SWMM - Pollutants

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

• Identification
  • Description - Use a friendly description when the item name is not enough
  • Name - name of the item
    Avoid names that are too long, or that contain the following characters: '*', '>', '<', '/', '\', '"', ':', ';', '|', '=', '`', '#', ',', '?'
  • Priority - Information about the current state of the item. It might be:
    • Neutral: no problem
    • Critical: Some issue that prevents the item from being calculated or used
  • Object Type - Object Type
• Swmm
  • Snow Only - YES, if the accumulation of pollutants only occurs when there is snow cover, NO, otherwise
  • Decay Coefficient - First order decay coefficient of the pollutant
  • Rain Concentration - Concentration of the pollutant in rainwater
  • Dry Weather Concentration - Concentration of the pollutant in any dry weather sanitary flow
  • I&I concentration - Concentration of the pollutant in any infiltration / Inflow
  • Initial Concentration - Concentration of the pollutant in the entire transport system at the beginning of the simulation
  • Underground Concentration - Concentration of the pollutant in groundwater
  • Unit - Unit in which the pollutant concentration is expressed
    • MG/L - milligram / liter
    • UG/L - microgram / liter
    • 1/L - units / liter
  • CoPollutant - Co-pollutants can also be defined in SWMM. For example, pollutant X may have a co-pollutant Y, which means that X's runoff concentration will have some fixed fraction of Y's runoff concentration added to it.
    • Co-Pollutant - Name of another pollutant whose runoff concentration contributes to the runoff concentration of the current pollutant
    • Co-Pollutant Fraction - Fraction of the run-off concentration of the co-pollutant that contributes to the run-off concentration of the current pollutant

The accumulation and elimination of pollutants from the sub-Catchment areas are determined by the land uses assigned to these areas. Pollutant input loads to the drainage system can also originate from external time series inputs as well as from dry weather inputs.