Study on Water Environmental Carrying Capacity Based on Improved Catastrophe Theory

The improved catastrophe theory is introduced into the study of water environment carrying capacity. With coupling of 4 subsystems which are, water resource factors, ecological environment factors, social resources allocation capacity factors, social and economic factors as the basic framework, 12 indexes were selected to construct the model of water environment carrying capacity. Based on the characteristics of normalization formula of aggregation, the rating scale refinement method was used to improve conventional catastrophe theory and to obtain the adjusted comprehensive value. Then according to the evaluation habits, fuzzy judgment was selected to determine the evaluation threshold, five grade evaluation was used to evaluate water environment carrying capacity. At the last, the water environment carrying capacity in Yichang city was evaluated, the results show that: during 2010-2015, water environmental carrying capacity in Yichang city was on the rise, but in 2020 the Yichang city water environmental carrying capacity will decrease sharply. We need to strengthen environmental protection and governance level.