20090107 Ver 2_Stormwater Plans_20090922

LETTER OF TRANSMITTAL
DEVELOPMENT CONSULTING SERVICES, INC.
1401 Aversboro Road, Suite 206
Garner, North Carolina 27529
[phone] phone
[phone] fax
OR - oi o 7
1@3@95W [a
S E P $ 2 2009
DENR - WATER WALITY
WETLANDS AND STORMWAM BRANCH
To: Annette Lucas
Company: DWQ
Address:
From: Dexter Howell
Date: Tuesday, September 22, 2009
RE: Coates Asphalt Plant
URGENT F-] Reply ASAP r - ] Please Comment F]Please Review A For Your Information
COPIES DATE NO. DESCRIPTION
1 09/22/09 Set of Stormwater plans
1 09/22/09 Stormwater approval letter
1 09/22/09 Wet Detention Pond Calculations
1 09/22/09 Nitrogen Calculations
1 09/22/09 Drainage Calculations

Comments:

fandkn le""Wff
DEPARTMENT OF PUBLIC UTILITIES
POST OFFICE BOX 2263
SMITHFIELD, N.C. 27577
July 17, 2009 [phone]
Crossroads Development Corporation
Attn: Mike Coates
12400 NC 50 N
Willow Springs, NC 27592
Re: Coates Corporation Asphalt Plant
Permit # 08-068
Stormwater Management Plan
Dear Mr. Coates:
We have reviewed the revised Stormwater Management Plan and calculations submitted
for the proposed Coates Corporation Asphalt Plant. Based upon the information
submitted, the stormwater management plan has been approved with the following
stipulations:
1. Please provide our office a copy of the approval letter from NCDENR Land
Quality for the Sedimentation and Erosion Control Plan.
2. Please provide our office a copy of the 401/404 Permit Approval for impacts
associated with the stream crossing.
3. Once construction of the stormwater management facilities is complete, please
provide a stormwater certification stating that all stormwater facilities were
constructed in accordance with the approved stormwater management plan,
4. Please indicate all drainage easements, riparian buffers, jurisdictional wetlands, and
flood hazard areas on the Final Plat. A 12' wide access easement shall be recorded
from the public right-of-way to the pond. A 20' shall be recorded around the high
water surface elevation of the pond. The easement shall extend around all edges of
the pond including the pond forebay and outlet structure.
5. Please provide a copy of the recorded operation and maintenance agreement for the
wet detention pond and the level spreader.
A copy of this letter will be forwarded to the Planning Office for their files. If you have
any questions or need additional information, please contact me at [phone] or by
email at jai-nic.guerrero(@-ioiijistojine.com.
Since ely,
amie Guerrero, PE
Stormwater Administrator
Cc: Berry Gray - Planner
Chandra C. Coats, PE --- Utilities and Environmental Engineer
Keith Roberts, PE - Development Consulting Services
Printed on recycled paper co
WET DETENTION POND
COATES GRADING AND HAULING
JOHNSTON COUNTY, NORTH CAROLINA
JOHNSTON COUNTY
PO BOX 2263
SMITHFIELD, NC 27577
SUBMITTED BY: DEVELOPMENT CONSULTING SERVICES, INC.
1401 AVERSBORO ROAD, SUITE 206
GARNER, NC 27529
[phone]
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ASPHALT PLANT
STORMWATER DETENTION POND DESIGN
DRAINAGE AREA: 20-00 AC
EXIST. IMP AREA: 0.00 AC 0.0%
PROP. IMP. AREA: 9.00 AC 45.0%
RUNOFF COEFFICIENT ( C )
Cpre= 20.00 AC x 0.25 + 0.00 AC x 1.0 = 0.25
20.00 AC
Cpost= 11.00 AC x 0.25 + 9.00 AC x 1.0 = 0.59
20.00 AC
STORM DATA
STORM EVENT INTENSITY (I) PRECIPITATION
DEPTH P
2 YEAR 5.76 in/hr 37"
10 YEAR 7.22 in/hr 5.8"
100 YEAR 10.00 in/hr 8.4"
2 YEAR STORM
10 YEAR STORM
100 YEAR STORM
Qpre=CIA= 0.25 x 5.76 x 20.00 = 28.80 cfs
Qpost=CIA= 0.59 x 5.76 x 20.00 = 67.68 cfs
Qpre=CIA= 0.25 x 7.22 x 20.00 = 36.10 cfs
Qpost=CIA= 0.59 x 7.22 x 20.00 = 84.84 cfs
Qpre=CIA= 0.25 x 10.0 x 20.00 = 50.00 cfs
Qpost=CIA= 0.59 x 10.0 x 20.00 = 117.50 cfs
DETERMINE SOIL STORAGE
CN= 98 x 0.50 + 55 x 0.10 + 61 x 0.40 = 79
S= 1000 -10 = 1000 -10 = 2
67"
CN 78.9 .
RUNOFF DEPTH Q* _ (P-0.2*S)2
(Q*) (P+0.8*S)
Q* x DA x 43560 SF/AC
TIME TO PEAK (Tp) Tp= 12 in/ft
1.39 x Qpost
2 YEAR STORM
Q* _ (3.7 - 0.2 x 2.7 )^2 = 1
72 in

