Robust Least-Cost Design of Water Distribution Networks Using Redundancy and Integration-Based Methodologies

Abstract

Two approaches to solving the problem of robust least-cost design of water distribution systems under uncertainty in input parameters are considered. The first approach (redundant design) is based on redundancy in design, where “safety margins” are added to the uncertain parameters and the resulting deterministic optimization problem is then solved. The values of safety margins are determined iteratively. This method requires no changes to the objective function or constraints formulation when used in conjunction with existing deterministic tools. The second approach (integration method) includes within the objective function the influence of uncertainty on system robustness. A fast numerical integration method is used to quantify uncertainties. System robustness is defined here as the probability of simultaneously satisfying minimum pressure head constraints at all nodes in a network. The sources of uncertainty analyzed here are future water consumption (at each node in the network) and hydraulic roughne...