Understanding Water Quality Models by Particle Forward and Backtracking Methods

The quality of water supplied to consumers through drinking water distribution networks is a matter of growing concern and is subject to increasingly stringent new regulations. The utilization of simulation models, which encompass the movement of water through pipes and storage tanks, has been demonstrated to provide valuable information with regard to the improvement of the system operation. However, once a calibrated quality model is available, justifying the evolution of the quality provided by the model at any junction in the network is not direct; however, this is sometimes necessary to carry out the appropriate interventions to improve quality parameters. A methodology to help the comprehension of the quality results provided by simulation models has been developed in this paper. This methodology is based on the principles of event-based transport methods, whereby the quality of a particle is tracked as it moves downstream from a starting point or upstream from an arrival point. Upon reaching a junction, an event occurs that determines the subsequent trajectory of the particle. The details of the method and its potential are demonstrated through an illustrative example, reinforced by its application in a more realistic case. Consequently, by monitoring the particles, it becomes feasible to interpret the quality values obtained at any junction in the network and at any designated moment. If the quality value were the result of a measurement, the method would also allow us to track the origin of that value; in this way, it could be used in the future to locate the possible source of a detected contaminant.