PERMFILE117357

• Permit No: M1988112
• IBM Index Class Name: Permit File
• Doc Date: 11/8/1988
• Section_Exhibit Name: APPENDIX H DRAINAGE AREAS AND WASHED PRINTOUTS
• Media Type: D
• Archive: No

t TABLE H.2
RIPRAP SIZING
i 1
' Reference: Urban Drainage Manual, Wright-McLaughlin Engrs, 1969.
SWRDF - Haul Road Culvert Riorao Sizing
t "
2-54
CMP - each conveys 107.5 cfs or 1/2 of the 100-yr flood
' Q/Dz.s = ]07.5/(54/12)Z•s = 2.5 < 6.0 use Fig 5-7
4t tailwater depth is unknown, use Yt/D = YL/H = 0.40 in Fig 5-7
' Q/D~.s = 107.5/(54/12)l~s = 11.26
Figure 5-1 yields a type M riprap or 12" dso
t
f
E
t
t
i
pro
x
en
o
ect
on
' Q/Dz.s = 2.5 and YL/D = 0.4
Fig 5-9 yields:
' 1 = 5 or 2 tan 6 - 0.2
2 tan e'
' L = (I/2 tan )(A~/Yt - W)
where: AL = Q/V
t V = acceptable velocity, use 5.5
Y /D = 0.4 YL = 0.4 x 54/12 = fps _
I.80'
A{, = 107.5/5.5 = 19.55
W = D = 54/12 = 4.5'
' '
'
L = d(5)(19.55/1.80 - 4.5) = 31.8
, say 35
' Summar use 12" d o riprap for a distance of 35' D/S of culvert outlet
use ~ x dso for riprap thickness in channel bottom, .e., 24"
' use 1.~ x dso on channel side slopes, i.e., 18"