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 lack of proper management of natural resources, accompanied with 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 climatic changes in the watershed such that the socio-economic revenue is maximized. 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 incorporates an assessment of the existing data and future needs, a GIS framework to facilitate processing and visualization, mathematical models of surface water and groundwater a planning model to evaluate the economic ramifications for different management options, and a multi-criteria decision analysis module.