Coastal-zone hazard maps and recommendations: Eastern Puerto Rico

A series of coastal zone hazard maps cover the area impacted by Hurricane Hugo (1989) in eastern Puerto Rico. The mapping strategy was to develop a tool for quick visualization of multiple hazards for use by coastal planners, managers, property owners, and potential property owners. The Puerto Rico shoreline is heavily developed in places and also highly compartmentalized in terms of shoreline types, geology, and adjacent shelf conditions. Hazards such as coastal erosion, storm surge, riverine flooding, landsliding, and seismic impact also may be compartmentalized. From a management perspective, resources therefore can be allocated on a compartment-by-compartment basis.

Six types of hazards were considered in this investigation: (1) shoreline-setting hazards (long-term coastal problems), (2) marine hazards (short-term impacts of coastal storms), (3) earthquake and slope hazards (ground shaking, landslides, and liquefaction), (4) riverine hazards (historical floods), (5) development hazards (high-density development at risk or lowdensity development in extreme-hazard settings), and (6) engineering hazards (special cases in which shoreline engineering projects such as breakwaters or sand mining have significant detrimental effects on portions of the shoreline). Shoreline segments were ranked as being at extreme, high, moderate, or low risk, depending on the number of hazards present within that segment. These rankings are likely to change, gradually over decades with natural coastal evolution, more rapidly as human development infringes on the coastal zone, or in an instant during a severe storm. The hazard maps provide a basis for hazard mitigation and management recommendations.