Comparison between Quantile Regression Technique and Generalised Additive Model for Regional Flood Frequency Analysis: A Case Study for Victoria, Australia

For design flood estimation in ungauged catchments, Regional Flood Frequency Analysis (RFFA) is commonly used. Most of the RFFA methods are primarily based on linear modelling approaches, which do not account for inherent nonlinearity rainfall-runoff processes. Using data from 114 catchments Victoria, Australia, this study employs Generalised Additive Model (GAM) and compares results with method known as Quantile Regression Technique (QRT). The GAM model performance found to be better smaller return periods (i.e., 2, 5 10 years) a median relative error ranging 16–41%. higher 20, 50 100 years), log-log regression (QRT) outperforms 31–59%.