Sentinel‐1 remote sensing data and Hydrologic Engineering Centres River Analysis System two‐dimensional integration for flash flood detection and modelling in New Cairo City, Egypt

Digital surface models, land use and rainfall data were used to simulate water areas using Hydrologic Engineering Centres River Analysis System (HEC-RAS) software. Multi-temporal synthetic aperture radar (SAR) was for the detection of flood prone area calibrate HEC-RAS, due lack validation in New Cairo City, Egypt. The thresholding method applied two Sentinel-1 images, one pre- post-flash event from April 24 27, 2018. threshold detect SAR images. Feature statistical agreement F1 F2 values ranged 73.4 77.7% between extracted based on backscattering 19.97 16.53 decibels (dB) reference obtained an optical image Sentinel-2 satellite. similarity simulated HEC-RAS two-dimensional (2D) 74.2 89.7% feature F2. It provides a clear suggestion that, absence field observations, can be model. Two hazard maps created velocity depth 2D simulation. indicated that 11% roads 50% buildings City are exposed high areas. Furthermore, 28% bare is situated very vulnerability area. We recommend map supporting emergency response, designing effective plans.