The evolution of optimizing water distribution system applications

Water distribution systems present many interesting and challenging optimization problems. For example in the pipe sizing problem, the interactions between decisions are complex and not always easily understood or expected. Also, assumptions about decision and problem form alter the problem structure and permit a range of methods to be applied. Constraints and the objective can be linear or nonlinear. Some problems can be posed in a stage-wise structure. Thus, an abundance of optimization applications are found in the literature for the range of water distribution problems. This talk attempts to provide context of the maturity of optimization techniques applied in the area over time. Clearly, computer power is central to the improvement of methodologies and movement toward more complex problems. From the initial consideration of branched systems, other key causes of change include the evolution to considering looped systems, the development of fast hydraulic simulation models that led to the linking of optimization and simulation models, the emergence of water quality as a central issue in distribution systems, and the movement of water distribution oriented optimization software from research to practice through commercialization. Timelines of advances in the application of optimization methods to water distribution system problems are presented. They relate the types of problem considered over time, the methods applied, and the general formulation structures with the changes listed in the previous paragraph and others that altered the way problems were posed and solved. Copyright ASCE 2006.