Every year, various parts of the Kingdom are exposed to the risk of floods due to the flow of rainwater into dry valleys. Often, water overflows from the valleys and submerges the streets and roads in some cases due to the intersection of the valleys with cities due to the absence of clear boundaries for the sanctuaries of those valleys as well as urban areas. Some major cities in the Kingdom, such as Riyadh, Al-Kharj, Jeddah, Makkah Al-Mukarramah, and others, witnessed exceptional rainstorms that led to torrential rains and the accumulation of rainwater in some neighborhoods, causing the loss of lives and property. The floods that swept the city of Jeddah in 2009 and 2011 are considered landmark events in this field. Through the responsibility assigned to the Saudi Geological Survey to review and approve all hydrological studies for various development projects throughout the Kingdom. On this basis, the Saudi Geological Survey is making intensive efforts to unify the foundations and standards and draw up methodologies on the basis of which hydrological studies are conducted for development and urban development projects, with the aim of preserving the paths of the valleys and their sanctuaries as a safe passage for torrents and to control torrential torrents and avoid the damage resulting from them.
