Grassed waterways are vegetated channels that transport runoff from a field. Vegetation within the waterways reduces flow velocities and protects the waterway from the scouring potential of concentrated flow. Grassed waterways are generally broad and shallow channels; the channel simulated in SWAT+ has a side slope of 8:1. Grassed waterways trap sediment and other contaminants by reducing flow velocities, which increases deposition of particulate contaminates.

This user-defined coefficient is used to compute the sediment transport capacity in the grassed waterway.

The name of the grassed waterway record is a primary key referenced by grww in landuse.lum. All names in the grassedww.str file must be unique.