GIS-based landslide hazard mapping in the Scotland District, Barbados

Abstract

Rationale The Scotland District occupies an area of approximately 60 km 2 forming the northeast coastline of Barbados (Fig. 1). The district is geologically and topographically distinct from the rest of Barbados in that the coral limestone cap that covers the remainder of Barbados is absent. The underlying Tertiary rocks exposed in the Scotland District are soft and erodible, and are themselves prone to landsliding and erosion. Land use in the district comprises forest, sugar cane, fruit and vegetable growing and pasture, and the district has high landscape value and eco-tourism potential. Low rise, low density housing has developed over the decades, predominantly along cart tracks and roads with alignments that tend to follow ridge and spur lines in an attempt to avoid potentially unstable side-long ground. However, there are numerous locations where erosion and ground movements have caused significant distress to road pavements, and where foundations to residential buildings have been undermined to the extent that some areas have been abandoned altogether. The Soil Conservation Unit (Ministry of Agriculture and Rural Development) has been tackling slope instability and erosion problems in the district for over half a century. A number of useful projects have been commissioned to examine and remediate areas of known ground instability, and several schemes involving drainage and earthworks have proved successful. However, realizing that there were several geological, topographical, drainage and land use factors distributed throughout the district that had a role to play in the pattern of ground instability and erosion.