SW5240101_Design Calculations_20240517

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STORMWATER MANAGEMENT NARRATIVE
SILER CITY WASTEWATER TREATMENT
PLANT IMPROVEMENTS
UTILITY DRIVE
SILER CITY, NORTH CAROLINA J
mcgill Shaping
Communities
Together

1STORMWATER MANAGEMENT NARRATIVE
SILER CITY WASTEWATER TREATMENT
PLANT IMPROVEMENTS
UTILITY DRIVE
SILER CITY, NORTH CAROLINA /
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/` 034999
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David L. Honeycutt, PE
NC Professional Engineer No. 034999
rncgiH Shaping
Communities
Together
5 Regional Circle, Suite A
Pinehurst, NC 28374
910.295.3159
NC Firm License #C-0459
November 2023
McGILL PROJECT NO. 18.04015

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FA Shaping Communities Together
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Table of Contents
PROJECT DESCRIPTION 2
SITE DESCRIPTION 2
BASIS OF DESIGN 2
Project Density 2
Stormwater Conveyance 3
METHODOLGY 3
Time of Concentration 3
Hydrologic Methodology 3
Rip Rap Outlet Protection/Aprons 3
Site Soils and Cover Type 3
DESIGN SUMMARY 4
LIST OF APPENDICES
A) Drainage Area Map
B) Stormwater Conveyance Drainage Area Map
C) Storm system 100s Calculations
D) Storm system 200s Calculations
E) Rip Rap Outlet Protection Calculations
F) Ditch Calculations
G) NOAA Atlas 14 — Precipitation Depth
H) NOAA Atlas 14 — Precipitation Intensity
I) NRCS Web Soil Survey Report
J) Stormwater Cost Estimate
MCGILL ASSOCIATES 5 REGIONAL CIRCLE, SUITE A, PINEHURST, NC 28374/910.295.3159/MCGILLASSOCIATES.COM
1

Stormwater Management Narrative
Siler City WWTP
December 20, 2023
PROJECT DESCRIPTION
The project consists of improvements to the existing Wastewater Treatment Plant located in Siler City,
Chatham County, North Carolina. Construction includes approximately 10,682 SF of new buildings,
replacement of existing facilities, 36,081 SF of new asphalt and gravel access areas. The project site is
located off Utility Drive in Chatham County, NC. The Wastewater Treatment Plant occupies
approximately 17 acres of the 55.95 acre property. This upgrade project will disturb approximately 6.38
acres. The work will occur on Chatham County parcel number 80788.
The project is considered low-density with a total BUA of 4.01 acres. Stormwater management for this
project includes grassed swales to carry sheet runoff. The swales have been designed to handle the
25-year storm event. There is an existing piped system on site that carries offsite drainage through the
developed area. Due to new improvements, a new piped system to collect this off-site drainage was
necessary to route the upper drainage through the site. Minimal piping is proposed for routing drainage
under roadways. The stormwater pipes will discharge on site prior to flowing into Loves Creek and
Rocky River respectively.
SITE DESCRIPTION
The project site can be described as a mix of an existing wastewater treatment plant, grasslands and
woodlands. The grading operations will occur where proposed grades are shown on the plans. Most of
the site drains towards the North to Loves Creek. While the southeastern most corner drains southeast
to Rocky River. The average slope is approximately 11.9%. The site is in the Cape Fear River Basin
but does not reside in an area subject to Riparian Buffer requirements.
BASIS OF DESIGN
Project Density
According to Chatham County Code of Ordinances, a high-density project has more than one
dwelling unit per 40,000 square feet or greater than 12% built-upon area. The proposed project is
classified as a low-density project and is designed to meet the applicable stormwater standards.
See the table below for the proposed built-upon area and project density calculations.
Project Density Calculation
Total Property Area: 55.95 ac
Water Surface Area: 0.69 ac
Total Project Area: 55.26 ac
Proposed Total Built-Upon Area (BUA): 4.01 ac
Project Density(%BUA): 7.25 %
MCGILL ASSOCIATES 5 REGIONAL CIRCLE, SUITE A, PINEHURST, NC 28374/910.295.3159/MCGILLASSOCIATES.COM
2

Stormwater Management Narrative
Siler City WWTP
December 20, 2023
Stormwater Conveyance
The storm sewer networks were designed using the 25-year/5-minute storm intensity with Rational
Method and open channel capacities. See the stormwater pipe calculations in Appendix E for
capacity calculations.
METHODOLGY
Time of Concentration
Time of concentration (ToC) was calculated for the stormwater management models using the
NRCS TR-55 method. Calculated ToC for the storm sewer networks were found to be less than 5
minutes. Therefore, an assumed 5-minute minimum ToC was used for all storm drainage pipe
calculations.
Hydrologic Methodology
NRCS TR-20 Method of stormwater analysis was used to model the pre- and post-developed
drainage areas and size stormwater management via HydroCAD. NOAA Atlas 14 Precipitation
Depth Table for the site was used for this method.
Rational Method of stormwater analysis was used to size storm pipes and inlets. NOAA Atlas 14
Precipitation Intensity Table for the site was used for this method.
Rip Rap Outlet Protection/Aprons
Rip rap outlet protection/aprons were dimensioned and designed with NCDEQ Erosion and
Sediment Control Planning and Design Manual Section 6.41 and Appendix Section 8.06. The outlet
protection was designed using the 25-year/24-hour peak runoff. The flows and velocities utilized for
sizing were sourced from the storm sewer network calculations.
Site Soils and Cover Type
The site's soil contains the following map unit names: Georgeville silt loam (GaC), 6 to 10 percent
slopes, HSG B; Nanford-Badin complex (NaB), 2 to 6 percent slopes, HSG B/C.
The NRCS Web Soil Survey Map in tandem with the Rational Method was used to assign the
appropriate C values based on the existing soil types and ground covers present on site. For the
pre/post-developed site, woodlands (C of 0.15), lawns with heavy, steep soil (C of 0.35),
asphalt/concrete (C of 0.85), gravel lots (C of .425), and rooftops (Cc of 0.8) were used for the
ground covers. It is important to note that the pervious areas and impervious areas have been
separated within each drainage area for calculation purposes. Composite C values have been
calculated for the pervious and impervious areas separately for each of the drainage areas
identified based on the uses defined above and delineated within each drainage area.
MCGILL ASSOCIATES 5 REGIONAL CIRCLE, SUITE A, PINEHURST, NC 28374/910.295.3159/MCGILLASSOCIATES.COM
3

Stormwater Management Narrative
Siler City WWTP
December 20, 2023
DESIGN SUMMARY
The project site consists of two main drainage areas, which mainly discharge to Loves Creek and
Rocky River.
Drainage area 1 contains 30.36 acres; 20.66 acres onsite and 9.70 acres offsite. This drainage area
discharges at the north of the site, eventually flowing into Loves Creek.
Drainage area 2 contains 154.23 acres; 33.61 acres onsite and 120.62 acres offsite. This drainage area
discharges to the southeast of the site eventually flowing into Rocky River.
The flow patterns of the drainage basins will be relatively unchanged in the proposed condition. The
post development drainage areas will continue to discharge to the same analysis points in the existing
condition.
MCGILL ASSOCIATES 5 REGIONAL CIRCLE, SUITE A, PINEHURST, NC 28374/910.295.3159/MCGILLASSOCIATES.COM
4

Appendix A -
Drainage Area Map

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ON—SITE:20.66 A.C.
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DRAINAGE AREA 2:
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- V GRAPHIC SCALE DIVISION VALUE=250 FEET
Pinehurst,NC 28374 0349 9
nicg' NC Fir Lice TOWN OF SILER CITY GFF EX-1
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NC Firm License#C-0459 ''.,t, SINE'�O l's �.C+ D.HONEYCUTT S.KIDD
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NO. DATE aY DESCRIPTION CHATHAM COUNTY, NORTH CAROLINA D.HONEYCUTT N.SAWYER November2023 18.04015 N/A

Appendix B -
Stormwater Conveyance Drainage Area Map

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mcgillassociates.com �'O%� HONEo`' ��GCINGFPQ� CHATHAM COUNTY, NORTH CAROLINA D.HONEYCUTT N.SAWYER November2023 18.04015 N/A
NO. DATE BY DESCRIPTION

Appendix C —
Storm System 100s Calculations

Land Use C Land Use C
To DIA(pipe#105)
Burn Lawns
Weighted Runoff Coefficient Downtown areas 070-095 Sandy sal flat,2% 005-010
Land Use Area(ft2) %of Area C C*A Neighborhood area 050-0.70 Sandy son,ave., 010-0.15
Residential: 7% 0.15-020
105a Woodlands 349140.2635 97% 0.15 52371.040 Sandy son,steep, 0.130.17
Single-family area 0.30-0.50 7% 0180.22
105b Heavy Soil,steep 11366.7398 3% 0.35 3978.359 Multi units.detached 040-080 Heavy soil,flat,2% 0250.35
Total: mixed use . 360507.0033 , 100% 0.156306 56349.398 Mum unms.Attached 060-0.75 Heavy son,ace.,
Suburban 0.25-0.40 2.7% I
Irqustnal. Heavy sal,steep,
Light areas 0.50-0.80 7% 0.20-0.50
Rational Method-Peak Runoff(Q) Heavy area 0 80-090
Agricultural pack land:
CO=CiA Parks,cemeteries 0.10-0 25 Bare packed soil 0 00 0.30
Peak runoff Q cfs Smooth 0.200.50
Runoff coefficient C Playgrounds 0.20-0.35 Rough 020-0.40
Cultivated rows 0.10-0.25
Rainfall intensity i in/hr Railroad yard area 0200.40 Heat''sal no amp
watershed area A acres Umq ,d area 0 t0030 ,Heavy sal with 0.15-0.45
crop 0.05-0.25
Streets. Sandy sal no crop 0.05025
C 0.16 Asphalt 0.70.0.95 Irby sat wM
8.17 in/hr (5 min/25 yr) Cone O 80-095 Pasture 010025
A 360507.0033 ft2 Brick 0.700.85 Heavy sal 0.15-0.45
8.28 acres Dines and walks 075-0.85 woodlands 005-025
Roofs 0.75-0 85
Q 10.57 cfs NOTE:The designer must use Judgement to select the appropnate C
value within the range for the appropriate land use Generally larger
havewith permeable soils.flat slopes and dense vegetation should
lowest C values Smaller areas with slowly permeable sods,steep
To DIA(pipe#103) slopes,and sparse vegetation should he assigned highest C values
Weighted Runoff Coefficient Some:Amencan Society&Civil Engineers
Land Use Area(k2) %of Area C C*A
103a Asphalt/Concrete 0 0% 0.85 0.000
103b Heavy Soil,steep 2715.4474 100% 0.35 950.407
Total: mixed use al 2715.4474 100% 0.35 950.407
Pipe D(in) D(ft) n Length(ft) Invert In Invert out slope(ft/ft)* Q(cfs) Required to pass(cfs) Q met?
Rational Method-Peak Runoff(Q) 105 24.00 2.00 0.013 57 518 517 0.01754386 29.83 10.57 TRUE
Q=CiA 104 24.00 2.00 0.013 84 516.9 513.6 0.039285714 44.64 10.57 TRUE
Peak runoff Q cfs 103 24.00 2.00 0.013 83 513.5 513 0.006024096 17.48 10.84 TRUE
Runoff coefficient C 102 24.00 2.00 0.013 93 512.9 512.1 0.008602151 20.89 10.84 TRUE
Rainfall intensity i in/hr 101 24.00 2.00 0.013 99 512 511 0.01010101 22.63 11.06 TRUE
watershed area A acres
C 0.35
i 8.17 in/hr (5 min/25 yr)
A 4061.1108 ft2
0.09 acres
Q 0.27 cfs
To DIA(pipe#101)
Weighted Runoff Coefficient
Land Use Area(k2) %of Area C C*A
101a Asphalt 890.0295 39% 0.825 734.274
nib Heavy Soil,steep 1378.2916 61% 0.35 482.402
Total: mixed use 2268.3211 100% 0.536377 1216.676
Rational Method-Peak Runoff(Q)
CO=CiA
Peak runoff Q cfs
Runoff coefficient C
Rainfall intensity i in/hr
watershed area A acres
C 0.54
8.17 in/hr (5 min/25 yr)
A 2268.3211 ft2
0.05 acres
Q 0.23 cfs

