Sampling uncertainty of UK design flood estimation

Abstract

The UK standard for estimating flood frequencies is outlined by the flood estimation handbook (FEH) and associated updates. Estimates inevitably come with uncertainty due to sampling error as well as model and measurement error. Using resampling approaches adapted to the FEH methods, this paper quantifies the sampling uncertainty for single site, pooled (ungauged), enhanced single site (gauged pooling) and across catchment types. This study builds upon previous progress regarding easily applicable quantifications of FEH-based uncertainty estimation. Where these previous studies have provided simple analytical expressions for quantifying uncertainty for single site and ungauged design flow estimates, this study provides an easy-to-use method for quantifying uncertainty for enhanced single site estimates. HIGHLIGHTS Bespoke bootstrap methods for quantifying uncertainty for ungauged and enhanced single site FEH design flow estimation.; Comparison of flood estimation uncertainty across catchment types.; Simple equations to derive variance and standard error for enhanced single site design flow estimates.;

Keywords

• flood frequency
• hydrology
• uncertainty analysis