Evaluating Environmental Impact in Water Distribution System Design

An index-based method for the evaluation of the environmental impact of water distribution systems is introduced. The method is developed according to a set of methodological criteria to assess the environmental effect of water networks. A number of environmental measures are incorporated into the index-based method to account for nonrenewable resource consumption, greenhouse gas emissions, and emissions to air, land, and water. The index-based method can be included into a multiobjective optimization program to find design solutions that minimize cost and environmental impact. The index-based method was applied to the design of a water transmission system over a 20-year design horizon. Design alternatives were compared on the basis of the environmental impact index and cost. For the system analyzed, results indicated that of the hydraulically feasible alternatives, the five most environmentally acceptable alternatives were the five most cost-effective alternatives. Results also showed that the environmental impact index is mainly influenced by pumping energy and partially influenced by pipe diameter selection.