20051881 Ver 4_More Info Received_20121015

JAMESTOWN ENGINEERING GROUP, INC.
CIVIL. ENGINEERS & SURVEYORS
LAND PLANNING • MUNICIPAL CONSULTING
E, inc. 117 East Main Street • P.O. Box 365 • Jamestown, N.C. 27282
Telephone [phone] Fax [phone]
www jamestownenginecring.com
October 15, 2012
Re: Lilliefield Subdivsion, Phase 3
401 Permit Application
JEG Number 2004 -068d
Ms. Sue Homewood
NC Division of Water Quality
585 Waughtown Street
Winston - Salem, NC 27107
Dear Ms. Homewood:
In response to the e-mail sent to Mr. Wendell Overby on October 3, 2012 regarding the 401 permit
application for Lilliefield Subdivision, a question was raised about the impacts created with the rip -rap
aprons at the culvert crossing. On the upstream side of the culvert, the main purpose of the apron is to
minimize scour around the culvert and at the base of the headwall. At the downstream location, the apron is
used to reduce the velocity of water flowing through the culvert before it discharges to wetland area.
Based on the calculations from the N.C. Erosion and Sediment Control Planning and Design Manual, the
rip -rap aprons should be sized with Class B rip -rap, and the upstream and downstream lengths are 18 feet
and 36 feet, respectively. At the discharge, changing the apron to a plunge pool (minimum of 1' drop) and
increasing the rip-rap to Class I stone, the length can be reduced to 20'. We feel that the upstream end
should have a minimum of 10' Class 1 rip -rap to prevent scour along the pipe inlet and headwall. Since the
culvert will be installed in an environmentally sensitive area, we have reduced the length as much as
possible while trying to achieve scour protection and velocity control. Calculations for the pipe rip-rap
crossings have been included.
If any additional information is needed or if you have any questions, please feel free to contact me at (336)
886 -5523.
Yours very truly,
JAMESTOWN ENGINEERING GROUP, INC.
Ravindra Bissram, P.E.
lvr 1S -•

AMESTOWN ENGINEERING GROUP, INC.
117 EAST MAIN STREET
JAMESTOWN, NC 27282
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Appendices
NEW Y09K DOT DISSIPATOR METHOD
FOR USE IN DEFINED CHANNELS
(Source: "Bank and channel lining procedures ", New York Department
of Transportation,- Division of Design and Construction, 1971.)
Note: To use the following chart you must know:
(1) Q full capacity
(2) Q10
(3) V14,11.
(4) V10
where Q = discharge in cfs and V = Velocity in FPS.
.ESTIMATION OF STONE SIZE AND. DIMENSIONS FOR
CULVERTAPRONS
Step 1) Compute flow velocity Vo at culvert or paved channel outlet.
Step 2) For.. pipe culverts Do is diameter.
For.pipe arch, arch and box culverts, and paved channel outlets,
o- o. mleI6 = _V Fm 6 S =SCC 16W ai oU
For multiple culverts, use Do= 1.25xDo of single culvert.
Step 3) For apron grades of 10% or steeper, use recommendations
For next higher•zone. (Zones 1 through 6).
25
20-
Is-
G.
F-
E3
O
w 10-
5-
o
��417�1
Awn -
m,n�ic aO� m��aal■am�acO Q®®��mtoma� gmmmmcamImnmp0 vvva1a7��0'1an aa�mm �ry �maQQm
t�� iaO s Y1smf�mm4vAa< a imLlcllmgil in =miulfuv`bsm a11alitm t6!fAn�nia0� Io q con - v n l 1 �� •�� l
IUK11dL�ma mG=�do.c®m�ammmtm�<m�� acQr mm vm-m
�m
©���iia ls�-lgyl=il7z imQ ow�
�Imm m�mi� m
_QLm= v ®Qf"■�
,1
0' S' 10c
im i mf� 0®.�Q•''
� m sm�m u m ti �c��aRQ. =�1■cm`► �®
.o® O� Q®amaQ® md Q.
mf
1/ 1 1
5�Q'
DIAMETER (F1
t.
a�)
Figure 8.06.b.1. �
0�
►
vt1 � �ao>mm�� lmd r>>nm� a=m ra n�1>n 0c 7r �
1
20' 2
5
8.06.5 WIIKE39Msat
I 019JIMu
n" cnn
c ®KMIM�iu mmM
WINK=
n aQL r
mT: �W U039=09MIKEEMI
n
ffmvu
mlauun �pra93[KKN
oi ®nmm L�------
mmYn
EXXIv1 gn 0= IM©u mg"
�rmWX=19 uysm =
cm -1nKKM3UUKKMFuamm
UT IsM!"nmVIK93MaV
WASKMIMI 111�0 O
ZUffM3EKM13MX
atmti�aa �_�
o
��417�1
Awn -
m,n�ic aO� m��aal■am�acO Q®®��mtoma� gmmmmcamImnmp0 vvva1a7��0'1an aa�mm �ry �maQQm
t�� iaO s Y1smf�mm4vAa< a imLlcllmgil in =miulfuv`bsm a11alitm t6!fAn�nia0� Io q con - v n l 1 �� •�� l
IUK11dL�ma mG=�do.c®m�ammmtm�<m�� acQr mm vm-m
�m
©���iia ls�-lgyl=il7z imQ ow�
�Imm m�mi� m
_QLm= v ®Qf"■�
,1
0' S' 10c
im i mf� 0®.�Q•''
� m sm�m u m ti �c��aRQ. =�1■cm`► �®
.o® O� Q®amaQ® md Q.
mf
1/ 1 1
5�Q'
DIAMETER (F1
t.
a�)
Figure 8.06.b.1. �
0�
►
vt1 � �ao>mm�� lmd r>>nm� a=m ra n�1>n 0c 7r �
1
20' 2
5
8.06.5 WIIKE39Msat
I 019JIMu
n" cnn
c ®KMIM�iu mmM
WINK=
n aQL r
mT: �W U039=09MIKEEMI
n
ffmvu
mlauun �pra93[KKN
oi ®nmm L�------
mmYn
EXXIv1 gn 0= IM©u mg"
�rmWX=19 uysm =
cm -1nKKM3UUKKMFuamm
UT IsM!"nmVIK93MaV
WASKMIMI 111�0 O
ZUffM3EKM13MX

