20220906_ESC_Calcs2

EROSION AND SEDIMENT CONTROL
CALCULATIONS AND SUPPORTING INFORMATION
FOR
HANSON AGGREGATES INC.
MIDEAST REGION
ROCKY MOUNT QUARRY
MINING PERMIT NO: 33-13
6.78 ACRE TRACT
EDGECOMBE COUNTY, NORTH CAROLINA
CITY OF ROCKY MOUNT
JANUARY 2010
(REVISED FEB. 2010)
RECEIVED
SEP 0 6 1022
°H canoe
LAND QUALITY =o.oFEsstoy �y9'',
MINING PROGRAMSEJ1L 9r;
'� � 022064
�Lsa�4yC� GIR E�ti�C�`
s/alp

HANSON AGGREGATES, INC.
MIDEAST REGION
ROCKY MOUNT QUARRY
EROSION AND SEDIMENTATION CONTROL CALCULATIONS AND
SUPPORTING INFORMATION
CONTENTS;
CHANNEL DESIGN
TEMPORARY SEDIMENT TRAP DESIGN
CULVERT DESIGN
CHANNEL SEND ARMORIZATION
OUTLET PROTECTION/LEVEL SPREADER

Rocky Mount Quarry
Diversion Channel Liner
DIVERSION
CHANNEL
NUMBER
STATION
A
B
C
FROM
TO
1
0+00
4+38
1.03
0.00
GRASS WITH TEMPORARY STRAW WITH NET LINER
2A
0+00
2+94
0.72
0.00
GRASS WITH TEMPORARY JUTE NET LINER
2B
2+94
5+79
0.66
0.00
GRASS WITH TEMPORARY STRAW WITH NET LINER
3
0+00
4+52
1.04
2.00
GRASS WITH TEMPORARY JUTE NET LINER

Rocky Mount Quarry
Diversion Channel Design
reTtuATcn e11u 9%00
DIVERSION
DRAINAGE
TIME OF
CONCENTRATION
12
110
126
1100
C
02
Q 10
Q25
Q100
CHANNEL
AREA
L
H Tc
NUMBER
(Ac)
(Ft
Ft Min
n/Hr
In/Hr
INN
(Mr)
CFS)
(CFS)
(CFS)
(CFS
1
2.2
701.1
45.0
5.0
5.6
7.4
8.3
9.6
0.6
7.3
9.6
10.7
12.4
2A
0.8
841.2
43.1
5.0
5.6
7.4
8.3
9.6
0.6
2.7
3.6
4.0
4.7
28
0.9
841.2
48.0
5.0
5.6
7.4
8.3
9.6
0.6
3.0
3.9
4.4
5.1
3
3.3
874.5
48.5
5.0
5.6
7.4
8.3
9.6
0.6
11.0
14.5
16.3
18.8
Whore;
Diversion number. From Plans
Drainage Area: From Plans (Ac)
Time of Concentration (Tc): Tc = ((L43 / H)"0.385 11128
12 : Intensity (In /Hr) - 2 yr, 24 hr (Raleigh IDFC Curve)
1 10 : Intensity (In Mr) -10 yr, 24 hr (Raleigh IDFC Curve)
126: Intensity (In/Hr) - 25 yr. 24 hr (Raleigh IDFC Curve)
1 100: Intensity (In/Hr) -100 yr. 24 hr (Raleigh IDFC Curve)
C: Run off coefficient (dimensionless)
0 2: 2 yr, 24 hr run off (ds)
0 10: 10 yr. 24 hr run off (ds)
Q 25: 25 yr, 24 hr run off (ds)
0100: 100 yr, 24 hr run off (ds)
2/16/2010

