The off-site effects of over-fertilization of Phosphorous for the water quality of Danish rivers have been recognized since the 1980s. The restriction of fertilization led to some improvements of water quality, however, elevated Phosphorous concentrations still affect creeks and rivers in Denmark. A possible source of Phosphorous are the banks or rivers and creeks where P-rich particles, initially deposited in the floodplain after erosion on agricultural land, are now mobilized. In this project, a detailed Phosphorous inventory is carried out along selected creeks near Aarhus. The results of the inventory are then applied on a larger scale using GIS to assess the potential release of temporarily stored Phosphorous to rivers and creeks as a result of bank erosion. Special attention is given to the potential effects of re-naturalization of watercourses and the changes in flood and runoff regimes in response to climate change.