Geohazards (floods and landslides) in the Ndop plain, Cameroon volcanic line

Abstract

Abstract:The Ndop Plain, located along the Cameroon Volcanic Line (CVL), is a volcano-tectonic plain, formed by a series of tectonic movements, volcanic eruptions and sedimentation phases. Floods (annually) and landslides (occasionally) occur with devastating environmental effects. However, this plain attracts a lot of inhabitants owing to its fertile alluvial soils. With demographic explosion in the plain, the inhabitants (143,000 people) tend to farm and inhabit new zones which are prone to these geohazards. In this paper, we use field observations, laboratory analyses, satellite imagery and complementary methods using appropriate software to establish hazard (flood and landslide) maps of the Ndop Plain. Natural factors as well as anthropogenic factors are considered. The hazard maps revealed that 25% of the area is exposed to flood hazard (13% exposed to high flood hazard, 12% to moderate) and 5% of the area is exposed to landslide hazard (2% exposed to high landslide hazard, 3% to moderate). Some mitigation measures for floods (building of artificial levees, raising foundations of buildings and the meticulous regulation of the flood guards at Bamendjing Dam) and landslides (slope terracing, planting of trees, and building retaining walls) are proposed.

Community-Based Approach in the Prevention and Management of Flood Disasters in Babessi Sub-Division (Ndop Plain, North West Cameroon)

“…Previous scientific data by [22] has revealed that the causes of floods in the area include natural causes (siltation, Although 40% of the respondents agreed that the population is educated on soil and water conservation methods, 53.3% affirmed that farming was carried out along the flood prone areas. This is in line with Wotchoko et al [22] who reported that 20% of the Ndop Plain is plantation land and that more people tend to farm near the main rivers. Also, most of the population holds a FSLC and might not properly master modern techniques of soil and water management.…”

“…Floods are the major hazard in the Ndop Plain due to its flat and extensive topography that make the easy evacuation of water difficult problem of space. Flood hazard may affect about 25% of the Ndop Plain, along a north-south stripe [22].…”

“…The alluvial soils (40%) and colluviall soils (35%) occur on the flooded plains, meanwhile hill slopes support lightly evolved soils (12%), andosolic soils (8%) and ferrallitic soils (5%) [22]. The main rock types are plutonic rocks (20% granite-gneiss), volcanic rocks (15% basalt, 4% trachyte, 5% rhyolite and 5% ignimbrite) [22]. Land use …”

Effect of Soil Geomechanical Properties and Geo-Environmental Factors on Landslide Predisposition at Mount Oku, Cameroon

“…The study area encompasses about 20 villages with a population density of 162.3 inhabitants/km 2 , according to the 2005 national institute of statistics census. The Mount Oku area plays a significant role in the northwest region in terms of infrastructure, grazing, and agriculture—therefore, it is important to better constrain the conditions that could lead to landslide disasters in that area and to provide indications allowing to prevent them [ 10 , 15 , 16 ].…”

“…Landslide studies conducted in Cameroon can be classified into four approaches. In the first approach, the authors studied landslide-predisposing factors including morphological, geological, hydrological, and geographical properties [ 15 , 22 , 23 ]. In this approach, no geotechnical characteristics of soils were taken into account, and landslide-conditioning factors were simplified.…”