Dekalb Rational Method

HydroCAD^® Stormwater Modeling - Since 1986

Dekalb Rational Method

Background

Runoff hydrographs can be generated for the Universal and DeKalb Rational methods by using a link. After populating the table with the values for the dimensionless hydrograph, set the Discharge Multiplier to the desired peak flow in CFS, and the Time Multiplier to the Tc in hours.

Detailed Instructions

This procedure requires HydroCAD 10.2-4b or later, which includes predefined tables for the Dekalb and Universal hydrographs.

1) Create a link.

2) Select "Import hydrograph from a file..."

3) Select the File tab and click the "Select" button.

4) Using the file selection box, navigate to the HydroCAD\Projects folder and select the "Rational.hce" file.

5) Under "File Hydrograph", select the desired option for Dekalb or Universal Rational Method. Note there are separate options for the Dekalb method depending on the Tc.

6) On the the Advanced tab, set the "Discharge Multiplier" to the desired peak flow in CFS, and the "Time Multiplier" to the Tc in hours.

7) Click "OK" to save the link, and route the outflow as required.

For further details please read about the Rational Method.