Comparison Between HEC-RAS and TELEMAC-2D Hydrodynamic Models of the Loire River, Integrating Levee Breaches

EasyChair Preprint no. 11509

Abstract

In the past and now, flooding has been a serious problem, causing significant property damage and a high number of fatalities despite the extensive risk mitigation measures and billions invested in flood defenses globally. The Loire River, which is the longest in France, has a considerable history of flooding. In order to prevent floods, levees have been built since the Middle Ages. For this study, a 2D hydraulic model was built using HEC-RAS. The model represents a 50-kilometer section of the river that goes from Gien to Jargeau. Considering that the IRSN had previously developed a numerical model of the study area with TELEMAC-2D, the HEC-RAS model was created according to its data and assumptions. The aim was to validate the model and assess the performance of both software by comparing the results obtained, including flood areas, water levels, velocities, and computational time. The numerical model has been calibrated for the largest flood event recorded, which occurred in 2003, and validated on two other major floods. This enables to estimate the flooding's effects focusing in particular on the simulation of a 1,000-year return period flood and to incorporate the analysis of multiple levee breach scenarios. Furthermore, the results obtained with the hydrodynamic models implemented using HEC-RAS and the existing TELEMAC-2D model were summarized including the performance, capabilities and limitations of the flood study, but also of the levee breaches analysis that test various breach parameters and modes of rupture. This analysis provides a solid basis of criteria, to select in further studies, the more suitable tool according with the objectives of each project.

Keyphrases: flood risk, HEC-RAS, hydrodynamic model, levee breaches, Loire River, TELEMAC-2D

@Booklet{EasyChair:11509,
  author = {Andrea Nathaly Rodriguez Orozco and Nathalie Bertrand and Lucie Pheulpin and Antonin Migaud and Morgan Abily},
  title = {Comparison Between HEC-RAS and TELEMAC-2D Hydrodynamic Models of the Loire River, Integrating Levee Breaches},
  howpublished = {EasyChair Preprint no. 11509},

  year = {EasyChair, 2023}}