References of "Nibigira, Léonidas"
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See detailEtude des risques naturels liés aux interactions entre les mouvements de masse et le réseau hydrographique dans la région des lacs Kivu et Tanganyika
Nibigira, Léonidas ULiege

Doctoral thesis (2019)

This PhD thesis is entitled ‘Etude des risques naturels liés aux interactions entre les mouvements de masse et le réseau hydrographique dans la région des Lacs Kivu et Tanganyika ’ (in English : ‘Analysis ... [more ▼]

This PhD thesis is entitled ‘Etude des risques naturels liés aux interactions entre les mouvements de masse et le réseau hydrographique dans la région des Lacs Kivu et Tanganyika ’ (in English : ‘Analysis of natural hazards related to the interactions between mass movements and the hydrographic network in the Lake Kivu and Lake Tanganyika regions’). The study area belongs to the East African Rift Valley. It is also located in a typically tropical climatic environment. Thus, it is regularly affected by landslides and recurring floods. Flood and landslide issues are often analysed separately while there are many cases of disasters where those types of hazards interacted; this is particularly true for the target region. Therefore, this thesis is focused on the interactions between those two types of natural hazards in order to provide clues to better assess them together. More specifically, this work will provide an inventory of the hydrological and geological hazards, will investigate cases experienced in the region, will highlight the level of exposure to direct and / or indirect impacts of landslides and will finally produce a related assessment. A methodology coupling field observations and measurements as well as laboratory analyses was developed. Laboratory studies were supported by remote sensing and numerical models to study slope stability as well as the triggering and evolution of landslides. Hydraulic simulations involving dam failure scenarios were run to assess related effects on floods in the downstream area. Important decision-support tools in the environmental and land management, urban and hydroelectric plant planning have been developed. They consist of maps illustrating the relative territory and hydrographic network susceptibilities to floods and landslides. Moreover, the configuration of the interplay mechanisms between landslides and floods is designed and discussed. These results make a valuable contribution to the understanding of geological and hydrological hazards in the Lake Kivu and Lake Tanganyika regions. They are also an important asset for further studies in this field and can be used for other zones located in a similar natural hazard context. [less ▲]

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See detailFormation, breaching and flood consequences of a landslide dam near Bujumbura, Burundi
Nibigira, Léonidas ULiege; Havenith, Hans-Balder ULiege; Archambeau, Pierre ULiege et al

in Natural Hazards and Earth System Sciences (2018), 18

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 ... [more ▼]

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 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-meter-high 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 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. [less ▲]

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See detailAnalysis of Migration in a Multi-Risk Context: Case of Bujumbura/Burundi
Nibigira, Léonidas ULiege; Ozer, Pierre ULiege; Havenith, Hans-Balder ULiege

in MAIER, ROBIN; REVELL, MARK (Eds.) THE AMERICAN ASSOCIATION OF GEOGRAPHERS, 2017 Annual Meeting, April 5 - 9, 2017 Boston, Massachusetts / PROGRAM (2017, April 08)

Human mobility affects land use and human density distribution. Unfortunately, this rarely takes into account the real and potential changes induced by hazards on the natural systems. Thus, migration and ... [more ▼]

Human mobility affects land use and human density distribution. Unfortunately, this rarely takes into account the real and potential changes induced by hazards on the natural systems. Thus, migration and natural hazards should be constantly analyzed through cross-sectional and global studies to reduce disastrous consequences resulting from their mutual interactions. In a multi-risk and demographic sprawl context, the study focused on the cross-analysis of human density and natural hazards in Bujumbura. The results show that migration of people should ideally be guided by knowledge of the area's sensitivity to natural hazards, taking into account other parameters such as hazards susceptibility maps and production opportunities. While the migration of people toward overcrowded centers constitutes a big challenge, it is an important asset when it concerns areas in need of manpower. It also allows the balance in relieving saturated areas, reducing human pressure on the environment. Therefore, there is a need that policymakers comply with those aspects, finding the right balance for a better situation. [less ▲]

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See detailLa responsabilité climatique dans les défis urbains contemporains: évaluation et mise en contexte pour la ville de Bujumbura, Burundi
Nibigira, Léonidas ULiege; Ozer, Pierre ULiege; Havenith, Hans-Balder ULiege

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

A Bujumbura, la capitale du Burundi, les préjudices liés aux risques naturels deviennent de plus en plus une réalité quotidienne. Les cas les plus ressentis sont ceux liés aux inondations, aux glissements ... [more ▼]

A Bujumbura, la capitale du Burundi, les préjudices liés aux risques naturels deviennent de plus en plus une réalité quotidienne. Les cas les plus ressentis sont ceux liés aux inondations, aux glissements de terrain et à l'érosion. Les épidémies relatives aux conditions sanitaires précaires deviennent de plus en plus récurrentes. [...] [less ▲]

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See detailGIS-Based Landslide Susceptibility Mapping in the Great Lakes Region of Africa, Case Study of Bujumbura Burundi
Nibigira, Léonidas ULiege; Draidia, Salah ULiege; Havenith, Hans-Balder ULiege

in Engineering Geology for Society and Territory - Volume 2: Landslide Processes (2015)

Abstract: Landslides in Central Africa represent a constant threat to the population. The present work took its motivation from the increasing number of recorded incidents in recent times. It is focused ... [more ▼]

Abstract: Landslides in Central Africa represent a constant threat to the population. The present work took its motivation from the increasing number of recorded incidents in recent times. It is focused on the analysis of mass movements in a regional context. Remote sensing based on the use of satellite images (Pleiades images of 2011) and aerial photographs (1957, 1958 and 1981) allowed us to identify instabilities at different scales. The study of these mass movements and the characterization of the processes governing ... [less ▲]

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See detailAssessing the vulnerability of sites in the East African Rift Valley to natural hazards: case study of Bujumbura, Burundi
Nibigira, Léonidas ULiege; Havenith, Hans-Balder ULiege; Dewals, Benjamin ULiege et al

Conference (2013, November 13)

Due to the geomorphologic, structural and climatic context, the East African Rift Valley is prone to many natural hazards. The locally high density of the population contributes to related risk. As a ... [more ▼]

Due to the geomorphologic, structural and climatic context, the East African Rift Valley is prone to many natural hazards. The locally high density of the population contributes to related risk. As a result, the impacts on the habitat and infrastructures are constantly increasing. This work is based on a case study near the city of Bujumbura, which, for decades, has been affected by severe floods. Based on a study focusing on one of its rivers, the river Ntahangwa, this work tries to answer some questions related to the potential causes and ways of prevention and management of flood risk. The analysis is based on hydrological considerations while having a look at the possible mutual influences between these hydrological risks and geodynamic hazards. The methodology uses rainfall, geographic, demographic, topographic, and elevation data. Hydraulic modeling reveals the extent of the flood hazard according to its likelihood of occurrence and its sensitivity to geodynamic disturbances. This led us to propose solutions and related prevention/remediation measures. Considering the vulnerability of the population, it is clear that a change of people’s behavior is needed to reduce the total risk they’re exposed to, both with respect to the choice of construction areas and to all kinds of activities related to rivers exploitation. [less ▲]

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