Although the land-source nutrients discharge from land into Jiaozhou Bay has been researched, but the contribution of groundwater is usually neglected.

To better understand the relationship between the natural environment-induced changes versus changes caused by human activities during the process of eutrophication,we tried to evaluate nutrient transportation over catchments and its contribution to lake eutrophication by working on the Honghu Lake Basin located at the middle reach of the Changjiang River,as an example.