Applicants shall use the following calculation and assessment methods:
Required Culvert area (square feet) = H x (W1 + W 2)
Table 1. Round culvert diameters and corresponding culvert area.
Culvert diameter (in.) | Culvert area (sq. ft.) |
18 | 1.80 |
24 | 3.10 |
30 | 4.90 |
36 | 7.10 |
42 | 9.60 |
48 | 12.60 |
54 | 15.90 |
60 | 19.60 |
66 | 23.80 |
Note: To find the area of any round culvert, use the following equation:
Culvert diameter (in.) divided by 2 = _____ divided by 12 = _____ (radius in ft.)
Radius x Radius x 3.14 = _________ (area of culvert in sq. ft.)
Table 2. Pipe arch dimensions and corresponding culvert area.
Pipe width or span (in.) | Pipe height or rise (in.) | Culvert area (sq. ft.) |
43 | 27 | 6.4 |
50 | 31 | 8.7 |
58 | 36 | 11.4 |
65 | 40 | 14.3 |
72 | 44 | 17.6 |
73 | 55 | 22.0 |
85 | 54 | 25.3 |
81 | 59 | 26 |
87 | 63 | 31 |
95 | 67 | 35 |
103 | 71 | 40 |
Wis. Admin. Code Department of Natural Resources NR 320.07