Cohesive sediment, or mud, is a mixture of clay particles, silt, (fine) sand, organic material, and water. It preferentially settles in low-energy environments such as sheltered coastlines, estuaries and harbours. Mud deposits give rise to highly bio-diverse and therefore ecologically valuable systems such as mud flats, mangroves and salt marshes. These ecosystems are not only ecologically important, but also play a role in coastal defenses. At the same time, sedimentation in navigation channels and harbour ports is an obvious negative aspect. A better understanding of mud transport and deposition is therefore important for ecologic, safety, and economic reasons.