Regional Flood Estimation in New South Wales Australia Using Generalized Least Squares Quantile Regression

Abstract

This paper investigates the applicability of quantile regression technique (QRT) as a viable regional flood frequency analysis (RFFA) method for the state of New South Wales in Australia. The study uses data from 96 small to medium-sized unregulated basins across New South Wales to develop a generalized least squares (GLS)-based QRT. An independent test employing a wide range of statistical diagnostics indicates that the developed regression equations based on the GLS regression can provide quite accurate flood quantile estimates with median relative error values in the range of 13–42%. The developed regression equations are relatively easy to apply and require data for only three predictors—basin area, design rainfall intensity, and stream density.