Abstract: Early impoundment at the end of flood season can improve the full storage rate of reservoirs at controllable risk and create significant benefits. Extensive studies have been conducted on the Three Gorges reservoir's operation schemes of water impounding at the end of flood season, but their focuses are quite different and they lack the support of decision-making technology in selecting water impounding schemes. This paper presents a group decision-making model of experts’ most-satisfaction to integrate the existing research fruits on the reservoir's impounding schemes for higher level decision making. We rank the available schemes using the method of cumulative prospect theory and the matrices of experts' decision, and then solve the model to maximize the satisfaction of the expert group. The results show that the best scheme is to start impoundment on September 11 and this can achieve greater benefits with a lower risk and agrees with the result of the traditional decision method, verifying the effectiveness of our group decision model. This model has fully considered experts' decision-making psychology and respects the group opinions of experts; thus it gives evaluation results that can be followed and provides a new effective approach to the reservoir's operation schemes of early water impounding.

Key words: Three Gorges reservoir, water impounding time, experts' satisfaction, prospect theory, group decision-making