Rocky Mount Quarry
Diversion Channel Design
ESTIMATED VELOCITY
Manning Equation: Q= (1.49/n) X (A) X (R"0.67) X (S"0.5)
Modf)r V= (1.49/n) X (R"0.67) X (S"0.5)
Diversion Channel Dimensions:
Diversion Channel 1
Bottom Width (b):
0 Ft
Side Slope (M):
3 to 1
Average Slope (Ft/Ft):
0.009 Ft/Ft
Roughness Coefficient
0.03 (Grass)
010 REQUIRED: 9.6 eft
ESTIMATED
A
Wp
R
Q
DEPTH
:::COMMENT:
S
t
CFS
P17
0.5
0.7500
3.0000
0.2500
1.41
.
Q= 1.41 < 9.6 Too Shallow
0.75
1.6875
4.5000
0.3760
4.15
2.46
Q= 4.16 < 9.6 Too Shallow
1.03
1 3.1827
1 6.1800
1 0.5150
1 9.68
1 3.04
1 V= 3.04 < 5.5 Fescuegrassed lined
Check for temporary liner requirement:
Diversion Channel Dimensions:
Diversion Channel t
Bottom Width (b): 0 Ft
Side Slope (M): 3 to 1
Average Slope (Ft/Ft): 0.009 Ft/Ft
Roughness Coefficient: 0.02 (Bare Earth)
02 REQUIRED: 7.3 cfa
ESTIMATED
A
WO
R
Q
V
DEPTH
COMMENT:
(SF)
(Ft)
CFS
(FPS)
0.5
0.7500
3.0000
0.2500
2.11
2.81
Q= 2.11 < 7.3 Too Shallow
0.75
1.6875
4.50W
0.3750
6.22
3.69
Q= 6.22 < 7.3 Too Shallow
0.8
1 1.9200
1 4.8000
1 0.4000
1 7.39
3.85
1 V= 3.a5 > 2.5 Temporary Liner Required
Permissible Shear Stress: = T = yds
where: To Sheer Stress
y = unit weight of water = 62.4 lbs/d
d = flow depth = It
s = gradient = fti t
To 0.46 Calculated shear stress is less than 1.45. therefore temporary Straw with Net Liner is acceptable.
2/16/2010

Rocky Mount Quarry
Diversion Channel Design
Diversion Channel Dimensions:
Diversion Channel 2A
Bottom Width (b):
0 Ft
Side Slope (M):
3 to 1
Average Slope (FVFt):
0.009 FVFt
Roughness Coefficient:
0.03 (Grass)
010 REQUIRED: 3.6 Cfs
ESTIMATED
A
Wp
R
Q
V
DEPTH
COMMENT:
(FT)
S
F
CFS
FPS
0.5
0.7500
3.0000
0.2500
1.38
1.85
0= 1.38 < 3.6 Too She low
0.6
1.0800
3.6000
0.3000
2.26
2.09
0= 2.25 < 3.6 Too Shallow
0.72
1.5552
4.3200
0.3600
3.67
2.36
V= 2.36 < 5.5 (Fescue) grassed lined
Check for temporary liner requirement:
Diversion Channel Dimensions:
Diversion Channel 2A
Bottom Width (b): 0 Ft
Side Slope (M): 3 to 1
Average Slope (Ft/Ft): 0.009 Ft/Ft
Roughness Coefficient: 0.02 (Bare Earth)
02 REQUIRED: 2.7 Cfa
ESTIMATED
A
Wp
R
Q
DEPTH
COMMENT:
8F
Ft
CFS
P21
0.5
0.7500
3.0000
0.2500
2.08
.
0= 2.08 < 2.7 Too Shallow
0.55
0.9075
3.3000
0.2750
2.68
2.95
0= 2.68 < 2.7 Too Shallow
0.56
0.9408
3.3600
0.2800
2.81
2.99
V= 2.99 > 2.5 Temporary Liner Required
Permissible Shear Stress: = T = yds
where: To Sheer Stress
y = unit weight of water = 62.4 Ibs/d
d = Row depth = ft
s = gradient = WIt
T= 0.31 Calculated shear stress is less than 0.45. therefore a temporary Jute Net Liner is acceptable.
2/16/2010

