Integrating water-related disaster and environment risks for evaluating spatial-temporal dynamics of water security in urban agglomeration.

Water security is a compound concept coupling multi-dimensional perspectives, such as resource utilization, environmental protection, and disaster prevention. With this concern, this study focuses on the spatial-temporal dynamics of water security with considering water disaster risk index (WDRI), water environment risk index (WERI), and water supply-demand. WERI centers on risk source's hazard, control effectiveness, and risk receptor's vulnerability. Indices related to hazard, exposure, and vulnerability are used for evaluating WDRI. A multi-objective fuzzy membership function is presented for determining the indices' weight, and the distribution pattern of water security is illustrated based on cluster analysis. A real-world case study of Beijing-Tianjin-Hebei urban agglomeration (BTHUA) is given for verifying availability of the evaluation framework. Results indicate the general water security in BTHUA with a critical safe state yet a downward trend. Opposite change characteristics of water security exist between its southern and northern cities. WDRI and WERI show the trends of increasing (with a growth rate of 0.48%) and decline (with an average decrement rate of 0.56%), respectively. Beijing has high-value WDRI and WERI, and the order of WDRI and WERI is presented as follows: Beijing (0.67) > Tianjin (0.54) > Hebei (0.33) and Beijing (0.69) > Tianjin (0.58) > Hebei (0.16), respectively. Cluster analysis reveals a poor match relation between water security and regional socio-economic development. Areas with high-level economic development (e.g., Beijing and Tianjin) have poor environmental performances, with WDRI and WERI of 0.54 ~ 0.68 and 0.57 ~ 0.70, respectively. Additionally, water resources overload index of BTHUA is 8.513, which is higher than Chengdu-Chongqing urban agglomeration (1.431), Triangle of Central China (0.228), and Yangtze River Delta urban agglomeration (0.742). Findings can provide a theoretical reference for promoting sustainable utilization of water resources in BTHUA and the other areas with prominent water problems.

Spatial-temporal collaborative relation among ecological footprint depth/size and economic development in Chengyu urban agglomeration.

This is the first attempt to simultaneously apply an improved three-dimensional ecological (EF3D) model and multivariate spatial-temporal collaborative relation model for evaluating the inter-regional ecological sustainability. Capital flow consumption and capital stock depletion can be tracked based on identification of variations in ecological footprint size (EFsize) and depth (EFdepth). Results display an unsustainable natural capital stock utilization in Chengyu urban agglomeration, especially in Neijiang, Chengdu, and Deyang with EFdepth higher than 35. There exists an obvious regional complementarity between EFsize and EFdepth, where cities with rich resources (or poor resources) are generally characterized as high EFsize and low EFdepth (or low EFsize and high EFdepth). The EF3D is slightly lower than traditional ecological footprint in value owing to its more concerns of intergenerational fairness and intrageneration fairness. Moreover, the spatial-temporal binary collaborative relation among EFsize, EFdepth, and GDP is generally higher than 0.6 with a medium level. Their temporal multivariate collaborative relation mostly lies in the intervals [0.30, 0.50] with an annual change rate of 10.22%, while slight variations exist in their spatial multivariate collaborative relation. GDP has a significant impact on the temporal collaborative relation of EFsize and EFdepth in Dazhou, Leshan, Luzhou, Mianyang, and Nanchong. There are slight impacts of EFdepth on the temporal collaborative relation of EFsize and GDP; meanwhile, GDP has a less effect on the spatial collaborative relation of EFsize and EFdepth. Findings can provide a reference for the coordinated development of social economy and ecological environment.

Fairness analysis and compensation strategy in the Triangle of Central China driven by water-carbon-ecological footprints.

This study proposes water-carbon-ecological footprints to form footprint family indicators for identifying the ecological compensation and regional development equilibrium in the Triangle of Central China (TOCC). The occupation of natural capital stock and flow consumption can be illustrated using a three-dimensional ecological footprint model, and Gini coefficient is integrated into the evaluation framework for fairness measurement from various aspects. Quantificational ecological compensation standards can be given with considering indicators associated with ecological resource conversion efficiency and willingness to pay. Results reveal that ecological and carbon footprints in the TOCC demonstrate rising trends from 2000 to 2015, while its water footprint presents a fluctuating trend. The majority of average Gini coefficients exceed the threshold value of 0.4 under different footprints, thereby indicating poor overall fairness of regional development. Water footprint in Jingmen, Xiangtan, and Yichun show relatively higher compensation expenses, while Yichang, Zhuzhou, and Fuzhou exhibit higher received compensation values compared with other cities. Carbon footprint in Wuhan, Loudi, and Xinyu indicate high compensation expenses due to their overuse of biological resources. Maximum amounts of compensation expense appear in Nanchang and Wuhan from the perspective of ecological footprint. This study can provide a theoretical reference for sustainable development in the TOCC by performing a comparative analysis with Beijing-Tianjin-Hebei urban agglomeration and developed countries.