To address water shortages, Libya has undertaken one of the most significant global civil infrastructure projects, the Great Man-Made River Project, aimed at transporting groundwater from southern well-fields to densely populated northern cities. The second phase of the project consisted of installing the water supply system, which comprises 479 well pumps, united to deliver around 2 million cubic meters of water to the north. Historical performance data for the water supply system were analyzed, and a model for the system’s reliability calculation was developed: a finite-source, multi-server queuing system with spares (M/M/c//N/Y). The model enabled the analytical calculation of the system’s reliability in different configurations. Each configuration was assessed using a unique risk score, defined as the product of reliability-based parameters and the consequences associated with water-shortage events resulting from system failures. The analysis identified two alternative configurations that satisfy all predefined performance and risk criteria. Both configurations require fewer resources than the original system design, with up to seven fewer spare pumps, allowing for decision-makers to select the most appropriate option based on additional operational and contextual considerations.
Al-Sifao et al. (Thu,) studied this question.