Designing pipes for no flood criteria

Step-by-step:

For drainage designs to be valid in the UK, they first have to meet the no-surcharge criteria, and then they must meet the no-flood criteria. In this example, the no-surcharge criteria have already been met, so now, it is necessary to check the no flood criteria.

1. On the ribbon, Rainfall/Pollutants tab, click Rainfall Manager.
2. In the Rainfall Manager Items tree view, expand the Design Storms node, then the FSR node, and select Rain 1 to edit it.
3. Click the Return Periods tab.
4. Click Add to add another return period.
5. Click Add to add another return period.
6. Enable the Use option for the new 30-year storm, and disable the 2-year storm to deactivate it.
   
7. Click the Storm Durations tab.
8. Leave all nine of these storms active.
   
9. Click the Parameters tab.
10. Enable both Summer and Winter.
    
11. In the Rainfall Manager toolbar, click Save.
    
12. Click Close.
13. On the ribbon, Analysis tab, Criteria panel, click Analysis Criteria.
14. In the Analysis Criteria dialog box, enable Rain 1.
15. Set the Output Interval to 1
16. Expand the Time Step drop-down and select Default.
17. Set Urban Creep to Apply Global Value and leave the percentage set to 0.
18. Set the Junction Flood Risk Margin to 300
19. Deselect Perform No Discharge Analysis.
20. Click OK.
    
21. On the ribbon, Analysis tab, Analysis panel, click Validate.
22. In the Validate dialog box, ensure the validation is okay.
    
23. Click OK.
24. Save the file.