An update on Data-Fusion-based Dam Breach Empirical Equations Based on a Worldwide Historical Dam Failure Database

Abstract This research concentrated on estimating breaching embankment dams with focus on i) the extraction of failure cases from the historical dam failure database, adoptable for dam breach parameters estimates, ii) an update on data-fusion-based (DFM) dam breach equations published by Azmi and Thomson (2024) using the adopted failure cases, and finally iii) a comprehensive comparative assessment of all models to estimate breach peak discharge, breach formation time, and average breach width. A multi-stage procedure was followed to select the empirical equations that showed higher similarities to observed data for all three dam breach parameters. Statistical evaluations included t- and F-tests, probability distribution analyses (K-S test, Q-Q plots, boxplots, scatter plots), along with the performance criteria (median of percentage error (MPE), root mean square errors (RMSE), coefficient of variation and Nash Sutcliffe efficiency (NSE)), were used for comparative assessments. The final selected methods are: i) Breach peak outflow: DFM 2024 and updated DFM, ii) Final breach average width: XZ9 (Xu and Zhang 2009) and updated DFM, and iii) Failure time: F8 (Froehlich 2008) and updated DFM. It is critical to note that the proposed equations are not recommended for concrete dams and or embankment dams with extensive safety elements (e.g., wave walls, additional rock mesh protections).