Identification of optimal number and location of isolation valves in an urban water distribution network

Urban water distribution networks (UWDNs) are critical infrastructures that provide essential services in an urban setting. Such infrastructures are subject to frequent breakdowns, disrupting services to downstream users. Installation of isolation valves (IVs) at strategic locations can reduce such adverse impacts by isolating small segments of the network and expediting repairs, which in turn contribute to water conservation and leak control. However, determining the optimal number of IVs and their placement is a disturbing question for the researchers. This study proposes a methodology to assess the optimal number of IVs in a UWDN and identify their placement in the best of the worst possible scenarios. Based on the network topology and the associated IV costs, it identifies the optimal numbers and their places to minimize the maximum undeliverable demand. The methodology is illustrated with the help of a small water distribution network. Thereafter, the proposed methodology is applied to a real-type UWDN. The results indicate that the optimal number of IVs for the case study is 10, which should be placed at strategic locations to reduce the maximum undeliverable demand to 18% of the total demand.