SW3230303_Stormwater Report_20230803

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UNIONCOUNTY
WAT E R
Twelve Mile Creek WRF 9.0 MGD Expansion
Post - Construction Stormwater
CA% Prepared by:
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GgIs r Hazen
FNG�NE�� ��� 1 a.6 2oa3
tiq£( D. P P� Hazen and Sawyer
9101 Southern Pine Boulevard, Suite 250
Charlotte, North Carolina 28273
July 2023

Post - Construction Stormwater
Twelve Mile Creek WRF 9.0 MGD Expansion
Waxhaw, North Carolina
Prepared by:
Hazen
Hazen and Sawyer
9101 Southern Pine Boulevard, Suite 250
Charlotte, North Carolina 28273
July 2023
H&S Project No.30831-061 Twelve Mile Creek WRF
Post Construction Stormwater Plan

TABLE OF CONTENTS
Project Description 1
Site Description 1
Water Resources 2
Post-Construction Stormwater 2
Future Construction Sequence 3
Other Permitting 4
References 5
LIST OF FIGURES
Figure 1 General Vicinity Map
Figure 2 Soil Distribution
Figure 3 USGS 1:24,000 Topographic Map—Waxhaw Quadrangle
Figure 4 Detailed Stormwater Drainage Maps
Figure 5 Future BUA Figure
LIST OF APPENDICES
Appendix A Contract Drawings
Appendix B FEMA Flood Insurance Rate Maps (FIRMs)
Appendix C Supporting Calculations
Appendix D USGS StreamStats Delineation
Appendix E Supplement Forms
Appendix F Wetland Certification Statement
Appendix G Current Property Deed
Appendix I-I Geotechnical Report
H&S Project No.30831-061 Twelve Mile Creek WRF
ii Post Construction Stormwater Plan

Project Description
This Post-Construction Stormwater narrative has been prepared for the proposed construction of
the 9.0 million gallons per day(MGD)expansion of the Twelve Mile Creek Water Reclamation Facility
(WRF). Proposed improvements include installing new influent piping, constructing a new influent
pump station (IPS),odor control facility,chemical facility,secondary clarifier,truck parking canopy,
electrical upgrades,and fiber optic upgrades.
The total property area is 56.66 acres. There is 3.42 acres of surface water on the property which
yields a total project area of 53.24 acres.Total land disturbance for the project is approximately 12
acres. The overall built upon area (BUA) will increase from 7.23 acres to 7.98 acres, for a final
coverage of 15 percent.
Prior to the implementation of stormwater rules on July 1,2007,there was a total of 5.63 acres BUA
on this site. Since then, BUA has been added to the site for a current total of 7.23 acres of BUA.This
permit application is seeking coverage for a total increase of 2.36 acres of BUA. This coverage area
includes this proposed project's BUA increase of 0.76 acres as well as the existing unpermitted BUA
of 1.63 acres.
Site Description
The Twelve Mile Creek WRF is a 7.5-MGD wastewater treatment facility located in Waxhaw, North
Carolina owned and operated by Union County,North Carolina.The WRF was originally built in 1997
with an initial permitted capacity of 2.5 MGD and has since undergone two plant expansion projects
to its current capacity. Current conditions at the site include approximately 7.23 acres of impervious
surface, 1.64 acres of non-impervious structures (aeration basins,thickening basins, and clarifiers,
1.6 acres of open water surface from Twelve Mile Creek and tributaries,and 46.18 acres open grassy
areas.
This property was originally deeded to Union County on October 7, 1981. This is the most current
property deed and is shown in Appendix G.
Soil types found at the WRF were identified based on information obtained from the United States
Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS). The USDA Soil
Distribution Map of the property is shown in Figure 2. Topography of the Twelve Mile Creek WRF
consists of silty clay loam soils with mostly 8 to 15 percent slopes. Smaller portions of the property
have steeper(15 to 45 percent)and flatter(2 to 8 percent)slopes.There is no evidence of significant
erosion under existing site conditions.
There are two existing berms located at the main entrance separated by the main road. The existing
storm drainage on sites consists of 11 separate systems(A-K)with numerous pipes and catchments,
each with a controlled outlet.All of the systems were previously implemented to convey flow under
roadways. Nine (9) are located on the main site and two (2) at the influent pump station. Much of
the site utilizes curb and gutter. All stormwater outlets have rip rap aprons and discharge to
vegetative areas in a non-erosive manner to promote dispersed flow. Existing storm drainage is
illustrated in Figure 4.
H&S Project No. 30831-061 Twelve Mile Creek WRF
Post Construction Stormwater Plan

Water Resources
The Twelve Mile Creek WRF is part of the Twelve Mile Creek watershed, which is a part of the
Catawba River Basin. The entire site ultimately discharges to Twelve Mile Creek. The
north/east/south sites drain directly to Twelve Mile Creek,while the west side drains to Twelve Mile
Creek Tributary 3,This tributary converges with Twelve Mile Creek at the southwest corner of the
property. USGS's StreamStats was used to delineate the drainage area at this conversion,and it was
determined to be 80.3 square miles (Appendix D).The Twelve Mile Creek WRF property boundary is
less than 0.001% of the total contributing drainage area. Due to the significant difference between
the total project area (53.24 acres) and the contributing drainage area, offsite drainage was not
considered in the BUA table (Drawing C6).BUA percentages were determined by using the property
line as the drainage area boundary (Drawing C5).This allows for the accurate comparison between
pre and post construction BUA.
A wetland investigation was performed at the site which found that no portion of the project's limits
of disturbance resides nor abuts wetlands. Refer to Note 1 on drawing C21 and the Wetland
Certification Statement in Appendix F for documentation.
Information provided by the Federal Emergency Management Agency (FEMA) was examined to
determine if designated floodplains are present at the Twelve Mile Creek WRF. Floodplains (Zones
AE and X)are present on the southern side of the property due to the neighboring Twelve Mile Creek.
Small portions of the work at the Influent Pump Station and Plant Outfall areas extend in to the 100-
year Floodplain and/or 100-ft Union County stream buffer. Please refer to FEMA Flood Insurance
Rate Map Panel 4474J,Map Number 3710447400J(October 16,2008)included in Appendix B of this
submittal.
Post-Construction Stormwater
Post-Construction Stormwater permitting at the site address is managed by the North Carolina
Department of Environmental and Natural Resources Division of Energy, Mineral and Land
Resources,under Rule 15A NCAC 2H.103(2).
According to Rule 15A NCAC 02H.1017 (4) of the North Carolina Administrative Code,a project shall
be considered a low-density project if it meets the low-density criteria set forth in Rule.1003(2)and
contains no more than 24 percent built-upon area(BUA).Based upon the built-upon area tabulation
in the application form,the project site meets this threshold with a total BUA of 15-percent.
The stormwater drainage system was evaluated using Stormwater Studio for drainage basins
affected by this project. This was done to determine whether the existing system and proposed
system changes could maintain sufficient capacity and conveyance in the pre and post construction
conditions. The storm systems that are affected by this project are Systems C, J, and K. The
Stormwater Studio model in Appendix C shows that the HGL lines in systems C, J, and K remained
below the grade line during the 10-year storm event.
Since Stormwater Studios calculates peak runoff based on the Rational Method,evaluating the runoff
generated during the 10-year storm event required calculating the variables in the Rational Equation.
H&S Project No. 30831-061 Twelve Mile Creek WRF
2 Post Construction Stormwater Plan

The runoff coefficient,C,is dependent upon the type of soil/cover in the drainage area. Since the land
use and soil cover is not homogeneous throughout the drainage area,the runoff coefficient value was
determined by a weighted average calculation (Appendix C). The time of concentration, Tc, was
assumed to be 5 minutes for each catch basin analyzed.Once Tc was determined,the intensity of the
design storm was determined using NOAA Atlas 14,Volume 2,Version 3 (Appendix C).
Stormwater Studio was also used to determine the velocity of the stormwater to develop proper
erosion control measures for each outfall affected by the project.These velocities were used against
Manning's equation for full pipe flow out of each outfall.Whichever velocity was greater was used to
calculate the required rip rap sizing and apron configuration.The riprap aprons were sized using NC
DEQ's design spreadsheet"Riprap Outlet Protection" (Appendix C).
Main Plant Drainage
The main plant refers to the northernmost section of the site where most of the plant resides.
Drainage in this area was delineated by drainage system,the extents of which were found by using
ArcGIS topographic data.This portion of the site uses a combination of curb and gutter in areas with
heavy truck traffic and soft shoulders where roadways are not subjected to heavy truck turning and
movement. There are a total of nine (9) existing disconnected stormwater systems that have been
constructed to convey stormwater under roadways.On this side of the plant this project will include
additional BUA in system C, as well as a modification of system C. Therefore, only system C was
analyzed for post construction stormwater on the main portion of the plant.The modification can be
seen in drawing C42.The modification includes a proposed catch basin near the new chemical facility,
which will only be used as a floor drain under a covered canopy. Additionally, there is a new yard
inlet(structure C3C)to reduce flow by an electrical box situated near an existing yard inlet(structure
C3).There are also roof drain pipes tied into the system (structures C4&C5) from the truck parking
canopy.The system was rerouted to avoid process piping and the canopy.Appendix C shows that the
system still maintains a 10-year level of service.
Influent Pump Station Drainage
The southernmost portion of the site is disconnected from the main plant area by a roadway running
along the crest of a hill.This part of the site is subjected to substantial truck traffic which is why the
pavement around the Influent Pump Station is lined with curb and gutter. Majority of the structures
in this area sit on a hill with storm drainage systems J and K conveying runoff to the lower and flatter
area surrounding it.Appendix C shows that even though there will be an increase in runoff coefficient,
the systems J and K still maintain a 10-year level of service.
Future Construction Sequence
See Figure 5 for planned future facilities.Planned facilities will be installed in at least one more plant
expansion project: 12.0 MGD Expansion. The exact scope of this expansion project, and any future
phased expansion,will be determined at a later date.The timing of the expansion will be dictated by
population growth and demand within the collection system.
H&S Project No. 30831-061 Twelve Mile Creek WRF
3 Post Construction Stormwater Plan

Other Permitting
In addition to the NC DEQ Post-Construction Stormwater permit,the following other permits will be
obtained:
• Army Corps of Engineers 401/404 Permit(submitted January 12, 2023)
O 401 Permit(WQC005722) received March 6, 2023
O 404 Permit(SAW-2023-00133) received April 6, 2023
• Union County Floodplain Development Permit(submitted April 4, 2023)
o Union County Permit(FP23002) received July 20,2023
• NC DEQ Erosion and Sediment Control Permit
o Initially submitted January 2023 (withdrawn) -UNION-2023-051
■ To be resubmitted with Post Construction Stormwater
o Have been in contact with NC DEQ Mooresville regional office
• Union County Commercial Site Plan Permit(submitted April 4, 2023)
o To be resubmitted with Post Construction Stormwater
• Union County Building Permit
o To be submitted upon Union County Commercial Site Plan approval
H&S Project No.30831-061 Twelve Mile Creek WRF
4 Post Construction Stormwater Plan

References
Federal Emergency Management Agency(FEMA). (www.fema.gov/nfip)
Natural Resources Conservation Service.United States Department of Agriculture(NRCS USDA).Web
Soil Survey. (http://websoilsurvey.nrcs.usda.gov/)
North Carolina Department of Environment and Natural Resources.Division of Land Resources.Land
Quality Section (NCDENR). Erosion and Sedimentation Control Planning and Design Manual. May
2013,revision.
North Carolina Floodplain Mapping Information System (NCFMIS).
(http://www.ncfloodmaps.com/firm indexes/) (Accessed December 2022).
H&S Project No.30831-061 Twelve Mile Creek WRF
5 Post Construction Stormwater Plan

Figures
Figure 1 -General Vicinity Map
Figure 2-Soils Distribution
Figure 3- USGS 1:24,000 Topographic Map- Waxhaw Quadrangle
Figure 4-Detailed Stormwater Drainage Maps
Figure 5-Future BUA Figure

THIS PAGE INTENTIONALLY LEFT BLANK

Figure 1 -General Vicinity Map

Figure 1—General Vicinity Map
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Figure 2-Soils Distribution

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Conservation Service National Cooperative Soil Survey Page 1 of 3

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Soil Map—Union County,North Carolina
Map Unit Legend
Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI
BaB Badin channery silt loam,2 to 5.1 3.3%
8 percent slopes
BaC Badin channery silt loam,8 to 19.2 12.4%
15 percent slopes
BdB2 Badin channery silty clay loam, 12.2 7.9%
2 to 8 percent slopes,
moderately eroded
BdC2 Badin channery silty clay loam, 26.5 17.1%
8 to 15 percent slopes,
moderately eroded
ChA Chewacla silt loam,0 to 2 56.3 36.3%
percent slopes,frequently
flooded
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45 percent slopes
TbC2 Tarrus gravelly silty clay loam, 2.6 1.7%
8 to 15 percent slopes,
moderately eroded
W Water 1.6 1.0%
WyC Wynott gravelly loam,8 to 15 8.2 5.3%
percent slopes
Totals for Area of Interest 155.2 100.0%
USDA Natural Resources Web Soil Survey 11/8/2022
Conservation Service National Cooperative Soil Survey Page 3 of 3

Figure 3- USGS 1:24,000 Topographic Map- Waxhaw Quadrangle

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Appendix A
Contract Drawings
(Full size drawings have been attached under a separate cover)

THIS PAGE INTENTIONALLY LEFT BLANK

Appendix B
FEMA Flood Insurance Rate Maps (FIRMs)
Panel 4474-Map No.3710447400J(1 sheet)

THIS PAGE INTENTIONALLY LEFT BLANK

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Appendix C
Supporting Data
NOAA Atlas 14 Precipitation Data
Weighted Runoff Coefficient(C) Calculations
Stormwater Studios Plan, Profiles& Tables
Riprap Outlet Protection Calculations

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NOAA Atlas 14 Precipitation Data

NOAA Atlas 14,Volume 2,Version 3
..-
SeCIN Location name:Waxhaw,North Carolina, USA* ;147,,
Latitude: 34.9531°,Longitude: -80.7644° ,
Elevation:555.27 ft**
®®,I *source:ESRI Maps
**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 5.03 5.93 6.88 7.58 8.39 8.94 9.46 9.91 10.5 10.8
(4.63-5.46) _(5.45-6.46) (6.31-7.49) (6.95-8.23) (7.66-9.10) (8.12-9.70) (8.54-10.2) (8.92-10.8) (9.31-11.4) (9.56-11.8)
10-min 4.01 4.74 5.51 6.07 6.68 7.12 7.51 7.86 8.26 8.52
(3.70-4.36) i (4.36-5.17) (5.06-6.00) (5.56-6.58) (6.10-7.25) (6.47-7.72) (6.79-8.14) (7.07-8.53) (7.36-8.98) (7.54-9.28)
15-min 1 3.34 3.98 4.64 5.11 5.64 6.01 6.33 6.61 6.93 7.13
(3.08-3.63) _(3.65-4.33) (4.26-5.06) (4.68-5.55) (5.15-6.12) (5.46-6.52) (5.72-6.86) (5.94-7.17) (6.18-7.54) (6.30-7.77)
30-min 2.29 2.74 3.30 3.70 4.18 4.53 4.85 5.15 5.52 5.77
(2.11-2.49) (2.52-2.99) (3.03-3.59) (3.39-4.02) (3.82-4.54) (4.11-4.91) (4.38-5.25) (4.63-5.58) (4.92-6.00) (5.10-6.29)
60-min 1.43 1.72 2.12 2.41 2.78 3.07 3.34 3.61 3.96 4.21
(1.32-1.55) (1.58-1.88) (1.94-2.30) (2.21-2.62) (2.54-3.02) (2.79-3.33)_ (3.02-3.62) (3.24-3.92)] (3.53-4.30) (3.73-4.59)
2-hr 0.826 0.999 1.24 1.42 1.66 1.84 2.02 2.20 2.44 I 2.63
(0.757-0.904) (0.914-1.09) (1.13-1.35) (1.29-1.55) (1.50-1.81) (1.66-2.00) (1.82-2.20) (1.97-2.40) (2.16-2.66) (2.30-2.87)
3-hr 0.585 0.705 0.879 1.01 1.20 1.34 1.49 1.65 1.86 2.02
(0.534-0.643) (0.645-0.776) (0.802-0.966) (0.923-1.11) (1.08-1.31) (1.21-1.47) (1.33-1.63) (1.46-1.80) (1.63-2.03) (1.75-2.21)
6-hr 0.352 0.424 0.529 0.612 0.726 0.817 0.910 1.01 1.14 1.25
(0.322-0.387) (0.389-0.466) (0.484-0.581) (0.559-0.670) (0.658-0.792) (0.736-0.889) (0.814-0.991) (0.892-1.10) (0.998-1.24) (1.08-1.36)
12-hr 0.207 0.249 0.312 0.363 0.434 0.491 0.551 0.614 0.703 0.775
(0.190-0.227) (0.229-0.274) (0.286-0.343) (0.331-0.398) (0.393-0.474) (0.442-0.535) (0.491-0.600) (0.541-0.668) (0.609-0.764)I(0.663-0.843)
24-hr 0.123 0.148 0.186 0.216 0.258 0.292 0.327 0.365 0.417 0.459
I(0.113-0.133) (0.137-0.160) (0.172-0.201) (0.199-0.234) (0.237-0.279) (0.267-0.316) (0.299-0.355) (0.331-0.395) (0.376-0.452) (0.411-0.499)
2-day 0.072 0.087 0.108 0.126 0.149 0.169 0.188 0.209 0.238 0.262
I(0.067-0.078) (0.081-0.094) (0.100-0.118) (0.116-0.136) (0.137-0.162) (0.154-0.183) (0.172-0.205) (0.190-0.228) (0.215-0.260) (0.235-0.286)
0.051 0.061 0.076 0.088 0.104 0.117 0.131 0.145 0.165 0.182
3-day (0.047-0.055) (0.057-0.066) (0.071-0.082) (0.081-0.095) (0.096-0.113) (0.108-0.127) (0.120-0.142) (0.132-0.158) (0.150-0.180) (0.163-0.198)
4-day 0.041 0.049 0.060 0.069 0.082 0.092 I 0.102 0.113 0.129 0.141
(0.038-0.044) (0.045-0.052) (0.056-0.065) (0.064-0.075) (0 075-0.088) (0.084-0.099) (0.094-0.111) (0.104-0.123) (0.117-0.140) (0.128-0.154)
7-day 0.027 0.032 0.039 0.045 0.052 0.059 0.065 0.072 0.081 0.089
I(0.025-0.029) (0.030-0.034) (0.036-0.042) (0.042-0.048) (0.049-0.056) (0.054-0.063) (0.060-0.070) (0.066-0.077) (0.074-0.088) (0.081-0.096)
10-day 0.021 0.026 0.031 0.035 0.040 0.045 I 0.049 0.054 0.060 0.066
(0.020-0.023) (0.024-0.027) (0.029-0.033) (0.033-0.037) (0.038-0.043) (0.042-0.048)1(0.046-0.053) (0.050-0.058) (0.055-0.065) (0.060-0.071)
20-day 0.014 0.017 0.020 0.022 0.026 0.028 0.031 0.034 0.037 0.040
(0.013-0.015) (0.016-0.018) (0.019-0.021) (0.021-0.024) (0.024-0.027) (0.026-0.030) (0.029-0.033) (0.031-0.036) (0.034-0.040) (0.037-0.043)
30-day 0.012 0.014 0.016 0.018 0.020 0.022 0.024 0.025 0.028 0.030
(0.011-0.012) (0.013-0.015) (0.015-0.017) (0.017-0.019) (0 019-0.021) (0.021-0.023) (0.022-0.025) (0.024-0.027) (0.026-0.030) (0.027-0.032)
45-day 0.010 0.012 0.013 0.014 0.016 0.017 0.019 0.020 0.021 0.023
(0.009-0.010) (0.011-0.012) (0.013-0.014) (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)
0.009 0.010 0.012 0.013 0.014 0.015 0.016 0.017 0.018 0.019
60-day
(0.008-0.009) (0.010-0.011) (0.011-0.012) (0.012-0.013) (0.013-0.015) (0.014-0.016) (0.015-0.017) (0.016-0.018)1(0.017-0.019) (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

