AutoCAD Civil 3D - Stormwater

[#1]

I have developed a model for a project that I am working on. It is a small but complicated model. I have 3 structures with 2 chambers and have weirs and orifices between the chambers. when I ran the model for 100 year storm and look at the animation, weirs go crazy  with zillion peaks. I am not sure why weirs are so unstable. Can anyone please suggest any solution? I have attached the model here.

Thanks,

KD

[#2]

You could try to increase your time step. Just don't go crazy with it or you could miss your true peak if the time step is too large.

[#3]

The best advice is to reduce your time step. When you use a large time step, the volume into the pond pushes the pond highwater level up, which corresponds to a discharge that allows more water to leave than the prior time step. Be sure your pond has sufficient stage information as it increments near the weir level.

[#4]

Matt, Do you mean reducing the routing time under "Analysis Options"? Currently I have it set at 30 sec (default value).

[#5]

Yes, reduce the hydraulic routing time step in Analysis options.