Climate change may increase the frequency and intensity of extreme rainfall. For better water management in the future, it is essential to identify flood characteristics. Urban flood modeling is a general way to quantify theirthe impacts of floods on urban catchments.
This research investigated the impact of changes in rainfall intensity-durationintensity and duration frequency (IDF) curves on flood characteristics in the urban area of Phnom Penh using the SWMM Model. The NSGA-II algorithm was used to auto-calibrate the SWMM model and obtain the parameter settings. The model was calibrated and validated by four rainfall events, and the results indicate the model performance is satisfactory, withthe Nash-Sutcliffe modelmodel's efficiency being between 0.658 toand 0.915.
A temporal decomposition model based on the ANN method was applied to create a monthly maximum next-day rainfall in Ho Chi Minh City and Can Tho from future daily rainfall data provided by five CORDEX models. The IDF curves of 22-, 55-, and 10-year (return period) forIDF curves over the historical period (1986-2005)between 1986-2005 in Phnom Penh City were regressed using the weighted average of sub-daily rainfall in Ho Chi Minh and Can Tho forin a given return period. This operation was also used to construct IDF curves for thea future period (2026-2045) based on regional climate model outputs. The alternating block method was used for generatingto generate a 7-hour time series and input toin the SWMM model.