The current silt dynamics in the Wadden Sea are markedly influenced by human activities and interventions, such as the dredging of waterways and the use of silt for land reclamation. In this context, ‘silt’ is taken to mean sediment with a grain size of less than 63 micrometres. For the trilateral Wadden Sea (the overall Wadden Sea area shared by the Netherlands, Germany and Denmark) there is a lack of solid insight into silt management. This inspired the Wadden Academy and Programme towards a Rich Wadden Sea (PRW) to ask Deltares to launch a study into this. Where does the silt come from, what happens to it in the Wadden Sea and what are the potential consequences of human intervention? The report Where Mud Matters is now complete. It provides the first silt balance assessment for the trilateral Wadden Sea. The report was presented to Bernd Scherer, chair of the Trilateral Programming Committee on Wadden Sea Research, during the 2nd Sediment Solutions webinar on Friday March 19th 2021.