Groundwater Basin Summaries
Yarmouk Basin

Well AD3036, in the northern part of the basin shows construction characteristics for a typical well completed in the Amman-Wadi Sir aquifer system. The 546-m deep well withdraws water from limestone between depths of 440 and 546 m, with a water level of about 364 m, and an average yield of about 15 L/s.

• The Basalt system of geologic unit Ba;
• The Riijam system, consisting of limestone in the upper part of geologic unit Ks;
• The Amman-Wadi Sir system, consisting of limestone and chert of geologic unit Ks; and
• The lower complex, consisting of sand- stone, limestone, and dolomite of geologic units Kk, Ja, and TRP.

Groundwater levels in parts of the basin have shown a long-term decline in response to pumpage-levels in well AD1148 declined about 10 m during 1974-95. Because recharge to the basin is about 40 MCM/yr and current ground-water pumpage is about 60-70 MCM/yr, there is a net deficit that results in water-level declines in wells.

The Amman-Wadi Sir system is the principal aquifer, with lesser amounts of freshwater available from the other systems. Groundwater levels vary greatly in the Yarmouk Basin, ranging from 12 m below land surface near the Yarmouk River, where aquifers are under water-table conditions, to 400 m near Irbid, where the aquifers are confined.

The quality of groundwater in the Yarmouk Basin is variable--dissolved solids concentrations range from 300-500 mg/L where aquifers are under water-table conditions, to 550-1,660 mg/L where aquifers are confined.