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Oct 17 2023
Pipe 105 with Headwall
Invert Elev Dn (ft) = 517.00 Calculations
Pipe Length (ft) = 57.00 Qmin (cfs) = 10.57
Slope (%) = 1.75 Qmax (cfs) = 10.57
Invert Elev Up (ft) = 518.00 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 24.0
Shape = Circular Highlighted
Span (in) = 24.0 Qtotal (cfs) = 10.57
No. Barrels = 1 Qpipe (cfs) = 10.57
n-Value = 0.013 Qovertop (cfs) = 0.00
Culvert Type = Circular Culvert Veloc Dn (ft/s) = 3.97
Culvert Entrance = Smooth tapered inlet throat Veloc Up (ft/s) = 5.57
Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 HGL Dn (ft) = 518.58
HGL Up (ft) = 519.16
Embankment Hw Elev (ft) = 519.73
Top Elevation (ft) = 521.00 Hw/D (ft) = 0.86
Top Width (ft) = 56.95 Flow Regime = Inlet Control
Crest Width (ft) = 5.00
Elev(It) Pipe 105 with Headwall H, Depth n,
522.00 4.00
521.00 3.00
520.00 2.00
Inlet a,ntral
519.00 1.00
518.00 0.00
517.00 - -1.00
516.00 -2.00
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
CircularCulvert HGL Embank
Reach(ft)

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Oct 17 2023
Manhole 104
Invert Elev Dn (ft) = 513.50 Calculations
Pipe Length (ft) = 84.00 Qmin (cfs) = 10.57
Slope (%) = 4.17 Qmax (cfs) = 10.57
Invert Elev Up (ft) = 517.00 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 24.0
Shape = Circular Highlighted
Span (in) = 24.0 Qtotal (cfs) = 10.57
No. Barrels = 1 Qpipe (cfs) = 10.57
n-Value = 0.013 Qovertop (cfs) = 0.00
Culvert Type = Circular Culvert Veloc Dn (ft/s) = 3.97
Culvert Entrance = Smooth tapered inlet throat Veloc Up (ft/s) = 5.57
Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 HGL Dn (ft) = 515.08
HGL Up (ft) = 518.16
Embankment Hw Elev (ft) = 518.73
Top Elevation (ft) = 521.49 Hw/D (ft) = 0.86
Top Width (ft) = 83.95 Flow Regime = Inlet Control
Crest Width (ft) = 5.00
Elev(ft) Manhole 104 Hw Depth(R)
522.00 5.00
521.00 4.00
520.00 3.00
519.00 2.00
Inlei coIrol
518.00 1.00
517.00 0.00
516.00 -1.00
515.00 -2.00
514.00 3.00
513.00
512.00 -5.00
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Circular Culvert HGL Embank
Reach(E)

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Oct 17 2023
Yard Inlet 103
Invert Elev Dn (ft) = 513.00 Calculations
Pipe Length (ft) = 83.00 Qmin (cfs) = 10.84
Slope (%) = 0.60 Qmax (cfs) = 10.84
Invert Elev Up (ft) = 513.50 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 24.0
Shape = Circular Highlighted
Span (in) = 24.0 Qtotal (cfs) = 10.84
No. Barrels = 1 Qpipe (cfs) = 10.84
n-Value = 0.013 Qovertop (cfs) = 0.00
Culvert Type = Circular Culvert Veloc Dn (ft/s) = 4.05
Culvert Entrance = Smooth tapered inlet throat Veloc Up (ft/s) = 5.60
Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 HGL Dn (ft) = 514.59
HGL Up (ft) = 514.68
Embankment Hw Elev (ft) = 515.25
Top Elevation (ft) = 520.48 Hw/D (ft) = 0.88
Top Width (ft) = 82.95 Flow Regime = Inlet Control
Crest Width (ft) = 5.00
Elev(ft) Yard Inlet 103 Hw Depth(0)
521.00 7.50
520.00 6.50
519.00 5.50
518.00 4.50
517.00 3.50
516.00 2.50
trel
515.00 1.50
514.00 0.50
513.00 -0.50
512.00 -1.50
0 10 20 30 40 50 60 70 80 90 100 110 120 130
Circular Culvert HGL Embank
Reach(E)

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Wednesday,Oct 18 2023
Manhole 102
Invert Elev Dn (ft) = 512.00 Calculations
Pipe Length (ft) = 93.00 Qmin (cfs) = 10.84
Slope (%) = 1.08 Qmax (cfs) = 10.84
Invert Elev Up (ft) = 513.00 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 24.0
Shape = Circular Highlighted
Span (in) = 24.0 Qtotal (cfs) = 10.84
No. Barrels = 1 Qpipe (cfs) = 10.84
n-Value = 0.013 Qovertop (cfs) = 0.00
Culvert Type = Circular Concrete Veloc Dn (ft/s) = 4.05
Culvert Entrance = Square edge w/headwall (C) Veloc Up (ft/s) = 5.62
Coeff. K,M,c,Y,k = 0.0098, 2, 0.0398, 0.67, 0.5 HGL Dn (ft) = 513.59
HGL Up (ft) = 514.18
Embankment Hw Elev (ft) = 514.78
Top Elevation (ft) = 518.62 Hw/D (ft) = 0.89
Top Width (ft) = 92.95 Flow Regime = Inlet Control
Crest Width (ft) = 5.00
Elev(a) Manhole 102 Hw Depth(ft)
519.00 1 1 1 1 600
518.00 5.00
517.00 4.00
516.00 3.00
515.00 2.00
.ntet ,nhul
514.00 1 1.00
1 r
lir-
513.00 0.00
512.00 -1.00
511.00 -2.00
0 10 20 30 40 50 60 70 00 90 100 110 120 130 140
Circular Culvert HGL Embank
Reach(It)

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Wednesday,Oct 18 2023
Yard Inlet 101
Invert Elev Dn (ft) = 511.00 Calculations
Pipe Length (ft) = 99.00 Qmin (cfs) = 11.06
Slope (%) = 1.01 Qmax (cfs) = 11.06
Invert Elev Up (ft) = 512.00 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 24.0
Shape = Circular Highlighted
Span (in) = 24.0 Qtotal (cfs) = 11.06
No. Barrels = 1 Qpipe (cfs) = 11.06
n-Value = 0.013 Qovertop (cfs) = 0.00
Culvert Type = Circular Culvert Veloc Dn (ft/s) = 4.12
Culvert Entrance = Smooth tapered inlet throat Veloc Up (ft/s) = 5.67
Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 HGL Dn (ft) = 512.60
HGL Up (ft) = 513.19
Embankment Hw Elev (ft) = 513.77
Top Elevation (ft) = 517.96 Hw/D (ft) = 0.89
Top Width (ft) = 98.95 Flow Regime = Inlet Control
Crest Width (ft) = 5.00
Elev(a) Yard Inlet 101 Hw Depth(1t)
518.00 6.00
517.00 5.00
516.00 I 4.00
515.00 I 3.00
514.00 2.00
Intet contrd
513.00 1.00
on-
512.00 0.00
511.00 11.11111111g11111 MINIM -1.00
510.00 -2.00
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Circular Culvert HGL Embank
Reach(It)

Appendix D -
Storm System 200s Calculations

Q=CiA
C
To DIA(pipe g201) Land Use C Land Use
Business Lawns:
Weighted Runoff Coefficient Downtown areas 070-095 Sandy soil,flat,2% 0.05-0.10
Land Use Area(k2) %of Area C C`A Neghbethood areas 050-0.70 Sandy son,awe., 0.100.15
Residential-
Single-family 2-7% 0.15020
201a Asphalt 8683 14% 0.825 7163.475Sandy sole,steep, 0.13-0.17
areas 030-0.50 7% 0.18-022
201b Heavy Soil,steep 51714 86% 0.35 18099.900 Mull'units.detaUted 040-0.80 Heavy soil,flat,2% 0.250.35
Total: mixed use 60397 86% 0.299682103 18099.900 Mull'units.Attached 060-0.75 Heavy soil,ave.,
Suburban 025-0.40 2-7%
Industrial. Heavy soil,steep,
Light areas aso-ae0 7% 0.
Rational Method-Peak Runoff(a) Heavy areas 060-09 Agricultural lane:
0 D0.50
Q=CIA Parks cemeteries 0.10-0.25 Bare packed soli 0.300.60
Peak runoff Q cfs Stnnom 02D0.50
Runoff coefficient C Playgrounds 020-0.35 Rough 0.20-0.40
Cultivated rows 0.10-0.25
Rainfall intensity iin/hr Radroad yard areas 020-0.40 Heavy soil no crop
Heavy soil with 0.154.45
watershed area A acres Unimproved areas 0.10-0.30 crop 0.05025
Streets. Sandy soil no crop 0.05-025
C 0.30 Asphan 070.0.95 Sandy soil with
8.17 in/hr (5 min/25 yr) Concrete 0.80-0.95 crofiu a 0.10-0.25A 60397 k2 Brick070085 Heavy soil 0.15.0.45
1.39 acres Dines and walks 0.75-0.85 SandWoo sail 0.0,5-0.25
dlands 005-025
Roofs 0 75-0 85
Q NOTE:The designer must use judgement to select the appropriate C
value vnthin the range for the appropnate land use Generally,larger
areas with permeable soils flat slopes,and dense vegetation should
have lowest C values Smaller areas with slowly permeable soils,steep
slopes,and sparse vegetation should be assigned highest C values.
Sauce:Arruncan Society of CArl Engineers
Pipe D(in) D(ft) n Length(ft) Invert In Invert out slope(ft/ft)' Q(cfs) Required to pass(cfs) Q met?
201 15.00 1.25 0.013 55 533.1 532.24 0.015636364 8.03 3.39 TRUE

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Monday, Nov 6 2023
Yard Inlet 201
Invert Elev Dn (ft) = 532.24 Calculations
Pipe Length (ft) = 55.00 Qmin (cfs) = 3.39
Slope (%) = 1.56 Qmax (cfs) = 3.39
Invert Elev Up (ft) = 533.10 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 15.0
Shape = Circular Highlighted
Span (in) = 15.0 Qtotal (cfs) = 3.39
No. Barrels = 1 Qpipe (cfs) = 3.39
n-Value = 0.013 Qovertop (cfs) = 0.00
Culvert Type = Circular Culvert Veloc Dn (ft/s) = 3.23
Culvert Entrance = Smooth tapered inlet throat Veloc Up (ft/s) = 4.47
Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 HGL Dn (ft) = 533.24
HGL Up (ft) = 533.84
Embankment Hw Elev (ft) = 534.20
Top Elevation (ft) = 535.58 Hw/D (ft) = 0.88
Top Width (ft) = 54.95 Flow Regime = Inlet Control
Crest Width (ft) = 5.00
Eie,[h! Yard Inlet 201 Hw Depth(ft)
53E.:C. - - - - - - - 2.90
535.00 1.90
Inlet control
534.00 0.90
r
rJ
rJ
533.00 -0.10
532.00 -1.10
531.00 -2.10
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
Circular Culvert HGL Embank
Reach(It)

