1. Watershed area

2. Watershed slope

3. Runoff curve number from Tables 2.2 — 2.4

4. Peak flow from watershed for 10 year storm
   Table 4.25-M to 4.31-M (4.25-I to 4.31-I)

5. Peak flow from watershed for 25 year storm from
   Table 4.25-M to 4.31-M (4.25-I to 4.31-I)

6. Obtain the storm duration for a 10 year storm from
   Table 4.25-M to 4.31-M (4.25-I to 4.31-I)

7. Obtain the storm volume expected for a 10 year storm from
   Table 4.25-M to 4.31-M (4.25-I to 4.31-I)

8. Determine the slope of ponding area upstream from storage berm from field measurements

9. Determine slope of side of ponding area upstream from storage berm from field measurements. If side slopes are different use the average of the two slopes.

10. Determine soil loss expected above ponding area from
    Table 4.32-M (4.32-I)

11. Storage required for eroded soil for 15 year life expectancy
    Line (10) x Line (1) x 15 = ________ x ________ x 15
    = ________ tonnes x 0.68 m³/tonne
    = ________ m³
    (________x ________ x 15
    = ________ tons x 21.7 ft³/ton
    = ________ft³)

12. Total pond storage
    Line (7) + Line (11)
    = ________ + ________
    = ________m³ (________ft³)

13. Determine volume factor
    Line (12) x Line (8) x Line (9)
    = _______ x _______ x _______
    = _______m³ (_______ft³)

14. Obtain pond depth (design berm height) from
    Table 4.33-M (4.33-I)

15. Determine pond length
    (Line (14) ÷ Line (8)) x 100
    = ________ x 100 m (________ x 100 ft)

16. Determine maximum pond width
    (Line (14) ÷ Line (9)) x 200
    = ________ x 200
    = ________m (________ ft)

If pond side slopes vary by more than 50%, the calculated pond width will be different than the actual field pond width. For accuracy, separate the sides and calculate individually.

17. Obtain maximum flooding time from Table 4.34

18. Determine outlet capacity
    (Line (7) ÷ (Line (17) - Line (6)) x 0.000277
    = _______ x 0.000277
    = _______ m³/s (_______ft³/s)

19. Determine the riser pipe and horizontal pipe sizes. Complete the following:

• horizontal pipe slope

• horizontal pipe diameter (Table 4.18-M (4.18-I) or Figure 4.31 or OMAFRA Publication 29, Drainage Guide for Ontario

• riser pipe diameter (Tables 4.19-M to 4.22-M (4.19-I to 4.22-I))

• orifice diameter (if required) (Tables 4.21-M to 4.22-M (4.22-I)

20. Check emergency overflow spillway type to be used

21. Determine emergency overflow spillway capacity from Line (5)

22. Determine emergency overflow spillway notch dimensions from Table 4.35-M (4.35-I) to meet capacity requirements from Line (21)

• notch width (L)

• notch width (D)

23. Actual berm height (Note: Freeboard is 10% of Line (14) to maximum of 0.15 m (6 in.))
    Line (14) + freeboard + notch depth (D) (Line (22))
    = _______ + _______ +_______
    = _______ m (_______ ft)

24. Actual berm length
    (Line (23) ÷ Line (9)) x 200
    = _______ x 200
    = _______ m (_______ ft)

25. Berm side slope (minimum 2:1; maximum 8:1)

26. Top width of berm
    (Note: Default width of 1.2 m (4 ft))

27. Bottom width of berm
    Line (26) + (2 x Line (23) x Line (25))
    = _______ + (2 x _______ x _______)
    = _______m (_______ ft)

28. Earth volume for berm from Table 4.36-M to 4.38-M
    (4.36-I to 4.38-I)