(3.7 + 0.8 x 2.67) .
.
1.72 in.
x 20.00 AC x 43560 SF/AC
Tp= 12 in/ft = 22.1 min.
1.39 x 67.68 cfs
? PEAK 67.68 cfs @ 22.1 min.
10 YEAR STORM
Q* _ (5.8 - 0.2 x 2.7 )^2 = 3.49 in

(5.8 + 0.8 x 2.67) .
3.49 in. x 20.00 AC x 43560 SF/AC
_
Tp 12 in/ft
=
35.8 min.
1.39 x 84 .84 cfs
? PEAK 84.84 cfs @ 35.8 min.
100 YEAR STORM
Q* _ (8.4 - 0.2 x 2.7 )^2 = 5.87 in

(8.4 + 0.8 x 2.67) .
5.87 in. x 20.00 AC x 43560 SF/AC
_
Tp 12 in/ft
43.5 min.
1.39 x 11 7.50 cfs
? PEAK 117.50 cfs @ 43.5 min.
ESTIMATE POND SIZE FOR 10 YEAR STORM
Vpond = (Qpost-Qpre) x Tp + 40%
Vpond =( 84.84 - 36.10) x 35.8 min. + 40%
Vpond = 146,672 CF
EMERGENCY SPILLWAY (SIZE FOR 100 YEAR STORM)
Q100=CIA= 0.59 x 10.0 x 20.00 = 117.50 cfs
WEIR EQUATION:
Q=Cw*L*H^3/2
Cw= 3.0
Q= 117.50 cfs
H= 1.00
L= Q = 117.50 cfs = 39.2'
Cw*H^3/2 3.0 x 1^3/2
USE 40' EMERGENCY SPILLWAY TO CARRY 100 YEAR STORM
SIZE ORIFICE
Q10=CA?2GH Q10 = 36.10 cfs
C = 0.93
G = 32.2 ft/s
H = 2.5'
A= Q100
C?2GH
A=Pi*r2
r
= 36.10 cfs = 3.06 S.F.
0.93 2*32.2*3
3.06 S.F. )= 11.84 in.
3.14
USE 12" DIAMETER ORIFICE
?raµ?dew rk baud o?1