Culvert Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Oct 31 2023
200 FES
Invert Elev Dn (ft) = 532.24 Calculations
Pipe Length (ft) = 55.00 Qmin (cfs) = 8.03
Slope (%) = 1.56 Qmax (cfs) = 8.03
Invert Elev Up (ft) = 533.10 Tailwater Elev (ft) = (dc+D)/2
Rise (in) = 15.0
Shape = Circular Highlighted
Span (in) = 15.0 Qtotal (cfs) = 8.03
No. Barrels = 1 Qpipe (cfs) = 8.03
n-Value = 0.013 Qovertop (cfs) = 0.00
Culvert Type = Circular Culvert Veloc Dn (ft/s) = 6.68
Culvert Entrance = Smooth tapered inlet throat Veloc Up (ft/s) = 6.95
Coeff. K,M,c,Y,k = 0.534, 0.555, 0.0196, 0.9, 0.2 HGL Dn (ft) = 533.42
HGL Up (ft) = 534.22
Embankment Hw Elev (ft) = 535.05
Top Elevation (ft) = 536.00 Hw/D (ft) = 1.56
Top Width (ft) = 53.00 Flow Regime = Inlet Control
Crest Width (ft) = 5.00
Elev (ft) Profile Hw Depth (ft)
537.00 3.90
536.00 2.90
535.00 Hw 1.90
Embankment
534.00 0.90
HGL
55.00 Lf of 15(in) @ 1.56 %
533.00 -0.10
532.00 • -1.10
531.00 -2.10
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0 60.0 65.0 70.0 75.0
Reach (ft)

Appendix E -
Rip Rap Outlet Protection Calculations

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: LR Date: 11/6/2023
Checked By: SB Date: 11/6/2023
Company: McGill Associates
Project Name: WWTP Improvements
Project No.: 18.04015
Site Location(City/Town) Slier City,Chatham Co
Culvert Id. 100 FES
Total Drainage Area(acres) 8.42
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter.it is classified minimum tailwater condition.
If it is greater than half the pipe diameter,it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a minimum tailwater condition unless reliable flood stage elevations
show otherwise.
Outlet pipe diameter,Do(in.) 24
Tailwater depth(in.) 22.16
Minimum/Maximum tailwater? Max TW(Fig.8.06b)
Discharge(cfs) 22.63
Velocity(ft./s) 7.47
Step 2. Based on the tailwater conditions determined in step 1.enter Figure
806a or Figure 8.06b,and determine dS0 nprap size and minimum apron length
(L). The d50 size is the median stone size in a well-graded nprap apron.
Step 3. Determine apron width at the pipe outlet,the apron shape,and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap d5o,(ft.) 0 0.5
Minimum apron length,La(ft.) 0 18
Apron width at pipe outlet(ft.) 6 6
Apron shape Trapezoid
Apron width at outlet end(ft.) 2 9.2
Step 4. Determine the maximum m stone diameter:
d�=1.5xd,a
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 0 0.75
Step 5. Determine the apron thickness:
Apron thickness=1.5 x d ,
Minimum TW Maximum TW
Apron Thickness(ft.) 0 1.125
Step 6. Fit the riprap apron to the site by making it level for the minimum
length,L., from Figure 8.06a or Figure 8.066. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary(Appendix 8.05). Where overfalls exist at
pipe outlets or flows are excessive,a plunge pool should be considered,see
page 8.06.8.

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: LR Date: 10/31/2023
Checked By: SB Date: 10/31/2023
Company: McGill Associates
1Project Name: WWTP Improvements
Project No.: 18.04015
Site Location(City/Town) Siler City,Chatham Co
Culvert Id. 200 FES
Total Drainage Area(acres) 1.17
Step 1. Determine the tailwater depth from channel characteristics below the
pipe outlet for the design capacity of the pipe. If the tailwater depth is less
than half the outlet pipe diameter,it is classified minimum tailwater condition.
If it is greater than half the pipe diameter.it is classified maximum condition.
Pipes that outlet onto wide flat areas with no defined channel are assumed
to have a niin,mu ii tailwater condition unless reliable flood stage elevations
show otherwise.
Outlet pipe diameter,Do(in.) 15
Tailwater depth(in.) 14.19
Minimum/Maximum tailwater? Max TW(Fig.8.06b)
Discharge(cfs) 8.03
Velocity(ft./s) 6.68
Step 2. Based on the tailwater conditions determined in step I.enter Figure
8.06a or Figure 8.06b,and determine dso riprap size and minimum apron length
(L). The da size is the median stone size in a well-graded nprap apron.
Step 3. Determine apron width at the pipe outlet,the apron shape,and the
apron width at the outlet end from the same figure used in Step 2.
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap dso,(ft.) 0 0.5
Minimum apron length,La(ft.) 0 10
Apron width at pipe outlet(ft.) 3.75 3.75
Apron shape Trapezoid
Apron width at outlet end(ft.) 1.25 5.25
Step 4. Determine the maximum stone diameter:
d =1.5xd,o
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 0 0.75
Step 5. Determine the apron thickness
Apron thickness= 15 x dm„
Minimum TW Maximum TW
Apron Thickness(ft.) 0 1.125
Step 6. Fit the nprap apron to the site by making it level for the minimum
length.L,, front Figure 8.06a or Figure 8.06b. Extend the apron farther
downstream and along channel banks until stability is assured. Keep the
apron as straight as possible and align it with the flow of the receiving stream.
Make any necessary alignment bends near the pipe outlet so that the entrance
into the receiving stream is straight.
Some locations may require lining of the entire channel cross section to assure
stability.
It may be necessary to increase the size of riprap where protection of the
channel side slopes is necessary(Appendix 8.05). Where ov-erfalls exist at
pipe outlets or flows are excessive,a plunge pool should be considered,see
page 8.06.8.

Appendix F -
Ditch Calculations

Table 4-5:Kerby Equation Retardance Coefficient Values Typical Range for
The Kerby Method Aeration Basin Swale Generalized terrain description Dimensionless retardancecoeffic lent(N) Type of Area Runoff Coefficient
= K(L x p 0.467-JJ,,-0.235 Pavement 0.02 Concrete Pavement 0.70-0.95
When V Smooth,bare,packed soil 0.10
ram,=overand now time of concemmtion,in minutes grass.cultivated row crops,ot moderately rough packed surfaces 02o Park or Cemetery 0.10-0.25
K=a units conversion cceficlenl.in which K=0.828 for traditional units and K=1 04 for Pasture,average grass 0.40 Downtown Business 0.70-0.95
61 units -
L=the overland-flow length,in feel or meters as dictated by K Deciduous forest 0.60
N.a dimensionless retamance coefficient Dense grass.coniferous forest or deciduous forest with deep later 0.80 Single Family
s=the dimensionless slope of terrain conveying Me overland Mow Residential Area 0.30-0.50
0.770S 0.385
The Kilpich Method tch= KL Variables: Rational Method Equation
Irv...
0.0078 T(overland)= 0.1309 min
=the time ofconeamratianinmimdes L= 434 Q = CiA
L(overland)= 204 Tlchannel)= 1.8899 min
K.a units conversion coefficient.inwhich K=0.0078 for traditional units and K=0.0195 L(channel)= 230 Where:
for SI units 5= 0.022 I TC= 5.00 min I C=runoff coefficient
L=the channel now length,in feet or metersas dictated by 5(overland)= 0.031863 i=rainfall intensity
s=the dimensionless main-channel slope
5(channel)= 0.033913 A=drainage area
N= 0.363296 0=peak flow
Kerby-Kirpich Method tc = tnv±tch Nea= 29989.06 fM2
C= 0.441050568
Where:
ilin/hr)= 8.17
toy=overland flow time A= 0.688453972 AC
IN25)= 2.48 cfs
tch=channel flow time N(composite)=[A(pay)aN(pav)l+14(soil)'N(soil))+IA(croprN(cropHA(grassr Nlgrass)l+(Alforest)a N(forest)HA(denser N(dense))/Total Area

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Nov 7 2023
Aeration Basin Swale SWALE #1
Triangular Highlighted
Side Slopes (z:1) = 2.50, 2.50 Depth (ft) = 0.55
Total Depth (ft) = 1.00 Q (cfs) = 2.480
Area (sqft) = 0.76
Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.28
Slope (%) = 3.40 Wetted Perim (ft) = 2.96
N-Value = 0.033 Crit Depth, Yc (ft) = 0.58
Top Width (ft) = 2.75
Calculations EGL (ft) = 0.72
Compute by: Known Q
Known Q (cfs) = 2.48
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 - 1.00
v
100.50 - 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7
Reach (ft)

Aeration Basin Swale Siler City WWTP
11/7/2023 me �I
Normal-Depth Procedure by: Spencer Kidd g
l
Shear Stress at Normal Depth
Q25= 2.48 cfs
n=p0.033 Selected Lining: If Bare Soil,Vp= ft/s
s avg= 3.39%ft/ft
M= 2.5 Side Slope W
Zreq'd= 0.298
A
Y Y
B= 0.0 feet •
Y= 0.5 feet B
A= 0.76 sq.feet
P= 2.96 feet
R= 0.26 feet
Zav= 0.304
V= 3.3 feet/sec Bare Soil Is Unacceptable,please select an adequate swale lining
W= 2.8
Check Shear Stress of Liner
Td= 1.16 lb/sq.ft
Permissible Unit Shear Stress,Td(lb/sq.ft) n values for Depth Ranges
Lining Category Lining Type 0-0.5 ft. 0.5-2.0 ft. >2.0 ft.
Lining type
Temporary Woven Paper Net 0.15 Woven Paper Net 0.016 0.015 0.015
Jute Net 0.45 Jute Net 0.028 0.022 0.019
Fiberglass Roving: Fiberglass Roving 0.028 0.021 0.019
Single 0.60 Straw with Net 0.065 0.033 0.025
Double 0.85 Curled Wood Mat 0.066 0.035 0.028
Straw w/Net 1.45 Synthetic Mat 0.036 0.025 0.021
Curled Wood Mat 1.55
Synthetic Mat 2.00 Unlined:
Bare Soil 0.023 0.02 0.02
d50 Stone Size(inches) Rock Cut 0.045 0.035 0.025
Gravel Riprap 1 0.33
2 0.67 Rip Rap:
Rock Riprap 6 2.00 D50=1" 0.044 0.033 0.03
9 3.00 D50=2" 0.066 0.041 0.034
12 4.00 D50=6" 0.038
15 5.00 D50=9" 0.04
18 6.00 D50=12" 0.042
21 7.80 D50=18" 0.044
24 8.00 D50=24" 0.047

Table 4-5:Kerby Equation Retardence Coefficient Values Typical Range for
Headworks Swale Type of Area Runoff Coefficient
The Kerby Method Generalized terrain description Dimensionless retardance coefficient(N)
0.467*S,-0.235 Pavement 0oz
to, = K(L x v)
Concrete Pavement 0.70-0.95
wh.n. smooth,bare.packed son 0.10
o.=venom now ume a conceare0on,in minutes
grass.cul0vated row sops,or moderately rough peas.surfaces 0.20
Park or Cemetery 0.10-0.25
K=a units conversion coefficient in which K=0.828 for traditional units and K=l44 for Pasture average grass 0.40 Downtown Business 0.70-0.95
sl oats Deciduous forest 0.80
L=the overlanddlow length,in teal or melees as dictated by K
N=a dimensionless retamance coefficient Dense grass,coniferous forest,or deciduous forest with deep liner 0.80 Single Family
s=the dimensionless slope of terrain cwweeng the overland now Residential Area 0.30-0.50
0.770 0.385
The Ki pich Method eh= KL ^� Variables: Rational Method Equation
NTarv; K= 0.0078 T(0verlandl= 0.0267 min
=the bmeof concentration,inmingles
162 Q = CiA
L(overland)= 30 T(channep= 0.4879 min
K=a units conversion coefficient,inwrhi*K=0.0078 for traditional units and K=0.0105 L(channel)= 57 Where:
for SI units 5= 0.522 I Too s.00 min I C=runoff coefficient
L=the channel flow long.,in feet or meters as dictated by K 5(overland)= 1.4 i=rainfall intensity
s=the dimensionless main-channel slope sknanneq= 0.070175 n=drainage area
o _ ter+C N= 0.548563 Q=peak flow
Kerby-Kidp ich Method h Area= 5956 ft^2
Where: C= 0.156305974
i(in/hrl= 8.17
to,=overland flow time A= 0.136730946 AC
IQI25)= 0.17 cfs I
tpa=channel flow lime N(composite)=[A(pav)*N(pev)]i[A(soil]*N(soil)].[A(crop)*Nlcrop)]i(A(grass)*N(grass)]i[A(forest]*N(forest)]i[A(dense)*N(dense)]/Total Area

