This book is an introduction to the physical processes of cohesive sediment in the marine environment. It focuses on highly dynamic systems, such as estuaries and coastal seas. Processes on the continental shelf are also discussed and attention is given to the effects of chemistry, biology and gas.The process descriptions are based on hydrodynamic and soil mechanic principles, which integrate at the soil-water interface. This approach is substantiated through a classification scheme of sediment occurrences in which distinction is made between cohesive and granular material. Emphasis is also placed on the important interactions between turbulent flow and cohesive sediment suspensions, and on the impact of flow-induced forces on the stability of the seabed. An overview of literature on cohesive sediment dynamics is presented and a number of new developments are highlighted, in particular in relation to floc formation, settling and sedimentation, consolidation, bed failure and liquefaction and erosion of the bed. Moreover, it presents a summary on methods and techniques to measure the various sediment properties necessary to quantify the various parameters in the physical-mathematical model descriptions. A number of examples and case studies have been included.

Cohesive sediment, or mud, is encountered in most water bodies throughout the world. Often mud is a valuable resource, synonymous with fertile land, enriching the natural environment and used as an important building material. Yet mud also hinders navigation and consequently, dredging operations have been carried out since ancient times to safeguard navigation. Unfortunately, many mud deposits are now contaminated, endangering the eco-system and increasing the costs of dredging operations. The transport and fate of mud in the environment are still poorly understood and the need for basic research remains. This text contains the proceedings of the INTERCOH-2000 conference on progress in cohesive sediment research. It was the sixth in a series of conferences initially started by Professor Ashish Mehta in 1984 as a "Workshop on Cohesive Sediment Dynamics with Special Reference to the Processes in Estuaries". During these conferences the character of the first workshop has always been maintained, that is, small scale and dedicated to the physical and engineering aspects of cohesive sediments, without parallel sessions, but with ample time for discussions during and after the presentations, and followed by a book of proceedings containing thoroughly reviewed papers. INTERCOH-2000 was integrated with the final workshop of the COSINUS project. This project was carried out as a part of the European MAST-3 programme, and almost all European cohesive sediment workers were involved. INTERCOH-2000 focused on the behaviour and modelling of concentrated benthic suspensions, i.e. high-concentrated near-bed suspensions of cohesive sediment. Special attention was paid to: sediment - turbulence interaction; flocculation and settling velocity; high-concentrated mud suspensions; processes in the bed - consolidation; processes on the bed - erosion; field observations on mud dynamics; instrumentation; and numerical modelling.

Many estuaries are located in urbanized, highly engineered environments. Cohesive sediment plays an important role due to its link with estuarine health and ecology. An important ecological parameter is the suspended sediment concentration (SSC) translated into turbidity levels and sediment budget. This study contributes to investigate and forecast turbidity levels and sediment budget variability at San Francisco Bay-Delta system at a variety of spatial and temporal scales applying a flexible mesh process-based model (Delft3D FM). It is possible to have a robust sediment model, which reproduces 90% of the yearly data derived sediment budget, with simple model settings, like applying one mud fraction and a simple bottom sediment distribution. This finding opens the horizon for modeling less monitored estuaries. Comparing two case studies, i.e. the Sacramento-San Joaquin Delta and Alviso Slough, a classification for estuaries regarding the main sediment dynamic forcing is proposed: event-driven estuary (Delta) and tide-driven estuary (Alviso Slough). In the event-driven estuaries, the rivers are the main sediment source and the tides have minor impact in the net sediment transport. In the tide-driven estuaries, the main sediment source is the bottom sediment and the tide asymmetry defines the net sediment transport. This research also makes advances in connecting different scientific fields and developing a managerial tool to support decision making. It provides the basis to a chain of models, which goes from the hydrodynamics, to suspended sediment, to phytoplankton, to fish, clams and marshes.