Q= CA J 9?
Q $ ( ?)? 4 a4) t?a2.z''CZ?
.161 CPS
vD?uoj- C? Z' dip 71, 7q4 ?F
21J?141946 +kia 32. y In,rS ai 1.ys
?j e A Z 9 k (` o n?li'ce ?la (.? ?ru l
Q = 18 cFs
. 18 cFS + . (ol e-FS , 3RS cfs
7-
2 t) 'L44 cF = 3006 way 2. a dau(S
. 39S CFS
M-111
Hydraflow Hydrographs by Intelisolve Wednesday, Jul 8 2009, 1:9 PM
Pond No. 1 - Asphalt Plant
Pond Data
Pond storage is based on known contour areas. Average end area m ethod used.
Stage / Storage Table
Stage (ft) Elevation (ft) Contour area (sqft) Incr. Storage (cuft) Total storage (cult)
0.00 260.00 8,443 0 0
1.00 261.00 8,585 8,514 8,514
2.00 262.00 8,976 8,781 17,295
3.00 263.00 9,568 9,272 26,567
4.00 264.00 10,205 9,887 36,453
5.00 265.00 11,375 10,790 47,243
6.00 266.00 12,307 11,841 59,084
7.00 267.00 12,739 12,523 71,607
8.00 268.00 14,284 13,512 85,119
Culvert / Orifice Structures Weir Structures
[A] IBl [C] [D] [A] [B] [C] [D]
Rise (in) = 48.00 4.00 0.00 0.00 Crest Len (ft) = 24.00 0.00 0.00 0.00
Span (in) = 48.00 4.00 0.00 0.00 Crest El. (ft) = 266.00 0.00 0.00 0.00
No. Barrels = 1 1 0 0 Weir Coeff. = 3.33 3.33 0.00 0.00
Invert El. (ft) = 260.00 260.00 0.00 0.00 Weir Type = Riser --- --- ---
Length (ft) = 60.00 0.00 0.00 0.00 Multi-Stage = Yes No No No
Slope (%) = 1.00 0.00 0.00 0.00
N-Value = .013 .013 .000 .000
Orif. Coeff. = 0.60 0.60 0.00 0.00
Multi-Stage = n/a Yes No No Exfiltration = 0.000 in/hr (Co ntour) Tailwater Elev. = 0.00 It
Note: Culvert/Orifice outflows have been analyzed under inlet and outlet control. Weir riser checked for orifice conditions.
Stage (ft) Stage / Storage Stage (ft)
8.00
6.00
4.00
2.00
0 00
8.00
6.00
4.00
2.00
0 00
0 9,000 18,000 27,000 36,000 45,000 54,000 63,000 72,000 81,000 90,000
Storage Storage (cuft)
Hydrograph Plot
Hydraflow Hydrographs by Intelisolve Wednesday, Jul 8 2009,11:17 PM
Hyd. No. 4
Asphalt Plant
Hydrograph type = Reservoir Peak discharge = 50.39 cfs
Storm frequency = 100 yrs Time interval = 1 min
Inflow hyd. No. = 3 Max. Elevation = 266.73 ft
Reservoir name = Asphalt Plant Max. Storage = 68,187 cuft
Storage Indication method used.
Q (cfs)
100.00
80.00
60.00
40.00
20.00
Hydrograph Volume = 95,594 cult
0.00
0.0
Q (cfs)
100.00
80.00
60.00
40.00
20.00
n M
1.7 3.3 5.0 6.7 8.3 10.0 11.7 13.3 15.0 16.7 18.3vvv
Time (hrs)
Hyd No. 4 Hyd No. 3 [111..1.1..1.IH Req. Stor = 68,187 cuft
NITROGEN CALCULATIONS
COATES GRADING AND HAULING-ASPHALT PLANT
JOHNSTON COUNTY, NORTH CAROLINA
JOHNSTON COUNTY
PO BOX 2263
SMITHFIELD, NC 27577
SUBMITTED BY: DEVELOPMENT CONSULTING SERVICES, INC.
1401 AVERSBORO ROAD, SUITE 206
GARNER, NC 27529
[phone]
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y-AL coq
n ?J o"-s%1 C ? b th
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'f ,,'''+++ 1 ?O•'Y'v,','y

