Forecasting Trinidad's Evolving Flood Future: A Susceptibility Mapping Approach with Long-Term Rainfall Projections (2010-2100)

Abstract. Global International Panel on Climate Change (IPCC) models highlight increasing incidence and intensity of rainfall events due to climate change in the Caribbean. However, more granular regional models are needed to guide sector-specific actions. This paper addresses this data gap by using recent remotely sensed data and other geographic information system layers to model flood susceptibility for Trinidad from 2010 to 2100. Data came from the Climate Hazards Group InfraRed Precipitation datasets, and IPCC’s mean average rainfall layers (assessed in five-year intervals, generating 19 files). Six layers of elevation, road density, drainage density, land cover and rainfall were integrated into a composite flood susceptibility GIS layer that covered the two main seasons- dry (December to May) and wet (June to November). The composite flood susceptibility layer was subdivided into five classes (very high, high, moderate, low, and very low). Results showed a consistent pattern of high and very high flood susceptibility worsening across both wet and dry seasons, in primarily urban/semi-urban communities. These flooding events, driven primarily by low topography, land cover/land use (urban development decisions), and (inadequate) built drainage infrastructure, will be exacerbated by climate change and short-term weather variations. Policy implications underscore the urgent need for radical mitigation strategies across current flood-prone urban areas in Trinidad, including climate-resilience building designs, redesign of drainage infrastructure, enforceable zoning regulations, community-led warning systems and the design of appropriate adaptation interventions that specifically target these currently flood-prone urban areas.