Modeling Rapid Flood Propagation in Andean Rivers: High-Resolution Simulations and Surrogate Models for Early Warning Systems
Abstract
Rapid floods induced by extreme precipitation are common events in regions near the Andes mountain range. Processes at a global scale, such as the climate change and El Niño phenomenon, combined with new urban developments, have increased the exposure of the population in many regions of South America. Simulations of floods in these watersheds are very challenging, due to the complex morphology, high flow velocities, insufficient hydrometeorological data, and the uncertainty posed by the variability of sediment concentrations. To understand the factors that control the dynamics of floods in these rivers, we develop a high-resolution numerical model of the non-linear shallow water equations, coupled with the mass conservation of sediment, and considering density and rheology effects in the momentum equation. We simulate multiple cases in a watershed in Santiago, Chile, to understand the influence of different parameters of the hydrometeorological events on the flood propagation. Based on these simulations we develop a surrogate model or meta-model, to create a real-time early-warning system. Using a small set of parameters, we create a database of flood propagations, computed by the high-fidelity model, for a wide range of hydrometeorological conditions. This surrogate approach considers a sophisticated interpolation/regression scheme to approximate efficiently the flow depths and velocities in urban settings from precomputed cases in the database. Coupling the models developed in this investigation can be used to improve the predictions of flood hazard in real conditions, employing low computational resources, helping decision makers and city planners in these mountain regions.
This work has been supported by CONICYT/FONDAP grant 15110017, and by the Vice Chancellor of Research of the Pontificia Universidad Catolica de Chile, through the Research Internationalization Grant, PUC1566 funded by MINEDUC.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H32A..02C
- Keywords:
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- 1816 Estimation and forecasting;
- HYDROLOGYDE: 1821 Floods;
- HYDROLOGYDE: 1847 Modeling;
- HYDROLOGYDE: 1860 Streamflow;
- HYDROLOGY