Problem

How do I model a retention pond?
HS1121549

Solution

A retention pond has no outlet device draining the pond. Therefore, a retention pond will catch the entire runoff volume into the pond.

There are two ways to calculate the volume draining into a retention pond: Compute a runoff hydrograph and integrate the area under the hydrograph to calculate the total runoff volume.

PondPack performs the volume calculation automatically. If using the SCS CN equation for runoff, compute the runoff depth using the CN and total rainfall depth. To compute total runoff volume, multiply the runoff depth by the contributing area.

To model a retention pond as part of a pond network, simply insert a pond node that does NOT have a pond routing link going out of the pond node. You can model the retention pond as shown below, with outfall set to boundary element and should be connected to the pond. 

See Also