Vulnérabilité aux risques de mouvements de masse dans la Commune de Bafoussam III.

Abstract

This research work is entitled: “Vulnerability to the risks of mass movements in the commune of Bafoussam III. The main objective is to assess the level of vulnerability of populations and their property to the risks of mass movements in the said municipality. On the methodological level, the data processing was done according to the nature of the data. Statistical Package for Social Sciences and Excel software were used to process climate data, as well as data from questionnaires collected in the field. Erdas Imagine 2011 software was used to process Landsat satellite images. This was done by following several steps, namely: the acquisition of images, the downloads, the exploration of the different bands, the combination of the layers, the mosaicking of the different sheets, the extraction of the study area. Filtering and layout were done in the Arc-gis software. The Surfer and Global Map software respectively allowed the production of 3D and the Lineament and Google Earth maps for the analysis of the occupation of space over 3 periods (2006-2014 and 2021), this software also made it possible to project the sampling map. In the end, the analyzes carried out in the laboratory on the geotechnical characteristics of the soils show a plastic clay material, with high porosity (≥45%), low cohesion (< 32 Kpa) and high angle of friction (33.5°–49 ,8°). These characteristics, associated with steep slopes (>30°), heavy rainfall (1400–2500 mm) and human action (deforestation, overexploitation, rock extraction, poor farming techniques, uncontrolled urbanization, etc.), are at the origin of the mass movements, the most important of which recorded so far was that of Gouache (October 28-29, 2019) which had been of the rotational and translational type and whose damage was significant. The recurrence of mass movements in the Western Highlands of Cameroon led to the proposal of solutions from the Gouache control site to reduce the extent of the damage. The phenomena are increasingly worrying because planning problems arise in terms of the occupation of areas unsuitable for housing, the fragility of built-up areas and the quality of sanitation facilities. The unsanitary conditions of the habitat and the health situation of the areas potentially at risk as well as the management of the environment are all challenges for the local authorities; the anarchic occupation of space, the progressive loss of control and regulation of public action being causes of this situation. They also integrate the improvement of urban governance, urban sanitation, and the management of the built environment.