Water from the desert: Minimizing costs of meeting Libya's water demands

Libya has two choices for meeting its water demands: the Mediterranean Sea and groundwater for the Sahara Desert. We performed two studies supporting Libya's decision regarding further investments in desalination and in groundwater pumping and conveyance system. We used static and dynamic mixed-integer optimization models to identify least-cost combinations of investments in infrastructure that would meet specified water demands at specified sites. Desalination does not appear to be an economically efficient alternative to the groundwater system, called the ‘Great Man-made River Project’ (GMRP). Results from the static models showed that as water demands increase, various new GMRP components are needed, then get replaced by other new units, and then, under higher demands, are needed again. This demonstrated the need for dynamic capacity-expansion-planning models. The results of both studies are contributing to the Great Man-made River Authority's decision making.