A Water Distribution System Model to Simulate Critical Scenarios by Considering Both Leakage and Pressure Dependent Demands

To simulate the behavior of water distribution networks under any supply pressure conditions it is necessary to use head driven models, considering both the leakage and pressure dependent demands. Up to the present, many authors [1], [2], [3] and [4] have proposed different methods to simulate the network behavior considering user's demand and/or leaks depending on pressure, but few of them are ready to be implemented from the practical point of view.With this aim, firstly the authors have analyzed the behavior of demand as a function of pressure (PDD), simulating the response of plumbing systems in different types of buildings in urban areas. Next, a new mathematical function has been proposed that fits the simulated dependence of demands with pressure. This function has the necessary mathematical properties to be integrated within a hydraulic model and its parameters have been adjusted in a specific sector of the Valencia water distribution network, using the field data taken during a four month test. Field data included the sector inflow, pressures at service connections and automated meter readings. On the other hand the authors have developed a procedure to find the leakage coefficients at each node that fit best for the total leakage volume in the sector, usually available in sectored water supply system.Finally the new PDD function and the leakage coefficients have been integrated in a realistic model to consider the dependence of leakage and demands with pressure so that, for any scenario simulation, the integrated model is able to provide in every node the value of pressure and the total consumed flow differentiating its two components, leakage and demand.Using this model, more realistic simulations can be carried out for new scenarios such as pressure reduction for leakage control, failure of critical components (water treatment plant, pumping station, pipe breaks, etc) or restrictions to be applied during an extended drought, in order to analyze in each case the demand satisfaction and leakage level.