Risers are represented as a single opening at some elevation above the invert of the pond. The flow from the riser is then controlled by the flow through the downstream conduit of the pond outlet with which the riser is associated.

A riser can be represented as either a stand pipe or a inlet box. The only distinction between the two is essentially the open area and perimeter of the opening. In other words, the area and perimeter for a stand pipe are determined from the input diameter, while the area and perimeter for an inlet box are input directly.