Quantitative Groundwater Resources Evaluation in the Lower Part of Yalamlam Basin, Makkah Al Mukarramah, Western Saudi Arabia

The search for and the development of new water resources in Makkah Al Mukarramah area are considered among the top priorities for the Saudi government as the water consumption is rising with time. Wadi Yalamlam is located 70 km south of Makkah. It drains a large catchment area of 1,600 km2, which is characterized by a high rate of annual rainfall of more than 200 mm. Perennial streams flow along the main channel of the wadi most of the year. This research is aimed to study the water resources in the lower part of Wadi Yalamlam as additional strategic future water supply to Makkah city. The research includes hydrological, hydrogeological and geophysical investigations for determining the potential areas for fresh water sources. It is also concerned with the determination of the geometrical size and the hydraulic properties of the groundwater aquifer in Wadi Yalamlam in order to determine the available water reserves. The study indicates the possibility of drilling 14 water wells for producing a renewable amount of 7500 m3/day to supply Makkah area, in addition to 9x106 m3 reserves in this basin.