Rocky Mount Quarry
Diversion Channel Design
Diversion Channel Dimensions:
Diverslorr Chancre/ 20
Bottom Width (b): 0 Ft
Side Slope (M): 3 to 1
Average Slope (Ft/Ft): 0.017 Ft/Ft
Roughness Coefficient 0.03 (Grass)
010 REQUIRED: 3.9 CIS
ESTIMATED
A
Wp
R
Q
V
DEPTH
COMMENT:
(FT)
SF
Ft)
(CFS)
(FPS
0.5
0.7500
3.0000
0.2500
1.93
2.57
0= 1.93 < 3.9 Too Shallow
0.6
1.0800
3.6000
0.3000
3.14
2.91
O= 3.14 < 3.9 Too Shallow
0.66
1.3068
1 3.9600
1 0.3300
1 4.05
3.10
1 V= 3.10 < 5.5 (Fescue) grassed lined
Check for temporary liner requirement:
Diversion Channel Dimensions:
D►versln Channe/ 20
Bottom Width (b): 0 Ft
Side Slope (M): 3 to 1
Average Slope (FVFt): 0.017 FVFt
Roughness Coefficient: 0.02 (Bare Earth)
02 REQUIRED: 3.0 cis
ESTIMATED
A
Wp
R
Q
V
DEPTH
COMMENT:
3
Ft)
(CFS)
(FPS)
0.45
0.6075
2.7000
0.2250
2.18
3.60
Q= 2.18 < 3.0 Too Shallow
0.5
0.7500
3.0000
0.2500
2.89
3.86
Q= 2.89 < 3.0 Too Shallow
0.51
1 0.7803
3.0600
1 0.2650
1 3.05
3.91
1 V= 3.91 > 2.5 Temporary Liner Required
Permissible Shear Stress: = T = yds
where: T= Sheer Stress
y = unit weight of water = 62.4 lbs/d
d = Row depth = ft
s = gradient = ft/ft
T= 0.55 Calculated shear stress is less than 1.45, therefore temporary Straw with Net Liner is acceptable.
2/16/2010

Rocky Mount Quarry
Diversion Channel Design
Diversion Channel Dimensions:
Diversion Channel
Bottom Vftth (b): 2 Ft
Side Slope (M): 3 to 1
Average Slope (Ft/Ft): 0.006 FVFt
Roughness Coefficient: 0.03 (Grass)
Q10 REQUIRED: 14 A e&
ESTIMATED
A
WO
R
Q
V
DEPTH
COMMENT:
(SF)
(Ft)
(CFS)
(FPS)
0.5
1.7500
5.0000
0.3500
3.20
1.83
Q= 3.20 < 14.5 Too Shallow
0.75
3.1875
6.5000
0.4904
7.31
2.29
Q= 7.31 < 14.5 Too Shallow
1.04 1
S.3248 1
8.2400 1
0.6462 1
14.69
2.76
V= 2.76 < 5.5 Fescue grassed lined
Check for temporary liner requirement:
Diversion Channel Dimensions:
Diversion Channel 3
Bottom VVtdth (b): 2 Ft
Side Slope (M): 3 to 1
Average Slope (FVFt): 0.006 FVFt
Roughness Coefficient: 0.02 (Bare Earth)
02 REQUIRED- Idl a fr.
ESTIMATED
A
WO
R
Q
V
DEPTH
:]Ft
COMMENT:
S
CF8(FPS)
0.5
1.7500
5.0000
0.3500
4.80
2.74
Q= 4.80 < 11.0 Too Shallow
0.6
2.2800
5.6000
0.4071
6.92
3.04
Q= 6.92 < 11.0 Too Shallow
0.76
3.2528 1
6.5600 I
0.4959 1
11.27
3.46
V= 3.46 > 2.5 Temporary Liner Required
Permissible Shear Stress: = T = yds
where: Ta Sheer Stress
y = unit weight of water = 62.4 lbs/d
d = flow depth = ft
s = gradient = ft/ft
T= 0.26 Calculated shear stress is less than 0.45. therefore a temporary Jute Net Liner is acceptable.
2/16/2010

