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

NR 320.07 Note Note: To find the area of any round culvert, use the following equation:

NR 320.07 Note Culvert diameter (in.) divided by 2 = _____ divided by 12 = _____ (radius in ft.)

NR 320.07 Note 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

NR 320.07(3) (3) Culvert length determination. The proper culvert length is determined by the following calculation:

NR 320.07 History History: CR 04-084: cr. Register April 2005 No. 592, eff. 5-1-05.