Enhancing Watershed Management through Adaptive Source Apportionment under Changing Environment

Abstract Source information and the related influencing variables are crucial for watershed management. However, identifying long-term changes in pollution sources and distinct patterns remains challenging. Here we explore the changing patterns of pollution sources in the Hangbu Watershed of Chaohu Lake, China, and propose an adaptive strategy. The results demonstrate significant variations in sources over the 36-year study period, with nitrogen and phosphorus increasing by 1.2 times and 2.2 times, respectively. Compared to the traditional method based on a specific year, the adaptive solutions accounted for 87.83% and 57.68% of the nitrogen and phosphorus contribution. Trends, periodicity, and mutagenicity of sources were quantified, which are influenced by the variations in rainfall, urbanization, and agriculture development. Specifically, farmland acts as a vital source that exports 90.93% of nitrogen and 58.01% of phosphorus under different conditions. Specific pollution sources with growth trends and control robustness have been recognized as vital contributors, even though their contributions to the watershed's outlets may not be the most prominent. The results of this study enhance the sustainable management of watersheds.