PDS-based intensity-duration-frequency (IDF) curves
Latitude: 34.9531', Longitude: -80.7644'
100.000 1 I r I I I I r I
Average recurrence
• interval
10.000 _ (years)
•
— 1
5
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— 1000
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c c Al A 6 N v 7. 77 a 7 7 77
LA LA O O "a N N r'1 t 1-- 0 O O Ln O
rl r-i in vo r-1 N rn C'l0
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10.000 __._�. . --- _ �
Duration
>,
.c 1.000 - — 5-min — 2-day
°i 10-min — 3-day
,-
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° •r :::: T -
— 6-hr — 45-day
— 12-hr — 60-day
0.001 — 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): Wed Nov 9 14:57:18 2022
Back to Top
Maps & aerials
Small scale terrain

Weighted Runoff Coefficient(C) Calculations

Pre-CN
Basin ID Cl Total Area 2.10 Basin ID C2 Total Area 0.30 Basin ID C2A Total Area 0.35
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 0.95 0.3 0.28 Grass 0.34 0.3 0.10 Grass 0.48 0.3 0.14
Road 0.05 0.95 0.05 Road 0.66 0.95 0.62 Road 0.52 0.95 0.50
Final C 0.33 Final C 0.73 Final C 0.64
Basin ID C3 Total Area 0.19 Basin ID C3A Total Area 0.56 Basin ID C3B Total Area 0.64
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 0.92 0.3 0.28 Grass 0.73 0.3 0.22 Grass 0.48 0.3 0.15
Road 0.08 0.95 0.08 Road 0.27 0.95 0.25 Road 0.52 0.95 0.49
Final C 0.35 Final C 0.47 Final C 0.64
Basin ID C4 Total Area 0.08 Basin ID C4A Total Area 0.17 Basin ID C4B Total Area 0.82
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 0.10 0.3 0.03 Grass 0.06 0.3 0.02 Grass 0.59 0.3 0.18
Road 0.90 0.95 0.86 Road 0.94 0.95 0.89 Road 0.41 0.95 0.39
Final C 0.89 Final C 0.91 Final C 0.57
Basin ID C4C Total Area 0.18 Basin ID C5 Total Area 0.19 Basin ID C5A Total Area 0.20
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 0.93 0.3 0.28 Grass 0.07 0.3 0.02 Grass 0.00 0.3 0.00
Road 0.07 0.95 0.06 Road 0.93 0.95 0.89 Road 1.00 0.95 0.95
Final C 0.34 Final C 0.91 Final C 0.95
Basin ID J1 Total Area 0.53 Basin ID J2 Total Area 0.12 Basin ID J2A Total Area 0.11
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 0.70 0.3 0.21 Grass 0.00 0.3 0.00 Grass 0.08 0.3 0.02
Road 0.30 0.95 0.28 Road 1.00 0.95 0.95 Road 0.92 0.95 0.87
Final C 0.49 Final C 0.95 Final C 0.90
Basin ID Kl Total Area 0.14
C Value
Type % C Weighted C
Grass 0.11 0.3 0.03
Road 0.89 0.95 0.85
Final C 0.88

Post-CN
Basin ID Cl Total Area 2.12 Basin ID C2 Total Area 0.30 Basin ID C2A Total Area 0.35
C Value C Value C Value
Type % C Weighted C _ Type % C Weighted C Type % C Weighted C
Grass 0.85 0.3 0.26 Grass 0.34 0.3 0.10 Grass 0.48 0.3 0.14
Road 0.15 0.95 0.14 Road 0.66 0.95 0.62 Road 0.52 0.95 0.50
Final C 0.40 Final C 0.73 Final C 0.64
Basin ID C3 Total Area 0.09 Basin ID C3A Total Area 0.51 Basin ID C3B Total Area 0.55
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 1.00 0.3 0.30 Grass 0.24 0.3 0.07 Grass 0.42 0.3 0.13
Road 0.00 0.95 0.00 Road 0.76 0.95 0.73 Road 0.58 0.95 0.55
Final C 0.30 I•inal C 0.80 Final C 0.68
Basin ID C3C Total Area I 0.16 Basin ID C3D Total Area 0.00
C Value C Value
Type % C Weighted C Type % C Weighted C
Grass 0.74 0.3 0.22 Grass 0.00 0.3 0.00
Road 0.26 0.95 0.25 Road 0.00 0.95 0.00
Final C 0.47 Final C 0.00
Basin ID C4 Total Area I 0.00 Basin ID C4A Total Area 0.89 Basin ID C4B Total Area 0.37
C Value C Value C Value
Type % C Weighted C _ Type % C Weighted C Type % C Weighted C
Grass 0.00 0.3 0.00 Grass 0.42 0.3 0.12 Grass 0.96 0.3 0.29
Road 0.00 0.95 0.00 Road 0.58 0.95 0.56 Road 0.04 0.95 0.04
Final C 0.00 Final C 0.68 Final C 0.32
Basin ID CRN Total Area 0.12 Basin ID C5 Total Area I 0.13 Basin ID CRS Total Area 0.12
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 0.00 0.3 0.00 Grass 0.14 0.3 0.04 Grass 0.00 0.3 0.00
Road 1.00 0.95 0.95 Road 0.86 0.95 0.82 Road 1.00 0.95 0.95
Final C 0.95 Final C 0.86 Final C 0.95
Basin ID J1 Total Area 0.53 Basin ID J2 Total Area 0.10 Basin ID J2A Total Area 0.11
C Value C Value C Value
Type % C Weighted C Type % C Weighted C Type % C Weighted C
Grass 0.73 0.3 0.22 Grass 0.00 0.3 0.00 Grass 0.08 0.3 0.02
Road 0.27 0.95 0.25 Road 1.00 0.95 0.95 Road 0.92 0.95 0.87
Final C 0.47 Final C 0.95 Final C 0.90
Basin ID K1 Total Area 0.15
C Value
Type % C Weighted C
Grass 0.09 0.3 0.03
Road 0.91 0.95 0.87
Final C 0.89

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Twelve Mile Creek WRF 9.0 MGD Expansion
Storm Inlet Calculations
10-Year Storm Event Exported From Stormwater Studio
System C.
Q Q Q Q Spread Spread Depth Depth
Inlet ID Inlet Type Catchment +CarryoverCapturedBypassedEfficiency
- = Gutter Inlet Gutter Inlet Line No.
(cfs) (cfs) (cfs) (cfs) Iftl Iftl Iftl Iftl
YI-C1 Drop Grate in Sag _ 6.4 _ 0.0 _ 6.4 0.0 43.5 43.5 0.4 0.4 --- 5
CB-C2A Combination on Grade _ 1.7 _ 0.0 _ 1.7 0.0 6.1 6.1 0.2 0.2 100 6
CB-C2 Combination on Grade _ 1.7 _ 0.0 _ 1.7 0.0 6.1 6.1 0.2 0.2 100 4
YI-C3 Drop Grate in Sag _ 0.2 _ 1.3 _ 1.5 0.0 17.7 17.7 0.2 1.6 --- 3
CB-C3A Combination on Grade _ 3.1 _ 0.8 2.6 1.3 8.8 8.8 0.2 0.2 66 7
CB-C3B Combindation on Grade _ 2.8 _ 0.0 2.1 0.8 7.7 7.7 0.2 0.2 73 12
YI-C3C Drop Grate in Sag _ 0.6 _ 0.0 0.6 0.0 10.3 10.3 0.1 0.1 --- 11
MH-C3D Manhole _ 0.0 _ 0.8 0.0 0.8 - - - - --- 8
MH-C4 Manhole _ 0.9 _ 0.6 0.0 1.5 - - - - --- 2
CB-C4A Combination on Grade _ 2.5 _ 0.0 1.9 0.6 7.3 7.3 0.2 0.2 76 9
CB-C4B Drop Grate in Sag _ 0.9 _ 0.0 0.9 0.0 13.2 13.2 0.1 0.1 --- 10
CB-05 Combindation on Grade 1 1.7 1.5 2.4 0.8 8.1 8.1 0.2 0.2 76 1
-
System J
Q Q Q Q Spread Spread Depth Depth
Inlet ID Inlet Type Catchment +Carryover -Captured BypassedEfficiency
yp ry p = Gutter Inlet Gutter Inlet Line No.
(cfs) (cfs) (cfs) (cfs) Ift) Iffl Ift) Ift)
CB-J1 Combination on Grade 1.91 0 1.56 ' 0.35 6.45 6.45 0.19 0.19 82 3
CB-J2A Combination on Grade 0.74 0 0.74 0 4 4 0.14 0.14 100 4
CB-J2 Combination on Grade 0.71 0.35 1.06 0 4.85 4.85 0.16 0.16 100 2
MH-J3 Manhole 0 0 0 0 - - - - 1
System K
Q Q Q Q Spread Spread Depth Depth
Inlet ID Inlet Type Catchment +CarryoverCapturedBypassedEfficiency
- = Gutter Inlet Gutter Inlet Line No.
(cfs) (cfs) (cfs) (cfs) Ift) Ift) Ift) Ift)
CB-K1 I Combination on Grade i 1.73 I 0 i 1.73 i 0 I 6.2 I 6.2 I 0.18 I 0.18 I 100 i 5

Riprap Outlet Protection Calculations

DESIGN OF RIPRAP OUTLET PROTECTION
User Input Data
Calculated Value
Reference Data
Designed By: QKT Date: 7/25/2023
Checked By: Date:
Company: Hazen&Sawyer
Project Name: Twelve Mile Creek WRF 9.0 MGD Expansion
Project No.: 30831-061
Site Location(City/Town) Waxhaw
Culvert Id. C6
Total Drainage Area(acres) 5.14
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 inmmnuun tailwater condition.
If it is greater than half the pipe diameter.it is classified maximum condition
Pipes that owlet onto wide flat areas with no defined channel are assumed
to have a nnunuun tailwater condition unless reliable flood stage elevations
show otherwise
Outlet pipe diameter,Do(in.) 24
Tailwater depth(in.) 0
Minimum/Maximum tailwater? Min TW(Fig.8.06a)
Discharge(cfs) 36.48
Velocity(ft./s) 11.61
Step 2. Based on the tailwater conditions detemuned in step 1.enter Figure
8.06a or Figure 8.06b.and determine d50 riprap size and minunum apron length
(Li). The d,.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
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap dso,(ft.) 0.5 0.5
Minimum apron length,La(ft.) 13 10
Apron width at pipe outlet(ft.) 6 6
Apron shape
Apron width at outlet end(ft.) 15 6
Step 4. Deternune the maximum stone diameter:
din„. 1.5xdw
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 0.75 0.75
Step 5. Determine the apron tlucktiesq
Apron thickne iS=1.5 x
Minimum TW Maximum TW
Apron Thickness(ft.) 1.125 1.125
Step 6. Fit the nprap apron to the site by making it level for the nutwnuun
length.Lr. from 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.
Sonic locations may require lining of the entire channel cross section to assure
stability
It may be necessary to increase the size of nprap 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: QKT Date: 7/25/2023
Checked By: Date:
Company: Hazen&Sawyer
Project Name: Twelve Mile Creek WRF 9.0 MGD Expansion
Project No.: 30831-061
Site Location(City/Town) Waxhaw
Culvert Id. J4
Total Drainage Area(acres) 0.733
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 imnun um tailwater condition.
If it is greater than half the pipe diameter.it is classified maxis nun condition.
Pipes that owlet onto wide flat areas with no defined channel are assumed
to have a nmunuun tailwater condition unless reliable flood stage elevations
show otherwise
Outlet pipe diameter,Do(in.) 15
Tailwater depth(in.) 0
Minimum/Maximum tailwater? Min TW(Fig.8.06a)
Discharge(cfs) 15.86
Velocity(ft./s) 12.93
Step 2. Based on the tailwater conditions detemuned in step 1.enter Figure
8.06a or Figure 8.06b.and determine d50 nprap size and nununtun apron length
(Li). The d,c size is the median stone size in a well-graded nprap apron_
Step 3. Detemune apron width at the pipe outlet.the apron shape.and the
apron width at the outlet end from the same figure used ui Step
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap dso,(ft.) 0.65 0.5
Minimum apron length,La(ft.) 14 34
Apron width at pipe outlet(ft.) 3.75 3.75
Apron shape
Apron width at outlet end(ft.) 15.25 14.85
Step 4. Deternune the maximum stone diameter.
dm„= 1.5xdw
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 0.975 0.75
Step 5. Detention the apron tlucknieser
Apron thickness=1.5 x
Minimum TW Maximum TW
Apron Thickness(ft.) 1.4625 1.125
Step 6. Fit the nprap apron to the site by making it level for the nunun un
length.Li. from Figure S 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 nprap where protection of the
channel side slopes is necessary(Appendix 3.05). 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: QKT Date: 7/25/2023
Checked By: Date:
Company: Hazen&Sawyer
Project Name: Twelve Mile Creek WRF 9.0 MGD Expansion
Project No.: 30831-061
Site Location(City/Town) Waxhaw
Culvert Id. K2
Total Drainage Area(acres) 0.257
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 innunnun tailwater condition.
If it is greater than half the pipe diameter.it is classified maximum condition.
Pipes that owlet 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.) 15
Tailwater depth(in.) 0
Minimum/Maximum tailwater? Min TW(Fig.8.06a)
Discharge(cfs) 14.15
Velocity(ft./s) 11.53
Step 2. Based on the tailwater conditions detemuned in step 1.enter Figure
8.06a or Figure 8.06b.and determine d50 nprap size and minimum apron length
(Li). The d,.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 to Step
Minimum TW Maximum TW
Figure 8.06a Figure 8.06b
Riprap dso,(ft.) 0.5 0.5
Minimum apron length,La(ft.) 14 19
Apron width at pipe outlet(ft.) 3.75 3.75
Apron shape
Apron width at outlet end(ft.) 15.25 8.85
Step 4. Determine the maximum stone diameter
L5xdw
Minimum TW Maximum TW
Max Stone Diameter,dmax(ft.) 0.75 0.75
Step 5. Determine the apron tluckties'
Apron thickne iS=1.5 x
Minimum TW Maximum TW
Apron Thickness(ft.) 1.125 1.125
Step 6. Fit the nprap apron to the site by making it level for the nununuu
length.Li. from Figure S 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 nprap where protection of the
channel side slopes is necessary(Appendix 3.05). Where overfalls exist at
pipe outlets or flows are excessive.a plunge pool should be considered,see
page 8.06.8.

Figure 8.O6a: Design of outlet protection from a round pipe flowing full, minimum
tailwater condition (Tw<0.5 diameter)
Outlet u De * La 90 I Return to Main Worksheet
pipe ...-...+.I
diameter(Do)
La �1 AO -- �i5./�.I
igililitlilwater<0.5Do `� �
toil.--e' l 70 p
VeP9�ro`Pp 6a / � a`°---
►� m la
i. ,50 o ,...:
30
20 �. } .s:,5 A s. 1.. _.� _ .. � 3
, ' , . Afff,iii:jp.),o,;;...1
10 j. . O'"
0 1 1 al 1 1 1 u r ` .� .: �� d b t. 2 N 0
3 5 10 20 50 100 200 500 1000
Discharge(f13/sec)
Curves may not be extrapolated.
Figure 8.06a Design of outlet protection protection from a round pipe flowing full,minimum tailwator condition(T,.<0.5 6ameter).
Rev.11 93 8.06.3

Figure 8.06b: Design of outlet protection from a round pipe flowing full, maximum
tailwater condition (Tw>=0.5 diameter)
i 3De
Outlet . �w. Do. 0.4La 120 ---- - Return to Main Worksheet
pipe 1 i
diameter(D3)1 La
v Tailwats! . .-5D0 ill..'_:
•
)
M
O
•C- 70 I
JAJIMI
�J�� ..�! ,�' i :... dre'� ,�,'A :e N firit!rillfilrfill
���1tN1pN�:.7 1 � III II: - NI IIIIN40 . 0
V
�r. ' �wll i aiin 3
. .
NN Jt ,
20 "3of
.. •:l r,•Ir.•.ligi ,p �r�,F. : : :• : . : :,.i . - rolipirw01d�! 2 r
q9911{{ 'amp is
10 l I l l �t
i ,811
Fr ,r r
i11 ! .80
3 5 10 20 50 100 200 500 1000
Discharge(ft3/sec)
Curves may not be extrapolated.
Figure 8.06b Dosign of outlet protection from a round pipo Sowing full,maxNmum talwater condition(T.5 0.5 diameter).
8.06.4 Rev.12+93

PIPE FLOW CALCULATIONS
Pipe Pipe Pipe Manning's Full-Flow Full Flow Full-Flow Flow Full-Flow Design-Flow
Location Diamater Slope n Area Wetted Perim. Hyd. Radius Capacity Velocity Velocity
(ft) (ft/ft) (sq ft) (ft) _ (ft) (cfs) (fps) (fps)
FES C6 2 0.026 0.013 3.14 , 6.28 0.50 36.48 11.61 9.48
FES J4 1.25 0.06 0.013 1.23 3.93 _ 0.31 15.86 12.93 3.56
FES K4 1.25 0.048 0.013 1.23 3.93 0.31 14.15 11.53 2.47
Note: Design flow was determined using the Stormwater Studio model, based on the 10-year design storm. Full
flow was calculated using the Manning's equation. The larger value between these two calculations were then
utilized to size the Riprap aprons for non-erosive discharge at the storm water outlets.

