Palestine the existence of fresh groundwater overlying saline water in groundwater systems is widespread. Fresh groundwater lenses are a vital water resource where other surface and sub-surface resources of water are not sufficient. Therefore, it is important to understand how to economically extract the maximum amount of fresh water from the aquifer whilst preventing the mixing of both fresh and saline waters. Many part of the West Bank including Jericho suffers from water scarcity, and at the same time from the phenomenon of salt water instruction. Drought and heavy exploitation in the district have led the water table to decline and salt water intrusion and upconing near some of the wells in the area. This is restricting the future utilization of the agricultural land in the area. It is of great importance to the response of the saline movement under a discharge well is required for the safe exploitation of a layer of limited thickness overlaying saline groundwater. This paper provides a better understanding of the saline water movement under a discharge well using the data of some wells in the Jericho area. Sensitivity analyses were carried out on each of the primary design parameters using the finite difference simulation model RASIM. A criterion for the design of the discharge wells in the Jericho district has been established in order to achieve optimal fresh water recovery from these wells.