Rainfall Floods and Their Influence on Sustainable Development in the Western Asir Region An applied Climatology Study

Abstract

This study investigates the characteristics of rainfall and flooding in the western Asir region, known for its high precipitation levels, especially in the eastern areas. It focuses on analyzing rainfall losses due to evaporation and infiltration to assess the temporal and spatial patterns of water surplus and deficit. Rainfall distribution is influenced by several factors, including the region’s geomorphological and morphological features. To accurately evaluate rainfall and water losses, the area has been divided into seven drainage basins. This division facilitates the identification of flood-prone zones, allows for classification based on risk levels, and supports assessments of impacts on urban development, transportation infrastructure, and agricultural activities. The study utilizes climate data from five meteorological stations—Abha, Al-Souda, Al-Namas, Mahayil, and Al-Majardah—spanning the years 1985 to 2019. Results show that rainfall is most effective in Al-Namas, Al-Souda, and Abha, while Mahayil and Al-Majardah, particularly Al-Birk and the eastern fringes of both, record the lowest effectiveness. The total surface runoff across the seven basins is estimated at around 27,153 million cubic meters. Among them, Wadi Nakb has the highest net runoff, approximately 3,750 million cubic meters, whereas Wadi Hali has the lowest, with about 393.7 million cubic meters. These findings highlight the critical importance of understanding rainfall and flood dynamics to support sustainable development and minimize risk across the region.