Appendix D
USGS StreamStats Delineation

THIS PAGE INTENTIONALLY LEFT BLANK

3/3/23,3:41 PM StreamStats
5
�. :Ei = Matthews-,=--..."--/
Pineville' 1::,
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_ ',I GCS4. q
(-)
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_ _ _ _ =__ _-- 0\„\ik,.
'" y Indian ail ad u
° ' iI II
li „ \ �7
\\ 'f11 arr roe
r, Fort Mill Rgnl ~
Rock Hill York Co -- y Airport
BryanjAlrport ,k', �!{ sVC::',rnyt r �,j . Mor>Iroe
_ ,:,:,
Project i 75
u /1 1 Area `
ax,�w Mineral I •
'Rock Hill - Springs jIr ,.
Y // y•,.N I) ;'
a
Lesslie'
1
a,
t� Jaar+
Townsend -
Airport 0cl
- ___
7 .
k
II
rr
11
S'I
LC06IMP Percentage of impervious area determined from NLCD 2006 4.69 percent
impervious dataset
PCTREG1 Percentage of drainage area located in Region 1 - Piedmont / 100 percent
Ridge and Valley
PCTREG2 Percentage of drainage area located in Region 2 - Blue Ridge 0 percent
PCTREG3 Percentage of drainage area located in Region 3 - Sandhills 0 percent
PCTREG4 Percentage of drainage area located in Region 4 - Coastal Plains 0 percent
PCTREG5 Percentage of drainage area located in Region 5 - Lower Tifton 0 percent
Uplands
https://streamstats.usgs.gov/ss/ 1/3

3/3/23,3:41 PM StreamStats
Peak-Flow Statistics
Peak-Flow Statistics Parameters [Peak Southeast US over 1 sqmi 2009 5158]
Parameter Code Parameter Name Value Units Min Limit Max Limit
DRNAREA Drainage Area 80.3 square miles 1 9000
PCTREG1 Percent Area in Region 1 100 percent 0 100
PCTREG2 Percent Area in Region 2 0 percent 0 100
PCTREG3 Percent Area in Region 3 0 percent 0 100
PCTREG4 Percent Area in Region 4 0 percent 0 100
PCTREG5 Percent Area in Region 5 0 percent 0 100
Peak-Flow Statistics Flow Report [Peak Southeast US over 1 sgmi 2009 5158]
PII: Prediction Interval-Lower, Plu: Prediction Interval-Upper, ASEp: Average Standard Error of
Prediction, SE: Standard Error (other -- see report)
Statistic Value Unit PII Plu ASEp
50-percent AEP flood 2730 ft^3/s 1 580 4730 34.5
20-percent AEP flood 4620 ft^3/s 2690 7950 34
10-percent AEP flood 5960 ft^3/s 3410 10400 35.1
4-percent AEP flood 7660 ft^3/s 4230 13900 37.5
2-percent AEP flood 9180 ft^3/s 4910 17100 39.6
1-percent AEP flood 10500 ft^3/s 5440 20300 41.9
0.5-percent AEP flood 11800 ft^3/s 5900 23600 44.3
0.2-percent AEP flood 13800 ft^3/s 6570 29000 47.7
Peak-Flow Statistics Citations
Weaver, J.C., Feaster, T.D., and Gotvald, A.J.,2009, Magnitude and frequency of rural floods in the
Southeastern United States, through 2006—Volume 2, North Carolina: U.S. Geological Survey
Scientific Investigations Report 2009-5158, 111 p. (http://pubs.usgs.gov/sir/2009/5158/)
USGS Data Disclaimer:Unless otherwise stated,all data,metadata and related materials are considered to satisfy the quality standards relative
to the purpose for which the data were collected.Although these data and associated metadata have been reviewed for accuracy and
completeness and approved for release by the U.S.Geological Survey(USGS),no warranty expressed or implied is made regarding the display or
utility of the data for other purposes,nor on all computer systems,nor shall the act of distribution constitute any such warranty.
USGS Software Disclaimer:This software has been approved for release by the U.S.Geological Survey(USGS).Although the software has been
subjected to rigorous review,the USGS reserves the right to update the software as needed pursuant to further analysis and review.No
warranty,expressed or implied,is made by the USGS or the U.S.Government as to the functionality of the software and related material nor
shall the fact of release constitute any such warranty.Furthermore,the software is released on condition that neither the USGS nor the U.S.
Government shall be held liable for any damages resulting from its authorized or unauthorized use.
USGS Product Names Disclaimer:Any use of trade,firm,or product names is for descriptive purposes only and does not imply endorsement by
https://streamstats.usgs.gov/ss/ 2/3

3/3/23,3:41 PM StreamStats
the U.S.Government.
Application Version:4.13.0
StreamStats Services Version:1.2.22
NSS Services Version:2.2.1
https://streamstats.usgs.gov/ss/ 3/3

Appendix E
Supplement Forms
Permit Application Form
Supplement-EZ Forms
Operations&Maintenance Agreement
Operation&Maintenance Manual

THIS PAGE INTENTIONALLY LEFT BLANK

Permit Application Form

DEMLR USE ONLY
Date Received Fee Paid Permit Number
Applicable Rules: ❑Coastal SW-1995 ❑Coastal SW-2008 ❑Ph II-Post Construction
(select all that apply) E Non-Coastal SW-HQW/ORW Waters ❑Universal Stormwater Management Plan
❑ Other WQ Mgmt Plan:
State of North Carolina
Department of Environment and Natural Resources
Division of Energy,Mineral and Land Resources
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
This form may be photocopied for use as an original
I. GENERAL INFORMATION
1. Project Name(subdivision,facility,or establishment name-should be consistent with project name on plans,
specifications,letters,operation and maintenance agreements,etc.):
Twelve Mile Creek WRF 9.0 MGD Expansion
2. Location of Project(street address):
8299 Kensington Drive
City:Waxhaw County:Union Zip:2S173
3. Directions to project(from nearest major intersection):
Nearest major intersection: NC-16 S(Providence Rd S)&Kensington Dr / Cuthbertson Rd
Traveling south on NC-16 S(Providence Rd CI,turn right onto Kensington Dr.
Continue 0,6 miles on Kensington Dr;Twelve Mile Creek WRF will be on the left.
4. Latitude:34°57' 16.92" N Longitude:-80°45'47.1594"W of the main entrance to the project.
II. PERMIT INFORMATION:
1.a.Specify whether project is (check one): New ❑Modification ❑ Renewal w/ Modificationt
tRenewals with modifications also requires SWU-102-Renewal Application Form
b.If this application is being submitted as the result of a modification to an existing permit,list the existing
permit number ,its issue date (if known) ,and the static of
construction: ['Not Started ❑Partially Completed* ❑Completed* *provide a designer's certification
2. Specify the type of project(check one):
ZLow Density ❑High Density ❑Drains to an Offsite Stormwater System ❑Other
3. If this application is being submitted as the result of a previously returned application or a letter from
DEMLR requesting a state stormwater management permit application,list the stormwater project number,
if assigned, and the previous name of the project,if different than currently
proposed,
4.a.Additional Project Requirements(check applicable blanks;information on required state permits can be
obtained by contacting the Customer Service Center at 1-877-623-6748):
❑CAMA Major ®Sedimentation/Erosion Control:12 ac of Disturbed Area
❑NPDES Industrial Stormwater Z404/401 Permit:Proposed Impacts Additional plant outfall and
piping
b.If any of these permits have already been acquired please provide the Project Name,Project/Permit Number,
issue date and the type of each permit:401 Water Quality Certification No.WQC005722(received March 6,
2023);all other permits are still in progress-
5. Is the project located within 5 miles of a public airport? No Dyes
If yes,see S.L.2012-200,Part VI: http://portal.ncdenr.org/web/lr/rules-and-regulations
Form SWU-101 Version Oct. 31,2013 Page 1 of 6

III. CONTACT INFORMATION
1.a.Print Applicant/ Signing Official's name and title(specifically the developer,property owner,lessee,
designated government official,individual,etc.who owns the project):
Applicant/Organization:Union County Water
Signing Official&Title:Thomas Mann P.E.
b.Contact information for person listed in item la above:
Street Address:500 N.Main Street,Suite 600
City:Monroe State:NC Zip:28112
Mailing Address(if applicable):
City: State: Zip:
Phone: (704 ) 292-2560 Fax: (
Email:[e-mail]
c.Please check the appropriate box.The applicant listed above is:
The property owner(Skip to Contact Information,item 3a)
❑Lessee*(Attach a copy of the lease agreement and complete Contact Information,item 2a and 2b below)
❑Purchaser*(Attach a copy of the pending sales agreement and complete Contact Information,item 2a and
2b below)
❑Developer*(Complete Contact Information,item 2a and 2b below.)
2.a.Print Property Owner's name and title below,if you are the lessee,purchaser or developer. (This is the
person who owns the property that the project is located on):
Property Owner/Organization:
Signing Official&Title:
b.Contact information for person listed in item 2a above:
Street Address:
City: Gt.te: Zip:
Mailing Address(if applicable):
City: State: Zip:
Phone: ( ) Fax: (
Email:
3.a. (Optional) Print the name and title of another contact such as the project's construction supervisor or other
person who can answer questions about the project:
Other Contact Person/Organization:Hazen&Sawyer
Signing Official&Title:Michael D. Parker
b.Contact information for person listed in item 3a above:
Mailing Address:9101 Southern Pine Boulevard,Suite 250
City:Charlotte State:NC Zip:28273
Phone: (704 ) 940-8910 Fax: ( )
Email:[e-mail]
4. Local jurisdiction for building permits:Union County Building Code Enforcement
Point of Contact:Jesse Langston Phone#: (704 ) 283-3594
Form SWU-101 Version Oct.31,2013 Page 2 of 6

IV. PROJECT INFORMATION
1. In the space provided below,briefly summarize how the stormwater runoff will be treated.
This project meets the low density requirements of having less than 24%impervious area.There for
stormwater runoff was designed to be treated by dispersed flow from rip rap lined outfalls to areas of heavy
vegitation.
2.a.If claiming vested rights,identify the supporting documents provided and the date they were approved:
n Approval of a Site Specific Development Plan or PUD Approval Date:
❑Valid Building Permit Issued Date:
❑Other: Date:
b.If claiming vested rights,identify the regulation(s) the project has been designed in accordairre with:
❑ Coastal SW-1995 ❑Ph II-Post Construction
3. Stormwater runoff from this project drains to the Catawba River basin.
4. Total Property Area:56.66 acres 5. Total Coastal Wetlands Area:0 acres
6. Total Surface Water Area:3.42 acres
7. Total Property Area(4)-Total Coastal Wetlands Area(5) -Total Surface Water Area(6)=Total Project
Area+:53.24 acres
+ Total project area shall be calculated to exclude the following: the normal pool of impounded structures, the area
between the banks of streams and rivers, the area below the Normal High Water(NHW)line or Mean High Water
(MHW) line, and coastal wetlands landward from the NHW(or MHIN)line. The resultant project area is used to
calculate overall percent built upon area(BUA). Non-coastal wetlands landward of the NHW(or MHW)line may
be included in the total project area.
8. Project percent of impervious area: (Total Impervious Area/ Total Project Area)X 100 =15.0
9. How many drainage areas does the project have?1 (For high density, count 1 for each proposed engineered
stormwater BMP. For low density and other projects, use 1 for the whole property area)
10. Complete the following information for each drainage area identified in Project Information item 9. If there
are more than four drainage areas in the project, attach an additional sheet with the information for each area
provided in the same format as below.
Basin Information Drainage Area 1 Drainage Area_ Drainage Area_ Drainage Area=
Receiving Stream Name Twelvemile
Creek
Stream Class * C
Stream Index Number* 11-138
Total Drainage Area(sf) 2,319,134
On-site Drainage Area(sf) 2,319,134
Off-site Drainage Area(sf) 0
Proposed Impervious Area**(sf)_ 347,620
% Impervious Area**(total) 15.0
Impervious**Surface Area Drainage Area 1 Drainage Area_ Drainage Area Vrainage Area_
On-site Buildings/Lots(sf) 31,300
On-site Streets (sf) 62,570
On-site Parking (sf) 0
On-site Sidewalks (sf) 8,320
Other on-site (sf) 0
Future (sf) 0
Off-site (sf) 0
Existing BUA***(sf) 245,430
Total (sf): 347,620
• Stream Cam end hula Number cos be detemdmd at: littpi/portal.ncdenr.org/web/wa/ps/csu/classifications
Form SWU-101 Version Oct.31,2013 Page 3 of 6

** Impervious area is defined as the built upon area including, but not limited to, buildings, roads,parking areas,
sidewalks,gravel areas,etc.
***Report only that amount of existing BUA that will remain after development. Do not report any existing BUA that
is to be removed and which will be replaced by new BUA.
11. How was the off-site impervious area listed above determined?Provide documentation.N/A
Projects in Union Counts:Contact DEMLR Central Office staff to check jf the project is located within a Threatened&
Endangered Species watershed that may be subject to more stringent atones aer requirements as per 1 Sd NCAC 0211.0600
V. SUPPLEMENT AND OAM FORMS
The applicable state stormwater management permit supplement and Opera lion and maintenance(O&M)forms
must be submitted for each BMP specified for this project. The latest very ,n of the foram can be downloaded
from http://portal.ncdenr.org/web/wq/ws/sta bmp-manual
VL SUBMITTAL RE
Only complete application packages will be accepted and reviewed by the Division of Energy,Mineral and
Land Resources (DEMLR). A complete package includes all of the items listed below. A detailed application
instruction sheet and BMP checklists are available from
http://portal.ncdenr.org/web/wq/ws/su/statesw/forms docs. The complete application package should be
submitted to the appropriate DEMLR Office. (The appropriate office may be found by locating project on the
interactive online map at http://portal.ncdenr.org/web/wq/ws/su/maps.)
Please indicate that the following required information have been provided by initialing in the space provided
for each item.All original documents MUST be signed and initialed in blue ink. Download the latest versions
for each submitted application package from http://portal.ncdenr.org/web/wq/ws/su/statesw/forms docs.
Ini '
1. Original and one copy of the Stormwater Management Permit Application Form.
2. Original and one copy of the signed and notarized Deed Restrictions&Protective Covenants N A.
Form. (if required as per Part VII below)
3. Original of the applicable Supplement Form(s)(sealed,signed and dated)and O&M M P
agreement(s)for each BMP.
4. Permit application processing fee of$505 payable to NCDENR. (For an Express review,refer to M f
http://www.envhelp.org/pages/onestopexpress.html for information on the Express program
and the associated fees. Contact the appropriate regional office Express Permit Coordinatox for
additional information and to schedule the required application meeting.)
5. A detailed narrative(one to two pages) describing the stormwater treatment/management for
6. A USGS map identifying the site location. If the receiving stream is reported as class SA or the i4F'
receiving stream drains to class SA waters within 1/2 mile of the site boundary,include the 1/x
mile radius on the map.7. Sealed,signed and dated calculations(one copy). t A
F
8. Two sets of plans folded to 8.5"x 14"(sealed,signed,&dated),including: /V\
a. Development/Project name.
b. Engineer and firm.
c. Location map with named streets and NCSR numbers.
d. Legend.
e. North arrow.
f. Scale.
g. Revision number and dates.
h. Identify all surface waters on the plans by delineating the normal pool elevation of
impounded structures,the banks of streams and rivers,the MHW or NHW line of tidal
waters,and any coastal wetlands landward of the MHW or NHW lines.
• Delineate the vegetated buffer landward from the normal pool elevation of impounded
structures,the banks of streams or rivers,and the MHW(or NHW) of tidal waters.
i. Dimensioned property/project boundary with bearings&distances.
j. Site Layout with all BUA identified and dimensioned.
k. Existing contours,proposed contours,spot elevations,finished floor elevations.
1. Details of roads,drainage features,collection systems,and stormwater control measures.
m.Wetlands delineated,or a note on the plans that none exist. (Must be delineated by a
qualified person. Provide documentation of qualifications and identify the person who
made the determination on the plans.
Form SWU-101 Version Oct.31,2013 Page 4 of 6

n. Existing drainage (including off-site),drainage easements,pipe sizes,runoff calculations.
o. Drainage areas delineated (included in the main set of plans,not as a separate document).
p. Vegetated buffers(where required).
9. Copy of any applicable soils report with the associated SHWT elevations(Please identify M 1
elevations in addition to depths) as well as a map of the boring locations with the existing
elevations and boring logs.Include an 8.5"x11"copy of the NRCS County Soils map with the
project area clearly delineated. For projects with infiltration BMPs,the report should also
include the soil type,expected infiltration rate,and the method of determining the infiltration zate.
(Infiltration Devices submitted to WiRO:Schedule a site visit for DEMLR to verify the SHWT prior
to submittal, [phone].)
10. A copy of the most current property deed.Deed book:351 Page No:482 Al*
11. For corporations and limited liability corporations(LLC): Provide documentation from the NC
Secretary of State or other official documentation,which supports the titles and positions held
by the persons listed in Contact Information,item 1a,2a,and/or 3a per 15A NCAC 2H.1003(e).
The corporation or LLC must be listed as an active corporation in good standing with the NC
Secretary of State,otherwise the application will be returned.
http://www.secretary.state.nc.us/Corporations/CSearch.aspx
VIL DEED RESTRICTIONS AND PROTECTIVE COVENANTS
For all subdivisions,outparcels,and future development,the appropriate property restrictions and protective
covenants are required to be recorded prior to the sale of any lot Iflot sizes vary significantly or the proposed
BUA allocations vvaaryry,a table listing each lot number,lot size,and the allowable built-upon area must be
provided as an a t to the completed and notarized deed restriction form. The appropriate deed
restrictions and protective covenants farms am be downloaded from ht t n:L portal.ncdenr.or ;'t\(.1_,:I t .Hit..
stormwater-forms dors.Download the latest versions for each submittal
In the instances where the applicant is different than the property owner,it is the responsibility of the property
owner to sign the deed restrictions and protective covenant form while the applicant is responsible for ensuring
that the deed restrictions are recorded.
By the notarized.Ignature(s)below,the permit holder(.)certify that the recorded property restrictions and
protective covenanb for this project,if required,shall include all the itemi required in the permit and listed
on the forms available on the website,that the covenanb will be binding an all parties and persons claiming
under them,that they will run with the land,that the required covenanb cannot be changed or deleted
without concurrence from the NC DEMLR,and that they will be recorded pdar to th.sale of any lot
VIIL CONSULTANT INFORMATION AND AUTHORIZATION
Applicant Complete this median if you wish to designate authority to another individual and/or firm(such as a
consulting engineer and/or firm)so that they may provide information on your behalf for this project(such as
addressing requests for additional information).
Consulting Engineer:Michael Parker P.E.
Consulting Firm: Hazen&Sawyer
Mailing Address:9101 Southern Pine Boulevard,Suite 250
City:Charlotte State:NC Zip:28273
Phone: (704 ) 940-8910 Fax: ( )
Email:[e-mail]
IX. PROPERTY OWNER AUTHORIZATION(if Contact Information, item 2 has been filled out, ccimplete this
section)
I, (print or type name of person listed in Contact Information, item 2a) ,certify that I
own the property identified in this permit application,and thus give permission to (print or type name of person
listed in Contact Information, item la) with(print or type name of organization listed in
Contact Information, item 1a) to develop the project as currently proposed. A copy of
the lease agreement or pending property sales contract has been provided with the submittal,which indicates the
party responsible for the operation and maintenance of the stormwater system.
Form SWU-101 Version Oct.31,2013 Page 5 of 6

