Spatio-Temporal Variation of Water Quality in Urban Lakes and Land Use Driving Impact: A Case Study of Wuhan

Urban lakes, as critical components of urban ecosystems, provide essential ecological services but face water quality deterioration due to rapid urbanization and associated land use changes. This study investigated the temporal and spatial characteristics and evolution mechanisms of water quality in Wuhan city lakes, with a focus on the Great East Lake basin (GELB), a typical urban lake cluster in the middle Yangtze River basin, encompassing six key lakes: East Lake (EL), Sha Lake (SL), Yangchun Lake (YCL), North Lake (NL), Yan East Lake (YEL), and Yan West Lake (YWL). The spa-tio-temporal variation of water quality was studied by analyzing monthly water en-vironment data from 2017 to 2023. The surrounding land use data of 2020 and the corresponding year's water quality data were integrated and examined to assess the impact of land use on major pollutants. The results showed that SL had the best water quality, EL, YEL, and YWL exhibited similar water quality evaluation results, while YCL and NL had the worst water quality. Seasonal variations in water quality were observed, influenced by the ecological functions of lakes and surrounding land use. Notably, understanding these seasonal dynamics provides insights into nutrient cycle operations and their effective management under varying climatic conditions. In ad-dition, the correlation between chlorophyll-a concentration and nutrient elements in urban lakes was not consistent, with some lakes showing significant negative correla-tions. The water quality of urban lakes is influenced by both land use and human management. Land use analysis indicated high impervious surfaces in EL, SL, and YCL exacerbated runoff-driven nutrient loads, YEL's nitrogen elevation from agricultural runoff, and NL's pollution from historical industrial discharge. This study highlights the urgent need for targeted water management strategies to mitigate the impact of urbanization on water quality and provide a scientific basis for effective governance and ecological restoration in rapidly urbanizing areas around the world. By adopting an integrated approach combining water quality assessments with land use data, this research offers valuable insights for sustainable urban lake management.