Assessment of the impact of the rise in Lake Victoria water levels on urban flooding using a GIS-based spatial flood modelling approach

During the period 2018-2021, Lake Victoria experienced a rapid rise in water levels that caused significant urban flooding consequences. However, there are no studies that have extensively investigated the effect of the rising lake water levels on urban flooding. This research responds to this by developing and applying a GIS-based spatial flood modelling approach to simulate the resulting flooding impacts in Entebbe City, Uganda, corresponding to the May 2021 observed maximum lake water level of 13.49 m. Using the validated GIS-based flood model, the simulated flooded area and average flood depth were determined as 9.1 km2 and 1.52 m, respectively. Furthermore, through application of GIS overlay analysis, the total number of affected buildings and length of urban roads were quantified. The proposed methodology provides a robust and computationally efficient approach for identification of at-risk buildings along the lake shoreline and for testing the effectiveness of potential adaptation strategies.