Method 2 is for residential, commercial and industrial developments
when the entire footprint of the roads, parking lots, buildings and any
other built-upon area is shown on the site plans. This method is
simpler and more accurate since it does not require estimating the
impervious surface. Method 2 is shown in Exhibit 3-2.
Exhibit 3-2 Method 2 for Quantifying TN Export from
Residential / Industrial / Commercial
Developments when Footprints of all Impervious
Surfaces are Shown
Step 1: Determine area for each type of land use and enter in
Column (2).
Step 2: Total the areas for each type of land use and enter at the
bottom of Column (2).
Step 3: Multiply the areas in Column-(2) by the TN export
coefficients in Column (3) and enter in Column (4).
Step 4: Total the TN exports for each type of land use and enter at
the bottom of Column (4).
Step 5: Determine the export coefficient for site by dividing the total
TN export from uses at the bottom of Column (4) by the
total area at the bottom of Column (2) and enter the result
at the bottom of Column (5).
'Pond
(I) (2) (3) (4) (5)
Type of Land Cover Site TN Export TN Export TN Export
Area Coeff. by Land Use From Site
Acres Ibs/ac/ r Ibs/ r Ibs/ac/ r
Permanently preserved undisturbed
6 t t,
open sace forest unmown meadow
Permanently preserved managed
c
-1 sv
1.2 p
open sa
e (grass, landscaping, etc.
Impervious surfaces (roads, parking 21
2
lots, driveways, roofs, paved storage 3 , 9 Z . 83, /
areas, etc.
Total Ig, 3 4 96.25
Average for Site S• 26

Method 2 is for residential, commercial and industrial developments
when the entire footprint of the roads, parking lots, buildings and any
other built-upon area is shown on the site plans. This method is
simpler and more accurate since it does not require estimating the
impervious surface. Method 2 is shown in Exhibit 3-2.
Exhibit 3-2 Method 2 for Quantifying TN Export from
Residential / Industrial / Commercial
Developments when Footprints of all Impervious
Surfaces are Shown
Step 1: Determine area for each type of land use and enter in

Column (2).
Step 2: Total the areas for each type of land use and enter at the
bottom of Column (2).
Step 3: Multiply the areas in Column-(2) by the TN export
coefficients in Column (3) and enter in Column (4).
Step 4: Total the TN exports for each type of land use and enter at
the bottom of Column (4).
Step 5: Determine the export coefficient for site by dividing the total
TN export from uses at the bottom of Column (4) by the
total area at the bottom of Column (2) and enter the result
at the bottom of Column (5):
(?) (2) (3) (4) (5)
Type of Land Cover Site TN Export TN Export TN Export
Area Coeff. by Land Use From Site
Acres Ibs/ac/ r Ibs/ r Ibslac/ r
Permanently preserved undisturbed
f fo ?? 0.6 3
g8
open sace
orest unmown meadow .
Permanently preserved managed
%
open space (grass, landscaping, etc.
-
1'2
t
Impervious surfaces (roads, parking 21
2
lots, driveways, roofs, paved storage
t
:
?Z .
g
8
areas, e
c .,
Total . ' 2.1 E3
Average for Site
??
c? 5 GraaL? Ag aLAJ ?inq - A-s-phxcul+ p (aA)t

'V i T(ro qe n l.Q,t Ct? ? c?'?tia-wS
S 1 o rnn y VYY?,I rt i t c? Tb De?-,ev, I >o r., o(
l?Cre 5 ?. 3l4 TkJ 6y?pr?'
1 awd use
w? 3S% ?ed,«?? - (02-.-56
7+

5?-ormwo?? ?Qa ?; H g -}-a 3v sr ?'w
kcr+es - (o . 88
I "Z . 7 8
?y load use
row VouCu?a??enS Srov. sire.
Rcre"s - 25.22
TO 67,c po,} 3y
by IOIAO( Use
11-TO bUXpor+ SnrovvA. Si
-?5.3q / Z,46. -17- = 3.99

