Modelling StormWater Attenuation Tank With Outlet Pumps

Hello Sayed,

Regarding the size of the tank, CivilStorm will let you know if a tank (or pond, as that is what appears to be modeled in the model you are providing) is full or overflowing, but it will not design it for you. CivilStorm comes with a tool called PondMaker that can help with the design of the pond. Note that the Explicit solver works best with Elevation-Area pond types.

Regarding the pump flow, the issue is likely related to the on and off elevations for the pump compared to the pond elevation. The pond has a maximum elevation of 3 meters, while the on elevation for the pump is 33 meters. You will want to adjust one of the other of these. I would recommend not setting the on and off elevations to the maximum and minimum elevations of the pond (or tank, if you use that element). 

Regards,

Scott

Hi Scott

Thanks for your answer , but i do not understand what you mean by "the Explicit solver works best with Elevation-Area pond types"

Regards

Sayed Elhagar

When your model is computed, the following user notifications are returned:

"SWMM does not directly support elevation-volume curves. An approximate depth-area curve was generated and applied to the SWMM engine."

Using the pond Volume Type "Elevation-Area" would reduce the model's complexity, get rid of the user notification, and ensure that your entered values are used (instead of an approximation).

"The upstream link of the pump is non-virtual.  The SWMM engine will treat this link as virtual."

"When using the explicit solver, it is preferable that pumps should be connected immediately upstream and downstream to short, virtual links."

A pressure pipe can be set as a virtual pipe through the properties dialog.

What is a virtual pressure pipe and how virtual pipes are handled by each solver?

When your model is computed, the following user notifications are returned:

"SWMM does not directly support elevation-volume curves. An approximate depth-area curve was generated and applied to the SWMM engine."

Using the pond Volume Type "Elevation-Area" would reduce the model's complexity, get rid of the user notification, and ensure that your entered values are used (instead of an approximation).

"The upstream link of the pump is non-virtual.  The SWMM engine will treat this link as virtual."

"When using the explicit solver, it is preferable that pumps should be connected immediately upstream and downstream to short, virtual links."

A pressure pipe can be set as a virtual pipe through the properties dialog.

What is a virtual pressure pipe and how virtual pipes are handled by each solver?