I am trying to figure out the hydroCAD program. I have ran through it and have a hydrograph that has an inflow and a primary plotted on it. I am assuming the inflow is the runoff entering the pond. What does the primary mean? Thanks.
A subcatchment or reach has only a single outflow. But a pond can have multiple outflows, depending on how you configure the outlet devices. These appear as primary, secondary, tertiary, and discarded flows. The total of these is displayed as the "Outflow"
If you're getting multiple outflows, it's because the pond outlets aren't all routed to the same place. The device routing can also be used to model compound outlet structures, such as a riser.