Understanding Flow (Additional Subsurface) and Flow (Additional Carryover)

Product(s): SewerGEMS, StormCAD, CivilStorm
Version(s): 08.11.XX.XX and 10.00.XX.XX
Area: Modeling


What are the fields "Flow (Additional Subsurface)" and "Flow (Additional Carryover)" and when should they be used?


These flows represent pre-calculated flows can be added directly to a catch basin.

If it the flow to be included is subsurface flow entering inside the catchbasin vault below the surface, you would use "Flow (Additional Subsurface)."

If the flow is overland flow that approaches the inlet opening (and can be captured or bypass), you would use "Flow (Additional Carryover)". 

These are useful in cases where you do not want to include catchment hydrology or do not want to include upstream gutter hydraulics.


Why isn't the catch basin property "Flow (Additional Carryover)" included in the System Flows alternative?

Flows that enter through the subsurface are considered System Flows and are therefore entered in the System Flows alternative as shown below.

Flows that are applied above the surface are considered Hydrology Flows and are therefore entered in the Hydrology alternative as shown below.

See Also

Understanding known flows

Entering catchment data directly to a catch basin