The name of the filter strip record is a primary key referenced by vfs in landuse.lum. All names in the filterstrip.str file must be unique.

Values from 30-60 are most common.

This parameter defines the fraction of the flow within the most concentrated 10% of the filter strip that is fully channelized. Flow that is fully channelized is not subject to filtering or infiltration effects.

Runoff generated upslope a filter strip is not uniformly distributed across the entire length of the strip. 10% of the filter strip can receive between 25 and 75% of the runoff from the field.

A filter strip is a strip of dense vegetation located to intercept runoff from upslope pollutant sources and filter it. Filter strips remove contaminants by reducing overland flow velocity which results in the deposition of particulates. The filter strip area also acts as an area of increased infiltration, reducing both the runoff volume and non-particulate contaminants. The filter strip algorithm used in SWAT+ was derived from White and Arnold (2009). Filter strips reduce sediment, nutrients, bacteria, and pesticides, but do not affect surface runoff in SWAT+.

References:

White, Michael J. and Arnold, Jeff G. (2009): Development of a simplistic vegetative filter strip model for sediment and nutrient retention at the field scale. Hydrological Processes 23, 1602– 1616. DOI: 10.1002/hyp.7291