Sanitary Sewer Modelling with SWMM

Hi All

Is it possible to model a sanitary sewer network with SWMM?
How are pumps and I incorporated?

Regards.

Tilake Weerasekara
Tilake.Weerasekara@GRIFFITH.NSW.GOV.AU

Tilake,

Yes, sanitary sewer models are commonly modeled in SWMM. You can best answer you own question about the format of the pumps and RDII? or I/I in by looking at the Extran.doc file for the pump input types (H1 lines) and the Runoff.doc file for the method of modeling RDII in SWMM.

The RDII method uses the F4 and H5 lines to characterize the infiltration or defect flows to a Runoff Sewershed. The flows are simulated with three unit hydrographs with nine parameters. The parameters are the r1, r2 and r3 values; the t1, t2, and t3 parameters and the k1, k2, and k3 values for the three unit hydrograph. The r values are the fraction of flow from a storm event that eventually infiltrates into the laterals, manholes or broken pipes of the sanitary network. The t values indicate the time base of the unit hydrographs and the k values the shape of the unit hydrograph.

The pumps defined on the H1 line may be pumps rated by wet well volume, depth at the wet well, dynamic head across the pump or elevation at the wet well with pump on and pump off elevations. I hope this helps you.

Best Regards,

Robert Dickinson
DickinsonRE@CDM.COM

Hi Rob,

Thanks for this information and your time.

I am new to SWMM. I have made a start with SWMM5 Beta - (still in the familiarisation stage). I also received a direct reply from Jim Dumont as well. He says my options are as follows (with respect to previous version of SWMM):

1. For simple sanitary sewerage generation and gravity (with no surcharge conditions)pipe routing with some lift stations, use TRANSPORT Block.
2. For sanitary sewerage generation and surcharged pipe flows and complex pump stations, use TRANSPORT Block followed by the EXTRAN Block.
3. Sanitary sewage generation, sewer inflow and infiltration, and surcharged pipe flows will involve RUNOFF Block, TRANSPORT Block and EXTRAN Block.
4. It is advisable to limit things to the TRANSPORT Block wherever possible to avoid the issues of transferring information between Blocks of SWMM.

It looks to me as if all the blocks (Runoff/Transpot/Extran) are now incorporated in V5. Is this correct? In the help file in V5, I do not see any reference to I/I. Will External Inflows feature help? According to the web, groundwater (& snowmelt) feature(s) will be incorporated in V5 very soon. Does this groundwater mean (or deal with) RDII? Sanitary sewer modelling being my objective at this stage, should I start looking at V44h instead of V5?

Regards.

Tilake Weerasekara
Tilake.Weerasekara@GRIFFITH.NSW.GOV.AU