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Nov 7 2023
Headworks Swale SWALE #2
Trapezoidal Highlighted
Bottom Width (ft) = 1.00 Depth (ft) = 0.12
Side Slopes (z:1) = 2.00, 2.00 Q (cfs) = 0.170
Total Depth (ft) = 1.00 Area (sqft) = 0.15
Invert Elev (ft) = 100.00 Velocity (ft/s) = 1.14
Slope (%) = 5.83 Wetted Perim (ft) = 1.54
N-Value = 0.065 Crit Depth, Yc (ft) = 0.10
Top Width (ft) = 1.48
Calculations EGL (ft) = 0.14
Compute by: Known Q
Known Q (cfs) = 0.17
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 - 1.00
100.50 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7
Reach (ft)

Headworks Swale Siler City WWTP
11/7/2023 �� ;"
Normal-Depth Procedure by: Spencer Kidd g
Shear Stress at Normal Depth
Q25= 0.17 cfs
n= 0.028 Selected Lining: If Bare Soil,Vp= ft/s
s avg= 0.0583 ft/ft
M= 2 Side Slope W
Zreq'd= 0.013
Y Y
B= 1.O�feet
Y= 0.1 feet B
A= 0.15 sq.feet
P= 1.54 feet
R= 0.10 feet
Zav= 0.031
V= 1.1 feet/sec V<Vp,Bare Soil is Acceptable
W= 1.5
Check Shear Stress of Liner
Td= 0.44 lb/sq.ft
Permissible Unit Shear Stress,Td(lb/sq.ft) n values for Depth Ranges
Lining Category Lining Type 0-0.5 ft. 0.5-2.0 ft. >2.0 ft.
Lining type
Temporary Woven Paper Net 0.15 Woven Paper Net 0.016 0.015 0.015
Jute Net 0.45 Jute Net 0.028 0.022 0.019
Fiberglass Roving: Fiberglass Roving 0.028 0.021 0.019
Single 0.60 Straw with Net 0.065 0.033 0.025
Double 0.85 Curled Wood Mat 0.066 0.035 0.028
Straw w/Net 1.45 Synthetic Mat 0.036 0.025 0.021
Curled Wood Mat 1.55 Grass 0.05 0.05 0.05
Synthetic Mat 2.00 Unlined:
Bare Soil 0.023 0.02 0.02
d50 Stone Size(inches) Rock Cut 0.045 0.035 0.025
Gravel Riprap 1 0.33
2 0.67 Rip Rap:
Rock Riprap 6 2.00 D50=1" 0.044 0.033 0.03
9 3.00 D50=2" 0.066 0.041 0.034
12 4.00 D50=6" 0.038
15 5.00 D50=9" 0.04
18 6.00 D50=12" 0.042
21 7.80 D50=18" 0.044
24 8.00 D50=24" 0.047

Table4-5:Kerby Equation Reterdence Coefficient Values Typical Range for
NW Outlet Swale — Type of Area Runoff Coefficient
The Kerby Method Generalized terrain description Dimensionless retardance coefficient(N)
to =K(L x!17)0.467S0.235 Pavement o.0z
Concrete Pavement 0.70-0.95
vda�v smooth,Pare.packed soil 010
,,,=overland aow Woe or concentration,in miades Poor grass cul0sated sow crops.or moderately rough packed sudeces 020 Park or Cemetery 0.10-0.25
K=aunits comersee coobo,.which K=0.828f«tradmorol units a.K=144 for Pasture,average grass 0.40 Downtown Business 0.70-0.95
SI nnna Deciduous forest 0.60
_. mmsl°n eu re ran«coo«metersn� as dictated byK Dense grass.coniferous forest.or deciduous forest with deep inter 0.80 Single Family
nt
s=the dimensionless slope of terrain 1m,eylnp the°Veda.s«v Residential Area 0.30-0.50
0.770S 0.385
The Kirpich Method tch— KL Variables: Rational Method Equation
YMraa K= 0.0078 T(overland)= 0.0530 min
4 148 Q = CiA
,,,=,.erne wslecsome°n.in m«nrs L(overland)= 48.5 T(channel)= 0.0000 min
version coefficient,in when K=0.e0/8 f«bane«al unm and K=0015n L(channe0= 0 Where:
for SI mid 5= 0.029072 I Too 5.00 min I C=runoff coefficient
channel ow length..n feet or meters as Masted by 5(ovedantl)= 0.029072 i=rainfall intensity
s=the dimensiondimensionlessm m dimensionless an. annel slope 8(channel)= NA A-'drainage area
3, . tc = toy N= 0.21 Q=peak flow
Kerby-Kirpich Method h &es= 4786.487 fM2
= 0.35
Where:
ihn/hr)= 8.17
toy=overland flow time A= 0.109882629 AC
IQ(25)a 11.75 cfs I
tcn=channel flow time Mcomposite)=[A(pav)*N(pav)MA(soilr N(soilHA(crop)*Mcrop)lt[A(grassrMgrassHA(forestrMforeshMA(denserMdense)]/Total Area

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Nov 7 2023
NW Outlet Swale SWALE #3
Trapezoidal Highlighted
Bottom Width (ft) = 5.00 Depth (ft) = 0.67
Side Slopes (z:1) = 2.50, 2.50 Q (cfs) = 22.81
Total Depth (ft) = 1.00 Area (sqft) = 4.47
Invert Elev (ft) = 100.00 Velocity (ft/s) = 5.10
Slope (%) = 4.30 Wetted Perim (ft) = 8.61
N-Value = 0.038 Crit Depth, Yc (ft) = 0.76
Top Width (ft) = 8.35
Calculations EGL (ft) = 1.07
Compute by: Known Q
Known Q (cfs) = 22.81
Elev (ft) Section Depth (ft)
102.00 - I 2.00
101.50 1.50
101.00 1.00
v
100.50 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8 9 10 11 12
Reach (ft)

NW Outlet Swale Siler City WWTP
11/7/2023 �� ;"
Normal-Depth Procedure by: Spencer Kidd g
Shear Stress at Normal Depth
Q25=p 22.81 cfs
n= 0.038 Selected Lining: If Bare Soil,Vp= ft/s
s avg= 4.30%ft/ft
M= 2.5 Side Slope W
Zreq'd= 2.805
A
Y Y
B= 5.00 feet •
Y= 1.00 feet B
A= 7.50 sq.feet
P= 10.39 feet
R= 0.72 feet
Zav= 6.037
V= 3.0 feet/sec Bare Soil Is Unacceptable,please select an adequate swale lining
W= 10.0
Check Shear Stress of Liner
Td= 2.68 lb/sq.ft
Permissible Unit Shear Stress,Td(lb/sq.ft) n values for Depth Ranges
Lining Category Lining Type 0-0.5 ft. 0.5-2.0 ft. >2.0 ft.
Lining type
Temporary Woven Paper Net 0.15 Woven Paper Net 0.016 0.015 0.015
Jute Net 0.45 Jute Net 0.028 0.022 0.019
Fiberglass Roving: Fiberglass Roving 0.028 0.021 0.019
Single 0.60 Straw with Net 0.065 0.033 0.025
Double 0.85 Curled Wood Mat 0.066 0.035 0.028
Straw w/Net 1.45 Synthetic Mat 0.036 0.025 0.021
Curled Wood Mat 1.55 Grass 0.05 0.05 0.05
Synthetic Mat 2.00 Unlined:
Bare Soil 0.023 0.02 0.02
d50 Stone Size(inches) Rock Cut 0.045 0.035 0.025
Gravel Riprap 1 0.33
2 0.67 Rip Rap:
Rock Riprap 6 2.00 D50=1" 0.044 0.033 0.03
9 3.00 D50=2" 0.066 0.041 0.034
12 4.00 D50=6" 0.038
15 5.00 D50=9" 0.04
18 6.00 D50=12" 0.042
21 7.80 D50=18" 0.044
24 8.00 D50=24" 0.047

Table 4-5:Kerby Equation Retardance Coefficient Values Typical Range for
Type of Area Runoff Coefficient
The Kerby Method Road Swale Generalized terrain description Dimensionless retardant*coefficient(N)
o.467s 0.235 Pavement 0oz
to, = K(L x N) Concrete Pavement 0.70-0.95
wh.n. smooth,bare.packed son 0.10
o.=venom now ume a concentration,on mimes Poor grass.culavated row crops,or moderately rough packed surfaces 0.20
Park or Cemetery 0.10-0.25
K=a units conversion coefficient,in which K=0.828 for traditional units am K=144 for Pasture.average grass 0.ao Downtown Business 0.70-0.95
sl oats Deciduous forest 0.80
L=de overlain.now length,in feel or meters as dictated by K
N=a dimensionless retardant*coefficient Dense grass,coniferous forest or deciduous forest with deep liner 0.80 Single Family
s=the dimensionless slope&terrain conveying the overland now Residential Area 0.30-0.50
0.770 0.385
The Kipich Method oh= KL S Variables: Rational Method Equation
NTerv; K= 0.0078 T(overlandl= 0.0701 min
�,=mebmeor concentration,inminutes
243 Q = CiA
yoverlandl= 94 T(channell= 1.1621 min
K=a units conversion coefficient in which K=0.0078 for traditional units and K=0.0195 L(channell= 149 Where:
for SI units 5= 0.166596 I Tc= s.00 min I C=runoff coefficient
L=the channel flow long.,in feet or meters as dictated by K 5(overland]= 0.111702 i=rainfall intensity
S=the dimensionless main-channel slope S(channel)= 0.050336 A=drainage area
o _ tor+C N= 0.389489 Q=peak flow
Kerby-Kinp ich Method h area= 60397 frnz
Where: C= 0.356036522
i(in/hrl= 8.17
toy=overland flow time A= 1.386524334 AC
IQ(25)= 4.03 cfs I
tpa=channel flow time N(composite)=[A(pev)*N(pev]]i[A(soil]*N(soill]ilA(crop)*Nlcrop]]i[A(grass)*N(gress]]i[A(forest]*N(forest)]i[A(dense)*N(dense]]/Total Area

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday, Nov 7 2023
Road Swale SWALE #4
Trapezoidal Highlighted
Bottom Width (ft) = 1.00 Depth (ft) = 0.56
Side Slopes (z:1) = 2.50, 2.50 Q (cfs) = 4.030
Total Depth (ft) = 1.00 Area (sqft) = 1.34
Invert Elev (ft) = 100.00 Velocity (ft/s) = 3.00
Slope (%) = 7.77 Wetted Perim (ft) = 4.02
N-Value = 0.065 Crit Depth, Yc (ft) = 0.53
Top Width (ft) = 3.80
Calculations EGL (ft) = 0.70
Compute by: Known Q
Known Q (cfs) = 4.03
Elev (ft) Section Depth (ft)
102.00 I I 2.00
101.50 1.50
101.00 - 1.00
100.50 - 0.50
100.00 0.00
99.50 I -0.50
0 1 2 3 4 5 6 7 8
Reach (ft)

