In 2005, analysis of dredged material from the Upper Rhine indicated a too high degree of sediment contamination. Thus, in 2005 a coordinated sediment management plan for the Rhine was commissioned. The result we now dispose of is the first plan for an international river basin district giving a global survey of the contamination of sediments in the main stream of the Rhine and in its main tributaries.
The sediment management plan for the Rhine is based on the following classification:
(1) In a first step, the most important contaminants and the areas polluted by them were identified.
(2) In a second step, sedimentation areas with more than 1000 m³ of contaminated sediments were identified. These sedimentation areas are called „areas of concern“, if there is no natural or man-made risk of re-mobilisation.
(3) In a third step it was investigated, in how far a re-mobilisation of contaminated sediments is liable to detrimentally impact the good status of water bodies further downstream. For these investigations, the assessment of the risk of re-mobilisation due to floods, wind, and anthropogenic impacts (dredging, navigation) plays an important role. In cases of considerable contamination and great amounts of sediments liable to be re-mobilised the area is classified as area presenting a risk.
18 of the 93 analysed sedimentation areas have been classified as „areas of concern“, 22 as areas presenting a risk. For areas presenting a risk, decontamination measures will be presented while it is recommended to intensively monitor the “areas of concern“.