Analysing the Cause of Urban Pluvial Flooding in a Hillside Settlement

Pluvial flood risk is increasing in urban and rural areas due to changes in precipitation patterns and urbanization. Pluvial flooding is often associated with insufficient capacities of the sewer system or low drainage efficiency of urban areas. In hilly areas hillside runoff additionally affects the risk of pluvial flooding. In the presented case study the cause of pluvial flooding at two selected sites in a settlement is investigated. To investigate all effects of pluvial flooding a coupled 1D-2D model of the whole catchment of the settlement is necessary. The results show that even though bottlenecks in the sewer system are important the effect of low drainage efficiency and hillside runoff greatly influence pluvial flooding. The knowledge of different causes of flooding can be further used for selecting and positioning appropriate adaption measures.