20072019 Ver 1_Stormwater Plans_20071203

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Storm Drainage and
Erosion Control Calculations
f.7-2019
Lufkin Road and Ten Ten Road
Roadway Improvements
Apex, North Carolina
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Prepared for: o~ ~ ~ znu ~
Town of Apex ~~r~~ _ wA-r~~ cxf~--lr~
©Kimley-Horn and Associates, Inc., 2007 iNETI_AlJt~gAA'D ~T4~M!".'''~~ER 9RAHun
^ ~ ^ Kimley-Horn
~ and Associates, Inc.

LUFKIN ROAD AND TEN TEN ROAD
ROADWAY IMPROVEMENTS
APEX, NORTH CAROLINA
STORM DRAINAGE AND EROSION
CONTROL CALCULATIONS
Prepared for:
TOWN OF APEX
P.O. BOX 250
APEX, NORTH CAROLINA 27502
Prepared by:
KIMLEY-HORN AND ASSOCIATES, INC.
P. O. BOX 33068
RALEIGH, NORTH CAROLINA 27636
MARCH 2007
REV. SEPTEMBER 2007
011200019

~ TABLE OF CONTENTS
OVERVIEW
. USGS QUADRANGLE MAP
SOIL CLASSIFICATIONS
• SOIL CLASSIFICATION SUMMARY
USDA SOIL SURVEY MAP
- FEMA FLOOD INSURANCE RATE MAPS
STORM DRAINAGE CALCULATIONS
PLAN VIEW
- INLET REPORT
PIPE REPORT
• HYDRAULIC GRADE LINE PROFILES
WATER QUANTITY
- PRE-DEVELOPMENT DRAINAGE AREA MAP
. POST-DEVELOPMENT DRAINAGE AREA MAP
FLOW EVALUATION (PRE-DEVELOPMENT VS. POST-DEVELOPMENT)
• WATER QUALITY
DITCH STABILIZATION CALCULATIONS
- CULVERT CALCULATIONS
~ CULVERT SUMMARY
HW/D CALCULATIONS
STORM DRAIN DESIGN COMPUTATIONS (25-YR STORM)
TEMPORARY SEDIMENT CONTROL
- SKIMMER SEDIMENT BASIN
SEDIMENT TRAP
- RIP RAP APRON SUMMARY

OVERVIEW
Back rg ound
This report contains stormwater calculations prepared for the Lufkin Road and Ten Ten Road
roadway improvements in Apex, North Carolina. The project consists of realigning approximately
1500 LF of Lufkin Road and widening approximately 1100 LF of Ten Ten Road. Additional
improvements consist of the installation of 2'-6" curb and gutter along the south side of Ten Ten
Road and along Lufkin Road near the intersection with Ten Ten Road.
The majority of stormwater runoff from Lufkin Road and a portion of the stormwater runoff from Ten
Ten Road will flow through the proposed roadway drainage system and discharge into an upper
tributary of Middle Creek.
The proposed storm drainage has been designed to maintain the natural flow of water; therefore, no
diversions are proposed.
Water QuantitX
The proposed stormwater system has been sized for the 10-year storm as required by the North
Carolina Department of Transportation. The standard NCDOT drainage structures and reinforced
concrete pipe are proposed for this project, including 6 catch basins, 2 grate inlets, 1 junction box, 5
piped-end sections, and reinforced concrete pipe. The proposed catch basins were placed using a
maximum spread of '/z a lane width with a 4-inch per hour intensity. The culverts were designed for
the 25-year storm as required by NCDOT. Since the proposed runoff at all three analysis points
meets the pre- vs. post-development runoff requirement of less than a 10% increase, no stormwater
detention or treatment facilities are required or proposed for this project.
Erosion Control
The appropriate erosion control measures have been taken to minimize sediment-laden stormwater
runoff created as a result of the project's land disturbance. Proposed erosion control measures
include temporary inlet protection, silt fence, grass Swale, ditch stabilization matting, temporary
diversion ditch, temporary sediment trap and temporary skimmer basin. The proposed project will
disturb approximately 5.25 acres of land.
Methods
The attached calculations, prepared using Haestad Method's StormCAD and FlowMaster software,
North American Green software and other spreadsheets, provide support documentation required for
review.
Conclusion
Based on the analysis provided herein, this design meets the stormwater and erosion control
requirements of the Town of Apex and NCDOT.

