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

Álvarez, Manuel; Puertas, Jerónimo; Peña, Enrique; Bermúdez, María

doi:10.3390/w9060432

Cited by 47 publications

(40 citation statements)

References 45 publications

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“…The method used by Alvarez et al (2017) was considered for the classification of flood hazard in high, medium and low categories. To be classified in the high category, the location must have a water depth higher than 1 m, a water velocity greater than 1 m s −1 or a product of the velocity and the water depth greater than 0.5 m s −2 .…”

Section: Flood Hazard Mapping Methodologymentioning

confidence: 99%

Formation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi

Nibigira¹,

Havenith²,

Archambeau³

et al. 2017

Preprint

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Abstract. This paper investigated the possible formation of a landslide dam on the Kanyosha River near Bujumbura, the capital of Burundi, as well as the interplay between the breaching of this landslide dam and the flooding along the river. We present an end-to-end analysis, ranging from the origin of the landslide up to the computation of flood waves induced by the dam 10 breaching. The study includes three main steps. First, the mass movement site was investigated with various geophysical methods that allowed us to build a general 3D model and detailed 2D sections of the landslide. Second, this model was used for dynamic landslide process modelling with the Universal Distinct Element Code. The results showed that a fifteen-meterhigh landslide dam may form on the river. Finally, a 2D hydraulic model was setup to find out the consequences of the breaching of the landslide dam on flooding along the river, especially in an urban area located downstream. Based on 2D maps 15 of maximum water depth, flow velocity and wave propagation time, the results highlight that neglecting the influence of such landslide dams leads to substantial underestimation of flood hazard in the downstream area.

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Section: Flood Hazard Mapping Methodologymentioning

confidence: 99%

Formation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi

Nibigira¹,

Havenith²,

Archambeau³

et al. 2017

Preprint

View full text Add to dashboard Cite

show abstract

“…However, in the data-scarce environment of the study area which is commonplace in many parts of Africa, a 10 m resolution is among the best in the region, especially when compared to Shuttle Radar Topography Mission (SRTM) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) provided by the US Geological Survey (USGS). The example of some recent work (Jacobs et al, 2016;Alvarez et al, 2017) showed that using medium-or low-resolution products remains a valuable intermediate step to advance the understanding of flood risk in data-scarce areas in Africa, provided that the results are interpreted in light of the uncertainties affecting the input data.…”

Section: Topographic and Geophysical Datamentioning

confidence: 99%

“…The method used by Alvarez et al (2017) was considered for the classification of flood intensity in high, medium and low categories. To be classified in the high category, the location must have a water depth higher than 1 m, a water velocity greater than 1 m s −1 or a product of the velocity and the water depth greater than 0.5 m 2 s −1 .…”

Section: Flood Intensity Mappingmentioning

confidence: 99%

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Formation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi

Nibigira

Havenith

Archambeau

et al. 2018

Nat. Hazards Earth Syst. Sci.

View full text Add to dashboard Cite

Abstract. This paper investigates the possible formation of a landslide dam on the Kanyosha River near Bujumbura, the capital of Burundi, as well as the interplay between the breaching of this landslide dam and the flooding along the river. We present an end-to-end analysis, ranging from the origin of the landslide up to the computation of flood waves induced by the dam breaching. The study includes three main steps. First, the mass movement site was investigated with various geophysical methods that allowed us to build a general 3-D model and detailed 2-D sections of the landslide. Second, this model was used for dynamic landslide process modelling with the Universal Distinct Element Code. The results showed that a 15 m high landslide dam may form on the river. Finally, a 2-D hydraulic model was set up to find out the consequences of the breaching of the landslide dam on flooding along the river, especially in an urban area located downstream. Based on 2-D maps of maximum water depth, flow velocity and wave propagation time, the results highlight that neglecting the influence of such landslide dams leads to substantial underestimation of flood intensity in the downstream area.

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“…Souza (2016) also mentions the impact that different Manning coefficients applied in the flood valley can generate in the results in relation to the peak flow. On the other hand, Rocha (2015) and Alvarez et al (2017) affirm that topography may be the main influencing factor in floodplain prediction, among other hydraulic variables of interest. In this 3/17 sense many research studies have been developed that connect the use of topography estimated by orbital sensors and large scale hydrodynamic modeling, presenting good results (YAN et al, 2015;ALSDORF et al, 2005;SCHUMANN et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Uncertainty assessment in hydrodynamic modeling of floods generated by dam break

Tschiedel

Paiva

2018

RBRH

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The objective of the present work was to evaluate sources of uncertainty in dam break simulations for areas with contrasting characteristics: one in a narrow valley with high slopes, and another an open valley with low slopes. A sensitivity analysis of the hydrodynamic model Hec-Ras 5.03 was performed, varying the input data of the model (Manning coefficient, breach configurations, reservoir volume, type of valley topography and equation considered). These variations cause different changes in peak flow, peak time, maximum depth and a maximum speed for different sections of the downstream watercourse. It was concluded that there are uncertainties in determining the input data that impacts in many ways at the generated flood wave, considering both a hydraulic variable of interest, the distance of the section from the dam and the mean geomorphological characteristic of the downstream valley. Topography is not always the most important input data, which allows the possibility of use of low resolution topographies to estimate the peak time in some sections, depending on the valley. Finally, safety coefficients for dam break studies are suggested, aiming to represent uncertainties of the input data in the generated results.Keywords: Geoprocessing; Hec-Ras 5.03; 2D Hydrodynamic modeling; Dam break; Safety coefficients. RESUMOO presente trabalho teve como objetivo realizar uma avaliação de fontes de incerteza em simulações de onda de cheia de rompimentos de barragens para áreas de características contrastantes: uma em vale encaixado e altas declividades e outro com vale aberto e baixas declividades. Uma análise da sensibilidade do modelo hidrodinâmico Hec-Ras 5.03 foi realizada, perturbando-se os dados de entrada do modelo (coeficiente de Manning, configurações da brecha, volume do reservatório, topografia do vale de jusante e tipo de equacionamento considerado). Após observou-se como essa variação alterava a vazão de pico, tempo de pico, profundidade máxima e a velocidade máxima para diferentes seções localizadas ao longo dos cursos hídricos. Concluiu-se que as incertezas existentes na determinação dos dados de entrada impactam de forma variada na onda de cheia gerada, considerando tanto a variável hidráulica de interesse como o distanciamento da seção em relação ao barramento e a característica geomorfológica média do vale de jusante. A topografia nem sempre é o dado de entrada de maior importância, o que permite, até certo ponto, a utilização de topografias de baixa resolução para estimar tempo de pico em algumas seções, dependendo do vale. Por fim, sugerem-se coeficientes de segurança para estudos de rompimento de barragens, que visam representar as incertezas dos dados de entrada nos resultados gerados. Palavras-chave:Geoprocessamento; Hec-Ras 5.03; Modelagem hidrodinâmica 2D; Rompimento de barragens; Coeficientes de segurança.RBRH, Porto Alegre, v. 23, e30, 2018Uncertainty assessment in hydrodynamic modeling of floods generated by dam break 2/17

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

Cited by 47 publications

References 45 publications

Formation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi

Formation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi

Formation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi

Uncertainty assessment in hydrodynamic modeling of floods generated by dam break

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