Rocky Mound Quarry
Temporary Sediment Trap
RegUlremeote
SEDIMENT
DRAINAGE
DISTURBED
RUNOFF
HYDRAULIC
ELEVATION TIME OF
INTENSITY (2
INTENSITY
BASIN
AREA
AREA
COEFFICIENT
LENGTH
DIFFERENCE CONCENTRATION
yr)
(10 yr)
06)
(se)
(A)
00 (whin)
rMAW)
(Iam)
TST-1
2.2
2.2
0.6
701.1
45.0 5.0
5.6
7.4
TST-2
1.7
1.7
0.8
841.2
48.0 5.0
6.6
7.4
TST-3
3.3
3.3
0.6
874.5
48.5 5.0
5.6
7.4
COLUMN No.1: BASIN DESIGNATION (SEE PLAN)
COLUMN No. 2: DRAINAGE FROM PLANS
COLUMN No. 3: DISTURBED AREA FROM PLANS
COLUMN No. 4: WIEIGHTFD RUN-OFF COEFFICIENT ( UNIMPROVED AREAS = 0.3, HEAVY INDUSTRIAL AREAS = 0.6)
COLUMN No. 5: FROM PLANS
COLUMN No. 6: FROM PLANS
COLUMN No. 7: Tc = (HYD. LENGTH"3 / ELEV. DIFFERENCE)"0.385 1128
COLUMN No. 8: Q FROM RALIEGH IDFC
COLUMN No. 9: 110 FROM RALIEGH IDFC
COLUMN No.10: 125 FROM RALEIGH IDFC
COLUMN No.11: 1100 FROM RALEIGH IDFC
COLUMN No.12: 02 = C X 12 X A
COLUMN No. 13: 010=CX110XA
COLUMN No.14: 026 = C X 125 X A
COLUMN No. IS: 0100 = C X 1100 X A
COLUMN No. IS: SEDIMENT VOLUME =1805 d X DISTURBED AREA
COLUMN No. 17: SURFACE AREA z 010 x .001 x 43560
REQUIRED
REQUIRED
INTENSITY
INTENSITY
ESTIMATED
ESTIMATED
ESTIMATED
ESTIMATED
SEDIMENT
SURFACE
(25 yr)
(100 yr)
RUNOFF
RUNOFF
RUNOFF
RUNOFF
STORAGE
AREA
(Inmr)
Crum
02 (da)
010 (ds)
025 (da)
0100 leis)
(d)
(at)
8.3
9.6
7.3
9.0
10.7
12.4
3895
4174
8.3
9.6
5.7
7.5
8A
9.8
3057
3276
8.3
9.6
11.0
14.6
16.3
18.8
5904
8328
NOTE:
TEMPORARY SEDIMENT TRAPS DENOTED IN RED ARE TO BE INSTALLED AT A LATER DATE, AS PIT ADVANCEMENT AND OVERBURDEN STORAGE AREA INCREASES

