Pumps (SWMM)

Pumps are used to model the pumping of fluid to higher elevations in the network. A pump may be considered to be an 'ideal' pump; this is a transfer pump whose flow rate equals the inflow rate at its upstream (inlet) node. For all other 'non-ideal' pumps, the relationship between a pump's flow rate and conditions at its upstream (inlet) and downstream (outlet) nodes can be defined in a pump curve, which is associated with the pump.

The on/off status of pumps can be controlled dynamically either by specifying startup and shutoff water depths for the upstream and downstream nodes which the pump is attached to, or through user-defined Control Rules. Rules can also be used to simulate variable speed drives that modulate pump flow.

In SWMM networks, pumps are directional devices that are not allowed to have reverse flow through them. The methodology and equations used to determine flow through a pump are described in the SWMM Reference Manual, Volume II, Hydraulics.