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Title: USGS Quadrangle Map (Apex , NC 1987)
Project: Lufkin Road and Ten Ten Road
Roadway Improvements
Kimley-Horn Apex, North Carolina
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Date: Scale: Project No. Figure:
3/6/07 NTS 011200019 1

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Title: USDA Soil Survey Map (Wake County, 1970)
Project: Lufkin Road and Ten Ten Road
Roadway Improvements
~ Kimley-Horn Apex, North Carolina
^ ~ ^ and Associates Inc.
Date: Scale: Project No. Figure:
3/6/07 NTS 011200019 3

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APPROXIMATE SCALE IN FEET
400 0 400
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NATIONAL FL000 INSURANCE PROGRAM
FIRM
FLOOD INSURANCE RATE MRP
WAKE COUNTY,
NORTH CAROLINA AND `
INCORPORATED AREAS
PANEL 492 OF 810
ISEE MAP INDEX FOR PANELS NOT PRINTED) PO
CONTAINS:
COMMUNIT9 NUMBER PANEL SUFFIX !.
APEX, TOWN OF 370461 0492 E
CART, TOWN OF 370238 0492 E
UNINCORPORATED AREAS 310368 0492 E
PANEL LOCATIpN
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MAP NUMBER:
3118300492 E
EFFECTIVE DATE:
MARCH 3, 1992
\ ~I Federal Emergency Management Agency
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To determine if Flood insurance is available, contact an insurance agent or call
the National flood Insurance Program at [phone].
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APPROXIMATE SCALE IN FEET
400 0 400
NATIONAL FLOOD INSURANCE PROGRAM
FIRM
FLOOD INSURANCE RATE MAP
WAKE COUNTY,
NORTH CAROLINA AND
INCORPORATED AREAS
PANEL 4910E 810
(SEE MAP INDEX FOR PANELS NOT PRINTEDI
CONTAINS:
COMMUNITY NUMBER PANEI SUFFIX
APEX, TOWN OF 370461 0491 E
UNINCORPORATED AREAS 370368 0491 E
PANEL LOCATION
MAP NUMBER:
3118300491 E
EFFECTIVE DATE:
MARCH 3, 1992
Federal Emergency Management Agency
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Scenario: Base
Inlet Report
Label Rim
Elevation
(ft) Sump
Elevation
(ft) Longitudinal
Slope
(ft/ft) Road
Cross
Slope
(ft/ft) Area
(ftZ) Inlet
C Time
of
Concentration
(min) Intercepted
Intensity
(in/hr) Total
Intercepted
Flow
(cfs) Total
Carryover
Flow
(cfs) Total
Bypassed
Flow
(cfs) Gutter
Ditch
Spread
(ft)
CB-7 437.30 433.55 0.040000 0.060 3,917 0.81 5.00 4.00 0.41 0.12 0.01 1.31
CB-9 439.91 436.19 0.045900 0.060 8,998 0.80 5.00 4.00 0.72 0.06 0.00 1.58
CB-11 451.18 447.46 0.069800 0.037 6,379 0.94 5.00 4.00 0.85 0.35 0.06 1.88
CB-12 456.75 452.73 0.012200 0.060 24,896 0.85 5.00 4.00 1.65 0.00 0.31 3.51
CB-13 456.57 452.85 0.012600 0.060 11,346 0.76 5.00 4.00 0.76 0.00 0.04 2.14
DI-14 457.99 455.29 0.001400 0.060 14,287 0.95 5.00 4.00 1.23 0.00 0.03 4.48
DI-10 440.45 437.75 0.045900 0.060 11,788 0.95 5.00 4.00 0.95 0.03 0.12 1.82
CB-8 437.48 433.96 0.040000 0.060 8,747 0.71 5.00 4.00 0.57 0.00 0.00 1.48
PES-5 427.50 427.50 0.060 0 0.00 5.00 0.00 0.00 0.00 0.00 0.00
PES-2 427.60 427.40 0.020 0 0.00 5.00 0.00 0.00 0.00 0.00 0.00
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\...\drainage\stormcad\lufkin_rev6-11-07.stm StormCAD v5.6 [05.06.012.OOj
09/13/07 06:23:40 PM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

