20131013 Ver 1_More Info Received_20131011 (7)

Strickland, Bev
From: Devane, Boyd
Sent: Tuesday, November 12, 2013 3:48 PM
To: Strickland, Bev
Subject: FW: Tom Allen Driveway 13 -1013
Attachments: Tom Allen Runoff Map.pdf; Tom Allen Calculations.pdf
From: Kevin Varnell [ mailto: kvarnell @stocksengineering.com]
Sent: Friday, October 11, 2013 8:54 AM
To: Devane, Boyd
Cc: Jeff Harbour
Subject: RE: Tom Allen Driveway
Enjoy your vacation. Attached are the calculations and Runoff Map. Most of the calcs are for erosion control but I have
included everything in case you need it.
Sincerely,
Stocks Engineering, PA
J. Kevin Varnell
From: Devane, Boyd [ mailto:boyd.devaneCa)ncdenr.gov]
Sent: Friday, October 11, 2013 8:46 AM
To: Kevin Varnell
Subject: Re: Tom Allen Driveway
Thanks. That was very helpful. I am on vacation until Tuesday and get projects confused. However I didn't see any
runoff map nor see and runoff calculations unless they were on the one site plan that I saw. The second page was only

basics about erosion control. Therefore if u email me info I will look at it on Tuesday .
Sent from my iPhone
On Oct 11, 2013, at 7:59 AM, "Kevin Varnell" < kvarnell @stocksengineering.com> wrote:
Boyd,
See my responses below to your comments for the Tom Allen Driveway.
1. Show on a drawing what the final elevations and slope of the road will be so I will know what
flows are going across the buffers at the crossing and what flows are diffused across the
landscape
The single family residential driveway will be constructed at grade. So the proposed contours
will match the existing for the centerline of the road except for the stream crossing where the
contours are shown. The fill side of the road will not have a ditch. The water will simply sheet
flow off the road and down the hill. For the cut side of the road, which is on the left prior to
getting to the creek crossing, the ditch is created by the fill and therefore will go straight into
the stream.
Show on a drawing if swales or ditches will line the road or if runoff from the road will flow in a
diffuse manner across the landscape.
See comment above.
3. Show on a drawing the drainage area that is contributing stormwater to the buffer area.
There should have been calculations with a Runoff Map submitted. If you do not have the
calculations or the Runoff Map, let me know and I will email one to you.
4. Calculation of velocity of stormwater going across the buffer and how the Diffuse Flow
Requirement of the Tar - Pamlico buffer rules will be met. The Tar - Pamlico buffer rules can be
found at this link. DOC
The Runoff Map may be useful for you here as the largest drainage area I have is 2.33 Acres. For
a non - erosive flow ( <2 ft /s), it only has to spread out 10 feet. For the cut areas the ditch created
by the fill slope will go straight into the stream with the drainage area being 7% impervious. I
don't really have many other options here as the driveway has to go over the culvert.
If you have any other questions, do not hesitate to let me know.
Sincerely,
Stocks Engineering, PA
Y. <e-� %la, X
Kevin Varnell

IN*
1100 Eastern avenue Phone: [phone]
PO Box 1108 Fax: [phone]
Nashville, NC 27856 Mobile: [phone]
Email: [e-mail]

Stocks Engineering, P.A.
1100 Eastern Avenue
PO Box 1108
Nashville, NC 27856
Project: Thomas Allen Driveway
Date: August 30, 2013
Page: 1 of 1
Post - Development
Tc
Area ID
Area (Ac.)
C
110
Q70 (cfs]
15
1
25.52
0.35
4.90
43.77
15
Ila
1.43
035
7.64
3.82
15
Ila
1.02
0.35
7.64
2.73
15
111
0.17
0.35
7.64
0.45
15
IV
2.33
0.35
7.64
6.23
15
V
0.10
0.35
7.64
0.27
15
VI
0.11
0.35
7.64
0.29
-
Total
30.68
-
57.56
Post - Development
Tc
Area ID
Area (Ac,]
C
125
::..026:16f,
15
la
25.52
0.35
5.42
48.41
15
Ila
1.43
0.35
8.40
4.20
15
Ila
1.02
0.35
8.40
3.00
15
III
0.17
0.35
8.40
0.50
15
IV
2.33
0.35
8.40
6.85
15
V
0.10
0.35
8.40
0.29
15
VI
0.11
0.35
8.40
0.32
-
Total
30.68
-
63.58
Runoff Computations
10 -Year Storm
25 -Year Storm

