If pipes are damaged in a water distribution network (WDN), adjacent valves are closed to isolate the pipes for repair. Due to the closed valves, parts of WDN are isolated from water supply sources. The isolated area is divided into Intended Isolation Area (IIA) and Unintended Isolation Area (UIA). The IIA occurs by intention to isolate the damaged pipe, while UIA is unintentionally disconnected from the sources due to IIA. Thus, the extension of isolated area and suspended flows are mainly affected by number and location of installed valves in WDN. In this study, optimization models were developed to determine optimal valve locations in WDN. In a single-objective model, total water supply suspension is minimized, while a multi-objective model intends to simultaneously minimize the suspended flow and valve installation cost. Optimal valve placement results obtained from both models were compared and analyzed using a sample application network.

1. Alvisi, S., and Franchini, M. (2014). “A Heuristic procedure for the automatic creation of district metered areas in water distribution systems.” Journal of Water Resources Planning and Management, Vol. 133, No. 2, pp. 145-155.  

2. Alvisi S., Creaco, E., and Franchini, M. (2011). “Segment identification in water distribution systems.” Urban Water Journal, Vol. 8, No. 4, pp. 203-217.  

3. Creaco, E., Franchini, M., and Alvisi, S. (2010). “Optimal placement of isolation valves in water distribution systems based on valve cost and weighted average demand shortfall.” Water Resources Management, Vol. 24, No. 15, pp. 4317-4338.  

4. Giustolisi, O., and Savic, D. (2010). “Identification of segments and optimal isolation valve system design in water distribution networks.” Urban Water Journal, Vol. 7, No. 1, pp. 1-15.  

5. Jun, H. (2005). “Isolating subsystems by valves in a water distribution system and evaluating the system performance.” Journal of Korea Water Resources Association, Vol. 38, No. 7, pp. 585-593.  

6. Jun, H. (2006). “An evaluation of the pipe failure impact in a water distribution system considering subsystem isolation.” Journal of Korea Water Resources Association, Vol. 39, No. 2, pp. 89-98.  

7. Li, P., and Kao, J. J. (2008). “Segment-based vulnerability analysis system for a water distribution network.” Civil Engineering and Environmental Systems, Vol. 25, No. 1, pp. 41-58.  

8. Walski, T. M. (1993). “Water distribution valve topology for reliability analysis.” Reliability engineering & system safety, Vol. 42, No. 1, pp. 21-27.  

9. Yoo, D., Kim, K., Park, M., and Joo, J. (2017). “Multi-objective optimal design for improving water supply serviceability considering segments in water distribution networks.” Journal of the Korean Society of Hazard Mitigation, Vol. 17, No. 2, pp. 29-37.