As the legal property owner I acknowledge,understand,and agree by my signature below,that it may designated
agent(entity listed in Contact Information,item 1)dissolves their company and/or cancels or defaults on their
lease agreement,or pending sale,responsibility for compliance with the DEMLR Stormwater permit reverts back
to me,the property owner.As the property owner,it is my responsibility to notify DEMLR immediately and
submit a completed Name/Ownership Change Form within 30 days;otherwise I will be operating a stormwater
treatment facility without a valid permit. I understand that the operation of a stormwater treatment facility
without a valid permit is a violation of NC General Statue 143-215.1 and may result in appropriate enforcement
action including the assessment of civil penalties of up to$25,000 per day,pursuant to NCGS 143- 15.6.
Signature: Date:
I, ,a Notary Public for the State of ,County of
,do hereby certify that personally appeared
before me this day of ,and acknowledge the due execution of the application for
a stormwater permit. Witness my hand and official seal,
SEAL
My commission expires
X. APPLICANT'S CERTIFICATION
I, (print or type name of person listed in Contact Information, item 1a) Thomas Mann
certify that the information included on this permit application form is,to the best of my knowledge,correct and
that the project will be constructed in conformance with the approved plans,that the required deed restrictions
and protective covenants will be recorded,and that the proposed project complies with the requirements of the
applicable stormwater rules under 15A NCAC 2H.1000 and any other applicable state stormwater requirements.
Signature: ' Dabs 5' 1 14
I, �^ /44;tg f 1 S•Te> ,a Notary Public for the State of ��ftl d&r.dallsitCOUrity of
►v; o vt^ ,do hereby certify that 74n--a personally appeared
before me this f day of a-il ,7.123 ,and ackn w g du execution of the application for
a stormwaterpermit. Witness myhand and official
seal,and
n SEAL
,�,tipTAR Y •
OW
` �°C.'8 L1G = My Comnisrlon Expires 10/7/2025
�� •a ., V s My commission expires
"1;0 /°•... ••,° �4'
•
Form SWU-101 Version Oct.31,2013 Page 6 of 6

Supplement-EZ Forms

SUPPLEMENT-EZ COVER PAGE
FORMS LOADED
PROJECT INFORMATION
1 Project Name Twelve MIN Creek WRF 9.0 MGD Expansion
2 Project Area(ac) 53.24
3 Coastal Wetland Area(ac) 0
4 Surface Water Area(ac) 3.246
5 Is this project High or Low Density? Low
6 Does this project use an off-site SCM? No
COMPUANCE WITH 02H.1003(4)
7 Width of vegetated setbacks provided(feet) 30
8 Will the veaetated setback remain veaetated? Yes
9 If BUA is proposed in the setback,does it meet NCAC 02H.1003(4)(c-d)? N/A
10 Is streambank stabilization proposed on this project? No
NUMBER AND TYPE OF SCMs:
11 Infiltration System 0
12 Bioretention Cell 0
13 Wet Pond 0
14 Stormwater Wetland 0
15 Permeable Pavement 0
16 Sand Filter 0
17 Rainwater Harvesting(RWH) 0
18 Green Roof 0
19 Level Spreader-Filter Strip(LS-FS) 0
20 Disconnected Impervious Surface(DIS) 0
21 Treatment Swale 0
22 Dry Pond 0
23 StormFilter 0
24 Silva Cell 0
25 Bayfilter 0
26 Filterra 0
FORMS LOADED I
DESIGNER CERTIFICATION
27 Name and Title: Michael Parker P.E.
28 Organization: Hazen&Sawyer
29 Street address: 9101 Sao Tern Pine Boulevard,Suite 250
30 City,State,Zip: Chzeigitte.North Carolina,28273
31 Phone number(s): [phone]
32 Email: mpterlhazenandsawyer.com
Certification Statement
I certify,under penalty of law that this Supplement-EZ form and all supporting information were prepared under my direction or supervision;that
the information provided in the form is,to the best of my knowledge and belief,true,accurate,and complete;and that the engineenng plans,
specifications,operation and maintenance agreements and other supporting information are consistenlulih the information provided here.
Desi ii n
"D CAR()?i ►�
Sig lure of IJezfigner
26432
7e, FHCINe ��
A£C D. ? 1/21/2023
Seat Date

DRAINAGE AREAS
I Is this a high density project? No
2 If so,number of drainage areas/SCMs 0
3 Does this project have low density areas? Yes
4 If so,number of low density drainage areas 1
Is all/part of this project subject to previous rule
5 versions? No
FORMS LOADED
DRAINAGE AREA INFORMATION Entire Site LD 1 —I
4 Type of SCM Dispersed flow Dispersed flow
5 Total drainage area(sq ft) 2319134 sf 2319134 sf
6 Onsite drainage area(sq ft) 2319134 sf 2319134 sf
7 Offsite drainage area(sq ft) n/a n/a
8 Total BUA in project(sq ft) 347620 sf 347620 sf
New BUA on subdivided lots(subject to
9 permittinq)(sq ft) n/a n/a
New BUA not on subdivided lots(subject to
10 permitting)(sf) 102190 sf 102190 sf
11 Offsite BUA(sq ft) n/a n/a
12 Breakdown of new BUA not on subdivided lots:
-Parking(sq ft) sf sf
-Sidewalk(sq ft) 8320 sf 8320 sf
-Roof(sq ft) 31300 sf 31300 sf
-Roadway(sq ft) 62570 sf 62570 sf
-Future(sq ft) sf sf
-Other,please specify in the comment box
below(sq ft) sf sf
New infiltrating permeable pavement on
13 subdivided lots(sq ft) sf sf
New infiltrating permeable pavement not on
14 subdivided lots(sq ft) sf sf
Existing BUA that will remain(not subject to
15 permittinq)(sq ft) 245430 sf 245430 sf
16 Existinq BUA that is already permitted(sq ft) sf sf
17 Existinq BUA that will be removed(sq ft)
18 Percent BUA 15% 15%
19 Design storm(inches) 7.6 in 7.6 in
20 Design volume of SCM(cu ft) n/a n/a
21 Calculation method for design volume n/a n/a
ADDITIONAL INFORMATION
Please use this space to provide any additional information about the
22 drainage area(s):
The 12 Mile Creek WRF property boundary is less than 0.001%of the total
contributing drainage area according to StreamStats(Appendix D).Due to
the significant difference,offsite drainage was not considered in the BUA
table(Drawing C6).Percent BUA includes all BUA that will be on site after
,.,,ncrr,„ai.,r, ,.,.n-,r,i r,,1

LOW DENSITY
DESIGN REQUIREMENTS FOR LOW DENSITY PROJECTS FROM 02H.1003
1 Is project below density thresholds set forth in the applicable stormwater rule? Yes
2 Does project maximize dispersed flow and minimize channelization of flow? Yes
3 Has the use of piping been minimized per.1003(2)(c)? Yes
4 Side slopes of the vegetated conveyances(H:V) n/a
5 Maximum velocity in the vegetated conveyances during the 10-year storm?
6 Are curb outlet swales proposed? No
7 Maximum longitudinal slope of curb outlet swale(s)(%) n/a
8 Bottom width of curb outlet swale(s)(feet) n/a
9 Maximum side slope of curb outlet swale(s)(H:V) n/a
10 Minimum length of curb outlet swale(s)(feet) n/a
11 Are treatment swales used instead of curb outlet swales? No
12 Is stormwater released at the edge of the setback as dispersed flow? Yes
13 Have stormwater outlets been designed to prevent downslope erosion? Yes
14 Are variations to rule.1003 proposed? No
ADDITIONAL INFORMATIONI
15 !Please use this space to provide any additional information about this low density project:
This site has a preexisting storm system that is required for convayance under roadways.The protective measures taken under
the project were to minimize impact to the existing stormwater design and provide aditional outfall protection with riprap in areas
where imperviousness in a storm systems catchbasin were made.
Drainage Pervious
Swale Area BUA area C Q Slope V,ibw V,ct i Flow depth
# (ac) (ac) (ac) (cfs) (%) (fps) (fps) (ft)
1
2 .
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
2

Operations&Maintenance Agreement

Operation & Maintenance Agreement
Project Name: Twelve Mile Creek WRF 9.0 MGD Expansion
Project Location: 8299 Kensington Drive Waxhaw, NC 28173
Cover Page
Maintenance records shall be kept on the following SCM(s). This maintenance record shall be kept in a log in a known set location.
Any deficient SCM elements noted in the inspection will be corrected, repaired, or replaced immediately. These deficiencies can
affect the integrity of structures, safety of the public, and the pollutant removal efficiency of the SCM(s).
The SCM(s)on this project include (check all that apply & corresponding O&M sheets will be added automatically):
Infiltration Basin Quantity: 0 Location(s):
Infiltration Trench Quantity: 0 Location(s):
Bioretention Cell Quantity: 0 Location(s):
Wet Pond Quantity: 0 Location(s):
Stormwater Wetland Quantity: 0 Location(s):
Permeable Pavement Quantity: 0 Location(s):
Sand Filter Quantity: 0 Location(s):
Rainwater Harvesting Quantity: 0 Location(s):
Green Roof Quantity: 0 Location(s):
Level Spreader- Filter Strip Quantity: 0 Location(s):
Proprietary System Quantity: 0 Location(s):
Treatment Swale Quantity: 0 Location(s):
Dry Pond Quantity: 0 _ Location(s):
Disconnected Impervious Surface Present: No Location(s):
User Defined SCM Present: No Location(s):
Low Density Present: Yes Type: Dispersed flow only
I acknowledge and agree by my signature below that I am responsible for the performance of the maintenance procedures listed for
each SCM above, and attached O&M tables. I agree to notify NCDEQ of any problems with the system or prior to any changes to
the system or responsible party.
Responsible Party: Union County Water
Title & Organization: Thomas Mann P.E.
Street address: 500 N Main Street, Suite 600
City, state, zip: Monroe, NC 28112
Phone number(s): 7042922560
Email: [e-mail]
Signature: g/ �l�,,r, Date:
3-1y-a3
/ ,L 4' 'V , a Notary Public for the State of /le/. /
County of C/4_; , do hereby certify that /� /ii
personally appeared before me this day of / / 2 C9-I and
acknowledge the due execution of the Operatippis n JVlainten nce Agreement .
Witness my hand,a0 official seal, 7 ---
♦may` •04Aar
v0,0.0,00•
"•f,$
4
t 0 i A �'s-
a
s Oe d 0 .�
pa 43,US
41.1 hn.11NHN My Commission Expires 1017/2025
Seal My commission expires
STORM-EZ 3/14/2023
Version 1.5 O&M Agreement Page 1 of 1

Low Density Maintenance Requirements
Important maintenance procedures:
_ The drainage area to the vegetated conveyance or vegetated receiving area will be carefully managed to
reduce the sediment load to the vegetated conveyance or vegetated receiving area.
_ After the initial fertilization to establish the grass in the vegetated conveyance or the vegetated receiving
area,fertilizer will not be applied to the vegetated receiving areas.
The vegetated conveyance or vegetated receiving area will be inspected quarterly. Records of operation and maintenance
will be kept in a known set location and will be available upon request.
Inspection activities shall be performed as follows.Any problems that are found shall be repaired immediately.
SCM element: Potential problem: How to remediate the problem:
Vegetation Vegetation is too short or Maintain grassed vegetation such that the swale or vegetated
too long. area does not erode during the peak flow from the 10-year storm
Trash/debris is present. Remove the trash/debris.
Vegetated receiving areas Areas of bare soil and/or Regrade the soil if necessary to remove the gully, and then re-sod
erosive gullies have (or plant with other appropriate species)and water until
formed. established. Provide lime and a one-time fertilizer application.
Clogging has occurred. Clean out the outlet device. Dispose of the sediment off-site.
The outlet device (if
applicable)
The outlet device is Repair or replace the outlet device.
damaged
Erosion or other signs of
damage have occurred at Repair the damage and improve the flow dissipation structure.
the outlet.
The receiving water Discharges from the site
are causing erosion or Contact the local NCDEQ Regional Office.
sedimentation in the
receiving water.
1

Appendix F
Wetland Certification Statement

THIS PAGE INTENTIONALLY LEFT BLANK

1-lazen Twelve Mile Creek 9.0 MGD Ex ansion Pro•Project
P
Wetland Investigation Summary
Hazen investigators conducted a preliminary desktop assessment of available maps and
geographic information systems (GIS) shapefiles to determine the potential presence of
jurisdictional wetlands and deepwater habitats in the vicinity of the project. Hazen investigators
then conducted a field investigation that included identification, classification, and delineation of
waters of the U.S. present within the proposed limits of disturbance. One jurisdictional stream
(Twelve Mile Creek)was present within the limits of disturbance. Additionally, Twelve Mile
Creek Tributary No. 8 abuts the project area but is not within it. No wetlands were present within
the limits of disturbance.
Qualifications of the Investigators
Linda Diebolt
35 total years, 13 years with Hazen
Ms. Diebolt is an Environmental Scientist and Project Manager specializing in natural systems
and resources, botany, and permitting. Her experience includes stream and wetland delineation;
protected species assessments; and environmental permitting. She has extensive experience in
Section 401-404 permit applications; wetland mitigation site searches; wetland mitigation design
and specifications; biological assessments; and preparation of environmental documents.
Jarrod Karl
26 total years, 8 years with Hazen
Mr. Karl is a restoration ecologist and environmental scientist specializing in ecosystem
restoration and environmental planning and permitting. He managed the City of Charlotte's
stream and wetland mitigation bank and Section 401-404 permitting program for 13 years. Mr.
Karl is experienced in mitigation site identification and prioritization,watershed condition
assessments and natural resource assessments, including stream and wetland jurisdictional
determinations, stream and wetland functional assessments, biological inventories and water
quality monitoring.
Hazen and Sawyer•9101 Southern Pine Blvd, Suite 250•Charlotte,NC 28273•704.357.3150

Appendix G
Current Property Deed

THIS PAGE INTENTIONALLY LEFT BLANK

0351
0482
es
P� ��,\F`y .5) BOOK 3 5 I PACE 8
•
sure or Real£static
,_ _,rt1 A.OO r'L r. T - Fled for record
l}a�K'Q' :� 4. 5 0 _ Date:../1. 4.7.(.a/..
we. -l.�r Time:..�,.,�.7..o clocM..P,.M. ..
NARY a.CARRR.IR, Pngstcr of D-ets -
Unioa County,Monroe,Will taroks
r
ache Tao $344.50 necorao,nine.Door and roue
Tax Lot No........ ... __ Parcel Identifier No.
Varidad bY County on the day of , 19 ...
by / pp
NO alter recording to .� ( /r B _.....
Tile ilad,waaas.s ww pnpe.sd 6g GRIFFIN.CA111WFLL A HEIOER,P.A. 1./onro.,N.C.
' Brief description for the index
NORTH CAROLINA GENERAL WARRANTY DEED
THIS DEED made this 7th day of October ID 81 ,by and between
GRANTOR GRANTEE
H. WATSON STEWART and wife, TAAVTS W. UNION COUNTY
STEWART
Eater la appropriate block for each psis: rune.address.and,II.ppreprl.le, ch.nelrr al snips.e.e corporation at partnership.
t
The designation Grantor and Grantee as used herein shall include said parties,their heirs,successors,and assigns,and
shall Include singular, plural, maeeuline, feminine or neuter as required by context,
WITNESSETH, that the Grantor, for a valuable consideration paid by the Grantee, the receipt of which is hereby
acknowledged, hu and by these presents does grant, bargain, sell and convey unto the Grantee in fee simple, all that
certain lot or parcel of land situated In the City of ., Sandy Ridge. Township,
l Union County,North Carolina and more particularly described as follow,:
BEGINNING at a point in the center of Highway No. 16 (Providence Road), said point being
in the center of the bridge over Twelve Mile Creek and runs thence with the center of
Twelve Mile Creek as follows: 1st., S. 79-38-30 W. 290.03 feet; 2nd., South 59-24-30 W.
f 522.36 foot; 3rd., S. 66-55 W. 183.0 feet, 4th., N. 41-53-30 W. 162.57 test; 5th., S. 65-
1 38 W. 381.91 feet; 6th., S. 60-34-20 W. 175.53 feet; 7th., S. 63-57-40 W. 255.24 feet;
8th., S. 55-09-20 W. 116.42 feet; 9th., S. 46-37-40 W. 366.92 feet; 10th., S. 75-40-30 W.
193.33 feet; 11th., N. 63-49-40 W. 197.21 feet; 12th., S. 89-08-20 W. 121.03 feet; 13th.,
iS. 76-42-40 W. 147.60 feet; 14th., S. 58-08-30 W. 766.99 feet; 15th., S. 56-58-50 W.
246.72 feet; 16th., N. 42-54-30 W. 94.70 feet; 17th., N. 47-19-40 W. 227.64 feet to a
point in the center of Twelve Mile Creek at the mouth of Still Brunch; thence up and with
the various courses of Still Branch as follows: let., N. 19-48-50 E. 327.76 feet; 2nd.,
N. 46-21 E. 224.42 feet; 3rd., N. 85-22-30 E. 242.56 feet; 4th., N. 55-29-40 E. 153.93
feet; 5th., N. 1-45-40 W. 160.98 feet; 6th., N. 24-34 E. 145.27 feet; 7th., N. 3-59-50 E. �'
193.67 feet; 8th., N. 61-56-50 W. 128.84 feet; 9th., S. 87-10 W. 85.56 feet; 10th., N. 24-
27-50 W. 204.49 feet; 11th., N. 7-11 E. 251.55 feet; 12th.. N. 0-17-GO W. t2.72 fart,
l 13th., N. 60-44-30 E. 111.40 feet to an old iron in a corner of the J.A. Deviant property;
I� thence along and with the line of the J.A. Davant property N. 71-51-20 E. 2137.44 feet to
6I an iron; thence N. 26-52 W. 777.0 feet to an old iron; thence N. 61-37-50 E. 214.83 feet
tpp to an old iron, a corner of the H.P. Griffin property; thence N. 60-52-40 E. 369.13 feet
t
to an old iron, the northwesterly corner of the R.P. Hunnicutt property; thence S. 32-12
• I
_-__'.-_,_..., .....

