Water, Water Everywhere: Meeting the Demands of Saudi Arabia’s Water Needs

The objective of this paper is to introduce models to determine an effective, feasible, and cost-efficient strategy for Saudi Arabia’s water supply system to meet its projected demand in 2025. This paper uses cost minimizing and production maximizing approaches to build the models. The water management system is divided into three processes–desalination, distribution, and wastewater treatment. For desalination and wastewater treatment aspects of the water supply, we use a Cobb-Douglas production maximization model. The model determines the optimal levels of different inputs that maximize the production of usable water, given the Saudi Arabia government’s budget constraints. For the water distribution model, a cost function is minimized with the 2025 water demand constraint and is used to determine the optimal diameter of the pipes and hydraulic head. Using the desalination process model, the paper found that the optimal level of input of electricity is 4.9 billion kWh and the maximized water output is estimated at 3.3 billion m3. In addition, using the wastewater treatment model, the paper found that the optimal level of electricity input is 26.5 billion kWh annually and the maximized level of water production is 7.7 billion m3. The water distribution model estimates that, given the 2025 water demand in Saudi Arabia, the set-up and operating cost of the water distribution grid is approximately $68.88 million. The model also estimates that a minimum pipe diameter of 5.37 m and hydraulic head of 1186.14 m is required to meet the demand of three sectors–agriculture, industry, and domestic.