DESIGN OF OPTIMAL RELIABLE MULTIQUALITY WATER-SUPPLY SYSTEMS

A methodology which integrates the optimal design and reliability of a multiquality water-supply system is presented and demonstrated. The s ystem designed is able to sustain prescribed failure scenarios, such a s any single random component failure, and still maintain a desired le vel of service in terms of the quantities, qualities, and pressures su pplied to the consumers. In formulating and solving the model, decompo sition is used. The decomposition results in an ''outer'' nonsmooth pr oblem in the domain of the circular hows, and an ''inner'' convex quad ratic problem. The method of solution includes the use of a nonsmooth optimization technique for minimizing the outer problem, for which a m ember of the subgradient group is calculated in each iteration. The me thod allows reversal of flows in pipes, relative to the direction init ially assigned. The methodology is applied to a system with 33 pipes, five pumps, and 16 nodes (two source nodes with treatment facilities a nd 14 consumer nodes) for a single loading condition and one quality p arameter.