Dynamic Tailwater for Risers

[CSavillle]

I have various SWM facilities that are outletting to stream valleys. These SWM facilities all have risers that then connect to a simple culvert or system with a single or double manhole before outletting adjacent to a stream. For these systems the tailwater is determined by the stream which is computed from a HEC-RAS model. So in the HydroCAD models the tailwater is set in a different model for each recurrence interval storm. The problem is the that tailwater is static throughout the 24-hour storm and the reviewer is not accepting this as an accurate model. Is there a way to enter a table of tailwater elevations for various discharges that way the tailwater is dynamic throughout the storm routing giving a more realistic model of the facility water surfaces and discharges.

 

[TerryScan]

In HydroCAD, you can use a LINK at the discharge location. Edit the link and set as follows:
General tab
Link Type->Internal
Elevation tab
Water Surface Elevation->Table
Check "Multi-Event"
Edit the table with the appropriate tailwater data for each event.