Relative Accuracy of Log Pearson III Procedures

Abstract

The U.S. Water Resources Council (WRC) has suggested that the log‐Pearson III distribution, fitted by the method of moments, should be used in flood frequency analysis. A Monte Carlo simulation assessment of the WRC procedures shows that the flood quantile estimates obtainable by these procedures are poorer than those obtainable by using an index flood type approach with either a generalized extreme value distribution or a Wakeby distribution fitted by probability weighted moments. It is suggested that the justification for using the WRC Bulletin 17B guidelines is in need of reevaluation.