Flow controls are considered to be either online or offline in MicroDrainage models, while InfoDrainage allows these to be specified as outlets.

Online/Outflow- restricts the flow directly out of the location.

Offline/Overflow - acts as an overflow with flow either being lost or directed to another location.  If a Loop to Index has been specified, a No Delay connection is created to connect the flow from the outlet to the destination node.

Single Flow Controls

The following flow controls are mapped directly:


This is imported as either a connection or an orifice.


  • If a Loop to Index has been specified, then the pipe is imported as a connection and connected to the destination node.
  • Otherwise, an Orifice outlet is created with the diameter set to the pipe diameter.

Third party MicroDrainage flow controls

Hydro-Brake® Classic, Crown Vortex Valve®, Garastor, ACO Q-Brake, and Hydrok Hydroslide are all third party flow controls, which are not supported and cannot be mapped directly. For each of these controls the Depth/Flow table has been created and imported.

Complex Flow Controls

Occasionally, more than one flow control is required to restrict the flow for varying levels at a given location.  To support this, the concept of a complex flow control was introduced to allow multiple flow controls to be considered at the same location. 

These are imported as a multiple outlet.