Scenario: Base
Pipe Report
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Upstream
Node Downstream
Node Label Length
(ft) Upstream
Invert
Elevation
(ft) Downstream
Invert
Elevation
(ft) Material Section
Size Constructed
Slope
(ft/ft) Upstream
Inlet
Area
(ft~) Upstream
Inlet
CA
(ft~) System C
(ft~) System
Flow Time
(min) System
Intensity
(in/hr) Average
Velocity
(ft/s) Total
System
Flow
(cfs) Full
Capacity
(cfs) Excess
Full
Capacity
(cfs)
CB-7 PES-6 P-10 40.00 433.55 432.85 Concrete 18 inch 0.017500 3,917 3,173 77,090 5.88 7.05 8.90 12.57 13.90 1.32
CB-12 CB-11 P-2 53.00 452.73 447.66 Concret 15 inch 0.095660 24,896 21,210 15,925 5.00 7.22 11.31 2.66 19.98 17.32
CB-11 CB-9 P-3 182.00 447.46 436.39 Concret 15 inch 0.060824 6,379 5,984 45,382 5.27 7.17 12.80 7.53 15.93 8.40
CB-13 CB-11 P-8 123.00 452.85 447.66 Concret 15 inch 0.042195 11,346 8,628 20,422 5.05 7.21 9.06 3.41 13.27 9.86
DI-14 CB-13 P-9 28.00 455.29 453.05 Concret 15 inch 0.080000 14,287 13,573 12,789 5.00 7.22 9.96 2.14 18.27 16.13
DI-10 CB-9 P-4 15.00 437.75 436.39 Concrete 15 inch 0.090667 11,788 11,199 11,915 5.00 7.22 10.20 1.99 19.45 17.46
CB-9 CB-7 P-7 62.00 436.19 433.75 Concrete 15 inch 0.039355 8,998 7,204 66,186 5.51 7.12 11.72 10.90 12.81 1.91
CB-8 CB-7 P-12 43.00 433.96 433.75 Concrete 15 inch 0.005000 8,747 6,178 5,993 5.00 7.22 0.82 1.00 4.57 3.57
PES-5 JB-4 P-13 56.00 427.50 426.40 Concrete 24 inch 0.019643 0 0 0 5.00 0.00 10.92 22.24 31.70 9.46
JB-4 PES-3 P-14 81.00 426.20 425.20 Concrete 24 inch 0.012346 N/A N/A 0 5.09 0.00 9.03 22.24 25.13 2.89
PES-2 PES-1 P-15 127.00 427.40 425.50 Concrete 36 inch 0.014961 0 0 0 5.00 0.00 7.61 9.06 81.58 72.52
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\...\drainage\stormcad\lufkin_rev6-11-07.stm StormCAD v5.6 [05.06.012.00]
09/13/07 06:00:53 PM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

Profile
Scenario: Base
Profile: LUFKIN PES-2 TO PES-1
Scenario: Base
Z5Y
Label: PES-2
Rim: 427.60 ft
Sump: 427.40 ft
Label: PES-1
Rim: 425.70 ft
Sump: 425.50 ft
0+00 L Label: P-15 1+00
Up. Invert: 427.40 ft
Dn. Invert: 425.50 ft
L: 127.00 ft
Size: 36 inch Station (ft)
S: 0.014961 ft/ft
430.00
_ , 425.00
2+00
Elevation (ft)
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\...\drainage\stormcad\lufkin_rev6-11-07.stm StormCAD v5.6 (05.06.012.00]
09/13/07 06:01:37 PM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

•••••••••••~•••••••~••••••••••••••i~~•••••••
Profile
Scenario: Base
Profile: LUFKIN PES-5 TO PES-3
Scenario: Base
(Z5 Y8A'Q S~6KM~
Label: JB-4
Rim: 433.10 ft
Sump: 426.20 ft
Label: pES-5
Rim: 427.50 ft
Sump: 427.50
435.00
430.00
Elevation (ft)
0
425.00
00
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\...\drainage\stormcad\lufkin_rev3-13-07.stm StormCAD v5.6 [05.06.012.00]
04/04/07 05:24:40 PM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1
L: 56.00 ft La~ei: r- i 4
Size: 24 inch Up. Invert: 426.20 ft
S: 0.019643 ft/ft Dn. Invert: 425.20 ft
L: 81.00 ft
Size: 24 inch Station (ft)
S: 0.012346 ft/ft

Profile
Scenario: Base
Profile: LUFKIN DI-14 TO PES-6
Scenario: Base
Label: DI-14
Rim: 457.99 ft
Sump: 455.29 ft
0+00
Label: CB-13
Rim: 456.58 ft
Sump: 452.86 ft
,,
\

Label: CB•11
~~ Rim: 452.25 ft
~
Label: P-9 Sump: 448.53 ft
Up. Invert: 455.29 ft
Dn. Invert: 453.06 ft
L:26.OD K
IZe:~S IAC
S: 0.085769 ftlft
~
Label: P-8
Up. Invert: 52.86 ft
Dn. Invert: 48.73 ft
L:112.~ h
Size:15 inc
S: 0.03687 ftlft