Road Swale Siler City WWTP
11/7/2023 �� ;"
Normal-Depth Procedure by: Spencer Kidd g
Shear Stress at Normal Depth
Q25= cfs
n= Selected Lining: If Bare Soil,Vp= ft/s
S avg= ft/ft
M= Side Slope W
Zreq'd= 0.883
Y Y
B= 1.O�
Y= 0.5 feetfeet B
A= 1.13 sq.feet
P= 3.69 feet
R= 0.30 feet
Zav= 0.509
V= 3.6 feet/sec Bare Soil Is Unacceptable,please select an adequate swale lining
W= 3.5
Check Shear Stress of Liner
Td= 1.24 lb/sq.ft
Permissible Unit Shear Stress,Td(lb/sq.ft) n values for Depth Ranges
Lining Category Lining Type 0-0.5 ft. 0.5-2.0 ft. >2.0 ft.
Lining type
Temporary Woven Paper Net 0.15 Woven Paper Net 0.016 0.015 0.015
Jute Net 0.45 Jute Net 0.028 0.022 0.019
Fiberglass Roving: Fiberglass Roving 0.028 0.021 0.019
Single 0.60 Straw with Net 0.065 0.033 0.025
Double 0.85 Curled Wood Mat 0.066 0.035 0.028
Straw w/Net 1.45 Synthetic Mat 0.036 0.025 0.021
Curled Wood Mat 1.55 Grass 0.05 0.05 0.05
Synthetic Mat 2.00 Unlined:
Bare Soil 0.023 0.02 0.02
d50 Stone Size(inches) Rock Cut 0.045 0.035 0.025
Gravel Riprap 1 0.33
2 0.67 Rip Rap:
Rock Riprap 6 2.00 D50=1" 0.044 0.033 0.03
9 3.00 D50=2" 0.066 0.041 0.034
12 4.00 D50=6" 0.038
15 5.00 D50=9" 0.04
18 6.00 D50=12" 0.042
21 7.80 D50=18" 0.044
24 8.00 D50=24" 0.047

Appendix G -
NOAA Atlas 14 — Precipitation Depth

11/3/23, 11:44AMP recipitation Frequency Data Server
NO AA Atlas 14,Volume 2,Version 3
`'°°` Location name: Siler City, North Carolina, USA* �'""'
3 Latitude: 35.7606°, Longitude: -79.4622° F none
Elevation: 674 ft**
*source:ESRI M a,s 'a /
**source:USG S �""'"'"`.
PO NT PRECIPITATIO NFREQ LENCY ESTIMATES
G M.Bonnin,D.Matin,B.Lin,T.Parzybok,M Yekta,and D.Riley
NO PA,National Weather Service,Silver Spring,M ayland
PF tabular I PF graphical I M 4ps & aerials
PF tabular
PDS-based point precipitation frequency estimates w kh 90% confidence intervals (in inches)1
Average recurrence interval(years)
Duration' 1 2 51 0 2 5 5 0 1 00 2 00 5 00 1 000
5-m n 0.414 0.491 0.570 0.623 0.681 0.720 0.753 0.781 0.809 0.829
(0.379-0.454) (0.449-0.539) (0.520-0.624) (0.568-0.682) (0.618-0.745) (0.650-0.787) (0.678-0.823) (0.699-0.855) (0.718-0.886) (0.729-0.908)
10-m in 0.662 0.785 0.912 0.996 1.09 1.15 1.20 1.24 1.28 1.31
(0.605-0.725) (0.718-0.862) (0.833-1.00) (0.908-1.09) (0.985-1.19) (1.04-1.25) (1.08-1.31) (1.11-1.36) (1.14-1.40) (1.15-1.43)
15-min 0.827 0.987 1.15 1.26 1.38 1.45 1.51 1.56 1.61 1.64
(0.756-0.906) (0.903-1.08) (1.05-1.26) (1.15-1.38) (1.25-1.50) (1.31-1.59) (1.36-1.65) (1.40-1.71) (1.43-1.76) (1.44-1.80)
30-m in 1.13 1.36 1.64 1.83 2.04 2.18 2.32 2.43 2.56 2.65
(1.04-1.24) (1.25-1.50) (1.50-1.80) (1.66-2.00) (1.85-2.23) (1.98-2.39) (2.08-2.53) (2.18-2.66) (2.28-2.81) (2.33-2.91)
60-m in 1.41 1.71 2.10 2.38 2.72 2.96 3.19 3.41 3.68 3.87
(1.29-1.55) (1.56-1.88) (1.92-2.30) (2.17-2.60) (2.46-2.97) (2.68-3.24) (2.87-3.49) (3.05-3.73) (3.26-4.03) (3.41-4.24)
2-hr 1.69 2.05 2.54 2.90 3.36 3.70 4.02 4.35 4.76 5.08
(1.54-1.86) (1.88-2.26) (2.32-2.80) (2.64-3.19) (3.03-3.68) (3.32-4.06) (3.60-4.42) (3.86-4.77) (4.18-5.23)_ (4.41-5.59)
3-hr 1.81 2.20 2.73 3.13 3.64 4.04 4.43 4.82 5.34 5.74
(1.65-1.99) (2.01-2.41) (2.49-3.00) (2.85-3.42)_ (3.30-3.98) (3.63-4.42)_ (3.96-4.84) (4.27-5.27) (4.67-5.85) (4.97-6.30)
6-hr 2.18 2.64 3.28 3.77 4.43 4.94 5.46 5.98 6.69 7.25
(2.00-2.38) (2.43-2.89) (3.00-3.59) (3.44-4.12) (4.01-4.82) (4.44-5.38) (4.87-5.94) (5.28-6.50) (5.82-7.28) (6.23-7.91)
12-hr 2.58 3.13 3.91 4.53 5.37 6.04 6.73 7.45 8.46 9.26
(2.38-2.82) (2.88-3.43) (3.58-4.28) (4.13-4.95) (4.86-5.84) (5.42-6.56) (5.98-7.30) (6.55-8.07) (7.30-9.16) (7.87-10.0)
24-hr 2.98 3.60 4.50 5.20 6.16 6.92 7.70 I 8.50 9.61 10.5
(2.78-3.19) (3.36-3.86) (4.20-4.82) (4.85-5.58) (5.73-6.62) (6.42-7.43) (7.12-8.28) (7.83-9.15) (8.80-10.4)_ (9.56-11.3)
2-day 3.49 4.21 5.23 6.01 7.08 7.91 8.77 9.65 10.9 11.8
(3.28-3.74) (3.94-4.51) (4.90-5.60) (5.62-6.45) (6.59-7.60) (7.35-8.49)_ (8.12-9.43) (8.90-10.4) (9.96-11.7) (10.8-12.8)
3-day 3.71 4.46 5.51 6.33 7.45 8.32 9.22 10.2 11.4 12.4
(3.47-3.97) (4.18-4.78) (5.16-5.90) (5.91-6.78) (6.93-7.98) (7.72-8.92) (8.53-9.91)_ (9.35-10.9) (10.5-12.3) (11.3-13.4)
4-day 3.92 4.70 5.80 6.65 7.82 8.74 9.68 10.6 12.0 13.0
(3.67-4.20) (4.41-5.04) (5.42-6.20) (6.20-7.12) (7.26-8.37) (8.09-9.36) (8.93-10.4) (9.80-11.4) (11.0-12.9) (11.9-14.1)
7-day 4.50 5.37 6.53 7.46 8.71 9.71 10.7 11.8 13.2 14.4
(4.24-4.81) (5.05-5.73) (6.13-6.97) (6.99-7.95) 1 (8.14-9.30) (9.04-10.4) (9.94-11.5), (10.9-12.6) (12.1-14.2) (13.1-15.5)
10-day 5.13 6.10 7.32 8.29 9.58 10.6 11.6 12.7 14.1 15.3
(4.84-5.46) (5.74-6.49) (6.89-7.80) (7.78-8.83) (8.97-10.2) (9.89-11.3) (10.8-12.4) (11.8-13.6) (13.0-15.2) (14.0-16.4)
20-day 6.88 8.12 9.59 10.8 12.3 13.6 14.8 16.1 17.8 19.2
(6.51-7.27) (7.69-8.58) (9.07-10.1) (10.2-11.4) (11.6-13.0) (12.7-14.4) (13.9-15.7) (15.0-17.1) (16.5-19.0) (17.7-20.5)
30-day 8.52 10.0 11.7 12.9 14.6 15.9 17.2 18.4 20.1 21.5
(8.13-8.98) (9.56-10.5) (11.1-12.3) (12.3-13.6) (13.8-15.3) (15.0-16.7) (16.2-18.1) (17.3-19.5) (18.9-21.3) (20.0-22.8)
45-day 10.9 12.7 14.6 16.0 17.8 19.2 20.6 22.0 23.8 25.2
(10.4-11.4) (12.1-13.3) (13.9-15.2) (15.2-16.8) (16.9-18.7) (18.2-20.2) (19.5-21.7) (20.7-23.1) (22.4-25.1) (23.6-26.6)
60-day 13.0 15.2 17.1 18.6 20.6 22.0 23.5 24.8 26.6 28.0
(12.5-13.6) (14.5-15.9) (16.4-17.9) (17.8-19.5) (19.6-21.5) (21.0-23.1) (22.3-24.6) (23.5-26.1) (25.2-28.1) (26.4-29.5)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Num hers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estim aces(for
a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estim des at upper bounds are not
checked against probable m adm t n precipitation(PM P)estimates and m ay be higher than currently valid PM P values.
Please refer to NO FA Atlas 14 docum ait form cre inform aion.
Back to Top
PF graphical
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.htm Plat=35.7606&Ion=-79.4622&data=depth&units=english&series=pds 1 /4

11/3/23, 11:44 AM P recipitation Frequency Data Server
PDS-based depth-duration-frequency (DDF) curves
Latitude: 35.7606°, Longitude: -79.4622°
Average recurrence
interval
25 - / (years)
c — 1
= 20 - J — 2
a / — 5
a)
• 15 - — 10
O — 25
y
Coa — 50
'▪ 10 - — 100
D
d — 200
a
_ _ — 500
5 �_- — 1000
0-
II
I - - - - - - 1 f—r—
C C C C f_ '- f_ - >, >.>, >+ >, >. > >.>.
•_ •_ •_ • •— L fL L ry L f43 r43-3 -30 N -33 -33 -33-3
u1 .i
4 m $ Duration r" ry 4 ^ 2 N M v 8
25 - -
c �_
- 20 - Duration
s
4.,
a)o 0111111111111011 — 5-min — 2-day
• 15 — - — 10-min — 3-day
ao 15-min — 4-day
a 10 — 30-min — 7-day
j ' — 60-min — 10-day
�� — — 2-hr — 20-day
=___---
5 — 3-hr — 30-day
— 6-hr — 45-day
0 r---- — 12-hr — 60-day
1 i i I - 24-hr
1 2 5 10 25 50 100 200 500 1000
Average recurrence interval (years)
NOAA Atlas 14,Volume 2,Version 3 Created(GMT} Fri Nov 3 15 44:39 2023
Back to Top
M aps & aerials
Small scale terrain
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.htm flat=35.7606&Ion=-79.4622&data=depth&units=english&series=pds 2 /4

11/3/23, 11:44 AM P recipitation Frequency Data Server
. + .
1' V '� '� —
3 3km
Slier City
2mi
Lar a scale terrain
0 •
Winston-Salem
• • Durham
Rocky M<
Greensboro I • Raleigh •
,;
NORTH CAROLINA
9 +
•Charlotte Fayettevill •
E
pit -
'� liwk
i. Ja
100km •
60m i
Large scale map
7
r' m
Inston-S Iem Greensboro
o Durham Rocky Mc
I o
Raleigh
•
© l rth Gi
Carolina
arl otte +
F etteville
•
100km Jai
60m i
r
Large scale aerial
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.htm Plat=35.7606&Ion=-79.4622&data=depth&units=english&series=pds 3 /4

