Quantitative evaluation and optimized utilization of water resources-water environment carrying capacity based on nature-based solutions

The water resources-water environment carrying capacity (WR-WECC) is an important indicator for judging the regional macro-control ability of water resources. The nature-based solutions (NBS) concept is related closely to sustainability, harmonious and green development, resources rational exploitation, coupled human and environment, and ecological protection priority. Participatory water management has necessitated the formation of village water resources committees and/or village environmental committees; while in the case of water management, a participatory approach has resulted in the formation of community water association, domestic water committees, cooperative societies, and various water user groups. The WR-WECC evaluation goal is to find the most appropriate water resources development and utilization to maximize benefits and system efficiency while minimizing costs and trade-offs. To realize the development and utilization of water resources, water ecological conservation, and water environment protection in Yuetang District, we constructed a dynamic evaluation index system including water resources, water environment and water ecological characteristics, applying the principal component analysis (PCA) method to evaluate the temporal scale variation tendency of WR-WECC, and explore a deep-seated reason based on NBS. The WR-WECC evaluation index system covered 16 indexes belonging to three subsystems of water resource, socioeconomic, and eco-environmental systems. We used Statistical Product and Service Solutions (SPSS) 19.0 software and adopted the improved PCA to integrate the urban economic-social-ecological development of the Xiangjiang (a tributary of the Yangtze River) River Basin. We applied the evaluation index system to analyse the trend variability of WR-WECC of Yuetang District from 2005 to 2015 based on NBS. The WR-WECC of Yuetang District was affected mainly by the urban sewage treatment rate, the water use amount per ten thousand Yuan gross domestic product (GDP), and per capita water resources. In addition to minor fluctuations in 2007 and 2011, the WR-WECC in Yuetang District was generally on the rise year by year and was related to socioeconomic development level, regional water environment comprehensive management, and awareness of water ecological protection. The WR-WECC of the Yuetang District in 2013-2015 was in a Class I (excellent) condition. The temporal variations analysis based on NBS was proposed through a combination of economic-social-ecological values provided by nature-based development and utilization patterns. Based on the relationship among regional water resources, economic society, and eco-environment protection, the paper supplied a WR-WECC improvement strategy that was suitable for the development and utilization of water resources in a water-rich area in south China.