Infiltration SWMM5

[Milena Collodel]

Hi,

I am modelling a drainage network with SWMM 5.0 and the peak flow values simulated are about 6 times lower than the observed ones.

To test what could be wrong, I changed the Horton parameters drastically, but the hydrograph didn't change at all, even when I set the parameters with 0.

Does anyone know how to help me?

Thanks,

Milena Collodel

[Chris Maeder]

I would have to review your model to determine where the problem is. You can post the file here or email it directly to me for me to review it.

[Milena Collodel]

Thank you, I already e-mailed you.

Milena Collodel

[Chris Maeder]

I never got the model. Can you send it again or post it here as a ZIP file?

[Milena Collodel]

I am sorry the file wasn't there.

I am posting it here.

Thank you,

Milena Collodel

[Chris Maeder]

I reviewed your EPASWMM model and have described my observations below.

1. Many links are surcharged and the water is overtopping the irregular cross sections and being lost from the system.
2. Many junctions are flooded and the water is overtopping on those junctions.
3. There is no overbank Manning’s n values defined for the irregular cross sections.
4. No bank stations are defined for any of the irregular cross sections.
5. There are no max depths defined for at least 60 junctions. So, those junctions have no depths at all and hence no water is being stored there and is being lost from the system. That is why your peak flow at the downstream most nodes is not changing.
6. In the “Simulations Options” under “General” tab, the “Allow Ponding” option is unchecked.
7. Also, please check your minimum and maximum infiltration rates defined for all the subbasins.

I have attached a screen capture illustrating the flooding of junctions and links using StormNET.

[Milena Collodel]

Thank you very much, I am going to work on it.

Milena Collodel