Optimal Maintenance Policy and Fund Allocation in Water Distribution Networks

In maintenance of a water distribution network, the allocation of limited funds for maintenance among a networkʹs pipes and the decision to repair or replace a single pipe when failure occurs are the most important issues. Although some researchers in the past have addressed these issues, more work is needed to support water authorities in making maintenance decisions. In this research paper, a mathematical model is developed that aims to support the decision to allocate funds among pipes of the network as well as the decision to repair or replace the pipes in the state of failure. The objective function of the model is to maximize the total weighted long-run availability of the whole system. The concept of hydraulic reliability is employed to determine the weight of pipes in the maintenance program. The deterioration behavior of the pipe is depicted by a semiMarkov process, and the Dantzig-Wolfe decomposition algorithm is applied to deal with the large-scale characteristic of the resulting program.