Evaluation of Selection Algorithms for Simultaneous Layout and Pipe Size Optimization of Water Distribution Networks

In this paper, a genetic algorithm is presented for the simultaneous layout and pipe size
optimization of water distribution networks and its eciency is evaluated and compared using
dierent selection mechanisms. An engineering concept of reliability is used, in which the number
of independent paths from source nodes to each of the demand nodes is considered as a measure
of reliability. The method starts with a predened layout, which includes all possible links. The
method is capable of designing a layout of predened reliability, including tree-like and looped
networks. It is shown that a layout optimization of a network, followed by size optimization, does
not lead to an optimal or a near-optimal solution. This emphasizes the need for simultaneous
layout and size optimization of networks, if an optimal solution is desired. The performance of
the method for layout optimization of pipe networks is tested against two benchmark examples
in the literature and the results are presented.