Rooky Mount outm
Tempormy sodm A Trap
START
ELEVATION
START
EkD
ELEVATION DROP
ELEVATION N
aw*iEL
ELEVATION
TST DRAINAGE
TST DISTURBED
DRAINAGE
DISTURBED
HYDRAULIC
CIMNEL
HYDRAULIC
ELEVATION
CHANNEL
ELEVATION
HYDRAULIC
CHANNEL
SLOP£
BEGIN
END
CHANNEL
SI.OPE
BEGIN
DEPTH
END
DEPTH
DROP
HYDRAULIC
ELEVATION
DROP CHANNEL
TST
AREA
AREA
AREA AREA
AREA
LENCTFI
LENGTH
LENGTH
nlSnNG
LENGTH
NO
(EXISTING
ELEVATIONELEVATION
(EXISTING
GRAL>E)
GRADE)
(EXISTM
GRADE)
GRADE)
LENGTH
GRADE)
TST 1
22
22
Ot
22
2.2
701.1
436.4
114.0
73.0
71.0
43.0
4.0
0.9
73.0
89.0
0.9
2.0
20
450
4.0
0 8
Q6
02A
0.8
0.8
8412
293 b
114.0
76 0
74.0
40.0
to
0.3
73.5
T0.9
0.9
1.5
31
41
2.8
TST 2
0.9
0.9
028
0.9
0.9
$41.2
285A
114.0
74.0
67.5
46.5
(1.5
2.3
70.9
86 0
1.7
31
1.5
s80
4.9
TST 3
1 3.3
3.3
03
1 3.3
3.3
874.5
451.E
114.0
69.5
67.5
46,5
2.0
OA
88.0
65.5
0.5
1.5
2.0
48.5
2.5
VKare:
Cakxm 0
1
BASIN DESIGNATION (FROM Pt ANSI
Cokxm 41
2
DRAINAGE (FROM PLANS)
Cakxnn!
3
OIS7WffiEOAREA (FROMPLANS)
CakU>tm •
4
VVEI HTED RUN-OFF COEFFICIENT (UNI11PROVED 0.03. HFAVY INDUSTRIAL 0.6)
Cokxmf!
5
FROM PLANS
C9kxm t
6
FROM PLANS
Coknm st
7
TOO (HYD LWW31 ELEV. DIFFEIM CE)"551128
CCkxm 6
g
Q FROM RAINFALL INTENSITY VALUES
Cok m e
9
00 FROM RAINFALL INTENSITY VALUES
cokrm f
10
125 FROM RAINFALL INTENSITY VALUES
Cokxm 0
11
1100 FROM RAINFALL. INTENSITY VALUES
Cokm 6
17
Q2-CxQzA
Cokxm•
13
Q10-Cx110XA
Cokrm0
14
025-Cx125xA
Columns
15
otoo.cxllooxA
Cokxrm t
16
REQUIRED SEDIMENT - I $M d x DISTURBED AREA
NOTE:
TEMPORARY SEO(MEW TRAPS DENOTED IN RED ARE TO BE INSTALLED AT A LATER DATE.
AS PIT ADVANCEMENT AND OVERBURDEN STORAGE AREA INCREASES

Rocky Mount Quarry
Temporary Sediment Trap
Dimensions
REQUIRED REQUIRED
TOTAL
SEDIMENT
SEDIMENT
SEDIMENT SEDIMENT SURFACE BOTTOM BOTTOM
BASIN
SURFACE STORAGE
STORAGE DRAINAGE WIER
TRAP STORAGE AREA WIDTH LENGTH
DEPTH
AREA DEPTH
VOLUME AREA LENGTH
(off M (ft) (ft)
(ft)
(so (ft)
(0 (ac) (ft)
TST-1 3895 4173.8 6.0 150.0
4.00
4420 2.50
4883 2.2 8
TST-2 3057 3275.6 8.0 100.0
4.00
3360 2.50
3883 0.8 6
TST-3 5904 6326.3 12.0 180.0
4.00
6400 2.50
8595 3.3 10
NOTE:
COLUMN No. 1: BASIN DESIGNATION (SEE EROSION CONTROL PLAN)
COLUMN No. 2: FROM PREVIOUS CALCULATIONS (SEE FIGURE #1)
COLUMN No. 3: FROM PREVIOUS CALCULATIONS (SEE FIGURE #1)
COLUMN No. 4: EXCAVATED BASIN BOTTOM WIDTH
COLUMN No. 5: EXCAVATED BASIN BOTTOM LENGTH
COLUMN No. 6: BASIN DEPTH
COLUMN No. 7: TOP SURFACE AREA AT TOTAL BASIN DEPTH
COLUMN No. 8: SEDIMENT STORAGE DEPTH
COLUMN No. 9: SEDIMENT STORAGE VOLUME PROVIDED
COLUMN No. 10: SEDIMENT STORAGE VOLUME PROVIDED
COLUMN No. 11: WIER LENGTH FROM CHART PG 6.60.03
NOTE:
TEMPORARY SEDIMENT TRAPS DENOTED IN RED ARE TO BE INSTALLED AT A LATER DATE, AS PIT ADVANCEMENT
AND OVERBURDEN STORAGE AREA INCREASES

