Effect of riverfront utilization transitions on riparian water quality in the middle-lower Yangtze River

The Yangtze River Protection Strategy aims to enhance water quality and mitigate environmental risks associated with riverfront utilization. This study targets a 2000-km stretch of the middle and lower Yangtze River, where we conducted field investigations and sampled at 76 locations. We investigated the relationship between riverfront utilization and riparian water quality, and proposed zoned management strategies. Our findings reveal that the riverfront development utilization rate decreased by 0.5 % from 2017 to 2022, with the transitions towards living-oriented utilization from production-oriented uses. The impact of riverfront utilization on water quality differs by type: living-oriented riverfronts significantly elevate NH₃-N levels, while production-oriented riverfronts notably increase TP levels. Regarding heavy metal pollutants, life-oriented riverfronts have a minimal impact, whereas production-oriented riverfronts significantly affect Zn concentrations. A strong positive correlation between changes in riverfront utilization rate and Zn levels suggests a primary influence from industrial sources. Based on these results, we have delineated four types of environmental management zoning for riverfront, pinpointed 29.0 % of critical riverfront segments, and outlined corresponding management measures. This research provides practical insights for advancing the scientific management of riverfront utilization along the Yangtze River and enhancing riparian water quality.