0351
0483
Borx 3 5 I roc 483
E. 609.72 feet to an old iron, the southwesterly corner of the H.R. Hunnicutt property;
thence along the H.R. Hunnicutt property line N. 58-17-30 E. 370.55 feet passing through
• an old iron on the westerly side of the right of way of Highway No. 16 to a point in the
center line of said Highway No. 16; thence with the center line of Highway No. 16 in six •
courses as follows: 1st, S. 28-24-15 E. 195.61 feet; 2nd., S. 23-54-30 E. 200 feet; 3rd.,
S. 19-55-30 E. 200 feet; 4th., S. 16-04-30 E. 200 feet; 5th., S. 8-01-40 E. 200 feet;
6th., S. 6-47-40 E. 584.80 feet to a point in the center of the bridge over Twelve Mile
Creek, the point or place of BEGINNING, containing 132.004 acres as shown upon the survey
of John R. Yarbrough, Registered Surveyor, dated February 25, 1971, and being the same
ill property conveyed to H. Watson Stewart and wife, Travis W. Stewart, by deed from.Stanley R.
Elrod and wife, Laurcl C. Elrod, dntcd Ap111 13, 1972, and recorded in Cook 147 at page
175 of the Union County Registry.
Grantee hereby assumes payment of 1981 Union County ad valorem taxes.
I
The property hereiuohove described wall acquired by Grantor by Instrument recorded in . - . .. .
Book 247, page 175, Union County Registry.
A map allowing the above described property is recorded In Plat)look .......... page............... .
TO HAVE ANI)TO 11OLU the aforesaid lot or parcel of land and all privileges and appurtenances thereto belonging to
I the Grantee in fee simple.
Ann the t,rouler cuvenlmts with the Grantee,that Grantor is seized of the premises in fee aimple,has the right to convey
the name in fee simple, that title la marketable and free and clear of all encumbrance., and that Grantor will warrant •
anti defend the title against the lawful claims of all persons whomsoever except fur the exceptions hereinafter stated.
Title to the property hereinal.ove described is subject to the following exceptions:
: i ,
Rights of way for roads and utilities that border or cross the subject property.
•
i
1
I
IN 111I t.*b NI.dame,lAo re.nl.r boo ld Il.t. lot el.gene t.a goal, e u "ND.a, I I cabled ten t mr of la a•sod.e/ 1• W
.....i i rattle•1r°r Ile duly e•1•.rnr/efllr.Ir.b/IN reel Is••a.r.uYta .files .Y .Yne111r .I Ile ee.r/ el are, a. 4Y 1.ef ant
1 d ..... . ....... ...- Ia[AI.)
...1lb!...►,rrala X.r•e) i . Watson Stew rt
A
er: O
ree.lent Trav s W. Stewart
ATTLSTt (.l 1
..1 ....... .... .. ............ Sc....( at.)
03
I a.rr.Urr tea,rva.Sul) 'I)
r,,,
;
Z
(Cod's/ale Nang 0 ( [AL)
aft G
rr.uea 14 U[wi)
•
•
MTTIMTI V
J (SEAL)
m i
e•/e/1•rj(C•1,41.110 Seal) W
i a (a5AL)
i
•
•
•
I .

0351
0484
BOOK 3 5 I P&CE'I 8 4
ORAL-STAMP NORTH CAROLINA. Union. .. .. Callgotr,
1,a Notary Public •1 In, C•usly and /tat♦I?,?.,.Id,certify In•?
H. WATSON STEWART end wife, TRAVIS W. STEWART,
YID••,,, parmoally Ap Wore.r.me lhts day and.rbndw Iemotionth l emotion of the foregoing •t,Yment-w1tb•aa MI
NE hand.god*finial tiaras.r..a,this 7th day of October _ IP.81
al.
IY1.!l /
‘'.rJTI,.I Y' .mmha
My
ctn e.n.e. 7-7-86._.. - ... .. CQi11nLCJ. ✓ Public
rYb .
o iRl U{l„rTLIC C•,. MORT??CAROLINA. County.
' f nl•.,�,�. 3 1.. N.l,ry Cubit, •I tn• County and u.n .In....u,tastily that _ ...
o personally APrrared before me MU day and•.bnhwl the r•reull,n,1 the I.ngoln(la.tram,nl,wltnrac Y.y
band and official.tamp or seal,thin day•I ... le.
My r•mml.slan.nplrr,: N•?ar,Pull?.
UAL- NORTII CANOI.INA, County.
1.a Notary P•bll<of the Colony and Slate•f. ee.111y that
OrSoly,
C personally appeared fie f.re m•Ihln day rod.rbnowledged the Ion sf In.Inrr<oing In.ham.al,Weta1M et7
head.nd official.tamp.r seal.INI• .._ day al II >
My commission,.pips.: Nolan P°►IN
O RAL•/TAM► NORTH CAROLINA, vaunt,.
I.,?holm,PY\Ile of the Comely ,certify that
Grantee,
• personally.pp.....►efore ma Ihls day and arbe.wl.4g.d the fa.t*laa at{N tar.g•lag WtrWRdat.Wltn.a.nay
hand.god official stamp sr.pal.tan day o1 ,IP......
Sly rumml..Iun e',sires. ......... Notary Public
REAL-/TAMP NORT11 CAROLINA, ... .. .... ... ('nun??
1,a Notary roil?,.1 she County and Mate alnr<.ald,certify Iliac
p4rt•n•111 ran.•before me thlt day and arenown..... N,l .-he Is Moamar,Sial �f
•north Cool? Ilse,and that by,SIN.rlty duly `
o Men and a•the art of the rarp.ratlon.Igoe Ioreaoin< Instrument wag at,n.d In Il•n.n.by Its •
rreadenl.scaled with It.corporate seal and atteased by a.It. Xee,rtagg.
Witn..s my hand and official.tamp.r sea:,thl. 4.1 at ,le...-..
my r,mml...on aspire` Nuley Pubel/
REAL•/TANP NORTH CAROLINA. Co.nty •
I.• Notary Public ,1 the County and Stair,aforesaid, entity that ,
per.an ally came before me this day and•cbnowle dgrd that..--ha It I.tleta,y Ni
North Carolina corporation...d that by authority duly
• liven end as the act of the corpora Il.n,the loregolna b,te,mrnt wan..ford In Its name by Its
• nraident waled satin to rarpnralr oral and abased at a,It. H.reetary.
Witness my nand and.meta.tamp or seal,this day at Ig
/ My c.mmio.l.n tapir"
N•lary Po ill.
TA•langnog Caner) yl,s.f.. •
IOW tonged I.be tweet.This manure(,ad t►la taro/e.ta are doll rranl.r.d.1 the data and Limo and In IA,Nob Lad Py•.b..R as U.
mrsosagername.
MARY B. CARRIKER
_.. R/OIRTER Or DRagog FOR-... .lILj.0 COUNTT
ar -1j(,�/ - /-. f�L/,�-..-r Oantr/Ae.b•ant-R.elatar of Dead..

Appendix H
Geotechnical Report

THIS PAGE INTENTIONALLY LEFT BLANK

FROEHLING & ROBERTSON , INC .
rsiz
Report of Subsurface Exploration
And Geotechnical Engineering Services
Twelve Mile Creek WRF 9.0 MGD Expansion
Union County, North Carolina
Prepared for:
Hazen & Sawyer, Inc.
9101 Southern Pine Boulevard, Suite 250
Charlotte, North Carolina 28273
Prepared by:
Froehling & Robertson, Inc.
3300 International Airport Drive, Suite 600
Charlotte, North Carolina 28208
16 September 2022
F&R Project No. 63A-0012
Corporate HQ: 3015 Dumbarton Road Richmond,Virginia 23228 T 804.264.2701 F 804.264.1202 www.fandr.com
VIRGINIA • NORTH CAROLINA • MARYLAND • DISTRICT OF COLUMBIA
A Minority-Owned Business

r8,RFROEHLING
ROBERTSON
Engineering Stability Since 1881
NC License No. F-0266
F&R Project No.:63A-0012 16 September 2022
Mr. Michael D. Parker, PE
Hazen and Sawyer
9101 Southern Pine Boulevard,Suite 250
Charlotte, North Carolina 28273
Re: Report of Subsurface Exploration and Geotechnical Evaluation
Twelve Mile Creek WRF 9.0 MGD Expansion
Union County, North Carolina
Mr. Parker:
The enclosed report presents the results of the subsurface exploration and geotechnical evaluation
undertaken by Froehling & Robertson, Inc. (F&R) in connection with the above referenced project. Our
services were performed in general accordance with the scope of work included in the Subcontract
Agreement for Professional Services, between Hazen and Sawyer and F&R, dated 27 January 2022. This
report presents our understanding of the project, reviews our exploration procedures, describes general
subsurface conditions at the boring locations, and presents our geotechnical evaluations and
recommendations.
Sincerely,
FROEHLING&ROBERTSON, INC.
,,,,,,,,
2022-0946 • =
16:44-0400 i SEAL •048021 -
Alexander T. Kuczero, P.E. ,ER T. 1"G JFew R. Frank, P.E.
Geotechnical Engineer ,,,,r,rr,r, Regional Senior Geotechnical Engineer
Email Distribution: [e-mail]; [e-mail];
F:\Projects 63A\63A-0012(Hazen and Sawyer-12-Mile Creek WRF 9.0 MGD Expansion)\Report\63A-0012(Hazen and Sawyer-12-Mile Creek WRF 9.0 MGD Expansion)GEO.RPT.doxx
704.596.2889 3300 International Airport Drive A Minority-Owned Business
Suite 600
Charlotte, NC 28208

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TABLE OF CONTENTS
SECTION PAGE
EXECUTIVE SUMMARY V
1.0 INTRODUCTION 1
1.1 SITE DESCRIPTION AND PROJECT INFORMATION 1
1.2 SCOPE OF SERVICES 3
2.0 EXPLORATION PROCEDURES 4
2.1 SUBSURFACE EXPLORATION 4
2.2 LABORATORY TESTING 6
3.0 REGIONAL GEOLOGY&SUBSURFACE CONDITIONS 7
3.1 REGIONAL GEOLOGY 7
3.2 SUBSURFACE CONDITIONS 7
3.2.1 GENERAL 7
3.2.2 SURFICIAL MATERIALS 8
3.2.3 FILL MATERIALS 8
3.2.4 RESIDUAL SOILS 8
3.2.5 PARTIALLY WEATHERED ROCK 8
3.2.6 AUGER REFUSAL MATERIALS 9
3.2.7 ROCK 10
3.2.8 GROUNDWATER CONDITIONS 10
3.3 LABORATORY TEST RESULTS 11
4.0 DESIGN RECOMMENDATIONS 12
4.1 GENERAL 12
4.2 FOUNDATION RECOMMENDATIONS 12
4.2.1 INFLUENT PUMP STATION 2 12
4.2.2 ODOR CONTROL—INFLUENT 13
4.2.3 SECONDARY CLARIFIERS 14
4.2.4 RAS PUMP STATION 3 15
4.2.5 CHEMICAL FACILITY 16
4.2.6 GENERAL SHALLOW FOUNDATION DESIGN RECOMMENDATIONS 16
4.3 CONCRETE SLABS-ON-GRADE 16
4.4 SEISMIC DESIGN CRITERIA 17
4.5 LATERAL EARTH PRESSURES 17
4.6 TEMPORARY EXCAVATION SUPPORT/SHORING 19
5.0 CONSTRUCTION RECOMMENDATIONS 20
5.1 GENERAL 20
5.2 SITE PREPARATION 20
5.3 SHALLOW FOUNDATION CONSTRUCTION 20
5.4 CONTROLLED STRUCTURAL FILL 21
5.5 SURFACE WATER CONTROL 22
5.6 GROUNDWATER CONDITIONS 22
5.7 EXCAVATION CHARACTERISTICS 23
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5.8 EXCAVATION GUIDELINES 24
5.9 TEMPORARY SLOPES 25
6.0 CONTINUATION OF SERVICES 26
7.0 LIMITATIONS 27
APPENDIX I
Site Vicinity Map(Drawing No. 1)
Boring Location Plan (Drawing No. 2)
APPENDIX II
Key to Soil Classification
Key to Boring Log Rock Classification
Soil Classification Chart
Subsurface Profiles(A and B)
Boring Logs (B-1 through B-14, B-1A, and B-7A)
Rock Core Summary and Photograph (B-1A and B-7A)
APPENDIX III
Material Test Reports
Proctor Reports
APPENDIX IV
Extent of Select Backfill for Retaining Walls (Drawing No.3)
APPENDIX V
GBA Publication "Important Information about This Geotechnical Engineering Report"
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F&R Project No.63A-0012 iv 16 September 2022

