Analysis of the Flood Performance of Stormwater Drainage Systems for Different Return Periods

Precipitation regimes and behaviours change depending on the climate change. As the duration of precipitation decreases its intensity increases. On the other hand, the density of buildings increases in urban areas, and drainage systems remain inadequate as a result of deterioration in the structure of natural streams and irregular structures. Due to the change in precipitation behaviour and the decrease in permeable surfaces in urban areas, urban floods lead to serious damage. In this study, it is aimed to analyse the flood performance of rainwater drainage systems currently serving in urban areas for precipitation with different repetition periods. For this purpose, the drainage line in Malatya provincial centre has been selected as the pilot application area. Considering the rainfall records observed in the past, a model was created for 15 minutes of precipitation and 2, 5 and 10 years repetition periods. In addition, the digital elevation model, drainage line and characteristic information and building layouts were taken into consideration in the application area. As a result of the analysis, flood spread maps were created. It has been observed that as the repetition period increases, the rainwater drainage line is insufficient in some areas and may cause loss of property and life.