The Zarqa River Basin extends from the Syrian border in northern Jordan to south of Amman and westward to the eastern slopes of Jordan Rift Valley and covers an area of 3739 km2 . The basin represents a transitional area between the semi-arid high lands in the west to the dry desert in the east. Annual rainfall ranges from more than 500 mm to less than 100 mm with a mean annual rainfall of 262 mm. The climate is semi-arid Mediterranean, and the mean annual temperature varies from 14.5 oC in the west to almost 18 oC in the southeast.
The Zarqa River basin is a highly populated area where more than 50% of Jordan population (2.7 million inhabitants) is concentrated. The major consumption of municipal water take place in the areas of Greater Amman and Zarqa. The rapid increase of population growth has led to over utilization of water resources. More than 30% of irrigated land exist within Zarqa River Basin where the main crops cultivated include vegetables, fruit trees and greenhouse crops. As a result, surface water in the basin is primarily used for irrigation purposes. The important role of agricultural sector is reflected in its contribution to Gross Domestic Product (GDP), and the employment of labor force. It is noteworthy that the average contribution of agricultural sector to GDP is 10%. Industrial activity is also intense in the area consuming 23% of the total available water resources of the Zarqa river basin including surface and groundwater resources. Chemical, textile and tanning are the main industries in the area. As a result, industrial waste disposal sites are pollution sources threatening both surface and groundwater quality.