Fariba Sherri - Department of Environmental Engineering, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran
Amir Hossein Mahvi - Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
Abbas Toloie Eshlaghy - Department of Industrial Management, Faculty of Management and Economic, Science and Research Branch, Islamic Azad University, Tehran, Iran
Amir Hessam Hassani - Department of Environmental Engineering, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran

Water distribution networks (WDNs) are facilities that require massive investment andtheir optimization is very important. This study aimed to optimization and development of models forpromoting WDNs with using engineering judgment. In this method, instead of controlling all system states,it is possible to search the optimal set of options based on engineering judgment and hydraulic and physicalstatus of the system. Thus, the time to solve the optimization problem is greatly reduced, which is veryimportant in widespread networks with many components. The case study was a WDN in western Tehran.Methods: To reduce the calculation size and increase the convergence rate using engineering judgment, theparts of the network where there was no possibility of parallel piping was ignored. For other parts with alow pressure problem, parallel piping was defined. A FMGA and WaterGEMS hydraulic software were usedto optimize the WDN. Cost minimization and pressure benefit maximization were the objective functionsand the diameters of the pipes were considered to be the decision variables.Results: The results of optimization the network showed that, the cost decreased 89.84% and the pressurein all nodes, except one node, reached within the standard range (26-60 mH20). It included 2387 m of pipewith diameters of 100, 150, 200, 250, 350, 400 and 500 mm.Conclusion: The results of optimization and modification of the network using engineering judgmentconfirm that the cost decreased significantly and the pressure level in all the nodes increased to above theallowable minimum pressure.

Water, Judgment, Software, Pressure, Engineering