Application of PCSWMM for assessing the impacts of urbanization and climate changes on the efficiency of stormwater drainage systems in managing urban flooding in Robe town, Ethiopia

Study region: This study was conducted in Robe town, Ethiopia.Study focus: In this, the PCSWMM was used to investigate the potential effects of climate change and land-use change on the peak flow magnitude and efficiency of stormwater drainage systems in managing urban flooding. Four simulation scenarios were developed to demonstrate the changes in the flooding volume and adequacy of existing systems. Moreover, the effectiveness of three low-impact developments: rain barrels, rain gardens, and a combination of both practices as a mitigation strategy in reducing flooding volume were investigated.New hydrological insights for region: The trend of landuse change showed that the increased peak flow and flooding volume of junctions increased from 45.13 to 68.72 m3/s and 35,418-50,106 x 106 Ltr respectively, due to the imperviousness increasing from 10% to 70%. Similarly, in response to climate change, the simulated peak runoff increased by 46.9%, 34.8%, and 37.5% for, RCA4, RACMO22T, and REMO2009, respectively. This findings showed that if the current landuse and climate changes continue in the coming years, the study area threatened by the increased flooding due to the drainage systems will fail to accommodate increased peak runoff. The present study suggests the adopted LIDs can be significantly reduced the effects of flooding problems in the town.