A practice-oriented framework for stationary and nonstationary flood frequency analysis.

In flood frequency analysis (FFA), choices of distribution and methods can hinder the reproducibility of results. Besides, changes in climate, land use/cover, and water management can induce nonstationarity. Frameworks to select between stationary FFA (S-FFA) and nonstationary FFA (NS-FFA) are lacking, and NS-FFA tools are limited. Therefore, this paper introduces a systematic and software-supported framework enabling repeatable workflows for both S-FFA and NS-FFA. The framework has three modules to a) process flood series for exploratory data analysis (EDA) and NS-FFA model determination (if needed), b) select the S-FFA or NS-FFA approach underpinned by the EDA, and c) perform FFA including model determination, parameter estimation, uncertainty quantification, and model performance assessment. The framework incorporates various distributions, methods, and metrics, and recent advancements in NS-FFA for model determination and uncertainty quantification and allows for the modeller's intervention while ensuring reproducibility. The software is freely available to the public. • A FFA framework enabling both the S-FFA and NS-FFA is proposed. • The EDA is employed to assist in the selection of the S-FFA and NS-FFA. • The framework contains decision points and allows for repeatable workflows. • The framework includes various models, metrics, and state-of-the-art methods. • The source codes and a user-friendly standalone GUI are freely available. [ABSTRACT FROM AUTHOR]