Landslide hazard data for watershed management and development planning, St. Lucia, West indies

ABSTRACT

Increasing annual losses resulting from landslides and associated hazards have prompted many island island goverments in the Eastern Caribbean to recognise the need to incorporate landslides hazrad data as an integrated component in watershed management programs and development planning. To be effectively used, however such data must not only be based on sound scientific principles but must olso communicate the technical information in a manner that is easily understood and interpreted by those potential users who are not landslide specialists. The paper describes the main features of a landslide hazard information package which was prepared for several watersheds in St. Lucia, West indies, primarily for use in the management of the islands' watersheds. The data set consists of a suite of three annotated maps, at 125000 scale, and a companion guidance document. The map database contains an updated landslide inventary map, a debris flow hazard map and a map of primary areas of debris flow initiation and existing and potential debris flow runout regions. Each map contains a detailed legend and explanatory text on the appropriate use of the map and map limitations. The guidance document provides recommendations on land use feasibility in zones of varying debris flow stability. Incorporation of the hazard data into proposed watershed management programs should lead to major reductions in the potential economic and social losses associated with debris flows. (AU)