R&D highlights edition 2019

PROJECTS Ecosystems and environmental quality 28 L arge-scale erosion of the upper Rhine branches in the Netherlands is causing more and more problems for all river functions. Overall river-bed and water levels are lowering with centimetres annually, but fixed elements such as the non-erodible layers at Nijmegen and St. Andries, as well as pipeline and cable crossings, are not following. As a result, low flows during the dry summer of 2018 made it very difficult for shipping to sail past the fixed layers near Nijmegen. These issues have been added urgently to long- term planning studies (such as “MIRT” and the “programme for integrated river management”). A useful tool was still needed to present the problems and support the discussions. The various government stakeholders (Rijkswaterstaat, provincial authorities and ministries) are best informed by a presentation of the problems and solutions in a digital map tool of the kind used in some other discussions (such as maps for the management of floodplain vegetation). The aim of the tool is to visualise the trends in bed levels in combination with the consequences for the various functions. A first version of this tool has now been completed and it is expected that further development will include the selection of potential measures by the user. In the future, this tool may become a “planning kit” for sediment management measures. Contact: Kees Sloff, Kees.Sloff@deltares.nl , t +31 (0)6 5757 0335 MAP TOOL FOR EROSION AND SEDIMENT MANAGEMENT IN THE RHINE A first version of a map tool has been developed to support the discussion about the large-scale erosion of the river bed in the Rhine branches, and the implications for river functions. The tool is needed to support the development of potential sediment-management and structural measures in the river. Screen shot with the digital map for erosion and sediment management in the Rhine. The colours show erosion trends (cm/year) and the symbols indicate risks for cables and fixed layers.