CHANNEL ARMORIZATION CALCULATIONS
Protection Length, Lp (Figure 8.05f)
Lp/R = 0.604*R"/6/nb
R = hydraulic radius = areatwetted perimeter
nb = Manning Roughness
Maximum Shear Stress, Tb
Tb = KbT
Kb = bend factor
T = computed shear stress in Ib/ft2
Sample Calculation:
Minimum nb = 0.022
Maximum R = 0.6832
Maximum LP = 25.8 feet
Rc = 20
Maximum B = 2'
Minimum Rc/B = 10
Maximum Kb = 1.05 (Figure 8.05e)
Maximum Tb = 1.05*0.78 = 0.82
Riprap DF,0 = 3 inches (Table 8.05g)
Use Class A Riprap

nb
0.5
0.1
0.05
0.01
a7
5.0 10.0 20.0 30.0 50.0
Lpl H
Figure 8.05f Protection length, Lp, downstream from a chanmfl bend.
nb a Manning Floucghnessof the lining material in the bend and the depth of fow {see tab!es 8.05a.. and f}.
R , Hydraulic Radius - Area/wetted perimeter
Adapted from: FHkVA.HEC 15, pg 48 - April 1988
8.05.16 flea-. 12M

Table 8.05f Manning's Roughness Coefficient
n - statue
n value for Depth Ranges
Lining Category
Lining Type
0-0.5 ft
0.5-2.0 ft
2.0 ft
0-15 cm)
15-60 cm) _
_ �a 60 cm)____
Rigid
Concrete
0.015
0.013
0.013
Grouted Rlprap
0.040
0.030
0.028
Stone Masonry
0.042
0.032
0.030
Soil Cement
0.025
0.022
0.020
Asphalt
0.018
0.016
0.016
Unlined
Bare Soil
0.023
0.020
0.020
Rock Cut
0.045
0.035
0.025
Gravel I iiprap
1-inch (2.5-cm) Dso
0.044
0.033
0.030
2-inch (5-cm) Dso
0.066
0.041
0.034
Rock Riprap
6-inch (I5-cm)No
0.104
0.069
0.035
12-inch (30-cm) Dso
--
0.078
0.040
Note: Values listed are rep«sentative values f6i the res]xctive d_pth ranges. Manning's roughness coefficients, n, vary with the flow depih.
DETE0-41NING SHEAR S'IR)✓SS
Shear stress, T, at normal depth is computed for the lining by the following
equation:
T = yds
Td = Permissible shear stress
where:
T = shear stress in Ih/ft�
y = unit weight of writer, 62.4 lb/ft'
d = flow depth in ft
s = channel gradient in ft/ft.
1; the permissible shear stress, Td, given in Table 8.05g is grassier than the
computed shear stress, the riprap or temporary lining is considered acceptable.
If a lining is unacceptable;, select a lining wide a higher permissible shearstress
and repeatt the calculations for normal delith and shear stress. In some cases it
may be necessary to alter channel dimensions to reduce the shear stress.
Computing tractive force around a channel --nd requires special considerations
because the change in flow dircction itnimses higher shear stress on the channel
bottom and banks. Tk- imaxitnum shear stress in a bend, Tb. is given by the
following equation:
Tb = KbT
vnc�re:
Tb = bend shear stress in ib/I't2
e
Kb = bend fac for
T = computed stress For straight channel in lb/ft2
The value of Kb is n:lated to die radius cif curvature of the channel at its center
Iine, Rc, and the bottom width of the channel, B, Figure 8.05c. The length of
channel requiring protection downstream from a bend, I-p, is a function of the
roughness of the lining material and the hydraulic radius as shown in figure
8.05 f.
8.05.12
kL'1'. ]W93