\\

%

abel: CB-9 i
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Rim:439.91 ft
~'
~ Sump:436.19ft
~ Label: P•3 ~
Up. Invert: 448.53 ft Label: CB•7
Dn. Invert: 436.39 ft \ Rim: 437.30 ft
~ i L:198.00 fl ~~ Sump: 433.55 ft
Size:l5inch
S: 0.061313 iUft
Label: PES-6
Label: P-l / Rim: 433.38 ft
Up.lnveri:436.19fl Sump:432.85h
Dn.lnverl:433J5fl ~
~Label:P-1D
L:62.ODft
S¢e:l5inch Up.lnvert:433.55ft
S: 0
039355ft1ft Dn.lnved:432.8`~ft
. L: 40.00 h
¢e:1 in h
Title: Lufin Road and Ten Ten Road
h:1...ldrainagelstormcadllufkin_rev3-13-07.stm
04/04107 05:20:21 PM
1+DO
2+DO
Station (ft)
3+OD
©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone]
4+00 S: 0.017500 ftlft
460.00
455.00
450.00
445.00
440.00
435.00
430.00
5+00
Elevation (ft)
Pro]ect Engineer; Elizabeth Waller, EI
StormCAD v5.6 [05.06.012.00]
Page t of t

•••s•••••••••••••••s••••••••••••s~•••~•••••s
Profile
Scenario: Base
Profile: LUFKIN CB-8 TO CB-7
Scenario: Base
440.00
Label: CB-8
Rim: 437.48 ft
Sump: 433.96 ft
Label: CB-7
Rim: 437.30 ft
Sump: 433.55 ft
435.00
~ L Label: P-12
Up. Invert: 433.96 ft
Dn. Invert: 433.75 ft ,
L: 43.00 ft
Size: 15 inch '
S 0 005000 ft/ft
_ -- -___..... _ -____ 430.00
0+00 1+00
Elevation (ft)
Station (ft)
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\.-.\drainage\stormcad\lufkin_rev3-13-07.stm StormCAD v5.6 [05.06.012.00]
03/19/07 10:33:07 AM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

__ _
Profile
Scenario: Base
Profile: LUFKIN DI-10 TO CB-9
Scenario: Base
Label: DI-10
Rim: 440.45 ft
Sump: 437.75 f
Station (ft)
445.00
440.00
435.00
Elevation (ft)
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\...\drainage\stormcad\lufkin_rev3-13-07.stm StormCAD v5.6 [05.06.012.00]
04/04/07 05:18:49 PM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1
0+00 Up. Invert: 437.75 ft 1+00
Dn. Invert: 436.39 ft
L: 15.00 ft
Size: 15 inch
S: 0.090667 ft/ft

•••••••••••••••••••~•!•••••i••••••••••••••••
Profile
Scenario: Base
Profile: LUFKIN CB-12 TO CB-11
Scenario: Base
Label: CB-12
Rim: 456.78 ft
Sump: 453.26 ft
0+00
Label: CB-11
Rim: 452.25 ft
Sump: 448.53 ft
i~
L Label: P-2
Up. Invert: 453.26 ft
Dn. Invert: 448.73 ft
L: 53.00 ft
Size: 15 inch
S: 0.085472 ft/ft
460.00
455.00
Elevation (ft)
450.00
445.00
1+00
Station (ft)
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\...\drainage\stormcad\lufkin_rev3-13-07.stm StormCAD v5.6 [05.06.012.00]
04/03/07 09:19:55 AM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

