Coastal Flooding Hazard Related to Swell Events in Cartagena de Indias, Colombia

In the city of Cartagena de Indias, the urban areas of Bocagrande and Castillogrande were built over large sandbars and are extremely sensitive to the risk of coastal flooding during storm surges. However, the risk of flooding is not directly related to local meteorological conditions, but results essentially from hydrodynamic phenomena due to the arrival of heavy swell from far away. A statistical study based on hourly sea-level observations from 1950 to 2000 showed the existence of overflow levels of 0.29, 0.34, and 0.37 m corresponding to return periods of 10, 50, and 100 years. Numerical modeling of overflows was performed from a reanalysis of atmospheric pressure as well as wind and wave data sets produced by the National Oceanic and Atmospheric Administration. The models used were ADCIRC (R) for the simulation of tides and wind setup, SWANS (R) for the simulation of wave setup, and pCOULWAVe (R) for wave run-up estimation. Coastal flooding that affected the city in January 2010 was validated using a HORUS (R) video monitoring system. Simulations were conducted on expected extreme sea levels during the 21st century. Flooding simulations were performed using both a light detection and ranging high-resolution digital elevation model and a water propagation model based on a recursive algorithm. Results showed the extreme vulnerability of Bocagrande and Castillogrande areas facing the risk of submersion. They raise questions for future risks of flooding taking into account the rates of sea-level rise as well as the effects of wave erosion.