Multiple scales of suspendend sediment dynamics in a complex geometry estuary

Many estuaries are located in urbanized, highly engineered environments. Cohesive sediment plays an important role because of its affect on estuarine health and ecology. An important ecological parameter is the suspended sediment concentration (SSC) translated into turbidity levels and sediment budget. Veel estuaria zijn gelegen in verstedelijkte gebieden. Cohesief sediment speelt een belangrijke rol in de gezondheid en ecologie van estuarine systemen. De concentratie van gesuspendeerd sediment (SSC), vertaald in turbiditeit en basis voor sediment budgetten, vormt een belangrijke ecologische parameter. This study investigates and forecasts turbidity levels and sediment budget variability in the 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 modelling less monitored estuaries. Comparing two case studies, i.e. the Sacramento-San Joaquin Delta and Alviso Slough, we proposed a classification for estuaries regarding the main sediment dynamic forcing: 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.