Rehabilitation of a water distribution system with diffused water losses

In this paper a rehabilitation plan for the water distribution system (WDS) of the small town of Fondi, located 100 km south of Rome (Italy), is presented. In particular the most concerning problem of this WDS is the high level of leakages, which are estimated to more than 60% of the supplied water volume. Due to the old age and very bad conditions of the pipes, the leakages are uniformly spread all over the network. For this reason the most effective strategy to reduce water losses can be only the renovation of the network. In particular the rehabilitation plan provides where to intervene (which pipes), how (pipe substitution with a defined diameter) and when (at a fixed moment in a time horizon). The optimal scheduling is achieved by means of the multi objective genetic algorithm NSGAII aimed to minimize the water losses and the costs of the interventions, and the pressure distribution variance. The applied methodology uses a 'pressure driven' hydraulic model of the WDS, which considers the leakages and locates them. The model calibration is carried out using a genetic algorithm (GA). © 2009 WIT Press.