Bias-corrected climate projections for intensity-duration-frequency (IDF) curve under uncertainty in Egypt

Intensity-duration-frequency (IDF) curves are essential for designing stormwater and flood mitigation systems. However, traditional IDF curves may no longer be reliable due to climate change. This study aims to assess the impact of climate change uncertainty on IDF curves for the entire of Egypt. Due to the significant lack of rainfall data in Egypt, historical rainfall data from three sources – GPM, PDIR, and Tutiempo – were collected and assessed for consistency using observed rainfall data. The Tutiempo dataset was to be the most reliable and was used as a reference for climate model evaluation based on statistical comparison. Eighteen climate models under RCP4.5 and RCP8.5 were downloaded and bias-corrected for 21 stations in Egypt. Rainfall analysis was achieved for the historical and future projected climate datasets. The results indicate a decline in annual maximum daily rainfall depths across all regions in Egypt for return periods of 100, 50, 10, and 5 years, with reductions ranging from 2% in coastal areas to 85% in the southwest desert. IDF curves for 21 rainfall stations in Egypt were created, including the uncertainty in climate change models, which offer decision-makers adaptable tools for planning and engineering applications.