I am currently attempting to model a problematic system in Civilstorm. The system consists of a typical pipe and catch basin system that discharges into an underground vault. A picture of the layout is below. I have the vault set up as an underground storage chamber system and I am using the Sewergems Dyanamic Wave Solver.
For smaller storm events the model runs well and seems to give valid results. However, for larger storm events where the vault becomes completely full, the model does not run and I get the following error message. "The model did not converge and no valid results are obtained, check the data or adjust calculation options." I am fairly certain it is the chamber becoming full that is causing the error, because if I increase the capacity of the chamber the model will run for the larger storms.
Unfortunately, this is an existing system and I can not enlarge the chamber. It is also very important that we see the results upstream of the pond when the pond is full. What should I do to get results when the chamber is full? Should I change solvers? Should I model the vault as something else?
Thanks,
George
George,
If the problem isn't directly caused by the storage chamber, which it may be, you'll have to do some troubleshooting to see if you can locate where the problem might be coming from. This wiki on troubleshooting dynamic wave models will help you. If after using these methods you are still having problems it's likely you'll want to submit your model for someone to have a look at. It's pretty difficult to determine where a model might be having trouble without being able to see it.
Changing solvers is usually a good idea as long as all the elements in the model are supported by both solvers and is usually one of the more simple fixes, so most definitely try that with some basic troubleshooting steps before submitting the model for review.
Mark
This wiki on storage chambers may also help you to make certain the chamber is set up correctly.
Ah, this might actually be what you're looking for. This article on modeling a surcharged storage tank is probably the solution.
So I looked at the article on modeling a surcharged storage tank and I added a "chimney" to the model. The chimney is modeling the surcharging as intended. A snapshot of the hydraulic grade for the ponds is below. Once the storms reach the top of the vault, the enters the chimney and you can see the elevation of the HGL.
However, the pipes entering the vault do not seem to be affected by the water elevation in the vault. Also below is a snapshot of the flow through one of the pipes into the vault. For reference the upstream invert of this pipe is 854, which is lower than the pond elevation. If the downstream HGL is above the invert of the pipe, shouldn't the pipe exhibit no flow or possibly even reverse flow?
Hello George,
Could you send us a copy of the model files to review? This link has information on how to send this.
Regards,
Scott
George Summers.stswpkg.zip
Attached is the zip for my Civilstorm Model. I am going out of town next week and need to try and wrap this up by the end of the day tomorrow. Any help this afternoon or tomorrow morning would be greatly appreciated.