Assessment and early warning of water resources carrying capacity in Dongting Lake Ecological Economic Zone
Authors: Fu Zeding , Ding Xiang , Wang Jiacheng , Fu Xiaohua , Huang Jing , Zhao Xuhong , Yin Hailong , Liu Junwu , Fang Yingchun , Liu Zhiming 
Published: May 2024

Assessment of water resource carrying capacity is a useful tool for measuring the degree of realization of resource and environmental planning. Scientific monitoring and evaluation of water resource carrying capacity is a basic requirement for building ecological civilization and implementing the development concept of "green water and green mountains are golden mountains and silver mountains". Taking 26 county units in the Dongting Lake Ecological and Economic Zone in Hunan Province as the evaluation object, 22 water resource carrying capacity evaluation indicators were selected, and the comprehensive weight method of subjective and objective combination of hierarchical entropy weight evaluation method and weighted summation comprehensive scoring method were used to calculate the comprehensive water resource carrying capacity values of 26 "county units" in the Dongting Lake Ecological and Economic Zone during the 25-year research period of 1997–2021. The results were analyzed using gray correlation method and Ridge regression modeling. After processing the input data of each layer based on the evaluation index system, BP neural network regression training was conducted to obtain a prediction model for the future trend of water resource carrying capacity for prediction and analysis. The results show that: (1) In terms of time trend, the water resource carrying capacity of the study area was generally stable, between overload and critical. The change trend of water resource carrying capacity changed greatly among districts and counties; (2) In terms of spatial distribution, there were differences in the water resource carrying capacity of the Dongting Lake ecological and economic zone: the water resource carrying capacity around the western districts and counties and the central South Dongting Lake was higher than the northern Yueyang urban area; (3) Among the four criteria layers, the weight of water resources supporting capacity was the highest, with the smallest change, and the economic supporting capacity index had the largest change. The decline in water resources carrying capacity in most districts and counties was during a period of relatively rapid economic development; (4) It was predicted that the water resource carrying capacity of Nanxian, Hanshou, and Xiangyin counties around the South Dongting Lake would significantly increase in 2025, shifting from overload to a critical state, and maintaining this trend in the coming years; (5) Dingcheng District of Changde City would gradually transform from critical to overload, and maintain this trend in the coming years. To sum up, the key to improve the water resources carrying capacity of Dongting Lake Ecological Economic Zone was to prevent water resources pollution, optimize water resources allocation and improve water resources utilization efficiency. It was recommended from our study that the government should continue to strengthen the awareness of water environment protection and water environment governance measures, and regularly conduct environmental governance performance evaluation to improve the accuracy of comprehensive governance. Based on the long-term objectives, we should formulate measures to protect Dongting Lake, promote the construction of new urbanization, and develop green industries such as ecological agriculture, ecological industry, and ecological tourism according to local conditions.