This command calculates the runoff and storage volumes for a detention pond. The program uses the method from the TR-55 program as described in the Urban Hydrology for Small Watersheds manual.
The command is run through the dialog box shown here. When the input values are filled in, click on the Calculate button to obtain the output values. The drainage area can be either entered directly or selected from AutoCAD by clicking on the Select Area button and then selecting the closed polyline from the screen. The peak inflow will use the value calculated in the Peak Flow-Graphical Method command. Likewise the runoff Q will use the value from the Curve Numbers & Runoff routine.
The output of this command, the storage volume value, can be applied to the Design Bench, Valley or Rectangular Pond routines. There is also an option to generate a TR-55 6A report.
Pulldown Menu Location: Structure > Detention Pond
Sizing > TR-55 Method
Keyboard Command: dpond
Prerequisite: None