Sedtrans05: An improved sediment-transport model for continental shelves and coastal waters with a new algorithm for cohesive sediments

The one-dimensional (vertical) sediment-transport model SEDTRANS96 has been upgraded to predict more accurately both cohesive and non-cohesive sediment transport. Sedtrans05 computes the bed shear stress for a given set of flow and seabed conditions using combined wave-current bottom boundary layer theory. Sediment transport (bedload and total load) is evaluated using one of five methods. The main modifications to the original version of the model are: (1) a reorganization of the code so that the computation routines can be easily accessed from different user interfaces, or may be called from other programs; (2) the addition of the Van Rijn method to the options for non-cohesive sediment transport; (3) the computation of density and viscosity of water from temperature and salinity inputs; and (4) the addition of a new cohesive sediment algorithm. This latter algorithm introduces variations of sediment properties with depth, represents the suspended sediment as a spectrum of settling velocities (i.e. size classes), includes the flocculation process, and models multiple erosion-deposition cycles. The new model matches slightly better the field measurements of non-cohesive sediment transport, than does the predictions by SEDTRANS96. The sand-transport calibration has been extended to high transport rates. The cohesive sediment algorithm reproduced well experimental data from annular flume experiments.