The southern section of the Umm er Radhuma- Dammam Aquifer System extends from the Gulf coast in the north and the Oman Mountains in the south-east over about 800 km. It covers a total area of about 680,000 km2, stretching across the vast Rub' al Khali Desert, the Dhofar-Najd Plain in Oman, and the northeastern Hadhramaut-Al Mahra Plateau in Yemen. The aquifer system in this section comprises three Paleogene (Paleocene-Eocene) Formations: the Dammam, the Rus and the Umm er Radhuma, of which the Rus is the least important.
Groundwater flow is generally from the central Arabian Peninsula in the west towards the Gulf coast in the east. Further south and east, flow is mainly north and north-eastward from the Hadhramaut-Dhofar Mountains, and westand south-west from the Oman Mountains. Most of the groundwater entered the system during the pluvial periods between 20,000 and 10,000 years ago, although there are indications of limited present-day recharge through the Oman Mountains and the Hadhramaut-Dhofar Mountains. Natural discharge occurs through springs emanating from the Umm er Radhuma Aquifer along the edge of the Hadhramaut-Al Mahra Plateau escarpment, or in the form of saline to hypersaline waters that form sabkhas in the lowlands.
At present, the only use of this aquifer system takes place in the Dhofar-Najd region in Oman and United Arab Emirates (UAE) where the water is used for agricultural and domestic purposes, and, to a lesser extent, for recreational or industrial purposes such as water injection for the oil industry.
|Riparian Countries||Oman, Saudi Arabia, UAE, Yemen|
|Alternative Names||Umm er Radhuma/Dammam, Hadhramaut Group|
|Renewability||Very low to low (0-20 mm/yr)|
|Hydraulic Linkage with Surface Water||Weak|
|Aquifer Type||Unconfined to confined|
|Lithology||Mainly limestone and dolomite, with some evaporites|
|Thickness||Dammam: 60-490 m
Umm er Radhuma: 50-550 m
|Average Annual Abstraction||Oman: 45 MCM
UAE: 7.7 MCM
|Storage||Najd area: 180-1,100 MCM|
|Water Quality||Fresh to hypersaline|
|Water Use||Agricultural, domestic and oil injection in Oman|