Assessment and screening of green and low-carbon restoration technologies for river and lake buffer zones and aquatic vegetation in the Yangtze River Basin

The Yangtze River Ecological Protection Initiative has now entered a critical phase of ecological restoration. As key measures to improve the ecological system of the basin, river and lake buffer zones and aquatic vegetation restoration technologies have been extensively researched and developed both domestically and internationally. There is an urgent need to conduct a systematic evaluation of these technologies from a green and low-carbon perspective to identify efficient and suitable technologies for the Yangtze River Basin. Accordingly, a hotspot analysis was conducted on research related to river and lake buffer zones and aquatic vegetation restoration technologies in China National Knowledge Infrastructure (CNKI) and Web of Science databases to analyze technological research trends. Additionally, 62 technologies that had been applied in engineering projects (including the National Key Research and Development Program for Water Pollution Control and Governance) were collected and organized. Their key engineering parameters were extracted, and a suitable technology assessment method was established to comprehensively evaluate the 62 technologies. Radar charts were used to analyze four typical outstanding technologies. The results showed: 1) Over the past 20 years, domestic and international research hotspots on river and lake buffer zones have focused on buffer zone interception functions, purification mechanisms, analysis of pollution causes, layout optimization, and management, while research hotspots on aquatic vegetation have focused on ecosystem reconstruction, synergistic restoration technologies, the role of different vegetation types in water quality improvement, and pollutant removal mechanisms. 2) A technical assessment indicator system for river and lake buffer zones and aquatic vegetation was proposed, based on four dimensions: technical readiness, economy, pollution reduction and carbon reduction, and ecological environment. The "entropy weight + TOPSIS" method was used for comprehensive assessment, with technical assessment grades determined by the relative proximity value. 3) A total of 32 green and low-carbon technologies suitable for the Yangtze River Basin were identified using the constructed technology evaluation method, including 9 river buffer zone restoration technologies, 9 lake buffer zone restoration technologies, 6 wetland ecological restoration technologies, and 8 aquatic vegetation restoration technologies. Among these, 6 technologies scored above 0.75, receiving an excellent rating. 4) The four typical outstanding technologies performed outstandingly in terms of technology readiness and ecological benefits, and were suitable for promotion and application. However, there was still room for improvement in terms of operating costs and pollution load removal performance. The research findings can provide green and low-carbon technological support for water ecological restoration in the Yangtze River Basin.