Author(s): Matthew Christopher Halso; C. L. Knusel; David F. Vetsch; Frederic M. Evers; Robert Boes

Linked Author(s): David Vetsch, Robert Boes

Keywords: Dam breach; composite modeling; overtopping; laboratory experiments; numerical modeling; parametric numerical modeling

Abstract: The failure of a dam can have catastrophic consequences for populations and infrastructure downstream. The processes of dam failure are typically studied with small to medium scale laboratory physical model investigations. Findings from laboratory scale studies should inform decision making for prototype scale dams, but upscaling introduces uncertainties and complexity. Detailed numerical models can simulate complex breach processes and depict larger dams, allowing for investigations at larger scale. But with increasing detail and numerical refinement comes increasing computational cost, making modeling of prototype systems potentially prohibitive. Parametric numerical models allow for efficient simulation at prototype scale, but with simplified geometries and limited erosion processes. These numerical options could connect findings from smaller scale studies to prototype scale, if the effect of scale in each method is accounted for. In this study, the effect of scale is investigated with medium laboratory scale (dam height = 0.5 m) and large laboratory scale (dam height = 1.0 m) breach modeling. Laboratory experiments, detailed numerical modeling, and parametric numerical modeling (with the Macchione and Peter methods) are performed at both scales. During initial breach formation (while reservoir head was constant), the laboratory experiments showed no effect of scale. Later, as the reservoir head fell, a faster increase in breach discharge occurred at large scale, leading to an earlier peak discharge. Detailed numerical modeling showed the effect of scale on breach growth, but with limited reproduction of the effect on breach discharge. Both parametric methods replicated the discharge hydrographs well, but only the Peter model adequately reproduced the effect of scale on timing of peak discharge.

DOI: https://doi.org/10.3929/ethz-b-000675921

Year: 2024