A HEURISTIC APPROACH ALGORITHM FOR THE OPTIMIZATION OF WATER DISTRIBUTION NETWORKS

Many optimization models to determine cost-effectiveness and obtain th e least-cost system designs for water distribution networks have been developed. An algorithm used for solving an optimization model, such a s the branch-and-bound or enumeration method, has deficiencies that ma y include efficiency problems and local optimal solution problems. A h euristic approach, with a bounded implicit enumeration (BIE) algorithm was developed in this study to improve searching efficiency. The heur istic approach first treats the system as a sub-system so that the sub -system's solution must spread widely at the solution space. Then, the optimal sub-system solution is found by a BIE algorithm. On the basis of the optimal solution for the initial system, one larger than and o ne smaller than its commercial diameter is used to form a new system d esign. Finally, an optimal solution is determined by using the BIE alg orithm until the same solution is found. In this study, five water dis tribution network designs were used to illustrate the performance of t his approach. The results show that a heuristic approach is more effic ient than the BIE alone. The efficiency becomes more obvious when the system becomes larger. Comparing the three case studies, the heuristic approach along with the BIE algorithm finds global optimal solution m ore efficiently. (C) 1997 IAWQ. Published by Elsevier Science Ltd.