EFFECTS OF STORM SURGE ON WATER LEVELS OF THE LAGOON SYSTEM OF JACAREPAGUÁ – RIO DE JANEIRO, BRAZIL

The Lagoon System of Jacarepagua is the most vulnerable coastal area of Brazil due to its high population density and important economic activities. Severe meteorological conditions due to climate changes are more likely to affect the lagoon system in the future, increasing the exposure of the area and the probability of flooding of the low-lying surrounding areas. To determine the vulnerability of the area to diverse agents, this work addressed the impact of different combinations of sea level rise, heavy rainfall and storm surges. The study cases considered two different bathymetry conditions, the actual silting bathymetry, and the resulting bathymetry after a planned dredging project. Tidal prism, the maximum water elevations and the time of occurrence were analyzed. The main results showed that storm surge has the most impact on the maximum water elevations, overcoming the impact of an increase in the sea level, river flow and changes in bathymetry. The results of time lags comparing the time of occurrence of maximum elevation recorded at the open sea and the time of occurrence of maximum elevation on the north margin, the most populated area, of the lagoon system showed a time lag of 13-17h. The benefits of the planned dredging project would be mostly to allow a better water renovation in the lagoons, due to a higher tidal prism.