Project 3.06: Impact of climate change on the transport behaviour of contaminated sediments and the maintenance of coastal waterways

Dr Norbert Grope, BfG,
Tel. +49 (0) 261/1306-5195, grope@bafg.de

Beate Burger, BfG,
Tel. +49 (0) 261/1306-5184, burger@bafg.de

Dr Carmen Kleisinger, BfG,
Tel. +49 (0) 261/1306-5137, kleisinger@bafg.de

Dr Birgit Schubert, BfG,
Department G1 - General Water Quality Issues,
Tel. +49 (0) 261/1306-5312, schubert@bafg.de


Objectives

The objectives of the project include making predictions concerning the influence of climate change on pollutant content in sediments and suspended matter and on their transport into the North Sea estuaries of the tidal rivers Elbe, Ems and Weser. Furthermore, the extent of the changes will be assessed in relation to the impacts which can be traced back to construction measures and maintenance strategies or to changes in input into the estuaries.

In order to maintain navigation, large volumes of sediment must be dredged from the North Sea estuaries every year; these are generally stored in the water at other sites. Some increases in the pollution of these sediments, which occurs especially in the upper tidal zones of the Elbe and, to a smaller extent, in the Weser, may cause problems during transfer of the dredged material and may generate considerable expense.
An increase in the intensity and frequency of high water events means that additional input of pollutant-laden solid matter from the inland areas into the North Sea estuaries can also be expected. If high water and storm events occur more frequently, an increase in resuspension, and thus, remobilisation of older pollutant-laden sediments from existing dump points (transfer of dredged material), from the sides of the navigation channel and flood plains cannot be ruled out. This aspect may contribute to an increase in pollutant load of the sediments that must be dredged at the present time. These transport dynamics of pollutant-laden suspended matter and sediments from side areas of the estuaries in the case of increasing high water and storm tide events still need to be resolved.