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LUFKIN ROAD AND TEN TEN ROAD PRE-DEVELOPMENT FIGURE
~~~ DRAINAGE AREA MAP
Kimley-HornantlAssociales,lnc. ROADWAY IMPROVEMENTS 4
SCALE 1 =200
THIS DOCUMENT, TOGETHER WITH THE CONCEPTS AND DESIGNS PRESENTED HEREIN, AS AN INSTRUMENT OF SERVICE, IS INTENDED ONLY FOR THE PURPOSE AND CLIENT FOR WHICH IT WAS PREPARED. REUSE
OF AND IMPROPER RELIANCE ON THIS DOCUMENT WITHOUT WRITTEN AUTHORIZATION AND ADAPTATION BY KIMLEY-HORN AND ASSOCIATES, INC. SHALL BE WITHOUT LIABILITY TO KIMLEY-HORN AND ASSOCIATES, INC.

^~~ LUFKIN ROAD AND TEN TEN ROAD POST-DEVELOPMENT FIGURE
ROADWAY IMPROVEMENTS DRAINAGE AREA MAP 5
Kimley-Horn and Associates, Inc. SCALE 1 "=200'
THIS DOCUMENT, TOGETHER WITH THE CONCEPTS AND DESIGNS PRESENTED HEREIN, AS AN INSTRUMENT OF SERVICE, IS INTENDED ONLY FOR THE PURPOSE AND CLIENT FOR WHICH IT WAS PREPARED. REUSE
OF AND IMPROPER RELIANCE ON THIS DOCUMENT WITHOUT WRITTEN AUTHORIZATION AND ADAPTATION BY KIMLEY-HORN AND ASSOCIATES, INC. SHALL BE WITHOUT LIABILITY TO KIMLEY-HORN AND ASSOCIATES, INC.
U:\01 1 20001 9 Lufkin Road\EXHIBITS\Lufkin_Drainaae Area Mao.dwa

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ICmley-Horn
~~~ and Aasaciates, Inc.
Flow Evaluation
Pre-Development vs. Post-Development
Project: Lufkin Road and Ten Ten Road Roadway Improvements
Job Number: 011200019
Date: 3/15/07
Prepared by: EKW
Checked by: AMK
('nnctantc•
Rational C: Rainfall Intensities:
C I (in/hr)
Woods 0.25 2-yr 5.76
Grass 0.35 10-yr 7.22
Pavement 0.95
AREA 1
Pre-Development Flows
Area (Ac) C A ` C
Woods 12.719 0.25 3.180
Grass 7.210 0.35 2.524
Pavement 2.381 0.95 2.262
22.311 7.966
Composite C = (A ` C) /Total Area = 0.357
Q2=C`I"A= 45.88 cfs
Quo=C"I"A= 57.51 cfs
Post-Development Flows
Area (Ac) C A * C
Woods 10.696 0.25 2.674
Grass 8.677 0.35 3.037
Pavement 3.082 0.95 2.928
22.455 8.639
Composite C = (A ` C) /Total Area = 0.385
Q2=C"I*A= 49.76 cfs
Quo=C"I`A= 62.37 cfs
Percent Increase:
Q2 = (Post-Pre)/Pre = 8%
Quo = (Post-Pre)/Pre = 8%
Page 1 of 3

AREA 2
Pre-Development Flows
Area (Ac) C A " C
Woods 0.372 0.25 0.093
Grass 0.458 0.35 0.160
Pavement 0.210 0.95 0.199
1.040 0.452
Composite C = (A " C) /Total Area = 0.435
Qz=C"I"A= 2.61 cfs
Quo=C'`I"A= 3.27 cfs
Post-Development Flows
Area (Ac) C A * C
Woods 0.372 0.25 0.093
Grass 0.457 0.35 0.160
Pavement 0.207 0.95 0.196
1.036 0.449
Composite C = (A " C) /Total Area = 0.434
Qz=C*I"A= 2.59 cfs
Quo=C`I*A= 3.25 cfs
Percent Increase:
Q2 = (Post-Pre)/Pre = -1
Qto = (Post-Pre)/Pre = -1%
Page 2 of 3

i
i
AREA 3
Pre-Development Flows
Area (Ac) C A " C
Woods 0.000 0.25 0.000
Grass 0.318 0.35 0.111
Pavement 0.034 0.95 0.032
0.353 0.144
Composite C = (A ` C) /Total Area = 0.408
Q2=C'`I*A= 0.83 cfs
Quo=C*I*A= 1.04 cfs
Post-Development Flows
Area (Ac)
Woods 0.000
Grass 0.249
Pavement 0.026
0.275
C A'C
0.25 0.000
0.35 0.087
0.95 0.025
0.112
Composite C = (A " C) /Total Area = 0.407
Qz=C"I`A= 0.64 cfs
Quo=C*I*A= 0.81 cfs
Percent Increase:
Qz = (Post-Pre)/Pre = -22%
Quo = (Post-Pre)/Pre = -22%
Page 3 of 3