11/3/23, 11:44 AM P recipitation Frequency Data Server
Winston-Salem
Greensboro Durham • Rocky Mo
•
Raleigh
• G
North •
Carolina
Charlotte •
Fayetteville
• Ja.
100km
60m i
Back to Top
US Departm(Ent of Comm ace
National 0 manic and Atm spheric Adm histration
National Weather Service
National Water Center
1325 East West Highway
Silver Spring,M D20910
Q Lestions?:HDSC.Q [e-mail]
Disclaim er
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.htm RIat=35.7606&Ion=-79.4622&data=depth&units=english&series=pds 4 /4

Appendix H -
NOAA Atlas 14 - Precipitation Intensity

8/8/23,9:47 AM Precipitation Frequency Data Server
NOAA Atlas 14,Volume 2,Version 3
° ° \ Location name:Siler City,North Carolina,USA* ''''
i If v. non
Latitude:35.7606°,Longitude: -79.4622° e I
Elevation:674 ft** i
4" *source:ESRI Maps "w
-.nu° **source:USGS "`" .
POINT PRECIPITATION FREQUENCY ESTIMATES
G.M.Bonnin,D.Martin,B.Lin,T.Parzybok,M.Yekta,and D.Riley
NOAA,National Weather Service,Silver Spring,Maryland
PF tabular I PF graphical I Maps & aerials
PF tabular
PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour)1
Average recurrence interval(years)
Duration
1 2 5 10 25 50 100 200 500 1000
5-min 4.97 5.89 6.84 7.48 8.17 8.64 9.04 9.37 9.71 9.95
(4.55-5.45) (5.39-6.47) (6.24-7.49) (6.82-8.18) (7.42-8.94) (7.80-9.44) (8.14-9.88) (8.39-10.3) (8.62-10.6) (8.75-10.9)
10-min 3.97 4.71 5.47 5.98 6.52 6.88 7.18 7.42 7.68 7.84
(3.63-4.35) (4.31-5.17) (5.00-6.00) (5.45-6.55) i (5.91-7.13) (6.22-7.52) (6.46-7.85) (6.65-8.13) (6.82-8.41) (6.89-8.58)
15-min 3.31 3.95 4.62 5.04 5.51 5.80 6.05 6.24 6.44 6.56
(3.02-3.62) (3.61-4.33) (4.22-5.06) (4.60-5.52) (5.00-6.02) (5.24-6.34) (5.44-6.62) (5.59-6.84) (5.72-7.06) (5.77-7.18)
30-min 2.27 2.73 3.28 3.65 4.08 4.37 4.63 4.86 5.13 5.31
(2.07-2.48) (2.49-2.99) (3.00-3.59) (3.33-4.00) (3.70-4.46) (3.95-4.78) (4.17-5.07) (4.35-5.32) (4.55-5.62) (4.67-5.81)
60-min 1.41 1.71 2.10 2.38 ' 2.72 2.96 I 3.19 3.41 3.68 3.87
(1.29-1.55) (1.56-1.88) (1.92-2.30) (2.17-2.60) (2.46-2.97) (2.68-3.24) I (2.87-3.49) (3.05-3.73) (3.26-4.03) (3.41-4.24)
2-hr 0.846 1.03 1.27 1.45 1.68 1.85 2.01 2.17 2.38 2.54
(0.772-0.931) (0.938-1.13) (1.16-1.40) (1.32-1.59) (1.52-1.84) (1.66-2.03) (1.80-2.21) (1.93-2.39) (2.09-2.62) (2.21-2.79)
3-hr 0.602 0.730 0.908 1.04 1.21 1.34 1.47 1.60 1.78 1.91
(0.550-0.661) (0.669-0.803) (0.830-0.997) (0.948-1.14) (1.10-1.33) (1.21-1.47) (1.32-1.61) (1.42-1.75) (1.56-1.95) (1.66-2.10)
6-hr 0.363 0.440 0.547 0.629 0.739 0.824 0.910 0.998 1.12 1.21
(0.334-0.398) (0.405-0.482) (0.501-0.599) (0.574-0.687) (0.669-0.805) (0.741-0.897) (0.813-0.991) (0.881-1.09) (0.972-1.22) (1.04-1.32)
12-hr 0.214 0.259 0.324 0.375 0.445 0.501 0.558 0.618 0.701 0.768
(0.197-0.234) (0.238-0.284) (0.297-0.355) (0.342-0.410) (0.403-0.484) (0.449-0.544) (0.496-0.605) (0.543-0.669) (0.605-0.760) (0.653-0.833)
24-hr 0.124 0.149 0.187 0.216 0.256 0.288 0.320 0.354 0.400 0.436
(0.116-0.132) (0.140-0.160) (0.175-0.200) (0.202-0.232) (0.238-0.275) (0.267-0.309) (0.296-0.344) (0.326-0.381) (0.366-0.431) (0.398-0.471)
2-day 0.072 0.087 0.108 0.125 0.147 0.164 0.182 ' 0.201 0.226 0.245
(0.068-0.077) (0.082-0.094) (0.102-0.116) (0.117-0.134) (0.137-0.158)1(0.153-0.176) (0.169-0.196)1(0.185-0.216) (0.207-0.244) (0.224-0.266)
3-day 0.051 0.061 0.076 0.087 0.103 0.115 0.128 0.140 0.158 0.172
(0.048-0.055) (0.057-0.066) (0.071-0.081) (0.082-0.094) (0.096-0.110) (0.107-0.123) (0.118-0.137) (0.129-0.151) (0.145-0.171) (0.157-0.186)
4-day 0.040 0.049 0.060 0.069 0.081 1 0.091 I 0.100 0.110 0.124 0.135
(0.038-0.043) (0.045-0.052) (0.056-0.064) (0.064-0.074) (0.075-0.087) (0.084-0.097)1(0.093-0.108) (0.102-0.119) (0.114-0.134) (0.123-0.146)
7-day 0.026 0.031 0.038 0.044 0.051 0.057 0.063 0.070 0.078 0.085
(0.025-0.028) (0.030-0.034) (0.036-0.041) (0.041-0.047) (0.048-0.055) (0.053-0.061) (0.059-0.068) (0.064-0.075) (0.072-0.084) (0.078-0.092)
10-day 0.021 0.025 0.030 0.034 0.039 0.044 0.048 0.052 0.058 0.063
(0.020-0.022) (0.023-0.027) (0.028-0.032) (0.032-0.036) (0.037-0.042) (0.041-0.047) (0.045-0.051) (0.049-0.056) (0.054-0.063) (0.058-0.068)
20-day 0.014 0.016 0.019 0.022 0.025 0.028 0.030 0.033 I 0.037 0.039
(0.013-0.015) (0.016-0.017) (0.018-0.021) (0.021-0.023) (0.024-0.027) (0.026-0.029) (0.028-0.032) (0.031-0.035) (0.034-0.039) (0.036-0.042)
30-day 0.011 0.013 0.016 0.017 0.020 0.022 0.023 0.025 0.027 0.029
(0.011-0.012) (0.013-0.014) (0.015-0.017) (0.017-0.018) (0.019-0.021) (0.020-0.023) (0.022-0.025) (0.024-0.027) (0.026-0.029) (0.027-0.031)
45-day 0.010 0.011 0.013 0.014 0.016 0.017 0.019 0.020 0.022 0.023
(0.009-0.010) (0.011-0.012) (0.012-0.014) (0.014-0.015) (0.015-0.017) (0.016-0.018) (0.018-0.020) (0.019-0.021) (0.020-0.023) (0.021-0.024)
60-day 0.009 0.010 0.011 0.012 0.014 0.015 0.016 0.017 0.018 0.019
(0.008-0.009) (0.010-0.011) (0.011-0.012) (0.012-0.013),(0.013-0.014) (0.014-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.019)1(0.018-0.020)
1 Precipitation frequency(PF)estimates in this table are based on frequency analysis of partial duration series(PDS).
Numbers in parenthesis are PF estimates at lower and upper bounds of the 90%confidence interval.The probability that precipitation frequency estimates(for
a given duration and average recurrence interval)will be greater than the upper bound(or less than the lower bound)is 5%.Estimates at upper bounds are not
checked against probable maximum precipitation(PMP)estimates and may be higher than currently valid PMP values.
Please refer to NOAA Atlas 14 document for more information.
Back to Top
PF graphical
https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=35.7606&Ion=-79.4622&data=intensity&units=english&series=pds 1/4

8/8/23,9:47AM Precipitation Frequency Data Server
PDS-based intensity-duration-frequency (IDF) curves
Latitude: 35.7606°, Longitude: -79.4622°
101 Average recurrence
interval
(years)
Z' 10° - _
2
� — 5
y — 10
— zs
o -- — 50
r.
'a
— 200
a \` — 500
'~- - — 1000
10-2 -
r 1 1 1 I II I 1 I III II III
E E E E E N OS u5 N 4 v vv -o 7 v v 77
i
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Appendix I -
NRCS Web Soil Survey Report

USDA United States A product of the National Custom Soil Resource
Department of Cooperative Soil Survey,
Agriculture a joint effort of the United Report for
NStates Department of
RCS Agriculture and other Chatham County,
Federal agencies, State
Naturalagencies including the North Carolina
Resources Agricultural Experiment
Conservation Stations, and local
Service participants
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November 3, 2023

Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nrcs)or your NRCS State Soil
Scientist(http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2

alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at [phone] (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call [phone] (voice)or(202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3

Contents
Preface 2
How Soil Surveys Are Made 5
Soil Map 8
Soil Map 9
Legend 10
Map Unit Legend 11
Map Unit Descriptions 11
Chatham County, North Carolina 13
BaE—Badin-Nanford complex, 15 to 30 percent slopes 13
GaC—Georgeville silt loam, 6 to 10 percent slopes 14
GoC—Goldston-Badin complex, 2 to 15 percent slopes 16
NaB—Nanford-Badin complex, 2 to 6 percent slopes 17
NaC—Nanford-Badin complex, 6 to 10 percent slopes 19
References 22
4

How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil-vegetation-landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5

Custom Soil Resource Report
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil-landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil-landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field-observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
6

Custom Soil Resource Report
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
7

Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
8

Custom Soil Resource Report
N Soil Map b
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Meters
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Map projection:Web Mercator Comer coordinates:WG584 Edge tics:UTM Zone 17N WGS84
9

Custom Soil Resource Report
MAP LEGEND MAP INFORMATION
Area of Interest(AOI) 14 Spoil Area The soil surveys that comprise your AOI were mapped at
Area of Interest(AOI) 1:24,000.
Q Stony Spot
Soilsit Very Stony Spot
0 Soil Map Unit Polygons Warning:Soil Map may not be valid at this scale.
Wet Spot
,..,. Soil Map Unit Lines Enlargement of maps beyond the scale of mapping can cause
p Other misunderstandingof the detail of mapping and accuracyof soil
p Soil Map Unit Points pp 9
.• Special Line Features line placement.The maps do not show the small areas of
Special Point Features contrasting soils that could have been shown at a more detailed
Blowout Water Features scale.
-_- Streams and Canals
kg Borrow Pit
Transportation Please rely on the bar scale on each map sheet for map
* clay Spot 1.44 Rails measurements.
0 Closed Depression
o,/ Interstate Highways
Gravel Pit Source of Map: Natural Resources Conservation Service
.r US Routes Web Soil Survey URL:
Gravelly Spot Major Roads Coordinate System: Web Mercator(EPSG:3857)
® Landfill Local Roads Maps from the Web Soil Survey are based on the Web Mercator
• Lava Flow Background projection,which preserves direction and shape but distorts
distance and area.A projection that preserves area,such as the
46 Marsh or swamp Aerial Photography Albers equal-area conic projection,should be used if more
It Mine or Quarry accurate calculations of distance or area are required.
4 Miscellaneous Water This product is generated from the USDA-NRCS certified data as
O Perennial Water of the version date(s)listed below.
v Rock Outcrop Soil Survey Area: Chatham County, North Carolina
+ Saline Spot Survey Area Data: Version 27,Sep 13,2023
Sandy Spot Soil map units are labeled(as space allows)for map scales
Severely Eroded Spot 1:50,000 or larger.
• Sinkhole Date(s)aerial images were photographed: Apr 23,2022—Apr
31 Slide or Slip 27,2022
oa Sodic Spot The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps.As a result,some minor
shifting of map unit boundaries may be evident.
10

