Robust Multi-Objective Optimization of Water Distribution Systems

The purpose of a water distribution network is to supply the required water at sufficient pressures. Water requirement/demand at the nodes is uncertain and can vary erratically. The network design should be able to meet this variation in demand. In addition to this variation in demand, the network should also be resilient to failure. When there is some leakage in a pipe, the network should have surplus energy to meet the required pressure demands at nodes. A new methodology is proposed for the multi-objective combinatorial and discrete water distribution network (WDN) design under uncertainty problem. The proposed methodology uses a combination of popular robust-counterpart (RC) techniques to handle the uncertainty and a meta-heuristic named multi-objective cuckoo search algorithm to handle the discrete combinatorial search space. The uncertain parameter considered here is the nodal demands. The objectives considered for the problem are minimizing construction cost and maximizing resilience index. The proposed methodology is applied to the Hanoi water distribution network. The obtained designs are compared with the standard designs obtained without considering uncertainty. Furthermore, the effect of variation in the uncertainty set of the demands is also reported and discussed.