20220492 Ver 1_Corr Alum Culvert Calc_20220324

Ravensbrook Dam Culvert Replacement--Cor Alum.
25 Yr Int.=
A= Area =
IA=
C= RO Const.=
3.62 in/hr
10,561,840 pr sf =
1,744,440 sf =
242.47 ac
40.05 ac
0.161 Type mix
0.292
soil =
Qdes (25-year) (cfs)
255.79
Orifice Coeff. (Cd)
0.6
Number of Barrels
1
Length (ft)
62
Entrance Invert ele. (ft)
356.70
Aggregate Loss (Ke)
0.5
Max. Allow. Upstrm Wtr Surf. Ele. (ft)
364.50
Manning's n
0.024
Expected Tailwater Ele. At Qdes (ft)
357
Center Rd=
366
Exit Invert ele. (ft)
354.75
EOP=
365.70
Headwater Depth HW (ft)
7.80
BOC=
366.20
Q (cfs) (per pipe)
255.79
H to MWSE=
1.70
>.2 ok
Head H (ft) under outlet control
7.5
Cover=
3.69
>.5 ok
Inlet Control for Circular Pipes (by orifice equation)
Q=Cd*A*(2gh)^(1 /2)
where:
can be converted to
Q =
Discharge (cfs)
Q=0.0437*Cd*D^2*(Z-D/24)^(1/2)
D =
Pipe Diameter (in)
and rearranged to solve for D:
Z =
Depth of water above entrance invert (ft)
Cd =
Coeff. Of discharge in British Cust. Units
Trials:
D (in) =
HW/D =
Q(D) (cfs) > 255.79
60
1.6
217.31
66
1.4
256.66
72
1.3
297.80
Za + Pa/Y +Va^2/2g = Zb + Pb/Y +Vb^2/2g + hf + hm + Em
can be converted to:
where:
Za = Zb +[522*Q^2/(D^4)]*[((5096*L*02)/D^1.33) + Ke]
Za =
Wtr. Surf. Ele. Upstream (ft)
Solve above eq. For D
Zb =
Wtr. Surf. Ele. Dwnstream (ft)
Trials
L =
Length of Pipe (ft)
D (in) =
Za (ft) <
364.5
Q =
Discharge (cfs) per pipe
D =
Pipe Diameter (in)
60
360.4
n =
Manning's n
.012 f/RCP
66
359.1
.024 f/CMP
72
358.4
Ke =
Aggregate Loss Coeff.
01111110
.‘`�H CARO .,
EA
027502
S. U , ‘S.
1���11,►►,`3./:-ZI
0.7IFES
0.65 RCP Bell end flush with headwall
0.6 Default
0.51 CMP Projecting from Slope
0.59 Square edeged entrance

Manning's Full Flow
(Circular Pipe):
Select:
area (inA2) 3421.1944
area (ft^2) 23.7582944
Pipe Flow (Manning's Equation):
Number of Pipes= 1 Slope S (ft/ft) 0.0314516
Diameter D (in)= 66 Manning's n 0.024
Qmax (cfs) = 323.29 (based on above S and n)
Vmax (fps = 13.61 (based on above S and n)
Qdes/Qmax= 0.79 Vdes/Vmax= 1 f/s
Velocity @ Design Q (fps) = 13.61 fps
Depth of flow @ Design Q (ft) = 0.5 ft
Culvert Design (Manning's Equation):
Number of Barrels:
1
Q (cfs) 256
Design Q (cfs)
I 255.79
Slope S (ft/ft)
0.0315
Manning's n I 0.024
(by hydraulic
D
radius equal
2.16*Q*n
to Area/Circum.)
^(3/8) D = ft
S = ft/ft
S^(0.5)
Required D (in )_I 60.51
72 Corr. Alum. To allow for 20% area loss due to sedementation
Rip Rap Dissipater
Figure 8.06 a
W-1 (ft)
W-2 (ft)
dmax
min TH
Nominal
TH
Type
RR
d-50
La
(ft)
(in)
0.80
25.0
18
31
1.20
14.40
18
24in.
1
I (In/hr) Determination
Use Fayetteville
2-yrr
10-yr
25-yr
100-yr
g=
149
226
271
341
h=
20
26
28
30
P=
2.5
2.9
5
6.3
25
e of Conc. & I (in/hr)
Drainage
Drainage
calc Tc. Min 5
Tc=
I (in/hr) 25-yr
Area
Area
Length
Height
Tc=
4,726 ft
98 ft
46.91 min.
46.91 Min.
3.62

incl Kirpich K=
2 long overland flow
Composite C=
Soil
%
Type
C
AeB
0.019
B
0.18
AeD
0.151
B
0.18
Bb
0.04
A
0.15
CaB
0.433
A
0.15
CaC
0.243
A
0.15
CbC
0.04
A
0.15
VaD
0.065
A
0.15
W
0.008
0.95
Watershed:
1.00
0.161
IA=
1,490,027 sf existing
95,964 sf exist + potential forest creek
50,424 sf to SCM 2
108,025 sf dam area
1,744,440