Potential Flood Hazard in Wadi Liyah Southwest Saudi Arabia
Mohammed I. Al-Zahrani, Saad G. Al Harthi, Hashim M. Al-Hawsawy, Faisal A. Al-Ammawi, Mohammed S. Theban, Hussam A. Khiyami, and Zekai Șen
Wadi Liyah is located in the southwestern part of the Kingdom of Saudi Arabia running towards the Red Sea coastal lands and ends up to the sea. It is in the Jizan quadrangle bounded by lat 16oN. and 17oN., and long 42o30´E. and 43o30´E., along the Jazan coastal area, which lies about 700 km south of Jeddah. Two different approaches are being suggested in this report to estimate the flood magnitude of Wadi Liyah. The first approach is the control cross-section calculation method. The second approach is the measurement of some physiographic parameters from the catchment’s area to construct a synthetic unit hydrograph. The potential flood hazard in the Kingdom of Saudi Arabia may have adverse effects on urban, industrial, infrastructural, and agricultural areas. This view emerges from the past experiences and therefore, recommends preparation of flood risk maps. Availability of such maps is the key requirement in any urban development including dams, tunnels, highways and bridges for the sustainable future. The completion of these maps would permit the setting up of safety protocols for construction and maintenance in accordance with the sound scientific methods. To maintain this growth and development, a long-term study against hazardous hydrological events is necessary. One of the main objectives of flood calculations is to show the inundation boundaries of each wadi on a digital elevation map (DEM), but because of its unavailability, classical topographic contour maps around representative cross-sections are presented as inundation boundaries.
Al-Zahrani, M.I., Al-Harthi, S.G., Al-Hawsawy, H.M., Al-Ammawi, F.A., Theban, M.S., Khiyami, H.A., and Şen, Z., 2007, Potential flood hazard in Wadi Liyah southwest Saudi Arabia: Saudi Geological Survey Technical Report SGS-TR-2006-2, 37 p., 30 figs. 9 tables, 6 apps.