Culvert Report
Hydrafiow Express by Intelisolve
= 48.41
Creek Crossing
= 48.41
Invert Elev Dn (ft) =
100.00
Pipe Length (ft) =
40.00
Slope ( %) =
1.00
Invert Elev Up (ft) =
100.40
Rise (in) =
42.0
Shape =
Cir
Span (in) =
42.0
No. Barrels =
1
n -Value =
0.012
Inlet Edge =
Projecting
Coeff. K,M,c,Y,k =
0.0045, 2, 0.0317, 0.69, 0.5
Embankment
= Inlet Control
Top Elevation (ft) =
105.00
Top Width (ft) =
26.00
Crest Width (ft) =
30.00
Elev (It)
106.00
105.00
104.00
103.00
102.00
101.00
U0.00
99.00
Creek Crossing
Thursday, Sep 5 2413
Calculations
Qmin (cfs)
= 48.41
Qmax (cfs)
= 48.41
Tailwater Elev (ft)
= (dc +D)12
Highlighted
Qtotal (cfs)
= 48.41
Qpipe (cfs)
= 48.41
Qovertop (cfs)
= 0.00
Veloc Dn (ftls)
= 5.79
Veloc Up (ftls)
= 7.64
HGL Dn (ft)
= 102.84
HGL Up (ft)
= 102.59
Hw Elev (ft)
= 103.61
Hw /D (ft)
= 0.92
Flow Regime
= Inlet Control
Hw Depth (ft)
5.60
4.60
3.60
2.60
1.60
0.00
Cir Culvert HGL Embank
Reach (ft)
-DAD
-1.40

Channel Report
Hydraflow Express by Intelisolve
Ditch Ila - Bare
Soil
Triangular
Area (sqft)
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 0.50
N -Value
= 0.020
Calculations
Compute by:
Known Q
Known Q (cfs)
= 3.82
M-
Section
Thursday, Sep 5 2413
Highlighted
Depth (ft)
= 0.64
Q (cfs)
= 3.820
Area (sqft)
= 1.64
Velocity (ft/s)
= 2.33
Wetted Perim (ft)
= 5.28
Crit Depth, Yc (ft)
= 0.57
Top Width (ft)
= 5.12
EGL (ft)
= 0.72
101.50
101.00
100.50
100.00
99.50
2 4 6
8
Reach (ft)
10 12 14 16
Depth (ft)
2.00
1.50
1.00
0.50
M
WiMM

Channel Report
Hydraflow Express by Intelisolve
Ditch Ila -Vegetated
Triangular
= 3.820
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 0.50
N -Value
= 0.035
Calculations
= 0.82
Compute by:
Known Q
Known Q (cfs)
= 3.82
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
0
2 4 6
Section
8
Reach (ft)
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.78
Q (cfs)
= 3.820
Area (sqft)
= 2.43
Velocity (ftls)
= 1.57
Wetted Perim (ft)
= 6.43
Crit Depth, Yc (ft)
= 0.57
Top Width (ft)
= 6.24
EG L (ft)
= 0.82
Depth (ft)
2.00
1.50
1.00
0.50
n Fn
10 12 14 16 VVV

Channel Report
Hydraflow Express by Intelisolve
Ditch Ilb -Vegetated
Triangular
= 2.730
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 2.00
N -Value
= 0.035
Calculations
= 0.63
Compute by:
Known Q
Known Q (cfs)
= 2.73
Section
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.54
Q (cfs)
= 2.730
Area (sqft)
= 1.17
Velocity (ftls)
= 2.34
Wetted Perim (ft)
= 4.45
Crit Depth, Yc (ft)
= 0.50
Top Width (ft)
= 4.32
EGL (ft)
= 0.63
101.50
101.00
100.50
100.00
v• �
2 4 6
8
Reach (ft)
Depth (ft)
2.00
1.50
1.00
0.50
F11 M
_n r�n
10 12 14 16 - --

Channel Report
Hydraflow Express by Intelisolve
Ditch Ilb - Bare Soil
Triangular
= 2.730
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 2.00
N -Value
= 0.020
Calculations
= 0.64
Compute by:
Known Q
Known Q (cfs)
= 2.73
Elev (ft) Section
102.00
101.50
101.00
100.50
99.50
2 4 6
8
Reach (ft)
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.43
Q (cfs)
= 2.730
Area (sqft)
= 0.74
Velocity (ft/s)
= 3.69
Wetted Perim (ft)
= 3.55
Crit Depth, Yc (ft)
= 0.50
Top Width (ft)
= 3.44
EGL (ft)
= 0.64
10 12 14 16
Depth (ft)
2.00
M1061
MKI111
0.50
F iM
_n rn

