Rain Induced Flash Floods, A Case Study of 2022 Floods in Pakistan

Pakistan is an agricultural country with more than 75% population directly or indirectly affiliated with this field. In the recent past, floods have devastated the country almost every other year, with low reservoir storage capacity and climate change being the most critical contributing factors. In 2022, the climate change-affected unprecedented rainfalls all over the country surpassed the drainage basin capacity by a great margin, resulting in water accumulation over the entire cropland in the south and generating flash flood conditions in the north. According to the National Disaster Management Authority (NDMA), the 2022 flood has claimed at least 1,033 lives, displaced 50 million people, and caused economic loss exceeding 10 billion dollars. This study covers the assessment of the flood extent based on the real-time rainfall data for 2022 floods, identifies the factors contributing to the flood, and provides recommendations to address the impact of flooding in the future. A change detection approach is used to create flood mapping using Sentinel-1 synthetic aperture radar (SAR) images available in the Google Earth Engine (GEE) catalog. Additional datasets in GEE were intersected with the derived flood extent layer in order to estimate the number of potentially exposed people, affected cropland, urban areas, and elevations in affected areas. A comparison with the real-time affected areas shows a promising accuracy. This will help facilitate the damage assessment, rehabilitation measures, and future planning for disaster mitigation.