The coastal aquifer of Israel serves as one of the main water resources. It extends from Mount Carmel in the north to the Gaza Strip in the south, bounded in the west by the Mediterranean sea and in the east by mountainous formations. The average natural recharge to the aquifer is around 270 MCM/Y. It consists basically of alterations of calcareos sandstones and eolinites with clay and loam intercalations which subdivide the aquifer to four subaquifers. The aquifer is subjected to salination by seawater encroacment from the west while salination occurs also in its eastern margins through lateral flow of brackish water from eastern aquitards. In addition, the aquifer is contaminated by downward flowing pollutants related to anthropogenic domestic, industrial and agricultural activity.
Due to the contineous deterioration of the water quality and the resultant onging shortage of high quality water for domesic use and agriculture, a new operational and water management policy was determined. It includes a reduce of seawater encroachment from the west, and active prevention of the flow from the aquitards in the east.
The southern part of the coastal aquifer is defined as the major operative storage for the national water system as well as for local consumers. As such, maintaining its quality is especially important. However, this part is threatened by over-exploitation, and successive drought years , resulting in reduction of the storage and depletion of groundwater levels. In addition, inflow of brakish water from an aquitard along its eastern boundary, as well intensive irrigation with treated sewage water affect its quality.
In order to minimize the salination processes and allow replenishment of the storage, a rehabilitation program has been established, introducing the concept of brackish water desalination as the basic outline for rehabilitation. The two main components of this plan are:
1. "The Eastern Interceptor", a battery of 33 production wells located along the eastern zone of the aquifer pumping 35 MCM/Y of water with salinities of 500 to 800 mg Cl/L, as raw water for desalination. This prevents the entrance of 30,000-35,000 tons of chloride per year into the western part of the southern coastal aquifer. The 30 MCM/Y of desalinated fresh water are delivered to the supply system, and the residual brine of 5 MCM/Y, are delivered to the Mediterranean Sea.
2. A balanced pumping in the western part of the aquifer, based on the annual recharge rate. This is intended to prevent the seawater from advancing to the east and salination of the aquifer.