Integration of paleotempestology with coastal risk and vulnerability assessment: case studies from the Dominican Republic and Nicaragua

Hurricanes account for a significant portion of damages, injuries, and fatalities in the Caribbean. The Dominican Republic has had 3 major hurricane strikes in this century resulting in loss of lives for thousands of people and billions of US $ in economic loss. Major hurricanes had been relatively infrequent in north-eastern Nicaragua’s modern history until Hurricane Felix, a Category 5 storm, made landfall in the north-east in 2007. It caused 130 confirmed deaths and brought devastation to many villages. These events highlight a need for re-evaluation of hurricane risk based on a more comprehensive and long-term hurricane history. Using paleotempestological methods, paleo- hurricane history of this region, going back 7,455 years in Nicaragua and 3,640 years in the Dominican Republic, was reconstructed. To achieve this, 27 cores of sediment from 4 coastal sites in the north-eastern part of Nicaragua and 5 sites on the coast of the Dominican Republic were collected. Presence of sand layers in a mainly lacustrine environment, were used as proxies to identify past storm events. Radiocarbon dating, 137Cs, and 210Pb analysis was used to establish chronology. Data from Nicaragua indicate a shift in the hazard regime occurring on a millennial scale - a high activity period in the last 950 years preceded by a low activity period between 950 - 3,350 BP. Using the average return period of hurricane landfall derived from prehistoric and historic data, Poisson probability of strikes was computed for all coastal provinces and municipalities in the study areas. Results reveal a redistributed likelihood of strike for the coastal areas. Vulnerability of coastal areas was determined using indicators and spatially represented. A hazard analysis was conducted by creating storm surge and wind speed models in ArcGIS. Ultimately, the probability information was combined with vulnerability and hazards data resulting in a comprehensive, spatial risk model for the case studies. Jurisdictions containing the seats of government for the Dominican Republic and RAAN face the highest risk