Defining Pollutants and Land Uses

Pollutants: Pollutants are defined in the Pollutant Editor of SWMM under the Quality category of the Object Panel. The minimum amount of data needed to define a new pollutant is a name and concentration units. Other characteristics include the pollutant’s concentration in various external (non-buildup) sources (rainwater, groundwater, and RDII), its first-order decay coefficient (day-1) and name of a co-pollutant that its buildup is dependent upon.

Land Uses: Different land uses will generate pollutants at different rates. Land uses are defined in SWMM under Quality Block of the Object panel. Their properties are edited using the Land Use Editor which is divided into three categories: General, Buildup and Washoff as shown in Figure 3.1. The General tab contains the land use name and details on street sweeping for that particular land use. The Buildup tab is used to select a buildup function, and its parameters, for each pollutant generated by the land use. The choice of normalizer variable (total curb length or area) is also defined here. Finally, the Washoff tab is used to define the washoff function and its parameters, for each pollutant generated by the land use, as well as removal efficiencies for street cleaning and BMPs.