Use of many-objective visual analytics to analyze water supply objective tradeoffs with water transfer

Abstract

The construction of water transfer projects can have a considerable impact on the operation of the receiving reservoir. This study investigates the change of the objective tradeoffs in multi-objective reservoir operation problems due to the introduction of water transfer using a case study of the East-to-West Water Transfer project in northeastern China. Two optimization cases are constructed to analyze the tradeoff changes: a base case with no water transfer which considers four objectives, i.e., minimizing industry water shortage, minimizing agriculture water shortage, minimizing water spillage, and maximizing ecological satisfaction; a future post-construction case which considers an additional objective to minimize the amount of water transferred. Results obtained from the case study show increasing water transfer substantially reduces the intensity of the competition between industrial and agricultural water shortages, and the objective tradeoffs among water spillage, ecological satisfaction and agricultural shortage index are substantially changed because of water transfer. In addition, the amount of water transferred with high efficiency regarding each objective is identified, and three solutions of different orders of magnitude in diverted water have been recommended for informed decision making considering efficiency and benefit. This study implies that many-objective visual analytics can be used to determine the optimal amount of water transferred in terms of water efficiency revealed in different objective tradeoff spaces.