Methodology for least-cost design of invulnerable water distribution networks

Water distribution networks are subjected to random failures. Since a breakdown in water supply is not acceptable for more than a few hours, the network should be invulnerable to some extent. Adopting an invulnerability degree of two alternative supplies, a new methodology is presented for the least-cost design of water distribution networks. According to this methodology the design process is controlled by the designer via three distinct stages. In the first stage the alternative paths are allocated using graph theory algorithms. In the second stage the minimum hydraulic capacity (diameters) of each path is determined using a linear programming model, and in the third stage the solution is tested by a network solver for various demand patterns.