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DWQ Project No
DIVISION OF WATER QUALITY -GRASSED SWALE WORKSHEET
I. PROJECT IN
Project Name
Contact Person:
Swale ID:
Grass Swale Length
Tributary Drainage Area
Impervious Area
Max. Velocity from 2 Yr. Storm
Max. Velocity from 10 Yr. Storm
Min. side slopes
Steepest Effective Slope
Cover Crop
60o ft.
K.7 ac.
Z.O ac.
LJ.78 fps
~C~_ fps
~ ; - ratio
~'la ft/ft
trR.k~S
(at least 100 ft. per tributary acre)
(on-site and off-site drainage to the swale)
(on-site and off-site drainage to the swale)
(2 fps max.)
(3:1 min.)
(check dams may be used)
II. REQUIRED ITEMS CHECKLIST
Initial in the space provided to indicate the following design requirements have been met and supporting documentation is attached. If a
requirement has not been met, attach an explanation of why. At a minimum, a complete stormwater management plan submittal includes
a worksheet for each BMP, design calculations, plans and specifications showing all BMPs and outlet structure details, a detailed
drainage plan and a fully executed operation and maintenance agreement. An incomplete submittal package will result in a request for
additional information and will substantially delay final review and approval of the project.
Applicants Initials
~KW Vegetation Plan provided on plans
FiK.h1 The underlying soils are permeable and non-compacted
,EKW Swale carries only stormwater flow
$KVJ Water table depth is greater than 1 foot.
~~W Plan details for the swale provided.
L~1 Plan details for the inlets and outlets are provided.
I~ W Check dams provided.
f,,~W The operation and maintenance agreement includes annual erosion and vegetation repair, and at least twice
G annual mowing.
Tim The operation and maintenance agreement signed and notarized by the responsible party is provided.

GRASS SWALE SYSTEM OPERATION AND MAINTENANCE AGREEMENT (3/2007)
Name of Project: Lufkin Road and Ten Ten Road Roadway Improvements
Address: Lufkin Road (near the intersection with Ten Ten Road)
Maintenance activities shall be performed as follows:
MAINTENANCE ACTIVITY FREQUENCY
Post-construction monitoring-inspect for vegetation, Check after every heavy rainfall for first 6 months
grading, and erosion. following construction.
Remove excess sediment, especially from the Once a month and after heavy rainfalls/storms.
upstream edge, to maintain original contours and
grading.
Inspect vegetation and revegetate the swale to Once a month and after heavy rainfalls/storms.
maintain a dense growth of vegetation.
Repair any erosion and regrade swale to ensure that Once a month and after heavy rainfalls/storms.
the runoff flows evenly in a thin sheet through the
swale. Check for damaged turf reinforcement or
riprap rolling downhill.
Mow grass to a 6" height. As needed during growing season (at least twice
annually).
Page 1 of 2

GRASS SWALE LOCATION ON SITE DESCRIBE HOW WILL IT BE ACCESSED?
1 Along the North side of Lufkin Road near the
intersection with Ten Ten Road Lufkin Road
I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance
procedures listed above. I agree to notify DWQ of any problems with the system or prior to any changes to
the system or responsible party.
Print name: Bruce Radford
Title: Town Manaaer
Address: PO Box 250, Apex, NC 27502
Phone
Signatur
Date: , ~ `~. ..-
Note: The legally responsible party should not be a homeowners association unless more than 50% of the
lots have been sold and a resident of the subdivision has been named the president.
1, ~~p~Q~Q,, ~ . ~VCUnq~~~ST , a Notary Public for the State of tJ U STN LA20l.1 Na.,
County of I~JA~E , do hereby certify that ~Q.P,(U~ IZA~~o2p
personally appeared before me this 20+~ day of tJOitErv~[3~ ~0°`7 ,and acknowledge the due
execution of the forgoing wet [wetland] detention basin maintenance requirements. Witness my hand and
official seal,
~G~P A. E V~~G'\
~ ~10TA/3y <N
- --~
'~OOt-Jt~ `~~
SEAL
My commission expires
Page 2 of 2
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Worksheet for Lufkin Ditch Sta 16+85 to 20+95
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.030
Channel Slope 0.02000 ft/ft
Left Side Slope 2.00 ft/ft (H:V)
Right Side Slope 3.00 ft/ft (H:V)
Discharge 17.74 ft'/s
Results
Normal Depth 1.22 ft
Flow Area 3.71 ft2
Wetted Perimeter 6.58 ft
Top Width 6.09 ft
Critical Depth 1.26 ft
Critical Slope 0.01696 ft!ft
Velocity 4.78 ft/s
Velocity Head 0.36 ft
Specific Energy 1.57 ft
Froude Number 1.08
Flow Type Supercritical
GVF Input Data ,
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
GVF Output Data
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 1.22 ft
Critical Depth 1.26 ft
Channel Slope 0.02000 ft/ft
Critical Slope 0.01696 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.066.00]
9!17/2007 12:56:16 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1

