Near-optimal activation device scheduling to react to intentional or accidental contaminations in water distribution systems

A procedure is here presented for near-optimal valve and hydrant activation scheduling in a water distribution system during a contamination event to minimize the water volume consumed by users. The constraints are represented by the number of response teams and the maximum speed at which these teams can move. The proposed procedure is based on a genetic algorithm (GA) that interacts with a mixed integer programming solver (MIP). The GA provides unconstrained operating times (in terms of speed), while the MIP solver modifies these times in order to satisfy the above-mentioned constraints while remaining as close as possible to their initial values. The optimization procedure is linked to a hydraulic and water quality simulator to calculate the amount of contaminated water consumed by users. The application of the procedure to a real and very complex water distribution system shows that the optimization process is robust and effective and reduces the impact of a contamination event on the population.