buy 'Do V-> A,
3.019 -- 3 . (Q 0.39 Ceso . s o?? 25.22-7 = t3,3&5.35
DRAINAGE CALCULATIONS
COATES GRADING AND HAULING-ASPHALT PLANT
JOHNSTON COUNTY, NORTH CAROLINA
JOHNSTON COUNTY
PO BOX 2263
SMITHFIELD, NC 27577
SUBMITTED BY: DEVELOPMENT CONSULTING SERVICES, INC.
1401 AVERSBORO ROAD, SUITE 206
GARNER, NC 27529
[phone]
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peen ?,aR /ass
023728
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ASPHALT PLANT
Storm Drainage
Pipe
Inlet DA EDA C I (in/hr) Q (cfs) Size Length Hw H
CB #1 1.65 1.65 0.8 8.5 11.2 24" 20' 0.9 0.1
CB #2 10.08 10.08 0.63 8.5 54.0 2-30" 16' 1.0 0.3
CB #3 0.38 0.38 0.8 8.5 2.6 24" 16' 1.3 0.4
CB #4 0.89 1.11 0.8 8.5 7.5 18" 64' 0.5 0.1
FES#1 4.44 4.44 0.41 8.5 15.5 24" 96' 0.3 0.1
FES#1A 0.3 4.74 0.8 8.5 32.2 36" 76' 0.4 0.1
FES#2 0.22 0.22 0.8 8.5 1.5 15" 88' 0.5 0.2
FES #3 0.38 1.49 0.8 8.5 10.1 24" 112' 0.5 0.1
HW #1 * 294.26 294.26 72" 44' 0.5 0.1
84" 44'
HW #2* 56.19 56.19 54" 46' 0.5 0.2
*Pipe designed using NC Map of Hydrological Contours
Dissipators
Outlet @ Q (cfs) Pipe Size Slope Vel (fps) Dissipator D50
CB #1 11.2 24" 2.5% 4.5 4.5'x6'x18" 6"
CB #2 54.0 2-30" 3.1% 2.7 4.5'x6'x18" 6"
CB #3 2.6 24" 4.2% 10.0 4.5'x9'x24" 13"
CB #4 7.5 18" 0.5% 10.1 4.5'x9'x24" 13"
FES#1 15.5 24" 2.5% 7.5 9'x18'x18" 6"
FES#1A 32.2 36" 2.5% 6.0 4.5'x6'x18" 6"
FES#2 1.5 15" 2.7% 4.8 4.5'x6'x18" 6"
HW #2* 98.73 54" 1.0% 14'x27'x30" 23"
FES #3 10.1 24" 0.5% 12.0 4'x8'x24" 13"
HW #1 * 423.1 72"&84" 1.0% 28'x65'x30" 23"
Asphalt Plant - DITCH PROTECTION
Street Name STA Da C I Q10(cfs) Slope Matting Type
From To
Commercial Offsets
* LT 14+00 15+75 0.39 0.45 7.22 1.27 0.75% unreinforced
RT 14+00 15+75 0.08 0.45 7.22 0.26 0.75% unreinforced
* LT 15+75 17+25 0.33 0.45 7.22 1.07 3.50% C350-Staple E
RT 15+75 17+25 0.08 0.7 7.22 0.40 3.50% C350-Staple E
LT 17+25 19+50 0.12 0.7 7.22 0.61 5.75% C350-Staple E
* RT 17+25 19+50 0.32 0.45 7.22 1.04 5.75% C350-Staple E
LT 19+50 HW-2 0.06 0.7 7.22 0.30 0.50% unreinforced
RT 19+50 HW-2 0.40 0.45 7.22 1.30 0.50% unreinforced
LT HW-1 HW-2 0.08 0.7 7.22 0.40 0.50% unreinforced
RT HW-1 HW-2 0.08 0.7 7.22 0.40 0.50% unreinfroced
LT 28+00 HW-1 0.13 0.7 7.22 0.66 2.90% C125
RT 28+00 HW-1 2.23 0.4 7.22 6.44 2.90% C350-Staple E
LT INT 28+00 0.14 0.7 7.22 0.71 1.50% C125
* RT INT 28+00 3.13 0.4 7.22 9.04 1.50% C350-Staple E
* Analysis attached
North American Green ECMOS Version 4.3 /21/2009 1Q46AM MPUTEDBY: JDH
PROJECT NAME..:. Asphalt Plan(., ______ OJECT,NO.
FROM STATION/REACH: INT TO STATIOWREACH: 26.00 DRAINAGE AREA: 3.13 ESIGN FREQUENCY:
HYDRAULIC RESULTS
Discharge
ds Peak Flow
Petiod hrs Velocity (fps) Area (s41Q Hydraulic
Radiu It Normal
Depth ft
9.0 0.1 1.48 6.09 0.68 1.42
C350 tn-0 3001
S-0.1500
1
golio
I WidthOOft
Not to Scale

