We use 20 mm, 25 mm and 30 mm rains to size the pond. For example, the Rating Curve “20mm” is sized under 20 mm rain for the scenario “Post-20mm-detention”, and “20mm-10mmIA” is sized under 20 mm rain for the scenario “Post-20mm-detention-10mm-IA”. The similar naming rule is applied to the other control scenarios.

The rating curves can be obtained from single-event simulations. For your exercise, please find the single-event model “…/model/solution/Detention Ponds – Single-event.voprj” and refer to tutorial – Sizing a Pond Using the Route Reservoir Command

You can find the rating curve for each control scenario in the sheet “Rating Curve” of the Excel file “…/data/Cross Section and Rating Curve.xlsx”. Simply copy and paste them to each scenario to continue the exercise for the rest of this tutorial.

For example, in the scenario “Post-20mm-detention”, select the RouteReservoir command on the Schematic view. Click the button next to the field Rating Curve in the Properties tab to open the Discharge Storage Editor window.

Open the EXCEL file and copy the corresponding rating curve table without header by Ctrl+c.

Go back to VO. Click on the first cell under the DISCH column in the Discharge Storage Editor window. Paste the copied table to the Discharge Storage Editor by Ctrl+v.

Use Scenario Comparison in the Simulation toolbar to compare the flow results. It can be seen that with the re-sized pond, the impact from new development is mitigated and the similar flow as under existing condition is achieved. Select from the drop-down list Design Storm to view the comparison results under 25mm and 30mm design storms.