relative root mean square error (RRMSE) and regional average relative bias (RBIAS) by Monte Carlo.