Evaluation of water resources alternatives in saudi arabia in multi-objective framework

In the last two decades, remarkable progress has been made in in the Kingdom of Saudi Arabia in exploiting groundwater resources, development of surface water resources and desalination of seawater and brackish water. Such developments were essential to meet growing demands of water in municipal, industrial, and agricultural sectors. For example, the per capita demand in municipal sector has increased from 165 liters per capita per day (l/c/d) in 1965 to above 400 l/c/d in 1989. Smilarly the agricultural water requirement has increase by manifolds in the last ten years due to implementation of large scale agricultural schemes in areas with high potential of groundwater resources. This paper presents an overview of various water resources developmentoptions such as groundwater, surface water desalination, interbasinwater transfer, use of treated waste effluents, and irrigation return flow in the Kingdom of Saudi Arabia. Cost-capacity models are developed for each alternative. Using both quantitative and qualitative statistics of each option, the cost minimization function in terms of allocated capacities is developed for a selected region in the Kingdom and the constraints on demand, supply, and quality are also defined. Considering various scenarios of water conservation options, the optimum plan for allocation and development of each option is formulated.