Decomposition approach for background leakage assessment: BBLAWN instance
This paper summarizes an approach for the assessment and control of background leakage on water distribution networks. The methodology was developed for the battle of background leakage assessment for water networks (BBLAWN) held at the Water Distribution System Analysis Conference 2014 in Bari, Italy. The problem instance posed for the conference considers an aging water network with high levels of background leakage. A range of operational and design changes including new valves, pipes, pumps, tanks, and controls are available to reduce the expenditure needed to operate the system. Constraints are imposed on nodal pressures and tank levels to meet service level requirements. The solution methodology proposed in this paper decomposes the problem according to the type of intervention, considering each type separately. An initial diagnosis of the network informs the manner and order of evaluating the various interventions. Custom implementations of network simulation, heuristic algorithms, and optimization models are used to identify improvements. The recommended program of network modifications reduced the annual cost of running the system from €4 million to €1.5 million and had a return on investment in network infrastructure of 430%.