Subject:   Mass Balance for Water Quality in SWMM 5

The rainfall concentration is listed in the wet deposition row of the Runoff Quality Continuity Table, the washoff such as EMC washoff is listed in the Surface Runoff row.  If you are simulating groundwater quality then it is listed as a separate value in a row of the Quality Routing Continuity table alongside RDII quality, DWF quality and WWF quality. 

via Blogger http://www.swmm5.net/2013/08/mass-balance-for-water-quality-in-swmm-5.html