Wetwell minimum elevation exporting as invert elevation in SWMM 5 file

  Product(s): Bentley SewerGEMS, SewerCAD
  Version(s): 08.11.05.113
  Environment: N\A
  Area: Output and Reporting

Problem

When exporting to SWMM 5 format (File > Export > SWMM 5), the wetwell “minimum” elevation in SewerGEMS is exported out as the wetwell invert elevation in SWMM5. Shouldn't the “base” elevation be exported out as wet well invert elevation in SWMM?

Solution

This is expected. The minimum elevation defined in SewerGEMS is expected to be the lowest possible water level. For a wetwell, this would be the physical invert of the tank itself. EPASWMM 5 only has an invert (wetwell bottom), max depth (wetwell top) and initial depth.

The base elevation in SewerGEMS is only for reference purposes and does not have a hydraulic effect. In a typical sewer wetwell, the base elevation would be the same as the wetwell bottom/invert (the minimum elevation) and would be set equal in SewerGEMS, but in some cases the actual bottom of the tank structure is lower than the invert. (think of an elevated storage tank in a potable water system) It also acts as a datum when defining the wetwell bottom, initial and top elevation as a "level". (Operating Range Type field). EPASWMM does not currently have such an ability.

When clicking the base elevation, min, max and initial fields in the wetwell properties, look at the description at the bottom.

See Also

"Pressure pipe stop invert is higher than the connected wet-well base elevation..."

Where can I find the definition of a property?

Anonymous
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