Multiobjective water distribution systems control of pumping cost, water quality, and storage-reliability constraints

This work describes a multiobjective model for trading-off pumping cost and water quality for water distribution systems operation. Constraints are imposed on flows and pressures, on periodical tanks operation, and on tanks storage. The methodology links the multiobjective SPEA2 algorithm with EPANET, and is applied on two example applications of increasing complexity, under extended period simulation conditions and variable energy tariffs. The proposed approach enables decision makers to take full advantage of the obtained information on a multiobjective scale for trading-off, cost, water quality, and storage-reliability requirements. Verification of the model outcomes through engineering judgment on all runs for both example applications confirmed the model suitability as a decision tool. Limitations of the proposed model reside in using variable speed pumps with assumed constant efficiency as representing an entire pumping station operation, the storage reliability constraint as an u-priori set parameter, and in the computational intensity required to obtain solutions for real sized systems.