| Product(s): | PondPack, SewerGEMS, CivilStorm |
| Version(s): | V8i, CONNECT Edition |
| Area: | Modeling |
Problem
What is the purpose of the "Elevation (on)" and "Elevation (off)" fields in the properties of an outlet component in the Composite Outlet Structure editor?
Solution
The on and off elevation fields in the properties of a composite outlet structure component enable you to specify the headwater elevation range in which the component contributes flow. When the pond's water surface elevation is below the "elevation (on)" or above the "elevation (off)", zero flow will pass through the structure, but can still pass through other structures unless they are downstream of the structure in question per the "downstream ID" field. For pond water surface elevations in between (elevations that are above the "elevation (on)" but below the "elevation (off)") flow can pass through the outlet component based on its rating table.
For example if you have a weir outlet component representing a notch on the side of a riser (see article below), you can use the on/off fields so that flow passes through the weir at headwater elevations below the top, and turn it off at headwater elevations above the top so that the weir component that is built into the riser "takes control" (so that you are not double-counting flow from both weirs). Using this example the "elevation (on)" would be left at zero or set to the invert of the weir, and the "elevation (off)" would be set to the riser crest elevation.
These fields are only used in special cases and would normally be left at zero, which means that the structure can always contribute flow (based on its rating table)