Explicit EPA SWMM

Question

I am looking for clarification and deferences when doing the model using EPA SWMM; so if I am using PCSWMM , InfowSWMM and Bentley SewerGEMS (Explicit EPA SWMM) to do a model network for a stormwater network, will be any discrepancy in the output since all of them using same engine (5.1.013)? if yes what is the discrepancy percentage and how will affect the design of the network? 
 Regards, Mohamad Azzam

Jesse Dringoli · Accepted Answer

Bentley cannot be aware of what changes to the SWMM solver have been done in InfoSWMM or PCSWMM, so we cannot comment on our revision of the SWMM solver versus the revision of the SWMM solver used in those other competitor products. It may be best to contact their vendor to understand the assumptions/changes they have made, if any and compare with the information we have provided regarding SewerGEMS. 
 As mentioned earlier in this thread, SewerGEMS has the ability to select the basic SWMM solver so that you know results will be compatible with EPA-SWMM. If those other software packages have a similar ability (or if their solver is already using the basic/unchanged SWMM solver), then you can indeed expect to see comparable results for the same exact model setup. 
 With the "Bentley enhanced" version of the SWMM solver, there are specific enhancements we have made as noted earlier, which could be considered as providing more accurate results for those modeling situations. Again, we do not know what InfoSWMM/PCSWWM has done (if anything) to enhance the SWMM solver on their side, so it is difficult to compare those enhancements with the Bentley enhancements.

Sushma Choure · Answer

Hello Mohamad, 
 As of SewerGEMS and EPA-sSWMM, latest version of SewerGEMS uses EPA-SWMM 5.1.012 solver, so results between these 2 should match. 
 If you are seeing results that don't match then please provide the model files (.stsw, and .sqlite) and let us know what results appear to be inconsistent. 
 The following article lists the versions of EPA SWMM used by each version of SewerGEMS and CivilStorm. 
 EPA SWMM solver versions used by SewerGEMS and CivilStorm

Ming Jin · Answer

Mohamad, 
 There is no results difference between Bentley extended SWMM solver and EPA SWMM, although we have added many additional results. The difference between Bentley SWMM solver and EPA SWMM is that we added some additional calculation features, such as node head loss calculations, incorporating HEC-22 inlet calculations, H2S calculations, Tractive force, etc. We also added a transition stability enhancement with a new calculation option. 
 Ming Jin

Jesse Dringoli · Answer

See the section "Solver Compatibility - EPA SWMM solver vs. "Bentley Enhanced"" in the wiki article that Sushma mentioned. The ability to choose between the basic solver and "Bentley enhanced" version was added in version 10.02.00.55.

Explicit EPA SWMM

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