2.o
1.9
1.8
1.7
1.5
Kb 1.5
1.4
1.3
1.2
1.1
Tb = 1<13 1-d
i �
1.0- i
0 2 3 4 5
nc
B
FIgUM 8.05a Ki, factor for maximum shear stress on channel bends.
AdapL,ld from: FHWA-HEC 15. Pg. 47 - April 1988
6 7 a 9 10
Appendices

Appendices
Table 8.05g
Permissible Shear Stresses
for Riprap and Temporary
Liners
Permissible Unit Shear Stress, Tlr
Lining Category
Lining Type
(lb/ft )
Temporary
Woven Paper Net
0.15
Jute Net
0.45
Fiberglass Roving:
Single
0.60
Double
0.85
Straw with Net
1.45
Curled Wood mat
1.55
Synthetic Mat
2.00
dso Stone Size (inches)
Gravel Riprap
1
0.33
2
0.67
Rock Riprap
6
2.00
9
3.00
12
4.00
15
5.00
18
6.00
21
7.80
24
8.00
Adapted l-rum: FUWA, tlt?C-14, April 1983, pgs. 17 do 37.
Design Procedure- The following is a step-by-step pros edurc for designing a temporary liner for a
Temporary Liners channel. Bc;ausc temporary liners have a short period of service, the design 0
may he reduced. For liners that are; uceded far six months or less, the 2-yr
frequency storm is recommended.
Step 1. Select a liner material suitable for site conditions and application.
Determine roughness coefficient from manufacturer's specifications or Table
8.05e, pg. 9,05.10.
Step 2. Calculate the normal l]ow depth using Mannino's equation (Figure
8.05d). Check to sec that depth is consistent with that Assumed for selection of
Manning's n in Figure 9.05d, pg. 8.05.11. For smaller runoff's Figure 8.05d is
not as clearly defined. Recommended sol utions can be determined by using thy
Manning equation.
Step 3. Calculate shc;ar stress at normal depth.
Step 4. Compare computed shear stress with the pennimihle shear stress for
the line.
Step 5. If computed shear is greater than permissible shear, adjust channel
dimensions to reduce shear or scicot a more resistant lining and repeat steps 1
through 4.
Design of a ch:annul with temporary lining is illustrated in Sample Problem
8.05b, pg. 8.05.14.
Rev. 12.143 8.05.13

F=•1
La
PLAN VIEW
DESIGN OF OUTLET PROTECTION
MINIMUM TAILWATER CONDITION (Tw <0.5 diam.)
90
Median stone diameter, d5o, is the I"•' ' "'
stone size which 50% of the riprap ,10 -..:-.--►••••{--•-
mixture, by weight, is larger than.
velocities shown are for 70—:---+--'►• ---
W di am . t La _ .
pipes Flowing full. ` ... •' I:y!'..:
60
11,1
tie .. �.,',:I,:I. 1►�. ..,. �I. i..• ..;.
Slope D imvm 40 t. •.:..' .y.. ....: , _.. •1- ,•" ::; : �..1..,
_ 1/ (-
Flow �1�...•.r r.f.►.•• •...J= w �.• •w`N. .�•.� ••f i••• •• 1 ,
r
30
4.
17
did
2 ................... .
_4­7 -T:
In
i:1 .I .. ~.. ...,. ..{....If_i.. -i t ,. '• •,• '"..•...I .., I..' ...t. ..� 1" •�. L ,
4 4-
• •��-r•� I.. • • •• ♦ a� 11..1._ .. •". •�-�� .� ' .d'Cll.q r:211 Lill
•i . �..: is +,.{ .r.l 1 ...i •I• .•1,1:•� .A,��. ...... ...._ _. .. � �.. •� _J
1K Aid
.t.. . .f..►... 1 �.. I .. 1 1...., ...
2 3 4 6 a to 20 30Di4pp r,� ltr l�q iiq to n 4U13 "-no ;11::►
scharge cfs
1 Source: Standards and Specifications for Soil Erosion and Sedimi_nt Control it, t,1UVL'1Qi+':f1Cj
Areas.•Prepared by: USDA/S Conservation Service, Maryland, July—Ij75