Minimum Cost Water Yield Strategy for Multiple Sources Water Distribution System

Abstract

Minimizing water supply costs has always been the goal of water companies. However, it is not an easy task to minimize costs and meet customers’ water pressure needs in a water supply system with multiple sources and different unit costs of water discharge. In this paper, we develop a search method that incorporates the concepts of local search and steepest descent. First, we establish the discharge pressure of each water source as a variable and start searching the neighborhood for a feasible initial solution. The steepest descent concept is then used to find the most cost-effective solution in the neighborhood, before the initial solution is updated. We then iterate the search as described above until either the constraint is met or the amount of cost variation reaches an acceptable level. A simple example is used to explore the optimal solution characteristics. This is then followed by an analysis of a practical water supply system with up to six water sources. Compared with the original operation model, the optimized result can save 15.6%, 9.0%, and 12.7% of the total cost of water supply during off-peak, normal, and peak periods, respectively. We use the commonly used hydraulic analysis software EPANET to build different functional valve classes to satisfy various constraints for the purpose of simplifying the optimized search codes automatically. This method uses low levels of computational resources to obtain an acceptable and reasonable solution in a short time.