The SWMM method can simulate the generation, inflow and transport of any number of user-defined pollutants. Required information for each pollutant includes:

Co-pollutants can also be defined. For example, pollutant X can have a co-pollutant Y, meaning that the runoff concentration of X will have some fixed fraction of the runoff concentration of Y added to it.

Pollutant buildup and washoff from subcatchment areas are determined by the land uses assigned to those areas. Input loadings of pollutants to the drainage system can also originate from external time series inflows, as well as from dry weather inflows.

Option

 

Description

Pollutant Selector

Select the pollutant to edit.

Add

Click to add a new pollutant to the project.

Delete

Click to delete a pollutant from the project.

Pollutant Name

The name assigned to the pollutant.

Units

The concentration units - (mg/L, ug/L, or #/L (counts/L) - in which the pollutant concentration is expressed.

Rain Concentration

Concentration of the pollutant in rain water (concentration units).

Ground Water Concentration

Concentration of the pollutant in ground water (concentration units).

Infiltration/Inflow Concentration

Concentration of the pollutant in any Infiltration/Inflow (concentration units).

Dry Weather Flow Concentration

Concentration of the pollutant in dry weather flow.

Initial Concentration

Concentration of the pollutant at the start of the simulation.

Decay Coefficient

First-order decay coefficient of the pollutant (1/days).

Snow Only

YES if pollutant buildup occurs only when snowfall occurs; or NO otherwise (default is NO). Double-click to toggle between YES/NO.

Co-Pollutant

Name of another pollutant whose runoff concentration contributes to the runoff concentration of the current pollutant. An example of a co-pollutant relationship would be where the runoff concentration of a particular heavy metal is some fixed fraction of the runoff concentration of suspended solids. In this case, suspended solids would be declared as the co-pollutant for the heavy metal.

Co-Fraction

Fraction of the co-pollutant's runoff concentration that contributes to the runoff concentration of the current pollutant.

You can edit the properties of existing pollutants, create new pollutants or delete existing pollutants.

See Also Land Uses, Pollutant Buildup, Pollutant Washoff, Inflows Editor.