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Lufkin Road and Ten Ten Road Roadway Improvements Kimley-Horn and Associates, Inc.
Apex, North Carolina Date: 3/15/2007
Culvert Summary Prepared by: EKW
NCDOT Guidelines were referenced in the following culvert calculation. The site met the criteria for using the Urban
Watershed Peak Discharge Method for calculating peak design discharge as outlined under Section VI, Hydrology, page
13. The guidelines state that if the watershed is less than 10 acres and is primarily composed of pavement, grassed
shoulders and slopes, and/or other mixed surface type runoff, the rational formula should be used for discharge
determination.
PROPOSED 24" RCP AT STA 18+50 (Lufkin Road)
A.) Is Pipe Adequately Sized?
Drainage Area = 5.73 acres
(,),o = 22.24 cfs
Design Storm = 25 year
Ozs = 25.2 cfs
Pipe Size = 24 inch
HW/D = 1.9
Pipe Invert Elevation = 427.5
Overtopping Elevation = 431.6
025 Elevation = 431.3
Road is not overtopped, therefore proposed 24" RCP is adequate.
PROPOSED 36" RCP AT STA 15+77.5 (Lufkin)
A.) Is Pipe Adequately Sized?
StormCad output (Rational Method)
(Table 4-3, page 18 for Secondary)
StormCad output (Rational Method)
(HW for culverts w/Inlet Control Nomograph)
Drainage Area = 3.45 acres
Q,o = 9.06 cfs StormCad output (Rational Method)
Design Storm = 25 year (Table 4-3, page 18 for Secondary)
Ozs = 10.3 cfs StormCad output (Rational Method)
Pipe Size =
HW/D = 24
0.85 inch
(HW for culverts w/Inlet Control Nomograph)
Pipe Invert Elevation = 431.6
Overtopping Elevation = 437.5
025 Elevation = 433.3
Road is not overtopped, therefore proposed 24" RCP is adequate. Use 36" RCP to match pipe
upstream.

Exhibit 11
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iSt ~ 000 a..i Lw. U.! fa'11
6~00o Q.1:o tf\ d.
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ME~-OwiTE>~t SC~l.ES 2s3 CONCRETE PIPE CULVERTS
~nsm MAY ~ WITH INLET CONTROL
•wtcw a n,~tc Ito.a +•x IrA
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Scenario: Base
Pipe Report
5 yF~A~2. S'i1~RWt

Upstream
Node
Downstream
Node
Label
Length
(ft)
Upstream
Invert
Elevation
(ft)
Downstream
Invert
Elevation
(ft)
Material
Section
Size .-
Constructed
Slope
(ft/ft)
Upstream
Inlet
Area
(ftZ)
Upstream
Inlet
CA
(ftZ)
System C
(ft~)
System
Flow Time
(min)
System
Intensity
(in/hr)
Average
Velocity
(fUs)
Total
System
Flow
(cfs)
Full
Capacity
(cfs)
Excess
Full
Capacity
(cfs)

PES-5
JB-4
PES-2 JB-4
PES-3
PES-1 P-13
P-14
P-15 56.00
81.00
127.00 427.50
426.20
427.40 426.40
425.20
425.50 Concrete
Concrete
Concret 24 inch
24 inch
36 inch 0.019643
0.012346
0.014961 0
N/A
0 0
N/A
0 0
0
0 5.00
5.09
5.00 0.00
0.00
0.00 10.92
9.03
7.61 22.24
22.24
9.06 31.70
25.13
81.58 9.46
2.89
72.52
Title: Lufin Road and Ten Ten Road Project Engineer: Elizabeth Waller, EI
h:\...\drainage\stormcad\lufkin_rev6-11-07.stm StormCAD v5.6 [05.06.012.00]
09/13/07 06:01.09 PM ©Bentley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 1

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C ~ ~ Kimley-Hom
~ and Associates, Inc.
EROSION CONTROL CALCS (SKIMMER SEDIMENT BASIN)
Project Information
Project Name: Lufkin Road and Ten Ten Road Roadwa y Improvements
KHA Project #: 011200019
Designed by: EKW Date: 3/22/2007
Checked by: AMK Date: 3/30!2007

Skimmer Basin #1
Drainage Area Total, AT= 5.73 Ac
Disturbed, Ao= 3.5 Ac
10-year Runoff (Qto) C = 0.40
T~ = 5.00 min
I,o = 7.08 inlhr
Qta = 16.2 cfs
Surface Area Required SA = 325sf x Qta
SA = 5,274 sf
Volume Required VR = 1800 cf/Ac x Ao
VR = 6,300 cf
Sediment Trap Dimensions L = 104 ft (Spillway Length)
W = 52 ft (Spillway Width)
D = 2 ft (Depth of Storage)
Side Slopes = 2 :1
40 =
Ltop = 110 ft
Lbot= 96 ft Wto Wbot
WtoP= 58 ft Lbot=
Wbpt= 44 ft
LIW Ratio= 2.0 :1 (must be 2:1 to 6:1)
Elevations Description Elevation
Top of Bem1 428.50 (allow 1ft freeboard above spillway flow height)
Emergency Spillway 427.00
Cleanout Mark 426.00 (half of storage height)
Bottom 425.00
Provided SAP= 5,408 sf > 5,274
VP = 9,632.0 cf > 6,300
Emergency Spillway - 25 Year SI I25 = 7.78
Qz6 = 17.83 cfs
h = 0.5 ft
C„, = 3
Lw= 17 ft (sized to pass Q25)

