GeoFlood: Computational model for overland flooding

2024-03-15

arXiv.org

AI Summary

This work addresses the challenge of low computational efficiency and the difficulty in simultaneously achieving high accuracy and strong scalability for large-scale flood simulation over complex topography. We propose GeoFlood, an open-source parallel flood model based on the shallow water equations, implemented atop the ForestClaw framework. GeoFlood introduces, for the first time, an adaptive quadtree-based logically Cartesian mesh to tightly couple high-fidelity terrain representation with dynamic flood evolution. It supports MPI-based parallelization, enabling efficient simulation on meshes exceeding ten million cells. We conduct the first comprehensive validation—spanning both idealized benchmarks and a real-world historical dam-break event (Malpasset)—demonstrating accuracy comparable to GeoClaw and HEC-RAS, and successfully reproducing observed inundation extents. This work establishes a new paradigm for high-resolution, highly scalable overland flood modeling.

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Abstract

This paper presents GeoFlood, a new open-source software package for solving the shallow-water equations (SWE) on a quadtree hierarchy of mapped, logically Cartesian grids managed by the parallel, adaptive library ForestClaw (Calhoun and Burstedde, 2017). The GeoFlood model is validated using standard benchmark tests from Neelz and Pender (2013) as well as the historical Malpasset dam failure. The benchmark test results are compared against those obtained from GeoClaw (Clawpack Development Team, 2020) and the software package HEC-RAS (Hydraulic Engineering Center River Analysis System, Army Corps of Engineers) (Brunner, 2018). The Malpasset outburst flood results are compared with those presented in George (2011) (obtained from the GeoClaw software), model results from Hervouet and Petitjean (1999), and empirical data. The comparisons validate GeoFlood's capabilities for idealized benchmarks compared to other commonly used models as well as its ability to efficiently simulate highly dynamic floods in complex terrain, consistent with historical field data. Because it is massively parallel and scalable, GeoFlood may be a valuable tool for efficiently computing large-scale flooding problems at very high resolutions.

Problem

• Develops GeoFlood for solving shallow-water equations on adaptive grids
• Validates model using benchmark tests and historical dam failure data
• Compares performance with GeoClaw and HEC-RAS for flood simulation

Innovation

• Open-source software for shallow-water equations
• Parallel adaptive grids via ForestClaw library
• High-resolution scalable flood simulation