A thesis submitted in partial fulfillment of the requirement for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1982

The study deals with the comparison between the costs of different pumping station arrangements and minimum service pressure variations of water distribution systems. The shortest path concept for flows in combination with a linear optimization model was used to determine the minimum cost of the alternatives in comparison. The model was applied to flat plain and hilly topography networks. A sensitivity analysis was carried out to determine the effects of cost functions of two different countries, a systematic variation of pumping station investment cost and of the determination of the hydraulic gradient by Prandtl-Colebrook or Hazen-William formula. The results indicated that the optimal designs is very sensitive to the relationship of piping and pumping costs. Total system costs increase almost linearly with the increase of the minimum service pressure as for the increasing service may be compensated by an increased pressure at the supply source. The optimal solutions were not very sensitive to changing the investment cost of pumping station and different determinations of hydraulic gradients. The Linear Optimization Technique was compared in one case with the Hardy Cross Technique. The first technique gave a more economical system than the second. Moreover, the Linear Optimization method can cover all design criteria simultaneously while the Hardy Cross demands for checking several criteria after the design calculations.