Study rainfall intensity duration frequency relationships under climate change for design of efficient urban stormwater drainage systems in Dodola town, Ethiopia

The variability in rainfall intensity caused by climate change has an impact on the efficiency of urban stormwater drainage systems. Therefore, this study presents the relationships between rainfall intensity and climate change using the global climate models MIROC-ESM, HadGEM2-ES, and CanESM2 under two representative concentration pathway scenarios (RCP4.5 and RCP8.5). The future projected daily rainfall was extracted and bias-corrected using the python scripts. The results show that the highest intensity of rainfall for a 100-year recurrence period in a 5-minute duration is 201.2 mm/hr. The relative difference between the RCP4.5 climate change scenario and historic rainfall ranges between 25.1% and 36.3% for the 2030s, 3.0% and 81.4% for 2050s, and 1.5% and 58.6% for 2080s, respectively. Similarly, the difference between the climate change scenario and historic rainfall for the 2030s ranged from 13.9% to 49.8%, with an average value of around 25.1% in the case of RCP8.5. As a result, the investigation of rainfall intensity relationships due to climate change will be used to design efficient drainage systems.