Channel Report
Hydraflow Express by Intelisolve
Ditch III - Bare
Soil
Triangular
Area (sqft)
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 3.00
N -Value
= 0.020
Calculations
Compute by:
Known Q
Known Q (cfs)
= 0.45
M-
Section
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.21
Q (cfs)
= 0.450
Area (sqft)
= 0.18
Velocity (ftls)
= 2.55
Wetted Perim (ft)
= 1.73
Crit Depth, Yc (ft)
= 0.24
Top Width (ft)
= 1.68
EGL (ft)
= 0.31
101.50
101.00
100.50
100.00
99.50
2 4 6
8
Reach (ft)
10 12 14 16
Depth (ft)
2.00
1.50
1.00
0.50
91"1
-0.5n

Channel Report
Hydraflow Express by intelisolve
= 0.25
Ditch III -Vegetated
Triangular
Area (sqft)
Side Slopes (z:1) =
4.00, 4.00
Total Depth (ft) =
1.50
Invert Eiev (ft) =
100.00
Slope ( %) =
3.00
N -Value =
0.035
Calculations
Compute by: Known Q
Known Q (cfs) = 0.45
Elev (ft) Section
102.00
101.50
101.00
100.50
100.00
4.61M]
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.25
Q (cfs)
= 0.450
Area (sqft)
= 0.25
Velocity (ft.1s)
= 1.80
Wetted Perim (ft)
= 2.06
Crit Depth, Yc (ft)
= 0.24
Top Width (ft)
= 2.00
EGL (ft)
= 0.30
D 2 4 6 S 10 12 14
Reach (ft)
16
Depth (ft)
2.00
1.50
1.00
0.50
-0.50

Channel Report
Hydraflow Express by Intelisolve
Ditch IV - Vegetated
Triangular
= 6.230
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 3.00
N -Value
= 0.035
Calculations
= 0.86
Compute by:
Known Q
Known Q (cfs)
= 6.23
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
2 4 6
Section
8
Reach (ft)
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.67
Q (cfs)
= 6.230
Area (sqft)
= 1.80
Velocity (ftls)
= 3.47
Wetted Perim (ft)
= 5.52
Crit Depth, Yc (ft)
= 0.69
Top Width (ft)
= 5.36
EGL (ft)
= 0.86
10 12 14 16
Depth (ft)
2.00
1.50
1.00
0.50
go-1011
-0.50

Channel Report
Hydraflow Express by Intelisolve
Duch IV - Bare
Soil
Triangular
Area (sqft)
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 3.00
N -Value
= 0.020
Calculations
Compute by:
Known Q
Known Q (cfs)
= 6.23
Section
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.55
Q (cfs)
= 6.230
Area (sqft)
= 1.21
Velocity (ftls)
= 5.15
Wetted Perim (ft)
= 4.54
Crit Depth, Yc (ft)
= 0.69
Top Width (ft)
= 4.40
EGL. (ft)
= 0.96
101.50
101.00
100.50
100.00
99.50
2 4 6
8
Reach (ft)
10 12 14 16
Depth (ft)
2.00
1.50
1.00
0.50
wiiZYiI

Channel Report
Hydraflow Express by Intelisolve
Ditch V - Bare Soil
Triangular
Side Slopes (z:1) =
= 4.00, 4.00
Total Depth (ft) =
= 1.50
Invert Elev (ft) =
= 100.00
Slope ( %) =
= 0.50
N -Value =
= 0.020
Calculations
Compute by: K
Known Q
Known Q (cfs) =
= 0.27
M_
101.50
101.00
100.50
100.00
99.50
Thursday, Sep 5 2013
Highlighted
Depth (fit) = 0.24
Q (cfs) = 0.270
Area (sgft) = 0.23
Velocity (ft/s) = 1.17
Wetted Perim (ft) = 1.98
Crit Depth, Yc (ft) = 0.20
Top Width (ft) = 1.92
EGi- (ft) = 0.26
Section
2 4 6
8
Reach (ft)
10 12 14 16
Depth (ft)
2.00
1.50
1.00
0.50
_n rin
Section
2 4 6
8
Reach (ft)
10 12 14 16
Depth (ft)
2.00
1.50
1.00
0.50
_n rin

Channel Report
Hydraflow Express by [nfelisolve
Ditch V - Vegetated
Triangular
= 0.29
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 0.50
N -Value
= 0.035
Calculations
Compute by: Known Q
Known Q (cfs) = 0.27
Elev (ft)
102.00 -----
101.50
101.00
100.50
100.00
99.50
Section
D 2 4 6 8
Reach (ft)
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.29
Q (cfs)
= 0.270
Area (sqft)
= 0.34
Velocity (ftls)
= 0.80
Wetted Perim (ft)
= 2.39
Crit Depth, Yc (ft)
= 0.20
Top Width (ft)
= 2.32
EGL (ft)
= 0.30
10 12 14
Depth (ft)
2.00
1.50
1.00
0.50
111MO
' - -0.50
16