EXECUTIVE SUMMARY
This Executive Summary is provided as a brief overview of our geotechnical engineering
evaluation for the project and is not intended to replace more detailed information contained
elsewhere in this report. As an overview, this summary inherently omits details that could be
very important to the proper application of the provided geotechnical design recommendations.
This report should be read in its entirety prior to implementation into design and construction.
The Project Information section of this report should be particularly reviewed by project
designers to confirm that the geotechnical engineer's understanding of the project concurs with
the current project parameters at the time of project design.
• The subsurface exploration consisted of fourteen (14) test borings (designated as B-1
through B-14)and rock coring in two offset borings(designated B-1A and B-7A)that were
performed between 5 and 25 July 2022. Site subsurface conditions generally consisted of
surficial soils underlain by existing fill, residual soils, partially weathered rock (PWR), and
auger refusal materials.
• The planned structures may be supported on shallow foundation systems based on the
anticipated settlements and our understanding of settlement tolerances for each
structure.
o To limit the anticipated settlement below the valve vault portions of the Influent
Pump Station 2 and RAS Pump Station 3, we recommend that ABC stone be
utilized to backfill from any temporary slopes excavated in PWR or rock to the
valve subgrade.
• PWR was encountered in each of the borings below the fill soils or residual soils at depths
of approximately 2 to 17 feet below existing site grades. Auger refusal materials were
encountered in 9 of the 15 borings at depths ranging from 14.3 to 28.4 feet below the
existing ground surface, as indicated in the table above. We anticipate that difficult
excavation techniques will be needed in areas where PWR or auger refusal materials were
encountered.
• Based on the boring SPT N-values, a seismic Site Classification of"C" was determined for
each of the planned structures, except for the Chemical Facility. The boring data further
indicates that a seismic Site Classification of"D" should be used for the Chemical Facility.
• Water was also noted on the split spoon samples recovered from borings B-1 and B-3 at
depths of 23.5 feet and 23 feet below existing grade (approximate elevations of 478 feet
and 485 feet), respectively. In each of these borings the wet sampler was about 2 feet
above auger refusal. The encountered water could have been perched over the auger
refusal materials / rock and may not represent sustained groundwater levels at those
locations. However, based on the planned Influent Pump Station 2 wetwell subgrade
elevation of 468.50 feet, some groundwater or perched water may be encountered
during excavation and construction.
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1.0 INTRODUCTION
1.1 Site Description and Project Information
Project information was provided to F&R by Hazen and Sawyer (H&S) via email and phone
correspondence. F&R was provided with new or refined project information as our services were
being performed on this project such that our project understanding evolved over the course of
our services. The following plans and information, prepared by H&S unless noted otherwise,
were also provided:
• 30%Drawings—Markups v2.pdf—Twelve Mile Creek WRF 9.0 MGD Expansion
• 30831-061 — Grading Plans.pdf— 30% Drawings Sheets C30 through C34 with some
sketched revisions
• Structural loads were provided in an email from Mr. Colby Whiteley, PE on 22 July 2022
F&R understands that the project will consist of a 9.0 MGD (Million Gallons per Day) expansion
of the existing 12-Mile Creek Water Reclamation Facility (WRF) at 3104 Providence Road South
in Waxhaw, Union County, North Carolina (Union County Parcel No. 06162001). The planned
expansion will include the addition of an influent pump station, odor control, two secondary
clarifiers (one future), an RAS pump station, a chemical facility, and multiple piping additions.
The areas of the proposed structures are adjacent-to or between existing structures and were
generally grass or brush covered at the time of this study.
The following is our understanding of each of the planned structures, including structure type,
resulting gross foundation bearing contact pressures, and required grading and excavation
depths:
• Influent Pump Station: Influent Pump Station 2 (IPS2) is planned on the southwest side of
the facility,to the west of the existing Influent Electrical Building. We understand that IPS2
will be a cast-in-place concrete structure consisting of a deeper wetwell connected to a
shallower valve vault. F&R was provided with average gross bearing pressures of 4,500
pounds per square foot (psf) and 1,500 psf for the wetwell and valve vault, respectively.
Existing grades in the footprint of IPS2 range from approximately 500 to 507 feet for the
wetwell and 507 to 510 feet for the valve vault. Planned subgrade elevations are 468.50 and
498.00 for the wetwell and valve vault, respectively. Based on these elevations, the
maximum excavation depths of approximately 38 feet and 13 feet will be required for the
wetwell and valve vault,respectively,to reach planned subgrade elevations. We understand
that excavation for construction of the IPS2 will require a temporary excavation support
system due to the proximity of existing facilities to the east of the area.
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• Odor Control—Influent: An Activated Carbon Scrubber,to provide odor control, is planned
to the south of Influent Pump Station 2. We understand the Activated Carbon Scrubber will
be constructed on top of an equipment pad further supported by a 12-inch thick concrete
slab. We were provided with an approximate gross contact pressure of 1,500 psf. Existing
grades in the slab footprint range from about 509 to 510 feet. Based on a provided subgrade
elevation of 510.00 feet, up to about 1 foot of fill will be required to prepare the subgarde
elevation.
• Secondary Clarifiers: Secondary Clarifier 3 and Future Secondary Clarifier 4 are currently
planned in the area in between the four existing secondary clarifiers. We understand the
secondary clarifiers will be approximate 100-foot diameter cast-in-place concrete structures.
The tanks will have a shallow conical bottom with a height of approximately 20 feet and 15
feet at the tank center and walls,respectively. F&R was provided with average gross contact
pressure of 2,000 to 2,500 psf. Existing grades in the footprints of the secondary clarifiers
range from approximately 550 to 551.5 feet for Secondary Clarifier 3 and 548 to 550 feet for
Future Secondary Clarifier 4. F&R was provided with subgrade elevations of 523.67 feet(in
the middle) to 535.50 feet (at the edges). Excavation depths ranging from about 13 to 29
feet from existing grades will be required in the footprints of the secondary clarifiers.
• RAS Pump Station: RAS Pump Station 3 is planned for the area adjacent to the southwest
side of Secondary Clarifier 3 and the northwest side of Future Secondary Clarifier 4. We
understand that the RAS pump station will be a cast-in-place concrete structure consisting
of a deeper wetwell connected to a shallower valve vault. F&R was provided with average
gross bearing pressures of 3,500 psf and 1,500 psf as well as planned subgrade elevations of
523.50 feet and 540.50 feet for the wetwell and valve vault, respectively. Based on an
existing grade of about 550 feet, maximum excavation depths of approximately 27 feet and
10 feet will be required to reach planned subgrade elevations for the wetwell and valve
vault,respectively.
• Chemical Facility: The Chemical Facility will be located to the northeast of existing Secondary
Clarifier 1. We understand the Chemical Facility will have a cast-in-place concrete
foundation and slab with a steel canopy superstructure. F&R was provided with an average
bearing pressure of 2,500 psf. Existing grades in the footprint of the chemical facility range
from approximately 552 to 555 feet. Planned subgrade elevations range from 551.00 to
554.00 feet. Cuts and fills up to about 4 feet and 2 feet,respectively, will be required in the
chemical facility footprint.
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1.2 Scope of Services
The purposes of our involvement on this project were to 1) conduct a subsurface exploration
program, 2) provide the geotechnical evaluations and analyses described below, and 3) prepare
this geotechnical report summarizing our work on the project, providing descriptions of the
subsurface conditions encountered, providing the results and recommendations of our
geotechnical evaluations, and discussing geotechnical related aspects of the proposed
construction. In order to accomplish the above objectives, we undertook the following scope of
services:
1) Reviewed readily available geologic information relative to the project site.
2) Coordinated utility clearance with NC-811.
3) Visited the site to observe existing surface conditions and features.
4) Executed a subsurface exploration program, performed between 5 and 25 July
2022, consisting of fourteen (14) standard penetration test (SPT) borings
(designated as B-1 through B-14) as well as rock coring in two offset borings
(designated as B-1A and B-7A). These borings were drilled to depths ranging
from 14.3 to 45 feet below the existing ground surface.
5) Performed laboratory testing on twelve (12) selected samples from the SPT
borings and three (3) bulk soil samples.
6) Prepared this report summarizing our work on the project, providing
descriptions of the subsurface conditions encountered, presenting the results
of field and laboratory testing, and discussing the results and
recommendations from our geotechnical engineering evaluations and
analyses.
By the nature of the work performed, our field exploration activities resulted in disturbances to
the site. Reasonable efforts were made to lessen potential impacts of the field exploration.
Following groundwater measurements, borings were backfilled with auger cuttings (soil).
Borings performed in paved areas were topped with asphalt cold-patch after backfilling. F&R
assumes no responsibility for borehole subsidence after demobilizing from the site and
recommends that others occasionally observe the boring locations and provide any additional
infill that may be needed.
F&R's geotechnical services did not include topographic or field surveying, development of
quantity estimates, preparation of plans and specifications, or the identification and evaluation
of wetlands or other environmental aspects of the project site.
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2.0 EXPLORATION PROCEDURES
2.1 Subsurface Exploration
The subsurface exploration program, performed between 5 and 25 July 2022, consisted of
fourteen (14)test borings (designated as B-1 through B-14) and rock coring in two offset borings
(designated as B-1A and B-7A). The requested test borings were performed at the approximate
locations provided by the design team and as shown on the attached Boring Location Plan
(Drawing No. 2).
F&R personnel marked test locations in the field by measuring from existing site features. The
test locations should be considered approximate, as they were not surveyed. Boring elevations
were interpolated from the provided grading plans. In consideration of the methods used in their
determination, the test boring locations shown on the attached Boring Location Plans and
elevations shown on the attached Subsurface Profiles and Boring Logs should be considered
approximate.
The test borings were performed in accordance with generally accepted practice using a CME
550X ATV-mounted drill rig equipped with an automatic hammer. Hollow-stem augers were
advanced to pre-selected depths and representative soil samples were recovered with a standard
split-spoon sampler(13/8 in. ID,2 in. OD)in general accordance with ASTM D 1586,the Standard
Penetration Test. Utilizing an automatic hammer, a weight of 140 pounds is freely dropped from
a height of 30 inches to drive the split-spoon sampler into the soil. The number of blows required
to drive the split-spoon sampler three consecutive 6-inch increments is recorded, and the blows
of the last two increments are summed to obtain the Standard Penetration Resistance (N-value).
In some of the Standard Penetration Tests, the blow count is recorded as "0" or weight of
hammer (WOH). In these cases, the static weight of the hammer, rods, and sampler penetrated
into the soft subsurface soil with no hammer blows. The N-value provides a general indication
of in-situ soil conditions and has been correlated with certain engineering properties of soils.
In some soils, it is not always practical to drive a split-spoon sampler the full three consecutive
6-inch increments. Whenever more than 50 blows are required to drive the sampler over a 6-inch
increment, or the sampler is observed not to penetrate after 50 blows, the condition is called
split-spoon refusal. Split-spoon refusal conditions may occur because of obstructions or because
the earth materials being tested, are very dense or very hard. When split-spoon refusal occurs,
often little or no sample is recovered. The SPT N-value for split-spoon refusal conditions is
typically estimated as greater than 100 blows per foot (bpf). Where the sampler is observed not
to penetrate after 50 blows,the N-value is reported as 50/0. Otherwise,the depth of penetration
after 50 blows is reported in inches, i.e. 50/5, etc.
Rock coring was performed in two(2) offset borings(designated as B-1A and B-7A)to explore the
auger refusal materials initially encountered in borings B-1 and B-7. The offset borings were
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advanced beyond auger refusal using rock-coring techniques generally following the procedures
outlined in ASTM D 2113. The rock cores were logged by a member of our professional staff and
relative hardness, rock type, percent recovery, and rock quality designation (RQD) were
measured. The percent recovery is the ratio of the sample length obtained to the total length of
the core run, expressed as a percent. The RQD is the percentage of the length of the core
recovered in segments 4 or more inches long, compared to the total length of the core run. Care
is taken during observation of the core to see that breaks in the core length caused by drilling or
handling are ignored in the RQD determination. The percent recovery and RQD are related to
rock soundness and continuity. The percent recovery and RQD values are shown on the attached
boring logs.
Groundwater level readings were taken in each of the borings immediately upon completion of
the soil drilling process. Temporary piezometers, consisting of slotted PVC pipe, were installed
at the completion of drilling at selected locations to aid in obtaining stabilized groundwater
measurements approximately 24 hours after drilling. Following groundwater readings, the
temporary piezometers were removed and all boreholes were backfilled with auger cuttings
(soil). Periodic observation and maintenance of the boreholes should be performed due to
potential subsidence at the ground surface, as the borehole backfill could settle over time.
Representative portions of the split-spoon soil samples obtained throughout the exploration
program were sealed in air-tight containers and transported to our laboratory. The collected
samples were classified by a member of our professional staff in general accordance with
techniques outlined in the visual-manual identification procedure(ASTM D 2488)and the Unified
Soil Classification System. The soil descriptions and classifications discussed in this report and
shown on the attached Boring Logs are generally based on visual observation and should be
considered approximate. Copies of the boring logs are provided and classification procedures
are further explained in the attached Appendix II.
Split-spoon soil and rock core samples recovered on this project will be stored at F&R's office for
a period of sixty days. After sixty days, the samples will be discarded unless prior notification is
provided to us in writing.
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2.2 Laboratory Testing
Twelve(12) split-spoon soil samples were selected for additional laboratory classification testing.
This testing included water content determination (ASTM D2216), Atterberg limits tests (ASTM
D4318), and percent passing#200 sieve (ASTM D 1140). Based on the results of these tests, the
soils from these selected samples were then classified in general accordance with Unified Soil
Classification System (ASTM D2487).
Laboratory Standard Proctor moisture density relationship (ASTM D698) tests and classification
testing were also performed on three (3) bulk samples.
The results of the laboratory testing program are summarized in tables in Section 3.3 of this
report and presented on the Material Test Reports and Proctor Reports included as Appendix Ill.
Unconfined compressive strength (UCS) testing was performed on portions of intact rock
selected from the core samples in general accordance with ASTM D7012 — Method C. The UCS
testing results are presented in Section 3.2.7 and as shown on the boring logs.
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3.0 REGIONAL GEOLOGY&SUBSURFACE CONDITIONS
3.1 Regional Geology
The project site is located in the Charlotte Belt of the Piedmont Physiographic Province.
According to the Geologic Map of North Carolina (1985), the site is underlain by metamorphic
rock, primarily consisting of phyllite and schist. The topography of the Piedmont Plateau consists
of well-rounded hills and long-rolling ridges with a northeast-southwest trend.
The soils resulting from in-situ weathering of the parent rock,without significant transportation,
are called residual soils and may retain some of the structure of the rock from which they
weathered. The residual soil profile generally grades downward gradually from fine-grained
plastic soils near the ground surface to coarser-grained soils at greater depth. A transitional zone
of"partially weathered rock" of varying thickness can occur between the coarser-grained residual
soils and the underlying bedrock. Partially weathered rock is defined, for engineering purposes,
as residual material with standard penetration resistances in excess of 100 blows per foot.
Weathering of the parent bedrock is generally more rapid near fracture zones and therefore,the
bedrock surface may be irregular. Irregular patterns of differential weathering may also result in
zones of rock and partially weathered rock embedded within the more completely weathered
coarse-grained soils.
3.2 Subsurface Conditions
3.2.1 General
The subsurface conditions discussed in the following paragraphs, and those shown on the
attached Boring Logs, represent an estimate of the subsurface conditions based on interpretation
of the field and laboratory data using normally accepted geotechnical engineering judgments. In
addition, subsurface profiles are presented in Appendix II. These profiles serve to conceptually
illustrate potential subsurface conditions in cross-sections of the project site. It should be noted
that the profiles do not necessarily reflect the actual relative distance changes between the
respective boring locations.
The strata breaks designated on the Boring Logs and Subsurface Profiles represent approximate
boundaries between soil types. Actual transitions between soil strata are generally less distinct
than the immediate transitions depicted on the Boring Logs and Subsurface Profiles. Although
individual soil test borings are representative of the subsurface conditions encountered at the
boring locations on the dates shown,they are not necessarily indicative of subsurface conditions
at other locations or at other times. Below the existing ground surface, the borings generally
encountered surficial soils or asphalt underlain by existing fill materials, residual soils, partially
weathered rock, auger refusal materials, and rock. These materials are discussed further below:
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3.2.2 Surficial Materials
Surficial soils were encountered in each of the borings to depths of approximately%to 4 inches.
Surficial soils are typically a dark-colored soil material containing roots, fibrous matter, and/or
other organic components,and are generally unsuitable for engineering purposes. We note that
no laboratory testing has been performed to determine the organic content or horticultural
properties of the observed surficial soil materials. Therefore, the term "surficial soils" is not
intended to indicate suitability for landscaping and/or other purposes. The surficial soil depths
provided in this report are based on driller observations and should be considered approximate.
The transition from surficial soils to underlying materials may be gradual and therefore the
observation and measurement of surficial soil depths is subjective. Actual surficial soils depths
should be expected to vary across the site.
3.2.3 Fill Materials
Existing fill materials include those materials deposited by man. Materials identified as existing
fill were encountered in 9 of 14 borings and extended to approximate depths ranging from 2 to
17 feet below existing grade. In general,the sampled fill materials were described as clayey sand
(SC), silty or sandy clay (CL), and clayey silt (MH). Standard penetration resistances (N-values)
within the sampled fill materials ranged from 4 to 43 blows per foot (bpf).
3.2.4 Residual Soils
Residual soils, formed by the in-place weathering of the parent rock, were encountered in each
of the borings below the surficial soils or fill soils. Sampled residual soils were generally described
as sandy or silty clay (CL), clayey silt (ML), clayey sand (SC), or silty sand (SM). Standard
penetration resistances in the sampled residuum ranged from 10 to 80 bpf.
3.2.5 Partially Weathered Rock
Partially weathered rock(PWR) is a transitional material between soil and rock,which retains the
relic structure of the rock and has very hard or very dense consistencies. PWR was encountered
in each of the borings below the fill or residual soils at depths of approximately 2 to 17 feet below
existing site grades.
Sampled partially weathered rock was generally described as sandy silt (ML) and silty sand (SM)
with penetration resistances ranging from 50 blows per 6 inches(50/6)of split-spoon penetration
to 50 blows per 0 inches (50/0) of split-spoon penetration. For the boring locations where PWR
was encountered, the depths of encountered PWR as well as the termination condition at the
bottom of the boring (i.e. Boring Termination or Auger Refusal) are summarized in the table
below.
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Table of PWR and Terminations
Approximate Approximate
Proposed
Boring No. Depth to top of PWR Termination Depth
Structure
(ft.) (ft.)/(ft-MSL+/-)
B-1 12 AR 25.4/476
Influent Pump B-2 12 AR 14.3/496
Station 2 B-3 12 AR 25.4/483
B-4 8 AR 23.1/486
B-5 17 BT 29.5/521
Secondary B-6 3.5 AR 28.4/523
Clarifier 3
B-7 6 AR 23.5/527
RAS Pump B-8 3.5 AR 16.6/533
Station B-9 2 BT 15/535
Future B-10 17 BT 45/504
Secondary B-11 2 BT 18.7/530
I Clarifier 4 B-12 6 AR 22.5/526
Chemical B-13 17 AR 23.3/530
Facility B-14 17 BT 28.7/525
BT=Boring Termination
AR=Auger Refusal
3.2.6 Auger Refusal Materials
Auger refusal occurs when materials are encountered that cannot be penetrated by the soil auger
and is normally indicative of a very hard or very dense material, such as boulders, rock lenses,
pinnacles, impenetrable debris within fill, or the upper surface of bedrock. Auger refusal
materials were encountered in 9 of the 15 borings at depths ranging from 14.3 to 28.4 feet below
the existing ground surface, as indicated in the table above.
Auger refusal discussed herein is based on conditions impenetrable to our drilling equipment
(CME-550X). Auger refusal conditions with a CME-550X do not necessarily indicate conditions
impenetrable to other equipment. Auger refusal conditions may exist intermediate of the boring
locations or in unexplored areas of the site.
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3.2.7 Rock
Rock coring was performed in borings B-1A and B-7A to further explore the auger refusal
materials encountered in their respective original borings (B-1 and B-7). Rock recovered during
the coring operations was generally described as greenish gray slate. Specific descriptions of
recovered rock are provided on the respective boring logs as well as an accompanying Rock Core
Summary and Photograph Log.
The following table summarizes Percent Recovery, Rock Quality Designation (RQD), and
unconfined compressive strength (UCS) of the rock core samples.
Boring Rock Core REC(%) RQD(%) UCS(psi) Generalized Description
Depth(ft)
22.2 to 25.2 94 94 -
B-1A 25.2 to 30.2 100 100 9,350 Greenish gray SLATE
30.2 to 32.2 100 100 -
22.3 to 25.8 100 100 -
B-7A 25.8 to 30.8 100 100 7,130 Greenish gray SLATE
30.8 to 32.3 100 100 -
3.2.8 Groundwater Conditions
Groundwater level readings were taken in each of the borings immediately upon completion of
the soil drilling process. Groundwater was encountered in boring B-10 at an approximate depth
of 39 feet below the existing ground surface (approximate elevation of 510 feet).
Water was also noted on the split spoon samples recovered from borings B-1 and B-3 at depths
of 23.5 feet and 23 feet below existing grade (approximate elevations of 478 feet and 485 feet),
respectively.
It should be noted that the groundwater levels fluctuate depending upon seasonal factors such
as precipitation and temperature. Additionally, several of the borings are likely in designated
flood plains. As such, soil moisture and groundwater conditions at other times may vary from
those described in this report.
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3.3 Laboratory Test Results
As outlined in Section 2.2, Laboratory Testing, selected split-spoon samples obtained during the
field exploration were tested in general accordance with applicable ASTM standards. The results
of the laboratory-testing program are summarized the following tables and additionally provided
as the Material Test Reports included in Appendix Ill.
Standard Proctor Test Summary
Boring Bulk Sample Natural Moisture Optimum Moisture Maximum Dry
No. Depth(ft.) Content(%) Content(%) Density(pcf)
B-2 2-8 14.2 14.0 1 113.6
B-6 2-8 11.8 11.5 124.5
B-12 2 -8 11.8 13.4 118.2
Soil Classification Test Summary
BoringSample Water %Finer Atterberg Limits USCS
Depth Content than No.
No. LL PL pi Classification
(ft) (%) 200 Sieve
B-1 3.5-5 14.3 49 43 26 17 SC
B-1 13.5-15 8.6 28 30 23 7 SC
B-2 3.5-5 19.3 57 41 26 15 CL
B-3 2-3.5 16.1 47 40 24 16 SC
B-3 18.5-20 12.7 29 31 22 9 SC
B-7 3.5-5 9.9 30 33 23 10 SC _
B-10 8.5-10 10.5 23 38 22 16 SC
B-12 2-3.5 8.0 57 41 25 16 CL
B-13 3.5-5 8.6 43 33 23 10 SC
B-13 8.5-10 9.9 30 36 24 12 SC
B-14 6.5-8 10.8 44 36 21 15 SC
B-14 13.5-15 11.2 30 32 24 8 SC-SM
B-2 2-8 (Bulk) 14.2 52 36 19 17 CL
B-6 2-8 (Bulk) 11.8 59 35 11 24 CL
B-12 2-8 (Bulk) 11.8 55 37 21 16 CL
Notes: LL-Liquid Limit, PL-Plastic Limit, PI-Plastic Index, NV-Non-Viscous, NP-Non-Plastic
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4.0 DESIGN RECOMMENDATIONS
4.1 General
The following evaluations and recommendations are based on interpretation of the field and
laboratory data obtained during this and previous explorations as well as our experience with
similar subsurface conditions and projects. Soil penetration data has been used to consider
allowable foundation capacities and estimate associated settlements using established
correlations. Subsurface conditions in unexplored locations may vary from those encountered.
If structure locations, loadings, or elevations are changed, we should be notified and requested
to confirm and, if necessary, re-evaluate our recommendations.
Determination of an appropriate foundation system for a given structure is dependent on the
proposed structural loads, soil and/or rock conditions, and construction constraints such as
proximity to other structures, etc. The subsurface exploration aids the geotechnical engineer in
determining the soil/rock stratum appropriate for structural support. This determination
includes considerations with regard to both allowable bearing/frictional capacities and
compressibility of the soil/rock strata. In addition, since the method of construction greatly
affects the soil intended for structural support, consideration must be given to the
implementation of suitable methods of site preparation, fill compaction, and other aspects of
construction.
4.2 Foundation Recommendations
Structure-specific evaluations and foundation recommendations are presented in the following
Sections 4.2.1 through 4.2.5. General direct support on shallow foundation recommendations
are presented in Section 4.2.6.
4.2.1 Influent Pump Station 2
We understand that IPS2 will be a cast-in-place concrete structure consisting of a deeper wetwell
connected to a shallower valve vault. F&R was provided with average gross bearing pressures of
4,500 psf and 1,500 psf for the wetwell and valve vault, respectively. Existing grades in the footprint
of IPS2 range from approximately 500 to 507 feet for the wetwell and 507 to 510 feet for the valve
vault. Planned subgrade elevations are 468.50 and 498.00 for the wetwell and valve vault,
respectively. Maximum excavation depths of approximately 38 feet and 13 feet for the wetwell and
valve vault, respectively, will be required to reach planned subgrade elevations.
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Wetwell:
Based on the subsurface conditions encountered in borings B-1 and B-3,and offset boring B-1A,the
wetwell portion of IPS2 will bear in/on rock. Excavation of up to approximately 15 feet of rock will
be required to reach to the planned subgrade elevation of 468.50 feet. Removal of the rock will
likely require blasting. See Section 5.8 Excavation Characteristics for more information.
Excavation of rock will likely cause an uneven surface which will need to be leveled prior to
construction of the wetwell. We recommend the placement of lean concrete to level the rock
surface in the wetwell footprint.
From a settlement point of view,the provided gross 4,500 psf bearing pressure is tempered by the
depth of excavation required for the wetwell (net bearing pressure of approximately 500 psf or less
due to the deep excavation). Considering the reduced net bearing and presuming that the structure
is fully bearing on a lean concrete leveling surface directly underlain by mass rock, anticipated
settlements should be nominal (i.e. less than%-inch).
Valve Vault:
We understand that the valve vault and wetwell will be connected with rigid piping and the
settlement tolerance between the two portions of the structure is very tight.
We further understand that the excavation to construct the wetwell will utilize a temporary sloped
excavation to meet subgrade levels including the area below the valve vault. Based on the
surrounding boring data, we anticipate that the entire temporary slope below the valve vault
footprint will likely be excavated into PWR. Following construction of the wetwell below-grade
walls, up to approximately 30 feet of backfill will be placed against the east wall of the wetwell to
the valve vault subgrade elevation of 498.00 feet.
If the area below the valve vault is backfilled with compacted Aggregate Base Course (ABC) stone
(98% of Modified Proctor Maximum Dry Density) from the temporary slope excavated in PWR to
the valve vault subgrade,we anticipate a total settlement on the order of%-inch for the valve vault.
The ABC stone backfill should extend beyond the valve vault footprint a horizontal distance equal to
the backfill depth at that location (to provide a 1H:1V slope from the edge of the footprint to meet
the temporary slope). If the%-inch of anticipated differential settlement between the wetwell and
valve vault would be detrimental, or if the volume of ABC stone required is deemed too costly, a
system of deep foundations could be utilized.
4.2.2 Odor Control—Influent
We were provided with an approximate gross contact pressure of 1,500 psf. Existing grades in the
slab footprint range from about 509 to 510 feet. Based on a provided subgrade elevation of 510.00
feet, up to about 1 foot of fill will be required below the structure.
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Based on the subsurface conditions encountered in the area of the proposed odor control pad
and a bearing pressure of 1,500 psf across a mat type foundation, total and differential
settlements of about %-inch and %-inch are anticipated, respectively.
We note that existing fill was encountered in boring B-3 to a depth of 8 feet below existing grade.
While the encountered fill appeared to have been placed with some compactive effort, bearing on
existing fill materials has inherent risks. In general, construction on existing fill materials requires
the project owner to accept some risks due to unforeseen conditions within the fill material.
Associated risks may be additional support related cost (i.e. undercutting, etc.) and excessive
foundation settlement. In order to eliminate the risks associated with supporting the odor
control pad on existing fill, the existing materials would need to be completely removed and
replaced with new controlled structural fill. However, provided the recommended engineering
evaluations are performed and the owner is willing to accept some risk,we believe that support
of the odor control pad on the existing fill is feasible with some subgrade modifications (to be
determined at the time of construction), if required.
4.2.3 Secondary Clarifiers
F&R was provided with average gross contact pressure of 2,000 to 2,500 psf. Existing grades in the
footprints of the secondary clarifiers range from approximately 550 to 551.5 feet for Secondary
Clarifier 3 and 548 to 550 feet for Future Secondary Clarifier 4. F&R was provided with subgrade
elevations of 523.67 feet (in the middle) to 535.50 feet (at the edges). Excavations ranging from
about 13 to 29 feet in depth from existing grades will be required in the footprints of the secondary
clarifiers.
Due to the deep cut/excavation depths, the net bearing pressure is anticipated to be on the order
of 1,000 psf or less. Further, based on the subsurface conditions encountered in the area, we
anticipate the majority of each of the secondary clarifiers will bear on PWR. Portions of the clarifiers
may also bear in dense soils underlain by PWR. While the boring data does indicate the definitive
presence of rock to the planned depths of clarifier excavation,rock and auger refusal materials were
encountered close to the clarifier bearing elevations and therefore,some rock requiring the use of
difficult excavation techniques may be encountered.
Support of the secondary clarifiers on the provided mat foundation is anticipated to yield a
maximum total settlement of about %-inch based on borings in the area. Therefore, shallow
foundation support for this structure appears feasible. Further recommendations on direct shallow
foundation support are presented in Section 4.2.6.
Based on the anticipated settlement of about%-inch, an initial modulus of subgrade reaction of 50
pci has been estimated. Modulus of subgrade reaction was approximated for the secondary
clarifiers using the provided gross contact pressure and the estimated maximum settlement.
Although a single modulus value is being provided, values can vary greatly across large mat
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foundations, as the mat is not completely rigid and actual contact pressures will vary. We note
that modulus of subgrade reaction is an iterative parameter, as the initial value is typically input
into software such as STAAD for structural modeling. Feedback from the structural engineer is
typically necessary to arrive at a reasonable range of moduli across a large mat.
4.2.4 RAS Pump Station 3
We understand that the RAS pump station will be a cast-in-place concrete structure consisting of a
deeper wetwell connected to a shallower valve vault. F&R was provided with average gross bearing
pressures of 3,500 psf and 1,500 psf with planned subgrade elevations of 523.50 feet and 540.50
feet for the wetwell and valve vault, respectively. Based on an existing grade of about 550 feet,
maximum excavation depths of approximately 27 feet and 10 feet will be required to reach planned
subgrade elevations for the wetwell and valve vault, respectively.
Wetwell:
Based on the subsurface conditions encountered in boring B-8,at least some portion of the wetwell
will bear on rock. In the area of boring B-8, it is envisioned that excavation of up to approximately
10 feet of rock will be required to reach to the planned subgrade elevation of 523.50. Removal of
the rock will likely require blasting. See Section 5.8 Excavation Characteristics for more information.
Excavation of rock will likely cause an uneven surface which will need to be leveled prior to
construction of the wetwell. We recommend the placement of lean concrete to level the rock
surface in the wetwell footprint.
The gross bearing pressure of 3,500 psf(net bearing pressure of approximately 500 psf or less due
to the deep excavation) is anticipated to incur nominal (i.e. less than %-inch) settlement if the
structure is fully bearing on rock and lean concrete is used to level the rock surface. Settlement on
the order of %-inch or less is anticipated for any portion of the structure bearing in PWR, if
encountered.
Valve Vault:
We understand that the valve vault and wetwell will be connected with rigid piping and the
settlement tolerance between the two portions of the structure is very tight.
We further understand that the excavation to construct the wetwell will utilize a temporary sloped
excavation to meet subgrade levels including the area below the valve vault. Based on borings B-8
and B-9,we anticipate that the entire temporary slope below the valve vault footprint will likely be
excavated into PWR. Following construction of the wetwell below-grade walls, approximately 17
feet of backfill will be placed against the west wall of the wetwell to the valve vault subgrade
elevation of 540.50 feet.
If the area below the valve vault is backfilled with compacted Aggregate Base Course (ABC) stone
(98% of Modified Proctor Maximum Dry Density) from the temporary slope excavated in PWR to
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the valve vault subgrade,we anticipate a total settlement on the order of%-inch for the valve vault.
The ABC stone backfill should extend beyond the valve vault footprint a horizontal distance equal to
the backfill depth at that location (to provide a 1H:1V slope from the edge of the footprint to meet
the temporary slope). If the%-inch of anticipated differential settlement between the wetwell and
valve vault would be detrimental, or if the volume of ABC stone required is deemed too costly, a
system of deep foundations could be utilized.
4.2.5 Chemical Facility
F&R was provided with an average bearing pressure of 2,500 psf. Existing grades in the footprint of
the chemical facility range from approximately 552 to 555 feet. Planned subgrade elevations range
from 551.00 to 554.00 feet. Cuts and fills of up to about 4 feet and 2 feet, respectively, will be
required in the chemical facility footprint.
Based on the subsurface conditions encountered in the area of the proposed Chemical Facility
and a bearing pressure of 2,500 psf across a mat type foundation, total settlements of 1 to
1%-inch and differential settlements of up to about%-inch are anticipated.
4.2.6 General Shallow Foundation Design Recommendations
To reduce the possibility of localized shear failures, spread and strip footings should be a
minimum of 3 feet and 18 inches wide, respectively. Exterior footing bottoms should be
constructed a minimum of 12 inches below adjacent exterior grades in order to bear below
normal frost depth.
4.3 Concrete Slabs-On-Grade
For structures designed with a conventional concrete slab-on-grade (not mat foundations), slabs
may be placed on properly compacted controlled structural fill over an approved soil subgrade
following subgrade preparation as discussed in Section 5.2 of this report.
A minimum 6-inch thick layer of Aggregate Base Course (ABC) stone or open-graded coarse
aggregate, such as No. 57 stone, should be placed beneath the floor slab. This granular base
would function as a leveling and load distributing material as well as a capillary break beneath
the slab. Proper jointing of the concrete slabs-on-grade is essential to reduce cracking. ACI
suggests that unreinforced, plain concrete slabs may be jointed at spacing of 24 to 36 times the
slab thickness, up to a maximum spacing of 15 feet. Slab construction should incorporate
isolation joints along walls and column locations to allow minor movements to occur without
damage. Utility or other construction excavations in the prepared subgrade should be backfilled
to a controlled fill criterion to provide uniform support.
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4.4 Seismic Design Criteria
The following seismic site class recommendations are based on American Society of Civil
Engineers (ASCE) 7-10 per Section 1613.3.2 as referenced by the International Building Code
(IBC), as adopted by the 2018 North Carolina Building Code.
The subsurface data from the areas of the proposed structures to the depths explored,as well as
a presumed N-value of 100+below the depths explored in borings terminated in PWR or at Auger
Refusal, were used to develop the seismic criteria. Based on the boring data,our experience with
similar conditions, and in general accordance with 1613.3.2 of the IBC, seismic Site Class was
determined for the structures.
The table below provides the seismic Site Class assigned for each of the planned structures.
SEISMIC SITE CLASS
Structure Seismic Site Class
Influent Pump Station 2 C
Odor Control—Influent C
Secondary Clarifier 3 C
Future Secondary Clarifier 4 C
RAS Pump Station C
Chemical Facility D
We note that the above provided Site Classifications are based on boring SPT N-values. Should
the project team deem an improved Site Class for the Chemical Facility advantageous, F&R can
perform a geophysical study to obtain subsurface shear velocity profiles. Based on the
subsurface conditions encountered in the area of the Chemical Facility, there is a high likelihood
that an improved Site Class can be achieved with shear wave velocity testing. This additional
testing would be beyond the currently authorized scope of services for this project.
4.5 Lateral Earth Pressures
The following information is provided to aid in analysis of soil loads on below grade walls. Earth
pressures on walls below-grade are influenced by structural design of the walls, conditions of
wall restraint, methods of construction and/or compaction, and the strength of the materials
being restrained. The most common conditions assumed for earth retaining wall design are the
active and at-rest conditions. Active conditions apply to relatively flexible earth retention
structures, such as freestanding walls, where some movement and rotation may occur to
mobilize soil shear strength. Walls that are rigidly restrained, such as basement, pit, and tunnel
walls, require design using at-rest earth pressures. A third condition, the passive state,
represents the maximum possible pressure when a structure is pushed against the soil, and is
used in wall foundation design to help resist active or at-rest pressures. Because significant wall
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movements are required to develop the passive pressure, the total calculated passive pressure
should be reduced by one-half to two-thirds for design purposes.
Based on the subsurface exploration, we envision that the near-surface site soils which might be
involved with the majority of the below-grade walls will predominately consist of silty clay (CL),
clayey silt (ML), and clayey sand (SC). If encountered during construction or if an off-site source
for material is required, we do not recommend the use of highly-plastic clays and silts (CH and
MH) behind below grade walls.
As previously stated in Sections 4.2.1 and 4.2.4,we recommend that ABC stone backfill be utilized
under the valve vault portions of the Influent Pump Station 2 and RAS Pump Station 3. Lateral
earth pressure parameters for ABC stone are provided below, but in order to utilize these, the
full theoretical failure wedge must consist of ABC stone backfill. Therefore,the ABC stone should
be extended laterally from back heel of the wall footing, a minimum distance of 0.5 times the
wall height at the top of the wall (see Extent of Select Backfill for Retaining Walls, Drawing No. 3,
Appendix IV). The ABC stone backfill below the valve vaults should exceed the required lateral
distance from the back of the wall.
The following tables provide lateral earth pressure parameters for both the onsite soils mixture
as well as ABC Stone.
ON-SITE SOILS MIXTURE (CL/ML/SC)
Earth Pressure Conditions Coefficient Recommended Equivalent
Fluid Pressure (pcf)
Active (Ka) 0.36 45
At-Rest(Ko) 0.53 66
Passive (Kr) 2.77 ---
*A compacted moist soil unit weight of 125 pounds per cubic foot should be used for design calculations.
ABC STONE
Earth Pressure Conditions Coefficient Recommended Equivalent
Fluid Pressure (pcf)
Active (Ka) 0.17 25
At-Rest(K.) 0.29 42
*A compacted moist unit weight of 145 pounds per cubic foot should be used for design calculations based
on ABC Stone compacted to 98%of Modified Proctor Max Dry Density.
For design calculations of resistance to sliding (regardless of selected backfill materials), a value
of 0.34 should be used as the coefficient of friction between concrete surfaces and the underlying
on-site soils. Increased frictional resistance can be attained by replacing the foundation soils with
compacted crushed stone to a depth of up to % the footing width. If needed, additional
recommendations regarding a potential increase in frictional resistance can be provided.
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Our recommendations assume that the ground surface above the wall is level. The
recommended equivalent fluid pressures assume that constantly functioning drainage systems
are installed between walls and soil backfill to prevent the accidental buildup of hydrostatic
pressures and lateral stresses in excess of those stated. In the event that a functioning drainage
system is not installed, the lateral earth pressures should be determined using the buoyant
weight of the soil and the appropriate above provided coefficient of earth pressure. Hydrostatic
pressures calculated with the unit weight of water(62.4 pcf)should then be added to these earth
pressures to obtain the total stresses for design.
Heavy equipment should not operate within 5 feet of below-grade walls to prevent lateral
pressures in excess of those cited. If footings or other surcharge loads are located a short
distance outside below-grade walls,they may also exert appreciable additional lateral pressures.
Surcharge loads should be evaluated using the appropriate active or at-rest pressure coefficients
provided above. The effect of surcharge loads should be added to the recommended earth
pressures to determine total lateral stresses.
These retaining/below grade wall recommendations should not be correlated for use in the
design of mechanically stabilized earth (MSE) walls. We recommend that soil parameters for any
MSE wall design be established through appropriate laboratory testing directed by the wall
designer.
4.6 Temporary Excavation Support/Shoring
As previously stated, temporary excavation support will be required for the construction of
Influent Pump Station 2 due to the proximity to existing facilities. Design of temporary excavation
support is typically handled by a specialty geotechnical contractor; however, we envision a
system of soil nails would work well to support the existing facilities to the east of the IPS2.
Locations of individual soil nails should be designed to avoid conflicts with any existing
underground obstructions.
Based on auger refusal in boring B-2 at an approximate elevation of 496 feet and existing grade
of about 510 feet in the area of the proposed temporary excavation support, we envision the
temporary excavation will be less than about 20 feet at the support. Therefore, soil nails will
likely need to be on the order of 20 feet in length or less.
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5.0 CONSTRUCTION RECOMMENDATIONS
5.1 General
The principal purpose of this section is to comment in general on the items related to earthwork
and associated geotechnical engineering aspects of construction that should be expected for this
project. It is recommended that F&R be retained to provide soil engineering services during the
construction phases of the project and perform appropriate evaluations to help confirm that
conditions encountered during construction are similar to conditions observed in the borings.
The geotechnical engineer can also assist in interpretation of differing subsurface conditions that
may be encountered and recommend remedial work, if needed.
5.2 Site Preparation
Before proceeding with construction, any surficial soils, roots, and any other deleterious non-soil
materials should be stripped or removed from proposed construction areas. During the clearing
and stripping operations, positive surface drainage should be maintained to prevent the
accumulation of water.
After stripping, areas intended to support new fill, pavements, and foundations should be
carefully evaluated by a representative of the geotechnical engineer. At that time,the engineer
may require proofrolling of the subgrade with a 20-to 30-ton loaded truck or other pneumatic-
tired vehicle of similar size and weight. Proofrolling should be performed during a time of good
weather and not while the site is wet, frozen, or severely desiccated. The purpose of the
proofrolling is to locate soft, weak, or excessively wet soils present at the time of construction
and provides an opportunity for the geotechnical engineer to locate inconsistencies intermediate
of the boring locations.
Undercutting or additional in-place compaction may be necessary if the exposed subgrade soils
become unstable during construction. Any fill materials, aggregate, and or pavement should be
placed as soon as possible over the approved subgrade in order to reduce exposure of the
subgrade to weather and construction activity. It is important to stress that if site preparation or
construction are performed during the winter months, additional undercutting of the subgrade
soils may be required if the subgrade is not properly prepared or protected.
5.3 Shallow Foundation Construction
All foundation subgrades should be observed, evaluated, and verified for the design bearing
pressure by a representative of the geotechnical engineer after excavation and prior to base
stone or reinforcement steel placement. If low consistency soils are encountered during
foundation construction, localized undercutting and/or in-place stabilization of foundation
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subgrades may be required. The actual need for, and extent of, undercutting or in-place
stabilization should be based on field observations made by a representative of the geotechnical
engineer at the time of construction.
Excavations for footings should be made in such a way as to provide bearing surfaces that are
firm and free of loose, soft, wet, or otherwise disturbed soils. Foundation concrete should not
be placed on frozen or saturated subgrades. If such materials are allowed to remain below
foundations, settlements will increase. Foundation excavations should be concreted as soon as
practical after they are excavated. If an excavation is left open for an extended period, a thin
mat of lean concrete should be placed over the bottom to minimize damage to the bearing
surface from weather or construction activities. Water should not be allowed to pond in any
excavation.
5.4 Controlled Structural Fill
The majority of the soil encountered in the borings consisted of silty clay (CL), clayey silt (ML),
and clayey sand (SC). Based on the boring data, controlled structural fill may be constructed
using the non-organic on-site soils, with some exclusions for the use of elastic silt (MH) soils. If
an off-site borrow source is required to balance the site, the imported materials should have a
classification of CL, ML, SC, or SM as defined by the Unified Soil Classification System. Other
materials may be suitable for use as controlled structural fill material and should be individually
evaluated by the geotechnical engineer. If encountered, CH soils should not be used for retaining
wall backfill or be placed within 2 feet of subgrade elevations in structural areas. Controlled
structural fill should be free of boulders, organic matter, debris, or other deleterious materials
and should have a maximum particle size no greater than 3 inches. In addition, we recommend
a minimum standard Proctor (ASTM D 698) maximum dry density of approximately 90 pounds
per cubic feet for fill materials.
Fill materials should be placed in horizontal lifts with maximum height of 8 inches loose measure.
New fill should be adequately keyed into stripped and scarified subgrade soils and should,where
applicable, be benched into the existing slopes. During fill operations, positive surface drainage
should be maintained to prevent the accumulation of water. We recommend that structural fill
be compacted to at least 95 percent of the standard Proctor maximum dry density. In confined
areas such as utility trenches, portable compaction equipment and thin lifts of 3 to 4 inches may
be required to achieve specified degrees of compaction. Each lift of fill should be tested in order
to confirm that the recommended degree of compaction is attained.
In general,we recommend that the moisture content of fill materials be maintained within three
percentage points of the optimum moisture content as determined from the standard Proctor
density test. We recommend that the contractor have equipment on site during earthwork for
both drying and wetting of fill soils. Moisture control may be especially difficult during winter
months or extended periods of rain. Attempts to work the soils when wet can be expected to
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result in deterioration of otherwise suitable soil conditions or of previously placed and properly
compacted fill. Where construction traffic or weather has disturbed the subgrade, the upper 8
inches of soils (or more if warranted) intended for structural support should be scarified and re-
compacted. Each lift of fill should be tested in order to confirm that the recommended degree
of compaction is attained.
5.5 Surface Water Control
If free water is allowed to stand on stable subgrade soils, the in-situ silty and clayey soils can
absorb water, swell, and experience a reduction in their support capability. As a result, we
recommend that the subgrade surface be graded to provide positive drainage away from the
construction areas and towards suitable drainage handling areas, such as a perimeter ditch,
French drain, culvert, or retention pond. Where pockets of silty and clayey soils exist,trapped or
perched water conditions could develop during periods of inclement weather and during
seasonally wet periods. Such conditions could cause seepage into excavations and deeper cuts.
In addition, if site grading is performed during the seasonally wet months or after extended
periods of inclement weather, wet and water softened near-surface soil conditions should be
expected across the site.
5.6 Groundwater Conditions
Groundwater was encountered in boring B-10 at an approximate depth of 39 feet below the
existing ground surface (approximate elevation of 510 feet). The lowest planned subgrade
elevation in the area of the proposed secondary clarifiers and RAS Pump Station 3 is 523.50 feet.
Therefore,we do not anticipate groundwater will be encountered in the area of these structures.
Water was also noted on the split spoon samples recovered from borings B-1 and B-3 at depths
of 23.5 feet and 23 feet below existing grade (approximate elevations of 478 feet and 485 feet),
respectively. In each of these borings the wet sampler was about 2 feet above auger refusal. The
encountered water could have been perched over the auger refusal materials/rock and may not
represent sustained groundwater levels at those locations. However, based on the planned
Influent Pump Station 2 wetwell subgrade elevation of 468.50 feet, some groundwater or
perched water may be encountered during excavation and construction.
Due to the presence of silty and clayey soils,which generally have very low hydraulic conductivity,
trapped or perched water conditions may be encountered at some point during project
development, especially during periods of inclement weather and seasonally wet periods.
Groundwater levels tend to fluctuate with seasonal and climatic variations as well as with some
types of construction operations. Generally, the highest subsurface water levels occur in late
winter and early spring and the lowest levels occur in late summer and early fall. If encountered
during construction, engineering personnel from our office should be notified immediately.
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5.7 Excavation Characteristics
PWR was encountered in each of the borings below the fill soils or residual soils at depths of
approximately 2 to 17 feet below existing site grades. Auger refusal materials were encountered
in 9 of the 15 borings at depths ranging from 14.3 to 28.4 feet below the existing ground surface,
as indicated in the table above
Rock coring was performed in borings B-1A and B-7A to further explore the auger refusal
materials encountered in borings B-1 and B-7, respectively. Rock recovered during the coring
operations was generally described as greenish gray slate. Laboratory Unconfined Compressive
Strength of 9,350 psi and 7,130 psi was measured for the tested samples of rock recovered from
borings B-1A and B-7A, respectively.
Based on the provided structure subgrade elevations as well as the locations and approximate
elevations where auger refusal and rock were encountered in the borings,we anticipate that rock
will be encountered in excavations for the wetwell portions of Influent Pump Station 2 and RAS
Pump Station 3. Excavation of up to approximately 15 feet of rock will be required at IPS2 to reach
to the planned subgrade elevation of 468.50. Removal of large quantities of rock is typically
achieved through blasting; however, due to the proximity of the proposed wetwells to existing
facilities, mechanical (non-explosive) rock fracturing utilizing an expanding chemical agent may be
prudent. Rock may also be encountered in the deeper portions of the excavations for the
Secondary Clarifiers.
Further, we anticipate PWR will be encountered during excavation for the construction of
Influent Pump Station 2, RAS Pump Station 3, and the Secondary Clarifiers.
Typically, material with a penetration resistance of 50 blows per 3 to 6 inches of penetration can
be excavated with moderate to heavy effort using appropriately sized equipment, such as a large
track-hoe (e.g., Caterpillar 330 with rock teeth). In confined excavations such as foundations,
utility trenches, elevator pits, etc., removal of partially weathered rock typically requires use of
large backhoes, pneumatic spades, or light blasting. Refusal materials will normally require
blasting for removal in all types of excavations. As previously stated,the use of mechanical (non-
explosive) rock fracturing in lieu of blasting may be required to avoid damage to existing facilities.
Any blasting in footing excavations must be done carefully to prevent damage to the bearing
materials.
Hazen and Sawyer Twelve Mile Creek WRF 9.0 MGD Expansion
F&R Project No.63A-0012 23 16 September 2022

