Pumps in the GVF-rational solver must have a wet well immediately upstream of the pump connected by a single conduit or pressure pipe with zero head loss; the exception being that a pond with no control structure can be connected to a downstream pump - in this case the pond would not need to be connected to a wet well. This accurately models submersible pumps and the suction losses in dry well pumps are usually small. Parallel pumps and variable speed pump batteries are not allowed. If detailed analysis of pumping and force (rising) mains is required, one of the other solvers should be used.

The following hydraulic and hydrologic behaviors apply to pumps and wet wells when using the Gradually Varied Flow - Rational engine:

Flows:

When the status of the pump is ON, then pump discharge is equal to wet well inflow. When the status is OFF, pump discharge is set to zero.

Profiles:

The pump curves specified in the other solvers are not used by the GVF solver. Instead, the suction head of the pump is taken as the wet well level and the discharge head on the pump is determined using the GVF backwater analysis from downstream elements. The heads can be used to determine pump selection.