Safety Evaluation of Water Environment Carrying Capacity of Five Cities in Ningxia Based on Ecological Footprint of Water Resources

[Objectives] To make safety evaluation of water environment carrying capacity of five cities in Ningxia based on ecological footprint of water resources. [Methods] With the help of the grey relational model, 15 indicators were selected from the natural, economic, and social aspects, and the most influential factors in the three fields were selected. Based on the concept of ecological priority, the water resources carrying capacity of the five cities in Ningxia from 2010 to 2019 was calculated with the help of the water resources ecological footprint model. Then, the indicators of the water resources ecological footprint model were coupled with the existing indicators to establish a comprehensive evaluation indicator system. Finally, the changes of the water environment carrying capacity of the five cities in Ningxia were analyzed with the help of the principal component analysis (PCA). [Results] The ecological pressure of water resources and the ecological deficit of water resources in the five cities were relatively large. Specifically, Yinchuan City had the most obvious deficit of water resources but good carrying capacity; Zhongwei City had a large ecological deficit of water resources, poor carrying capacity, and the largest ecological pressure index of water resources; Guyuan City had low water resources ecological deficit, water resources ecological carrying capacity and water resources ecological pressure index. [Conclusions] Through the analysis of the coupling indicator system, it can be seen that the water environment carrying capacity of the five cities is in an upward trend, indicating that the water environment in each region tends to become better.