Tidal flood area mapping fronts the climate change scenarios: case study in a tropical estuary of Brazilian semiarid

Abstract. Previous studies on tidal flood mapping are mostly with continental and/or global scale approaches. Besides, the few works on local scale perception are concentrated in Europe, Asia, and North America. Here we present a case study approaching a flood risk mapping methodology against climate change scenarios in a region with a strong environmental and social appeal. The study site is an estuarine cut in the Brazilian semi-arid, covering part of two state conservation units, which has been in recent years suffering severe consequences from flooding by tides. In this case study, high geodetic precision data (LiDAR DEM), together with robust tidal return period statistics and data from current sea level rise scenarios were used. We found that approximately 118.26 km² of the estuary understudy is at high risk, extremely high risk and urgently in need of mitigation measures. This case study can serve as a basis for future management actions as well as a model for applying risk mapping in other coastal areas.