If you select the STP Transport Model (p. 50), you must first of all specify whether you want to use the classical two-dimensional (2DH) approach to calculate the sediment transport rates, or whether the quasi three-dimensional (Q3D) approach should be used.
In the classical (2DH) approach it is assumed that the flow is mainly described by wave-driven currents, i.e. the angle between the wave and current direction is betweeen 0 and 90 degrees.
If this is not the case, e.g. by river outflow or tidal currents, you may apply the Q3D approach (that covers all angles between 0 and 360 degrees) or use the option parameters for using input values outside the limits of the transport table (see Table 5.1).