Comparison of annual maximum and peaks-over-threshold methods with automated threshold selection in flood frequency analysis: a case study for Australia

Flood frequency analysis (FFA) involves fitting of a probability distribution to observed flood data. Two main models, annual maximum (AM) and peaks over threshold (POT), are generally adopted in FFA. The POT model is underemployed due its complexity uncertainty associated with selection meeting independence criteria selecting data series. This study evaluates the AM models using from 188 gauged stations southeast Australia. this applies different average numbers events per year fitted generalized Pareto (GP) an automated detection method. For model, GP also adopted, quantiles estimated by two compared. It has been found that there notable differences design estimates between models. uses catchment characteristics understand quantile percentage can be explained mean rainfall (MAR) evapotranspiration (MAE) (ARIs 1.01–5 years), MAR (10-year ARI), stream density (SDEN) (for 20- 50-year ARIs) SDEN, slope (S1085) MAE 100-year ARI). Stations showing smaller % have relatively higher (indicating wetter condition); conversely, (drier condition).