Sanmi O. Odeyemi^{1, 2,}, Dominic Fontana², Eberechi Ichi³, Ene S. Ajonye¹, Ossai Alu¹

The vulnerability of coaster regions to flooding due to extreme sea level rise and storm surge has become notable since the late 20^th century to date this 21^st century. This vulnerability can be attributed among other things to the global rising sea level due to anthropogenic climate change. A platform is needed to integrate the necessary data to mitigate the impact of flooding and aid plans intended to safeguard these vulnerable regions. Geographic Information Systems (GIS) technique has given that stage by which different bits of past, present, and future information can be incorporated to get spatial-based data, from which areas in danger of unavoidable flood peril can be recognised. This study utilised GIS techniques to develop a spatial flood model of rising sea level scenarios. The expected rising sea level data (RCP 4.5 scenario), LiDAR Digital Elevation Model (DEM), estimated 2011 UK census, and the building & height alpha data were used to estimate the approximate number of buildings that might be exposed to inundation. Also, an estimated number of people that could be affected and land area were obtained. The outcome shows that for 3.11mOD extreme rising sea level value, 1074-unit houses, 2.79km² (6.91%) of the land area were inundated with an estimated population of about 2,000 people. Whereas for the 3.59mOD rising sea level value, 14,500-unit houses, covering 4.63km² (11.5%) of land were immersed, with an estimated population of about 71,500 people. The result also shows, among other places in the city, that an estimated 5,900-unit building and 33,931 people will be impacted in the south, Southsea, and Portsea areas. In comparison, about 5,000 structures and 17,500 people will be affected on the eastern side of Portsea Island. These areas were distinguished as regions possibly in danger of coaster flooding because of storm surges and extremely rising sea levels.

GIS, flooding, global warming, extreme sea level rise and storm surge, spatial modelling, SEEDED-FLOOD