Adjusting the Q/Qp-T/Tp Unit Hydrograph
Q/Qp-T/Tp is a dimensionless unit hydrograph that is used with the SCS Unit Hydrograph method. The Qp and Tp are determined based on subarea characteristics. Typically, the SCS method uses a default curvilinear unit hydrograph. Drainage and Utilities allows you to assign your own Q/Qp-T/Tp hydrograph to better suit your local conditions.
To create a new Q/Qp-T/Tp Unit Hydrograph:
- Highlight a catchment in the model.
- In the Property Editor, change the value in the Runoff Method field to Unit Hydrograph.
- Change the Unit Hydrograph Method to SCS Unit Hydrograph.
- Change the Unit Hydrograph Method Type to Dimensionless Unit Hydrograph.
- Click the Dimensionless Unit Hydrograph field and select the Edit Dimensionless Unit Hydrograph command.
- In the Dimensionless Unit Hydrographs dialog that appears, click the New button.
To import a Q/Qp-T/Tp Unit Hydrograph from an Engineering Library:
- Highlight a catchment in the model.
- In the Property Editor, change the value in the Runoff Method field to Unit Hydrograph.
- Change the Unit Hydrograph Method to SCS Unit Hydrograph.
- Change the Unit Hydrograph Method Type to Dimensionless Unit Hydrograph.
- Click the Dimensionless Unit Hydrograph field and select the Edit Dimensionless Unit Hydrograph command.
- In the Dimensionless Unit Hydrographs dialog that appears, click the Synchronization Options button and select the Import From Library command from the menu that appears.
- In the Engineering Libraries dialog that appears, find the desired library, highlight it, and click the Select button to import it.