Pollutants (SWMM)

Pollutants are used to define the water quality constituents entering the SWMM network from one or more of the following sources:

• direct precipitation
• surface runoff
• lateral groundwater flow
• rainfall dependent inflow/infiltration (RDII)
• dry weather flow (dwf)

Each pollutant can have a co-pollutant assigned to it. During a simulation, a specified fraction of the co-pollutant is added to the concentration of the main pollutant.

The build up and washoff of pollutants during a simulation is determined by the Land Uses associated with each subcatchment in the network, and for each subcatchment, you can also specify, if applicable, the quantity of the pollutant which has already built-up before the simulation starts.

The removal of pollutants is defined by a set of treatment functions which are applied to nodes in the network.

Pollutant parameters are edited in the Pollutant Grid Window of the Subcatchments Grid or the Pollutant Property Sheet.