Custom Soil Resource Report
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
BaE Badin-Nanford complex, 15 to 0.6 0.9%
30 percent slopes
GaC Georgeville silt loam,6 to 10 19.8 30.7%
percent slopes
GoC Goldston-Badin complex,2 to 1.6 2.5%
15 percent slopes
NaB Nanford-Badin complex,2 to 6 24.7 38.3%
percent slopes
NaC Nanford-Badin complex,6 to 10 17.8 27.6%
percent slopes
Totals for Area of Interest 64.6 100.0%
Map Unit Descriptions
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
11

Custom Soil Resource Report
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha-Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
12

Custom Soil Resource Report
Chatham County, North Carolina
BaE—Badin-Nanford complex, 15 to 30 percent slopes
Map Unit Setting
National map unit symbol: 1 Ivrt
Elevation: 300 to 650 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost-free period: 200 to 240 days
Farmland classification: Not prime farmland
Map Unit Composition
Badin and similar soils: 50 percent
Nanford and similar soils: 30 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Badin
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap- 0 to 6 inches: silt loam
Bt- 6 to 24 inches: clay
BC-24 to 32 inches: channery silty clay loam
Cr-32 to 80 inches: weathered bedrock
Properties and qualities
Slope: 15 to 30 percent
Depth to restrictive feature: 20 to 40 inches to paralithic bedrock
Drainage class:Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low(about 5.5 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: C
Ecological site: F136XY830NC -Acidic upland forest, depth restriction, dry-moist
Hydric soil rating: No
Description of Nanford
Setting
Landform: Hillslopes on ridges
13

Custom Soil Resource Report
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap- 0 to 3 inches: silt loam
E-3 to 7 inches: silt loam
Bt1 - 7 to 12 inches: silty clay
Bt2- 12 to 27 inches: silty clay
BC-27 to 38 inches: silty clay loam
C-38 to 57 inches: silt loam
Cr-57 to 80 inches: weathered bedrock
Properties and qualities
Slope: 15 to 30 percent
Depth to restrictive feature:40 to 60 inches to paralithic bedrock
Drainage class:Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.8 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: B
Ecological site: F136XY820GA-Acidic upland forest, moist
Hydric soil rating: No
GaC—Georgeville silt loam, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol: 2vy6n
Elevation: 160 to 820 feet
Mean annual precipitation: 43 to 47 inches
Mean annual air temperature: 57 to 61 degrees F
Frost-free period: 200 to 230 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Georgeville and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
14

Custom Soil Resource Report
Description of Georgeville
Setting
Landform: Hillslopes
Landform position (two-dimensional): Shoulder, backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Convex
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or residuum
weathered from argillite and/or residuum weathered from phyllite and/or
residuum weathered from sericite schist
Typical profile
Ap- 0 to 7 inches: silt loam
BE- 7 to 10 inches: silty clay loam
Bt- 10 to 44 inches: clay
BC-44 to 53 inches: silty clay loam
C- 53 to 80 inches: loam
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water(Ksat): Moderately high to high
(0.57 to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: High (about 9.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: F136XY820GA-Acidic upland forest, moist
Hydric soil rating: No
Minor Components
Tarrus
Percent of map unit: 10 percent
Landform: Interfluves
Landform position (two-dimensional): Shoulder, backslope
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across-slope shape: Convex
Hydric soil rating: No
15

Custom Soil Resource Report
GoC—Goldston-Badin complex, 2 to 15 percent slopes
Map Unit Setting
National map unit symbol: 1 Ivvr
Elevation: 200 to 650 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost-free period: 200 to 240 days
Farmland classification: Not prime farmland
Map Unit Composition
Goldston and similar soils: 55 percent
Badin and similar soils: 30 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Goldston
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
A -0 to 7 inches: very channery silt loam
Bw- 7 to 11 inches: very channery silt loam
Cr- 11 to 23 inches: weathered bedrock
R-23 to 80 inches: unweathered bedrock
Properties and qualities
Slope: 8 to 15 percent
Depth to restrictive feature: 10 to 20 inches to paralithic bedrock; 20 to 40 inches
to lithic bedrock
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Very low(about 1.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4s
Hydrologic Soil Group: D
Ecological site: F136XY880GA-Acidic high hills and isolated ridges, depth
restriction, dry
16

Custom Soil Resource Report
Hydric soil rating: No
Description of Badin
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Backslope
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
A -0 to 2 inches: channery silt loam
E-2 to 9 inches: channery silt loam
Bt1 -9 to 21 inches: channery silty clay loam
Bt2-21 to 36 inches: silty clay
Cr-36 to 45 inches: weathered bedrock
R-45 to 80 inches: unweathered bedrock
Properties and qualities
Slope: 8 to 15 percent
Depth to restrictive feature: 20 to 40 inches to paralithic bedrock; 40 to 80 inches
to lithic bedrock
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 6.1 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: F136XY830NC -Acidic upland forest, depth restriction, dry-moist
Hydric soil rating: No
NaB—Nanford-Badin complex, 2 to 6 percent slopes
Map Unit Setting
National map unit symbol: 1 Ivxl
Elevation: 300 to 650 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost-free period: 200 to 240 days
Farmland classification: All areas are prime farmland
17

Custom Soil Resource Report
Map Unit Composition
Nanford and similar soils: 36 percent
Badin and similar soils: 33 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nanford
Setting
Landform: Interfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap- 0 to 3 inches: silt loam
E-3 to 7 inches: silt loam
Bt1 - 7 to 12 inches: silty clay
Bt2- 12 to 27 inches: silty clay
BC-27 to 38 inches: silty clay loam
C-38 to 57 inches: silt loam
Cr-57 to 80 inches: weathered bedrock
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature:40 to 60 inches to paralithic bedrock
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 7.9 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: B
Ecological site: F136XY820GA-Acidic upland forest, moist
Hydric soil rating: No
Description of Badin
Setting
Landform: Interfluves
Landform position (two-dimensional): Summit
Landform position (three-dimensional): Interfluve
Down-slope shape: Convex
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap- 0 to 6 inches: silt loam
Bt- 6 to 24 inches: clay
18

Custom Soil Resource Report
BC-24 to 32 inches: channery silty clay loam
Cr-32 to 80 inches: weathered bedrock
Properties and qualities
Slope: 2 to 6 percent
Depth to restrictive feature: 20 to 40 inches to paralithic bedrock
Drainage class:Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low(about 5.5 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 2e
Hydrologic Soil Group: C
Ecological site: F136XY830NC -Acidic upland forest, depth restriction, dry-moist
Hydric soil rating: No
NaC—Nanford-Badin complex, 6 to 10 percent slopes
Map Unit Setting
National map unit symbol: 1 Ivxn
Elevation: 300 to 650 feet
Mean annual precipitation: 37 to 60 inches
Mean annual air temperature: 59 to 66 degrees F
Frost-free period: 200 to 240 days
Farmland classification: Farmland of statewide importance
Map Unit Composition
Nanford and similar soils: 50 percent
Badin and similar soils: 30 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Nanford
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap- 0 to 3 inches: silt loam
E-3 to 7 inches: silt loam
Bt1 - 7 to 12 inches: silty clay
19

Custom Soil Resource Report
Bt2- 12 to 27 inches: silty clay
BC-27 to 38 inches: silty clay loam
C-38 to 57 inches: silt loam
Cr-57 to 80 inches: weathered bedrock
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature:40 to 60 inches to paralithic bedrock
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Moderate (about 7.9 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: B
Ecological site: F136XY820GA-Acidic upland forest, moist
Hydric soil rating: No
Description of Badin
Setting
Landform: Hillslopes on ridges
Landform position (two-dimensional): Summit, shoulder
Landform position (three-dimensional): Side slope
Down-slope shape: Linear
Across-slope shape: Convex
Parent material: Residuum weathered from metavolcanics and/or argillite
Typical profile
Ap- 0 to 6 inches: silt loam
Bt- 6 to 24 inches: clay
BC-24 to 32 inches: channery silty clay loam
Cr-32 to 80 inches: weathered bedrock
Properties and qualities
Slope: 6 to 10 percent
Depth to restrictive feature: 20 to 40 inches to paralithic bedrock
Drainage class:Well drained
Runoff class: Medium
Capacity of the most limiting layer to transmit water(Ksat):Very low to high (0.00
to 1.98 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Available water supply, 0 to 60 inches: Low (about 5.5 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: F136XY830NC -Acidic upland forest, depth restriction, dry-moist
20

Custom Soil Resource Report
Hydric soil rating: No
21

References
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of
wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife
Service FWS/OBS-79/31.
Federal Register. July 13, 1994. Changes in hydric soils of the United States.
Federal Register. September 18, 2002. Hydric soils of the United States.
Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric
soils in the United States.
National Research Council. 1995. Wetlands: Characteristics and boundaries.
Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service.
U.S. Department of Agriculture Handbook 18. http://www.nres.usda.gov/wps/portal/
nres/detail/national/soils/?cid=nres 142p2_054262
Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for
making and interpreting soil surveys. 2nd edition. Natural Resources Conservation
Service, U.S. Department of Agriculture Handbook 436. http://
www.nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053577
Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of
Agriculture, Natural Resources Conservation Service. http://
www.nres.usda.gov/wps/portal/nres/detail/national/soils/?cid=nres142p2_053580
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and
Delaware Department of Natural Resources and Environmental Control, Wetlands
Section.
United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of
Engineers wetlands delineation manual. Waterways Experiment Station Technical
Report Y-87-1.
United States Department of Agriculture, Natural Resources Conservation Service.
National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
home/?cid=nres142p2_053374
United States Department of Agriculture, Natural Resources Conservation Service.
National range and pasture handbook. http://www.nres.usda.gov/wps/portal/nres/
detail/national/landuse/rangepasture/?cid=stelprdb1043084
22

Custom Soil Resource Report
United States Department of Agriculture, Natural Resources Conservation Service.
National soil survey handbook, title 430-VI. http://www.nres.usda.gov/wps/portal/
nres/detail/soils/scientists/?cid=nres142p2_054242
United States Department of Agriculture, Natural Resources Conservation Service.
2006. Land resource regions and major land resource areas of the United States,
the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook
296. http://www.nres.usda.gov/wps/portal/nres/detail/national/soils/?
cid=nres142p2_053624
United States Department of Agriculture, Soil Conservation Service. 1961. Land
capability classification. U.S. Department of Agriculture Handbook 210. http://
www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf
23

