Coupled Continuous-Discontinuous Galerkin Finite Element Solver for Compound Flood Simulations

TL;DR

This paper introduces a coupled DG-CG finite element solver integrated into ADCIRC for simulating compound floods, including runoff and storm surge interactions, with demonstrated accuracy on laboratory and hurricane-scale tests.

Contribution

It develops a novel locally conservative coupled DG-CG discretization for the shallow water equations, incorporating variable rainfall into flood simulations.

Findings

The method conserves mass and momentum effectively.

Numerical tests show robustness and accuracy in small and large scale flood scenarios.

The approach captures complex interactions in compound flooding.

Abstract

Several recent tropical cyclones, e.g., Hurricane Harvey (2017), have lead to significant rainfall and resulting runoff. When the runoff interacts with storm surge, the resulting floods can be greatly amplified and lead to effects that cannot be correctly modeled by simple superposition of its distinctive sources. In an effort to develop accurate numerical simulations of runoff, surge, and compounding floods, we develop a locally conservative coupled DG-CG discretization of the shallow water equations and integrate it into the Advanced Circulation Model (ADCIRC). We also modify the continuity equation to include spatially and temporally variable rainfall into the model using parametric rainfall models. We demonstrate the capabilities of the scheme though a sequence of physically relevant numerical tests, including small scale test cases based on laboratory measurements and large scale experiments with Hurricane Harvey in the Gulf of Mexico. The results highlight the conservation properties and robustness of the developed method and show the potential of compound flood modeling using our approach.