Extreme Events Assessment Methodology Coupling Rainfall and Tidal Levels in the Coastal Flood Plain of the Sao Paulo North Coast (Brazil) for Engineering Projects Purposes

The North Coastal Region of the State of São Paulo, which comprises the Municipalities of Caraguatatuba, São Sebastião, Ilhabela and Ubatuba, is one of the most prone to flooding Brazilian areas, owing to hydrological extreme rainfall events usually coupled with extreme tidal levels. This risk is also high due to human lives and material assets, with increasing population rates and the settling of large Companies such as the Oil industry, with reduced defense measures and works. The catastrophic scenario of the city of Caraguatatuba, in March of 1967, resulted from one of the most serious natural disasters in Brazil, fosters discussions about probabilities of rainfall events and rise in the sea level in coastal areas. Hence, this research is a consequence of this reality. The research presented is founded on an innovative methodology based on the analysis of past data of rainfall stations and tidal stations in the region of the North coastal zone of the State of São Paulo (Brazil). The analysis developed approached the meteorological, hydraulic and statistical knowledge areas. Practical results were used for designing macro-drainage, fluvial and maritime projects, that associate the probability of occurrence of certain types of rainfall coupled with their corresponding increase in tidal level