Optimal Operation of Water Distribution Systems Under Uncertainty

The goal of water distribution systems (WDS) is to supply water to consumers subject to different constraints such as demand satisfaction, water quality, pressure boundaries, etc. The operation of WDS is an energy-intensive process that is subject to many constraints. Thus, operating WDS such that all constraints are satisfied while energy costs are minimized is a highly complex problem. While many studies tackled the WDS optimal operation problem, almost all of them used deterministic approaches where all the problem parameters were assumed to be known. Recently, there is a growing interest in decision making under uncertainty. Global trends such as urbanization, growing population, and environmental crisis, require that operational decisions will be robust as possible while decision making is getting more complex. WDS is an example of a critical infrastructure that needs to be operated under uncertainty. This paper presents two approaches to optimize the operation of WDS under uncertainty. A stochastic approach based on chance constraint optimization and a non-stochastic approach based on robust optimization. The paper explores different types of uncertainties that have not been studied before and also combinations of multiple uncertainties factors. A case study network is used to compare the methods, and to analyze the trade-offs between robustness, optimality, and tractability, all towards suggesting guidelines on when and how to use the different methods for WDS optimal operation under uncertainty.