Urban water security evaluation based on similarity measure model of Vague sets

The urban water security is an important part of urban ecological security, which is directly related to the sustainable development of urban society and economy. A comprehensive evaluation of the urban water security is a complex, vague and multi-level evaluation process. This paper presents a Vague set-based water security evaluation method and establishes a similarity measure model of Vague sets. AHP and Delphi methods are used to conduct index weighting in order to evaluate the level of urban water security assurance. The empirical study is done on the case study of Chengdu, China. Among the nine indexes of the city water security evaluation, the index values for socio-economic environment and socio-economic pressure are 0.24 and 0.41 respectively, which indicates that there is a relatively greater pressure on the city's social, economic and environmental pillars. The WSAI values of water resource index and water environment pressure are 0.94 and 0.96 respectively. These relatively higher values show that the city's water resources are relatively fully exploited and its environment is relatively well-protected. The similarity measure evaluation model of Vague sets can be used to quantitatively evaluate the degree of urban water security support.