Optimal design of water distribution networks using fuzzy optimization

A new heuristic approach for the design of water distribution networks invo lving a robust fuzzy linear program optimization in which the capital costs of the network are minimized while maintaining the nodal heads at demand n odes within a satisfactory region as defined by the customers at those node s is presented. Iterative interaction between the fuzzy linear program and a network solver is used to ensure hydraulic consistency. Level of service is modelled by the residual nodal head available at demand nodes with the s ubjective nature of customers' satisfaction with the nodal head being repre sented through fuzzy sets which reflect more realistically consumers' attit udes toward pressure variations in the supply of water. Non-probabilistic u ncertainty in the demand is modelled by a trapezoidal possibility distribut ion function. The model is demonstrated by application to an example networ k.