r&R
The definition of rock can be a source of conflict during construction. The following definitions
have been incorporated into specifications on other projects and are provided for your general
guidance:
GENERAL EXCAVATION:
Rip Rock- Any material that cannot be removed by scrapers, loaders, pans, dozers, or
graders; and requires the use of a single-tooth ripper mounted on a crawler
tractor having a minimum draw bar pull rated at not less than 56,000 pounds.
Blast Rock - Any material which cannot be excavated with a single-tooth ripper mounted
on a crawler tractor having a minimum draw bar pull rated at not less than
56,000 pounds (Caterpillar D-8K or equivalent) or by a Caterpillar 977
front-end loader or equivalent; and occupying an original volume of at least
one(1) cubic yard.
TRENCH EXCAVATION:
Blast Rock - Any material which cannot be excavated with a backhoe having a bucket
curling force rated at not less than 25,700 pounds (Caterpillar Model 330 or
equivalent, with rock teeth ), and occupying an original volume of at least
one-half(1/2) cubic yard.
5.8 Excavation Guidelines
Mass excavations and other excavations required for this project must be performed in
accordance with the United States Department of Labor, Occupational Safety and Health
Administration (OSHA) guidelines (29 CFR 1926, Subpart P, Excavations) or other applicable
jurisdictional codes for permissible temporary side-slope ratios and or shoring requirements. The
OSHA guidelines require daily inspections of excavations, adjacent areas and protective systems
by a "competent person" for evidence of situations that could result in cave-ins, indications of
failure of a protective system, or other hazardous conditions.
Excavated soils, equipment, building supplies, etc., should be placed away from the edges of the
excavation at a distance equaling or exceeding the depth of the excavation. F&R cautions that
the actual excavation slopes will need to be evaluated frequently each day by the "competent
person" and flatter slopes or the use of shoring may be required to maintain a safe excavation
depending upon excavation specific circumstances. The contractor is responsible for providing
the "competent person" and all aspects of site excavation safety.
Hazen and Sawyer Twelve Mile Creek WRF 9.0 MGD Expansion
F&R Project No.63A-0012 24 16 September 2022

