A Heuristic for Strategic Valve Placement

An iterative heuristic is proposed to improve the distribution of isolation valves within an existing water distribution network to decrease the magnitude of service interruptions while using the minimum number of valves required to isolate any individual segment within the system. The method takes advantage of graph theory concepts to create a valve augmentation scheme that provides gradual upgrades using the minimum number of new isolation valves at each step. The developed algorithm seeks to provide a tradeoff between an increase in the number of isolation valves and a reduction in water shortages resulting from disconnected pipe segments. The approach is applied to an actual water distribution network with known existing valve locations. The results demonstrate the feasibility and utility of the procedure for multiple operational constraints (i.e., maximum number of valves per segment, or maximum allowable water shortage evaluated over all segments). By use of an incremental performance target set by the user, the algorithm can prove beneficial even for utilities with limited financial resources.