Most of you who work with the Danube or live near the river are probably aware of the fact that a river does not only carry water, but also solid particles called sediment. Sediments can be small particles of clay, silt, sand or coarser gravel. Their movement in the river is quite complex because they can either settle on the riverbed or be suspended and transported by the water. The movement of sediment depends on the water flow, the sediment size, shape, and the type of material it is made up of. As a consequence, sediments play a major role in the development of the structure of the river.
Due to the complex physical background of sediment transport processes in rivers, our knowledge is far from complete. Many problems concerning river management issues are strongly connected to river morphology and the movement of sediment. Let’s focus on the Danube River: just think about how flood events can fill floodplains with sediment, or reservoirs with fine sediment deposits, thereby decreasing their water retention capacity; or the problems that low-water levels cause for navigation in the free-flowing sections of the river. All of these sediment-related aspects influence human life and the ecology and economy of the Danube Region.
Despite the direct and indirect links between various water management problems, the ICPDR has not officially declared sediment to be one of the “Significant Water Management Issues” in the Danube River Basin. The ICPDR has however taken significant steps to reveal the knowledge gaps concerning sediment in the “Danube Basin Analysis Report” of 2004, the “Sediment Issue Paper” in 2006, and the first and second “Danube River Basin Management Plans” in 2009 and 2015. Furthermore, other relevant organisations, such as the SedNet European network, are also working to bring together experts in the field of sediment in order to improve sediment management strategies.
The ongoing DanubeSediment project, which is being implemented within the framework of the Danube Transnational Programme, will also provide a substantial contribution towards basin-wide sediment management. The project will develop the first transnational Danube Sediment Management Guidance (DSMG) containing concrete recommendations and explaining what types of measures can be implemented to improve sediment management. This information will support the ICPDR in developing both the next Danube River Basin Management Plan and Danube Flood Risk Management Plan.
Working on sediment-related issues, we believe that all the efforts made to develop and improve river-wide sediment management, involving researchers, practitioners and relevant stakeholders, will lead to a more sustainable use of the Danube River that will benefit both people and nature alike.