Geographic information systems based demarcation of risk zones: the case of the Limbe Sub-Division – Cameroon

Abstract

In the Limbe Subdivision of Cameroon, landslides and flooding are frequent threats. The worst recorded event occurred in June 2001, when floods and landslides took the lives of some 30 persons, left over 2000 people homeless, and destroyed property and social amenities including roads and telephone lines worth hundred of thousands of US Dollars. The objective of this project was to assist local administrative officers, other decision makers and planners to understand which areas to concentrate their efforts on in order to develop mitigation actions to protect the lives of the population in these zones that are affected by flooding and associated landslides. To meet this objective the project made extensive use of geospatial tools and existing digital spatial datasets. Series of field data collection exercises constituted an integral part of the project. The project focused on the Limbe subdivision in the south-western part of Cameroon. Areas with high (greater than 60%) probability of sliding to occur, occupy 23% while areas with medium (greater than 40% and less than 60%) probability of sliding to occur occupy 44% and areas with low (less than 40%) probability of sliding occupy 33%. Settlements along the Atlantic coast all lie less than ~50m above sea level. These settlements (villages) are susceptible to flooding. Again settlements in the town of Llimbe along the Djenguele river, i.e., Animal Farms, Cassava Farms, Lumpsum areas, Church Street, New Town and Down Beach, are more susceptible to inundation during raining periods and therefore have experienced persistent flooding over the years.