Reach Malting Type
Stability Analysis Vegetation Charactetislics
Permissible
Calculated
Safety Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(PSI) Shear Stress
(psfl
Straight C350 Vegetation 2 C Bunch 50.75% 10.00 13.34 0.75 UNSTABLE
StapleE Sod Clay Loam 3.000 0.048 63.12 STABLE
Eay io:lnput Scrmn
Discharge Peck Flow Velocity (fps) Area (sq.lt) Hydraulic Normal
cfs Period hrs R_adiuslltl. Depth (It)
.1 0.1 1.20 0.92 0.26 0.55
C350 (n-0 3001
S-0.3500
1 to 3.01
Not to Scale

Reach Malting Type
Stability Analysis Vegetation Characteristics
Permissble
Calculated
Usty Factor
Remarks
Staple Pattern Phase Class Type Densely Shear Stress
(psi Shear Stress
(psi)
Straight C350 Vegetation 2 C Bunch 50.75% 10.00 12.07 0.83 UNSTABLE
StapleE Sod Clay Loam 3.000 0.129 23.33 STABLE
2a?-t la LrFr/.`.unen...
North American Green - ECMDS Version 4.3 V210009 J 1 D52 AM COMPUTED BY: JDH _
PROJECT NAME;. Asphalt Plan) . __ OJ.E..C..T.NO .
FROM STATION/REACH: 17+25 ! TO STATION/REACH: 19+50 DRAINAGE AREA: ,32 ESIGN FREQUENCY:
HYDRAULIC RESULTS
Discharge
ds Peak Flow
Period Ms Vebeity(fps) Area(srl.01 Hydraulic
Radu ft Namal

ft
Depth
1.0 0.1 1.41 0.71 0,23 0.49
(n-0 300)
S -0+5750
Bottom JI
1L 'Width-0.00ft 301
Not to Scale

Reach Matting Type
Stability Analysis Vegetation Characteristics
Permissible
Calculated
Safely Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(Psf) Shear Stress
(PSI)
Straight C350 Vegetation 2 C Bunch 5075: 10.00 17.43 0.57 UNSTABLE
Staple E Sod Clay Loam 3.000 0.195 15.36 STABLE
Fait ra I??pt Srsern
North American Green - ECMDS Version 4.3 4/21 /2009 1111 AM COMPUTED BY: JDH
PROJECT NAME. As[Jmll Ptanl PROJECT NO.-
FRQM STATIUN,REACH: 14+00 TU STATIONIREACH: 15.75 DRAINAGE AREA:.39 ESIGN FREQUENCi.
HYDRAULIC RESULTS
Urveinlorced Vegetation In-03001
Discharge Peak Flow Vebcily (Ips) Area (sq.ll) ic Normal
cls Period hrs lal, Radius1tl De lh ft
.3 0.1 0.70 1.85 0.37 0.79
S-0.0750
gotto
1I 'Width-(?.00II 1
Not to Scale

Reach Matting Type
Slability Analysis Vegetation Chataclerislics
Permissible
Calwlaled
Safely Factor
Remarks
Staple Pattern Phase Class Type Density Shear Stress
(psQ Shear Stress
(PSI)
Straight Unreittorced Vegetaon C Bunch 50.15%. 4.20 3.68 1.14 STABLE
Sod Clay Loam 0.050 0.006 8.39 STABLE
Back to lnpk S
j ??S ? t?l YlS Q.Np? CiRMn.I KS
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SKIMMER DESIGN
SEDIMENT BASIN # 1
SEDIMENT BASIN VOLUME: 14 .142.0
0.2:
o. t
1000
--4 0.25 day -f- 0.5 day - I day
2 days -E- 3 days 7 days
---}-- 5days 10 days
10000 100000. 1000000
N
SKIMMER ORIFICE DIAMETER:. ?' ZS

SKIMMER DESIGN
SEDIMENT BASIN # X31 4
SEDIMENT BASIN VOLUME: 1128
0.21
4
M
SKIMMER ORIFICE DIAMETER:. - 7 5
o.
1000 10000 100000, 1000000