WaterCAD and SewerCAD

[doorf]

For a network analysis project, I need to know the interoprability between watercad and sewercad (e.g. if the model is built in sewercad, can we import it to watercad and use it?) and what are the issues involved.

On a more theoretical note, I also want to know if the two softwares use different solution algorithms and modules as it appears that there is significant difference in their solution times (15 minutes for sewercad as against 1-2 minutes for watercad). I know that both of them use genetic algorithms.

I am aware that the basic purpose of the two is for different waters and there are some associated differences such as watercad does not have gravity mains and loading to wetwells with diurnal variations. Does anyone also know to get around this issue if we model wastewate network in watercad? Any insights/ comments are welcome.

Thanks

Doorf

 

[francesca]

I've never had want to import a WaterCAD model into SewerCAD, so I don't know if it's possible, but I strongly suspect that it isn't; it's not possible to import a SewerCAD model into another SewerCAD model directly. (You can export a SewerCAD model to MS Access database and import the database, but there are remaining glitches that you have to fix yourself.)

I somewhat doubt that exporting a WaterCAD model to a database would give you much joy reimporting to SewerCAD because the variables (database fields) are quite different.

My experience with SewerCAD, which involved many small projects and one 40-lift station/900 pipe model, was highly dissatisfying. I've not gotten my feet as wet with WaterCAD (i.e. only many small models), but that experience has been more satifactory. WaterCAD won't let you run a model without a tower, however, so good luck if you only have a known pressure at a node. (You have to convert the pressure in psi to feet and throw in a reservoir.)

I would imagine that the two packages use different solution algorithms because SewerCAD does open channel flow, which WaterCAD does not. They may use the same pressure flow algorithm - I've never looked into this. You can change the calculation increment in the "Run" tab of SewerCAD. I've run an extended period analysis on 5-minute increment pressure calculations (15-minute increment gravity) and boy howdy did I get too much data to deal with and my PII-500 took a long, long time trying to crunch trough it.

Be extremely wary using SewerCAD if you have multiple local high points downstream of the controling high point. SewerCAD cannot model an air (and vaccuum) release valve and you need to employ a complicated work around, particularly if you're modeling an extended period analysis where the controling point shifts during the run.

Before my company purchased SewerCAD, they used to use WaterCAD to model pressure sewer systems, and they didn't have too much trouble. I'd use the right tool for the job.

One of the consultants who developed a similar large model (multiple lift stations, manifolding forcemains and hundreds of pipes) refused to use SewerCAD and used SWMM. I can't comment on the suitability of SWMM to the task, but apparently they didn't have half the trouble we had with the gravity/pressure interface issues I alluded to above.

 

[LHA]

Haestad has a user's forum. They should be able to give you an answer

Remember: The Chinese ideogram for “crisis” is comprised of the characters for “danger” and “opportunity.”
-Steve

 

[TWPE]

Because WaterCAD only deals with full pipes and SewerCAD can handle both pressure adn graavity pipes, you can't directly import models from one program to the other. If you need to shuttle files between the two programs, contact Haestda/Bentley tech support.

Concerning issues with force mains with intermediate high points, you should model from the pump to the highest point as pressure pipe and pipes after that as gravity pipes (becuase they may flow partly full under certain conditions). Beleive me that SewerCAD is much easier to use for this type of problem than SWMM.