Three-way decision approach for water ecological security evaluation and regulation coupled with VIKOR: A case study in Beijing-Tianjin-Hebei region

Abstract

Owing to the great correlation between human survival and water ecological security (WES), the research on the evaluation and regulation of WES is of great significance. However, the evaluation thought of WES is not clear enough and most of the evaluation methods can only get ranking results subjectively, which are not suit to judge the grade, especially in the complex and uncertain decision environment. Thus, under the guidance of the resilience idea, it is proposed to build an evaluation indicator system of WES from three aspects: resistance, restorative and adaptability. Then the data were transformed into Pythagorean fuzzy number (PFN), and the resilience index was obtained based on VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje) method to realize ranking; After that, the comprehensive thresholds were estimated by the resilience index, and a new three-way decision (3WD) model for the WES evaluation was constructed for grade evaluation; Finally, the model was applied to the evaluation of WES in Beijing-Tianjin-Hebei region (BTH) of China from 2006 to 2020. The results show that the WES in BTH has significant spatial-temporal differentiation; From 2006 to 2020, except Hebei, the WES level has not been significantly improved; Beijing, Tianjin and Hebei were respectively in grade III, V and I in 2016–2020; The resistance of WES is an urgent direction to be optimized in Beijing and Tianjin, while Tianjin and Hebei should strengthen the restorative of WES. The model framework constructed in this study is effective and has good generalizability, which can provide a new way for WES evaluation.