n
W
Z RO
APWN
PamuCwEA
L1
TO PREVEW SCOUR
HOLE USE L2 ALWAYS
L2
1
ISTONE FILLING (FINE) . : CL. A
3 x Do
4 x Do
2
STONE FILLING (LIGHT) CL B
3 x Do
6 x Do
3
STONE FILLING (MEDIUM) CL 1
4 x Do
8 x Do
4
STONE FILLING (HEAVY);: CL 1
4 x Do
8 x Do
5
STONE FILLING (HEAVY)? . CL 2
5 x Do
10 x Do
6
STONE FILLING (HEAVY) ; CL. 2
6 x Do
10 x Do
7 SPECIAL STUDY -REQUIRED :(ENERGY DISSIPATORS, STILLING
BASIN OR LARGER SIZE STONE).
Fig. 8.06.b.2
Width = 3 iimes' i -dii: QL)
P Pe � r
DETERMINATION. OF STONE SIXES FOR DUMPED STONE
CHANNEL LININGS AND. REVETMENTS
Step 1) -Use figure 8.0611 to determine maximum stone size (e.g. for 12
V ps= 0' or 5501 09. - -- - --
Step 2) Use figure 8.06.b.4 to determine acceptable size range for stone
(for 12 FPS it is 1Z -500 lbs. for 75% of stone, and the maximum
and minimum . ante in weight should be 25 -500 lbs.)
Note: In determining channel velocities for stone linings and revetment, use
the following. coefficlents of roughness:
Diametgr Mannin's Min. thickness
(tnches� "n" of lining (inches)
Fine 3 0.031 9 12
Light --.6. ' 0.035 12 18
Medium.. 0.040 18 24
.13
Heavy .. M. 0.044 30 36
(Channels) (Dissapators)
8.06.6
Rev t?193 r

Circular Channel Analysis & Design
Solved with Manning's Equation
Open Channel - Uniform flow
Worksheet Name: Lilliefield Crossing
Comment: 72" Pipe Culvert
Solve For Full Flow Diameter
Given Input Data:
Slope ............. 0.0120 ft /ft
Manning's n....... 0.130
Discharge......... 150.00 cfs
Computed Results:
Full Flow Diameter.....
9.32
ft
Full Flow Depth........
9.32
ft
Velocity..........
2.20
fps
Flow Area.........
68.17
sf
Critical Depth....
2.91
ft
Percent Full......
100.00
%
Full Capacity.....
150.00
cfs
QMAX @.94D........
161.36
cfs
Froude Number.....
FULL
Open Channel Flow Module, Version 2.01 (c) 1990
Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708

9
Exhibit 11
Lit
HEADWATE-R DEPTH FOR
HEADWATER SCALES 283 CONCRETE PIPE CULVERTS
OUREAU Of PWLIC 1wnoI Ax im REVISED MAY 1964 WITH I N L Z T- CONTROL
VI -11
18a
0
10,000
168
8,000 EXAMPLE
(!)
(2)
(3)
156
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6•
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120
1108
(1) L.5 9.3
4.
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(3) to 7.7
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3.
so In t «r
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96
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84
-- —�
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2.
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=
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=
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U. rn `
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HW NTRANCE
°
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30 are edge h
(I) Squ
<
'9
.9
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he•a.ell
a
.9
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30
headwall
(3) Groove end
•8
2T
projecting
10
24
8
•T
.T"
.T
6 To wee scale (2) or (3) project
21
S horizontally to scale (1),1hen
4 was straight Inclined lino thr•eiph
0 sold 0 scale•,.r reverse se
6
3 illustrated,
.
• 6
la
2
15
1.0
L
.s
.s
.5
Lit
HEADWATE-R DEPTH FOR
HEADWATER SCALES 283 CONCRETE PIPE CULVERTS
OUREAU Of PWLIC 1wnoI Ax im REVISED MAY 1964 WITH I N L Z T- CONTROL
VI -11