Appendix J -
Stormwater Cost Estimate

CHATHAM COUNTY
• SILER CITY WWTP
, A
mcgillNOVEMBER 2023
Slier City WWTP Stormwater Cost Estimate 11/7/2023
Item # Description Unit Quantity Unit Cost Total Amount
Stormwater System
1 Manhole EA 2 $3,000.00 $6,000.00
2 Open Throat Inlet EA 1 $3,500.00 $3,500.00
3 Yard Inlet EA 3 $3,000.00 $9,000.00
4 15"HDPE Pipe LF 55 $65.00 $3,575.00
5 24"HDPE Pipe LF 416 $80.00 $33,280.00
6 Concrete Flared-End Section EA 2 $4,000.00 $8,000.00
7 Rip-Rap Outlet Protection LS 2 $4,000.00 $8,000.00
Subtotal $71,355.00
Estimated Construction Costs $71,355.00
Contingency(25%) $17,838.75
Total Estimated Stormwater Cost $89,193.75
Notes
1.The ENGINEER maintains no control of labor costs,materials,equipment or services furnished by others,the Contractor(s)'methods for determining
prices,or competitive or market conditions.The estimates herein for project and construction costs represent the ENGINEER'S best judgment,and are
based on his experience and qualifications as a Professional Engineer who possesses familiarity with the construction industry.The ENGINEER does not
guarantee the accuracy of the cost estimates,which may vary from bids or actual project and construction costs.
2.Engineering and Permit fees are excluded from this estimate.
PROJECT NO. 18.04015 PAGE 1 OF 1

Appendix F -
REVISED
Ditch Calculations
001Y44111666661
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4 ` w innp (/ 0i
034999
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6m6a6661N1,>,1ee

Hydrology Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Feb 27 2024
Aeration Basin Swale 1
Hydrograph type = Rational Peak discharge (cfs) = 1.735
Storm frequency (yrs) = 10 Time interval (min) = 1
Drainage area (ac) = 0.670 Runoff coeff. (C) = 0.44
Rainfall Inten (in/hr) = 5.886 Tc by User (min) = 5
IDF Curve = Siler City.IDF Rec limb factor = 1.00
Hydrograph Volume=521 (cuft);0.012(acfl)
Runoff Hydrograph
Q (cfs) 10-yr frequency Q (cfs)
2.00 2.00
1.00 1.00
0.00 0.00
0 5 10
Time(min)
Runoff Hyd -Qp= 1.74 (cfs)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Tuesday,Feb 27 2024
Aeration Basin Swale 1
Triangular Highlighted
Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.45
Total Depth (ft) = 1.00 Q (cfs) = 1.740
Area (sqft) = 0.61
Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.86
Slope (%) = 3.40 Wetted Perim (ft) = 2.85
N-Value = 0.033 Crit Depth, Yc (ft) = 0.47
Top Width (ft) = 2.70
Calculations EGL (ft) = 0.58
Compute by: Known Q
Known Q (cfs) = 1.74
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 - 1.00
100.50 0 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8
Reach (ft)

Hydrology Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Tuesday,Feb 27 2024
Road Swale 2
Hydrograph type = Rational Peak discharge (cfs) = 2.863
Storm frequency (yrs) = 10 Time interval (min) = 1
Drainage area (ac) = 1.390 Runoff coeff. (C) = 0.35
Rainfall Inten (in/hr) = 5.886 Tc by User (min) = 5
IDF Curve = Siler City.IDF Rec limb factor = 1.00
Hydrograph Volume=859(cult);0.020(acft)
Runoff Hydrograph
Q (cfs) 10-yr frequency Q (cfs)
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 5 10
Time(min)
Runoff Hyd -Qp = 2.86 (cfs)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Feb 27 2024
Road Swale 2
Trapezoidal Highlighted
Bottom Width (ft) = 1.00 Depth (ft) = 0.34
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 2.860
Total Depth (ft) = 1.50 Area (sqft) = 0.69
Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.16
Slope (%) = 7.77 Wetted Perim (ft) = 3.15
N-Value = 0.035 Crit Depth, Yc (ft) = 0.43
Top Width (ft) = 3.04
Calculations EGL (ft) = 0.61
Compute by: Known Q
Known Q (cfs) = 2.86
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 1.00
100.50 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8 9 10 11 12
Reach (ft)

Hydrology Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Feb 27 2024
Headworks Swale 3
Hydrograph type = Rational Peak discharge (cfs) = 0.132
Storm frequency (yrs) = 10 Time interval (min) = 1
Drainage area (ac) = 0.140 Runoff coeff. (C) = 0.16
Rainfall lnten (in/hr) = 5.886 Tc by User (min) = 5
IDF Curve = Siler City.IDF Rec limb factor = 1.00
Hydrograph Volume=40(cuft);0.001 (acft)
Runoff Hydrograph
Q (cfs) 10-yr frequency Q (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 0.10
0.05 0.05
0.00 0.00
0 5 10
Time (min)
Runoff Hyd -Qp= 0.13 (cfs)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Tuesday,Feb 27 2024
Headworks Swale 3
Trapezoidal Highlighted
Bottom Width (ft) = 1.00 Depth (ft) = 0.10
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 0.130
Total Depth (ft) = 1.00 Area (sqft) = 0.13
Invert Elev (ft) = 100.00 Velocity (ft/s) = 1.00
Slope (%) = 5.83 Wetted Perim (ft) = 1.63
N-Value = 0.065 Crit Depth, Yc (ft) = 0.08
Top Width (ft) = 1.60
Calculations EGL (ft) = 0.12
Compute by: Known Q
Known Q (cfs) = 0.13
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 - 1.00
100.50 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8 9
Reach (ft)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Wednesday, Feb 28 2024
Blind Swale
Trapezoidal Highlighted
Bottom Width (ft) = 6.00 Depth (ft) = 1.09
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 5.050
Total Depth (ft) = 2.00 Area (sqft) = 10.10
Invert Elev (ft) = 510.50 Velocity (ft/s) = 0.50
Slope (%) = 0.01 Wetted Perim (ft) = 12.89
N-Value = 0.025 Crit Depth, Yc (ft) = 0.27
Top Width (ft) = 12.54
Calculations EGL (ft) = 1.09
Compute by: Known Q
Known Q (cfs) = 5.05
Rational Method:
Q1 =(.4)(1.5)(8.42)=5.05 cfs x 10'=50.5 LF Blind Swale
Elev (ft) Section Depth (ft)
513.00 2.50
512.50 2.00
512.00 1.50
v
511.50 - 1.00
511.00 0.50
510.50 0.00
510.00 -0.50
0 2 4 6 8 10 12 14 16 18 20 22
Reach (ft)

SW5240101
Appendix F -
REVISED
Ditch Calculations
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034999
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Hydrology Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Feb 27 2024
Aeration Basin Swale 1
Hydrograph type = Rational Peak discharge (cfs) = 1.735
Storm frequency (yrs) = 10 Time interval (min) = 1
Drainage area (ac) = 0.670 Runoff coeff. (C) = 0.44
Rainfall Inten (in/hr) = 5.886 Tc by User (min) = 5
IDF Curve = Siler City.IDF Rec limb factor = 1.00
Hydrograph Volume=521 (cuft);0.012(acfl)
Runoff Hydrograph
Q (cfs) 10-yr frequency Q (cfs)
2.00 2.00
1.00 1.00
0.00 0.00
0 5 10
Time(min)
Runoff Hyd -Qp= 1.74 (cfs)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Tuesday,Feb 27 2024
Aeration Basin Swale 1
Triangular Highlighted
Side Slopes (z:1) = 3.00, 3.00 Depth (ft) = 0.45
Total Depth (ft) = 1.00 Q (cfs) = 1.740
Area (sqft) = 0.61
Invert Elev (ft) = 100.00 Velocity (ft/s) = 2.86
Slope (%) = 3.40 Wetted Perim (ft) = 2.85
N-Value = 0.033 Crit Depth, Yc (ft) = 0.47
Top Width (ft) = 2.70
Calculations EGL (ft) = 0.58
Compute by: Known Q
Known Q (cfs) = 1.74
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 - 1.00
100.50 0 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8
Reach (ft)

Hydrology Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Tuesday,Feb 27 2024
Road Swale 2
Hydrograph type = Rational Peak discharge (cfs) = 2.863
Storm frequency (yrs) = 10 Time interval (min) = 1
Drainage area (ac) = 1.390 Runoff coeff. (C) = 0.35
Rainfall Inten (in/hr) = 5.886 Tc by User (min) = 5
IDF Curve = Siler City.IDF Rec limb factor = 1.00
Hydrograph Volume=859(cult);0.020(acft)
Runoff Hydrograph
Q (cfs) 10-yr frequency Q (cfs)
3.00 3.00
2.00 2.00
1.00 1.00
0.00 0.00
0 5 10
Time(min)
Runoff Hyd -Qp = 2.86 (cfs)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Feb 27 2024
Road Swale 2
Trapezoidal Highlighted
Bottom Width (ft) = 1.00 Depth (ft) = 0.34
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 2.860
Total Depth (ft) = 1.50 Area (sqft) = 0.69
Invert Elev (ft) = 100.00 Velocity (ft/s) = 4.16
Slope (%) = 7.77 Wetted Perim (ft) = 3.15
N-Value = 0.035 Crit Depth, Yc (ft) = 0.43
Top Width (ft) = 3.04
Calculations EGL (ft) = 0.61
Compute by: Known Q
Known Q (cfs) = 2.86
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 1.00
100.50 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8 9 10 11 12
Reach (ft)

Hydrology Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk, Inc. Tuesday,Feb 27 2024
Headworks Swale 3
Hydrograph type = Rational Peak discharge (cfs) = 0.132
Storm frequency (yrs) = 10 Time interval (min) = 1
Drainage area (ac) = 0.140 Runoff coeff. (C) = 0.16
Rainfall lnten (in/hr) = 5.886 Tc by User (min) = 5
IDF Curve = Siler City.IDF Rec limb factor = 1.00
Hydrograph Volume=40(cuft);0.001 (acft)
Runoff Hydrograph
Q (cfs) 10-yr frequency Q (cfs)
0.50 0.50
0.45 0.45
0.40 0.40
0.35 0.35
0.30 0.30
0.25 0.25
0.20 0.20
0.15 0.15
0.10 0.10
0.05 0.05
0.00 0.00
0 5 10
Time (min)
Runoff Hyd -Qp= 0.13 (cfs)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Tuesday,Feb 27 2024
Headworks Swale 3
Trapezoidal Highlighted
Bottom Width (ft) = 1.00 Depth (ft) = 0.10
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 0.130
Total Depth (ft) = 1.00 Area (sqft) = 0.13
Invert Elev (ft) = 100.00 Velocity (ft/s) = 1.00
Slope (%) = 5.83 Wetted Perim (ft) = 1.63
N-Value = 0.065 Crit Depth, Yc (ft) = 0.08
Top Width (ft) = 1.60
Calculations EGL (ft) = 0.12
Compute by: Known Q
Known Q (cfs) = 0.13
Elev (ft) Section Depth (ft)
102.00 2.00
101.50 1.50
101.00 - 1.00
100.50 0.50
100.00 0.00
99.50 -0.50
0 1 2 3 4 5 6 7 8 9
Reach (ft)

Channel Report
Hydraflow Express Extension for Autodesk®Civil 3D®by Autodesk,Inc. Wednesday, Feb 28 2024
Blind Swale
Trapezoidal Highlighted
Bottom Width (ft) = 6.00 Depth (ft) = 1.09
Side Slopes (z:1) = 3.00, 3.00 Q (cfs) = 5.050
Total Depth (ft) = 2.00 Area (sqft) = 10.10
Invert Elev (ft) = 510.50 Velocity (ft/s) = 0.50
Slope (%) = 0.01 Wetted Perim (ft) = 12.89
N-Value = 0.025 Crit Depth, Yc (ft) = 0.27
Top Width (ft) = 12.54
Calculations EGL (ft) = 1.09
Compute by: Known Q
Known Q (cfs) = 5.05
Rational Method:
Q1 =(.4)(1.5)(8.42)=5.05 cfs x 10'=50.5 LF Blind Swale
Elev (ft) Section Depth (ft)
513.00 2.50
512.50 2.00
512.00 1.50
v
511.50 - 1.00
511.00 0.50
510.50 0.00
510.00 -0.50
0 2 4 6 8 10 12 14 16 18 20 22
Reach (ft)