A multi-criteria decision analysis method for sustainability improvement of the hydropower megaproject system

The sustainable development of the hydropower megaproject (HM) is a vital component of watershed sustainable water resources management. Multiple measures should be taken to enhance the HM system's overall performance and sustainability when environmental changes disrupt it. Hence, making scientific and applicable decisions on various measures to improve the HM system's sustainability is a critical and complex problem. This study proposed a novel multi-criteria decision analysis method for sustainability improvement (MCDA-SI) of the HM system. The MCDA-SI method develops the multi-criteria evaluation indicator system, the Cloud-EM-AHP weight solution model, the comprehensive development index (CDI) model, and the coupling coordination degree (CCD) model. The Three Gorges Project (TGP) is selected as a case study, and the key measure to improve the TGP system's sustainability is determined. The results showed that from 2003 to 2023, the CDI of the TGP rose from 0.40 to 0.61, and the CCD indicated a fluctuating increasing trend with a mean value of 0.42, revealing that the TGP system's comprehensive development level and coupling coordination development degree are gradually improving. The sustainability assessment results indicate that the critical factors influencing the TGP system's sustainable coordinated development are flood control safety, resettlement compensation, biodiversity protection, and prevention of water pollution. The multi-criteria decision analysis results illustrated that optimizing the TGP's scheduling, operation, and management is the most effective measure for enhancing the system's sustainability, which aligns with the TGP's actual state. Compared to traditional MCDA technology for hydropower and reservoirs, this study integrates Cloud-EM-AHP, CDI, and CCD within a unified MCDA-SI model framework to enhance the applicability of the MCDA method in sustainable hydropower assessment and decision-making. Meanwhile, the novel MCDA-SI framework can serve as an evaluation index and provide policy insights for coordinating the protection of watershed ecological environments and sustainable hydropower development. • A decision framework for sustainable hydropower development (MCDA-SI) is proposed. • The indicator weight determination method based on minimum deviation is developed. • Sustainable hydropower development research is improved based on the MCDA-SI model. • Three Gorges Project (TGP)'s sustainability improvement measures have been decided. • The main factors affecting the TGP system's sustainable development are identified.