The utilisation of satellite imagery and community perceptions to assess the impacts of sea encroachment in the West Coast of Cameroon at Limbe

Abstract

Coastal erosion associated to sea encroachment is a major problem at the West Coast of Limbe, specifically in the Debundscha Fishing Port (DFP). This study sought to assess the physical vulnerability of the West Coast of Limbe to coastal erosion associated to sea encroachment. This was achieved by assessing: i) the physical vulnerability of the West Coast to coastal erosion; ii) land cover changes and iii) community perception at DFP to sea encroachment and coastal erosion in the past 30 years. Three variables: rock type, adjacent land use and coastal protection were used to assess the vulnerability of the West Coast to coastal erosion. Landcover / coastal changes were assessed from satellite images from 1986 to 2018. Semi-structural interviews were used to acquire knowledge on the population’s perception and impact of the studied hazards. A cost benefit approach was used to weigh the potentials of these localities to adapt to coastal erosion. The DFP and Idenau Beach were identified as major hotspots of coastal erosion with an annual rate of >100 m².  Landcover changes showed a net increase in water levels inland and into settlements. The population is knowledgeable and is aware of the risk of sea encroachment and coastal erosion. The physical, socio-economic and health effects were: destruction of mangroves;
relocation; malaria, typhoid and abdominal illnesses respectively. Coping strategies included the use of sandbags, building on higher grounds and on embankments. Cost benefit analysis ranked vegetative cover as the best option environmentally and financially viable to reduce coastal erosion from sea encroachment at the West Coast.

Key words: Sea encroachment, coastal erosion, physical vulnerability, perception, Debundscha Fishing Port