Arid and semi-arid regions are generally characterized by water scarcity and low per
capita water allocation. This situation is further exacerbated when such areas are
agriculturally dominated and encounter a high population growth rate. Faria watershed,
Palestine, is one of these semi-arid regions where the recent prolonged drought periods in
the watershed have negatively affected the existing obtainable surface water and
groundwater resources. This situation has compelled the motivation for developing
optimal water allocation policies that consider the available water resources under the
dramatic climatic changes in the watershed such that the economic revenue is maximized.
Since the available water resources in the watershed have a sustainable-yield limits that
should not be exceeded and owing to the fact that water demand is increasing to fulfill the
agricultural and residential requirements, alternative water resources need to be utilized
including the use of wastewater effluent and brackish water. In addition, possible changes
in land use classes and associated practices impact the water resources availability,
spatially and temporarily. The utilization of wastewater and brackish water though
economically feasible yet leads to the long-term degradation of water resources
accompanied with possible serious harmful health ramifications and the likelihood of
negatively affecting the land productivity especially when dealing with brackish water.
Therefore, decision criteria have to be developed to account for the economic
ramifications, environmental consequences, and water resources availability. This paper
conceptually demonstrates a decision support system to integrate different work plans and
components in order to assess the conjunctive use of the different water resources in the
watershed under different management scenarios driven by climatic changes and land use
planning. The framework involves diverse modules for the development of scenarios and
management options, a GIS technology to facilitate processing and visualization,
mathematical models of surface water and groundwater quantity and quality, an
economic model to evaluate the economic ramifications for different management
options, and a multi-criteria decision analysis module.