Outlets (SWMM)

Outlets are used to model special head-discharge relationships that cannot be modelled by pumps, orifices, or weirs. They are flow control devices that are normally used to control outflows from storage nodes, such as a pond, and may contain a flap gate to prevent blackflow.

A rating curve, which determines an outlet's discharge flow as a function of either the freeboard depth above the outlet's opening or the head difference across it, may also be associated with an outlet. Control rules may also be used to dynamically adjust this flow where applicable.