Possible pathways of seawater intrusion along the Mount- Cameroon coastal area using remote sensing and GIS techniques

Coastal aquifers are vulnerable to salinisation due to seawater intrusion. Lineaments generally play the role of pathways for this intrusion. This paper investigates the lineament pattern in the region of southern-Cameroon with the main purpose of understanding the mechanism of the eventual contamination of groundwater by salinity. 472 lineaments are mapped in the study area using both Landsat-8 OLI and 7 ETM + images. 15 of those lineaments connect 19 contaminated boreholes to the shore. A total of 24 out of 58 boreholes are contaminated by seawater. A statistical analysis of this network depicts the responsibility of lineaments in seawater intrusion. Other aggravating factors are elevation (<100 m) and slope (<7°). A wide NE-SW-oriented fractured zone is detected within the flat area extending between Mount-Cameroon and Limbe-Mabeta Massif. Furthermore, several new fractured zones are highlighted, and will be considered when elaborating policy of local water management. This low-cost and time-saving approach which combines remote sensing and GIS has been effective, and recommended for similar investigations worldwide. A geophysical campaign with the purpose of characterizing local aquifer and upgrade hydrological, geological and electrical parameters of the local aquifer is scheduled.