This paper is the result of environmental geolgical survey engineering.

Objective Wabu Lake is the largest lake in the Huaihe River basin in Anhui Province and also a crucial part of the Yangtze River to Huai River Water Diversion Project, clarifying the changes in the area and morphology of Wabu Lake is of great significance for the ecological safety along the Yangtze River Diversion to Huai River route.

Methods Based on a total of 15 periods of Landsat and high-resolution satellite images from 2002 to 2022, with three scenes per year at five-year intervals, this study employed visual interpretation techniques to extract vector data of Wabu Lake during both its dry season (November to April), wet season (May to Augest) and level season (September to October). The shoreline index analysis was applied to investigate morphological changes, while correlation coefficients were used to explore the factors influencing the lake's evolution over time.

Results Over the past two decades, the area of Wabu Lake during the level season has increased by 19.25 km², with its shoreline extending by 62.46 km. Affected by extreme flood events, Wabu Lake experienced its maximum shoreline length and area during the wet season of 2007. This period also marked the highest level of shoreline development and the largest fractal dimension value, reflecting the lake's highly complex shoreline morphology at that time. Over these two decades, the lake’s shape during dry seasons has become increasingly complex.

Conclusions In general, the evolution of Wabu Lake in the past two decades has been the result of the combined effects of human activities and climate change, and heavy precipitation associated with extreme weather events was the primary driver of the evolution of Wabu Lake during the abundant water period in 2002 and 2007.