Skimmer Basin #1 (Continued)
Skimmer Size
Dewatering Volume 9,632 ct
Skimmer Size 2.0 in.
Average Head { h }: 0.167 ft
Select:
Orifice Diameter { d }:
Area { A }:
Discharge Coefficient (C):
Flowrate { O }:
Draw Down Time { T }:
Skimmer
S¢e Head
2" 0.167 ft.
2.5" 0.167 ft.
3" 0.25 ft.
4" 0.275 ft.
5" 0.333 ft.
6" 0.417 ft.
2 in = 0.167
0.022 sq ft
0.60
O =CA sgrt(2gh) = 0.043
224,376 seconds = 2.6
2.6
ft
cfs
days > 1 day
days < 3 days

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~ Kimley-FIWn
C t~ ~ and Assodates, Inc.
EROSION CONTROL CALCS (SEDIMENT TRAP)
Project Information
Project Name: Lufkin Road and Ten Ten Road Roadway Improvements
KHA Project #: 011200019
Designed by: EKW Date: 3/26/2007
Checked by: AMK Date: 3!30/2007
Sediment Traa #1
Drainage Area
10-year Runoff (Qte)
Surface Area Required
Total, AT= 2.41 Ac
Disturbed, Ao= 0.47 Ac
C = 0.40
To = 5.00 min
Ite = 7.08 inlhr
Q~e = 6.8 cfs
SA = 435sf x Qte
SA = 2,969 sf
Volume Required VR = 3600 cflAc x Ao
VR = 1,692 cf
Sediment Trap Dimensions L = 78 ft (Spillway Length)
W = 39 ft (Spillway Width)
D = 3 ft (Depth of Storage)
Side Slopes = 3 :1
Lto = 87
LtoP = 87 ft
Lbat= 63 ft Weot= 24
Wtop = 48 ft Ltot= 63 WtoP 48
Weot= 24 ft

LIW Ratio= 2.0 :1 (must be 2:1 to 6:1)
Elevations Description Elevation
Top of Beml 439.50 (allow tft freeboard above spillway flow height)
Emergency Spillway 438.00
Cleanout Mark 436.75 (haK of storage height)
Bottom 435.50
Provided SAP= 3,042 sf > 2,969
VP = 5,692.5 cf > 1,692
Emergency Spillway - 25 Year S1 IZS = 7.78
Qzs = 7.50 cfs
h = 0.5 ft
Cw = 3
Lw= $ ft (sized to pass l]26)

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RIP RAP APRON SUMMARY
(NYDOT Dissipator Method)
Lufkin Road and Ten Ten Road Roadway Improvements
Apex, North Carolina Prepared by: EIC1N
Job Number: 011200019 Date: 3/15/07
1. PES-1
CULVERT:
Diameter 24 inches
Q,o 9.1 cfs
V, 0 11.0 ft/s
Zone (1-4) 2
APRON DIMENSIONS:
Length 12
Width 14
Thickness 22
Class Stone B
2. PES-3
(StormCAD output)
(StormCAD output)
(Figure 8.06.b.1)
feet (Figure 8.06.b.2)
feet (Figure 8.06a)
inches
(Figure 8.06.b.2)
CULVERT:
Diameter 24 inches
Q, 0 22.2 cfs
V, 0 8.2 ft/s
Zone (1-4) 2
APRON DIMENSIONS:
Length 12
Width 14
Thickness 22
Class Stone B
(StormCAD output)
(StormCAD output)
(Figure 8.06.b.1)
feet (Figure 8.06.b.2)
feet (Figure 8.06a)
inches
(Figure 8.06.b.2)

3. PES-6
CULVERT:
Diameter 18 inches
Q,o 13.3 cfs
V, 0 8.8 ft/s
Zone (1-4) 2
APRON DIMENSIONS:
Length 9 feet
Width 10.5 feet
Thickness 22 inches
Class Stone B
(Storm CAD output)
(StormCAD output)
(Figure 8.06.b.1)
(Figure 8.06.b.2)
(Figure 8.06a)
(Figure 8.06.b.2)