Channel Report
Hydraflow Express by Intelisolve
Ditch VI - Vegetated
Triangular
= 0.290
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 0.50
N -Value
= 0.035
Calculations
= 0.31
Compute by:
Known Q
Known Q (cfs)
= 0.29
Elev (ft)
102.00 -
101.50
101.00
100.50
100.00
99.50 1
0
Section
2 4 6 8
Reach (fit)
Thursday, Sep 5 2413
Highlighted
Depth (ft)
= 0.30
Q (cfs)
= 0.290
Area (sqft)
= 0.36
Velocity (ftls)
= 0.81
Wetted Perim (ft)
= 2.47
Crit Depth, Yc (ft)
= 0.21
Top Width (ft)
= 2.40
EG L (ft)
= 0.31
10 12 14
Depth (ft)
2.00
1.50
1.00
0.50
11M
1 -0.50
16

Channel Report
Hydraflow Express by Intelisolve
Ditch VI - Bare
Soil
Triangular
Area (sgft)
Side Slopes (z:1)
= 4.00, 4.00
Total Depth (ft)
= 1.50
Invert Elev (ft)
= 100.00
Slope ( %)
= 0.50
N -Value
= 0.020
Calculations
Compute by:
Known Q
Known Q (cfs)
= 0.29
Elev (ft)
102.00
101.50
101.00
100.50
100.00
99.50
2 4 6
Section
8
Reach (ft)
Thursday, Sep 5 2013
Highlighted
Depth (ft)
= 0.25
Q (cfs)
= 0.290
Area (sgft)
= 0.25
Velocity (ftls)
= 1.16
Wetted Perim (ft)
= 2.06
Crit Depth, Yc (ft)
= 0.21
Top Width (ft)
= 2.00
EGL (ft)
= 0.27
Depth (ft)
2.00
1.50
too
0.50
[ +IrIi�
_n Fn
10 12 14 16 vvv

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ter,
P �:�
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Skimmer Sediment Basin Worksheet
(Draina.ge Area Must be Less Than 10 Acres)
Area Disturbed -Acres
Runoff Area = Acres
Q 10 = C x I x A x '7, 3-7 S x
Assume - foot of basin depth, therefore area of the pit Square Feet
Try ( wide) x ( — long) x ( foot deep) Sediment Basin
Use ,o wide) x to long) x foot deep) Sediment Basin
Zo<x',. Surface Area —
Qj() = L w r, �i cfs; Q = CLH 1/2;
H = [Q/CL1213
12.68)( 10 )]213
feet
Velocity Check 4 ( )/( to ) ( o,X) ) = _1 1_6, fps, OK V-"',3;4"-"

Skimmer Sediment Basin Worksheet
(Draina.ge Area Must be Less Than 10 Acres)
-- I
Area Disturbed e, -Acres
Runoff Area'' Acres
Q 1 o = C x I x A = L� x 73-38, x L�LL
cfs
Volume of Sediment g 1 Ac.) x (1800 cf sed./year) x (1 year)
2,­ Cf
Surface Area (SF) = Qjo x 325 sf/cfs
&
0. 2,if
x
325 sf/cfs
Velocity Check 2- i c) Z
� , 2 (5_
_ fps,
0 K
ss
sf
Use /o t wide) x( 9(v long) x( 2- foot deep) Sediment Basin
ri'5(0 () Surface Area — e� k--'
312; ]2/3
Q10 613- cfs; Q = CLH H = [Q/CL
= [ .2, - ( � 3, (2.68)( leg )]213
0. 2,if
feet
Velocity Check 2- i c) Z
� , 2 (5_
_ fps,
0 K

%
Skimmer Sediment Basin Worksheet
(Drainage Area Must be Less Than 10 Acres)
Area Disturbed = r , 2. -, 2 � Acres
Runoff Area = 14.I_"I'5 —Acres
Q10 = C x I x A
,� x­'?, 3t x J. q'3
2
� a �/v 9 CfS
Basin Volume Calculation-
Volume of Sediment Ac.) x (1800 cf sed./year) x (1 year)
17 ("', Cf
Assume Z foot of basin depth, therefore area • the pit I "18, Square Fe(M
Try ( wide) x ( long) x foot deep) Sediment Basin
Surface Area Calculation:
Surface Area (SF) = Qjo x 325 sf/cfs
"? ", e,
5, (-,,A x 325 sf/cfs
sf
Surface Area —
Use wide) x :5t.) long) x foot deep) Sediment Basin
'Z5 6
Surface Area — 0 tl-
Q 10 efs; 0 = CLH 312; H 6 [Q/CL]211
(2,68)( ` )]213
-SHE _ feet
Velocity Check 4 1`01 22,-?'� 3 ­7 _ fps, 0 K 4

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