Two-Dimensional Dam-Break Flood Analysis in Data-Scarce Regions: The Case Study of Chipembe Dam, Mozambique

Manuel Álvarez,Jerónimo Puertas,Enrique Peña,María Bermúdez

doi:10.3390/w9060432

Abstract

This paper presents the results of a modeling study of the hypothetical dam break of Chipembe dam in Mozambique. The modeling approach is based on the software Iber, a freely available dam break and two-dimensional finite volume shallow water model. The shuttle radar topography mission (SRTM) online digital elevation model (DEM) is used as main source of topographic data. Two different DEMs are considered as input for the hydraulic model: a DEM based on the original SRTM data and a hydrologically-conditioned DEM. A sensitivity analysis on the Manning roughness coefficient is performed. The results demonstrate the relevant impact of the DEM used on the predicted flood wave propagation, and a lower influence of the roughness value. The low cost modeling approach proposed in this paper can be an attractive option for modeling exceptional flood caused by dam break, when limited data and resources are available, as in the presented case. The resulting flood-inundation and hazard maps will enable the Regional Water Management Administration of Mozambique (ARA) to develop early warning systems.

Highlights

Dams play an essential role in meeting water supply demands from towns, agriculture, industry or power generation, as well as in managing flood events
Ta is the elapsed time between dam failure and initial wetting, allowing a margin of time to evacuate the population at risk
The results show that the use of the digital elevation model (DEM) shuttle radar topography mission (SRTM) combined with a low Manning’s value is insufficient to match the flood wave travel times obtained with the DEM

Summary

Introduction

Dams play an essential role in meeting water supply demands from towns, agriculture, industry or power generation, as well as in managing flood events. They pose a potential risk of failure, which can cause serious material damage and loss of life. In the African continent, the failure of the Virginia No 15 tailing dam in South Africa in 1994 is worth noting [7]. A compilation of historical dam failure events, classified into flood severity categories, is provided by the U.S Bureau of Reclamation [8]

Methods

Results

Conclusion