Performances of the New HEC-RAS Version 5 for 2-D Hydrodynamic-Based Rainfall-Runoff Simulations at Basin Scale: Comparison with a State-of-the Art Model

Pierfranco Costabile,Carmelina Costanzo,Gabriella Petaccia,Francesco Macchione,Domenico Ferraro

doi:10.3390/w12092326

Pierfranco Costabile, Carmelina Costanzo + Show 3 more

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https://doi.org/10.3390/w12092326

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Journal: Water	Publication Date: Aug 19, 2020
Citations: 52	License type: CC BY 4.0

Affiliation: University of Calabria, University of Pavia

Abstract

The Hydrologic Engineering Centre-River Analysis System (HEC-RAS), developed by the US Army Corps of Engineers, is one of the most known, analyzed and used model for flood mapping both in the scientific literature and in practice. In the recently released version (release 5.0.7), the HEC-RAS model has been enriched with novel modules, performing fully 2-D computations based on the 2-D fully dynamic equations as well as the 2-D diffusion wave equations; moreover the application of rainfall to each cell of the two-dimensional domain is now possible. Contrarily to the common applications for flood propagation in river reach, this specific module has never been analyzed in the literature. Therefore, the main purpose of this work is to assess the potential and the capabilities of the 2-D HEC-RAS model in rainfall-runoff simulations at the basin scale, comparing the results obtained using both the options (fully dynamic equations and diffusion wave equations) to the simulations obtained by using a 2-D fully dynamic model developed by the authors for research purposes. Both models have been tested in a small basin in Northern Italy to analyze the differences in terms of discharge hydrographs and flooded areas. The application of a criterion for hazard class mapping has shown significant variations between the two models. These results provide practical indications for the water engineering community in the innovative research field related to the use of 2-D SWEs at the basin scale.

Highlights

IntroductionFlood hazard and flood risk maps are key elements for flood risk management around the world
Flood hazard and flood risk maps are key elements for flood risk management around the world.They are an essential tool for flood warming, mitigation of property damage and loss of life and for flood risk communication to the stakeholders
2-D Hydrologic Engineering Centre-River Analysis System (HEC-RAS) model in rainfall-runoff simulations at the basin scale, comparing its results to the simulations obtained by using a 2-D fully dynamic model developed by the authors already used in the literature

Summary

Introduction

Flood hazard and flood risk maps are key elements for flood risk management around the world. They are an essential tool for flood warming, mitigation of property damage and loss of life and for flood risk communication to the stakeholders. In the United States, the Federal Emergency Management Administration (FEMA) produced the Flood Insurance Rate Maps (FIRMs) that identify flood insurance rate zones. These maps are graphical representations of the results obtained using hydrodynamic simulations and, the identification of the most suitable model for addressing this task is of fundamental importance to enhance the overall flood risk assessment.

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