r8p
5.9 Temporary Slopes
Our exploration did not include a detailed analysis of slope stability for any temporary or
permanent condition. However, we generally recommend temporary slopes no steeper than
1.5(H):1(V) up to a maximum height of 20 feet, for construction in undisturbed residual soils or
compacted soil fill placed in accordance with our recommendations. For temporary slopes in
existing fill materials, flatter slopes of 2.0(H):1(V) or flatter may be required depending on the
conditions observed at the time of construction. Accordingly and due to the variability of soil
conditions inherent to fill materials, temporary slopes in fill materials should be regularly
observed for signs of instability during construction.
These general excavation slope recommendations are appropriate for slopes underlain by
competent materials. However, the provided recommendations should not be used to deviate
from OSHA regulations. Construction should be performed in accordance with applicable OSHA
regulations. During construction, temporary slopes should be regularly evaluated for signs of
movement or unsafe conditions. Soil slopes should be covered for protection from rain, and
surface runoff should be diverted away from the slopes.
Hazen and Sawyer Twelve Mile Creek WRF 9.0 MGD Expansion
F&R Project No.63A-0012 25 16 September 2022

6.0 CONTINUATION OF SERVICES
F&R recommends that we be retained for professional and construction materials testing services
during construction of the project. Our continued involvement on the project helps provide
continuity for proper implementation of the recommendations discussed herein.
Additionally,we request the opportunity to review the plans and project specifications when these
construction documents approach completion. This review evaluates whether the
recommendations and comments provided herein have been understood and properly
implemented. The above listed services are not part of the currently authorized scope of services.
Hazen and Sawyer Twelve Mile Creek WRF 9.0 MGD Expansion
F&R Project No.63A-0012 26 16 September 2022

7.0 LIMITATIONS
There are important limitations to this and all geotechnical studies. Some of these limitations are discussed
in the information prepared by the Geoprofessional Business Association (GBA), which is included in
Appendix V. We recommend that you review the GBA information.
This report has been prepared for the exclusive use of Hazen and Sawyer for the specific application to the
proposed Twelve Mile Creek WRF 9.0 MGD Expansion project located in Union County, North Carolina, in
accordance with generally accepted soil and foundation engineering practices. No other warranty,express
or implied, is made. Our recommendations are based on design information furnished to us at the time
the work was performed; the data obtained from the previously described subsurface exploration
program, and generally accepted geotechnical engineering practice. The findings and recommendations
do not reflect variations in subsurface conditions,which could exist in unexplored areas of the site. In areas
where variations from the available subsurface data become apparent during construction, it will be
necessary to re-evaluate our recommendations based upon on-site observations of the conditions.
Regardless of the thoroughness of a subsurface exploration,there is the possibility that conditions in other
areas will differ from those at the boring locations,that conditions are not as anticipated by the designers,
or that the construction process has altered the soil conditions. Therefore, our experienced geotechnical
engineers should evaluate foundation construction to verify that the conditions anticipated in design
actually exist. Otherwise, we assume no responsibility for construction compliance with the design
concepts,specifications,or recommendations. In the event that changes are made in the design or location
of the proposed structures, the recommendations presented in this report shall not be considered valid
unless the changes are reviewed by our firm and recommendations of this report modified or verified in
writing. If this report is copied or transmitted to a third party, it must be copied or transmitted in its
entirety, including text, attachments, and enclosures. Interpretations based on only a part of this report
may not be valid.
Hazen and Sawyer Twelve Mile Creek WRF 9.0 MGD Expansion
F&R Project No.63A-0012 27 16 September 2022

r&R
APPENDIX I
Site Vicinity Map (Drawing No.1)
Boring Location Plan (Drawing No.2)

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r&R
APPENDIX II
Key to Soil Classification
Key to Boring Log Rock Classification
Soil Classification Chart
Subsurface Profiles (A and B)
Boring Logs (B-1 through B-14, B-1A, and B-7A)
Rock Core Summary and Photograph (B-1A and B-7A)

MOB
IBM
KEY TO BORING LOG SOIL CLASSIFICATION
Particle Size and Proportion
Visual descriptions are assigned to each soil sample or stratum based on estimates of the
particle size of each component of the soil and the percentage of each component of the soil.
Particle Size Proportion
Descriptive Terms Descriptive Terms
Soil Component Particle Size Component Term Percentage
Boulder > 12 inch Major Uppercase Letters >50%
Cobble 3 - 12 inch (e.g., SAND,CLAY)
Gravel-Coarse 3/4-3 inch
-Fine #4-3/4 inch Secondary Adjective 20% - 50%
Sand-Coarse #10-#4 (e.g., sandy, clayey)
-Medium #40-#10
-Fine #200-#40 Minor Some 15% -25%
Silt(non-cohesive) <#200 Little 5% - 15%
Clay(cohesive) <#200 Trace 0% -5%
Notes:
I. Particle size is designated by U.S. Standard Sieve Sizes
2. Because of the small size of the split-spoon sampler relative to the size of gravel,the true percentage of gravel
may not be accurately estimated.
Density or Consistency
The standard penetration resistance values (N-values) are used to describe the density of
coarse-grained soils (GRAVEL, SAND) or the consistency of fine-grained soils (SILT, CLAY).
Sandy silts of very low plasticity may be assigned a density instead of a consistency.
DENSITY CONSISTENCY �I
Term N-Value Term N-Value
II II II
Very Loose 0-4 Very Soft 0- 1
Loose 5 - 10 Soft 2-4
Medium Dense 11 -30 Firm 5 -8
Dense 31 -50 Stiff 9- 15
Very Dense >50 Very Stiff 16-30
Hard >30
Notes:
I. The N-value is the number of blows of a 140 lb.Hammer freely falling 30 inches required to drive a standard
split-spoon sampler(2.0 in.O.D., 1-3/8 in.I.D.) 12 inches into the soil after properly seating the sampler 6
inches.
2. When encountered,gravel may increase the N-value of the standard penetration test and may not accurately
represent the in-situ density or consistency of the soil sampled.
L
F:\Branch 62\GEOWORD\REPORTS\kcyblsc.cnc.doc

•u s.
us'
KEY TO BORING LOG ROCK CLASSIFICATION (PAGE 1 OF 2)
Classification of rock is based on the following characteristics: Weathering, Discontinuities, Color and
Grain Size, Hardness,Voids, Geologic Lithology, and Rock Quality Designation (RQD).
WEATHERING
TERM SYMBOL DESCRIPTION
Fresh F No visible sign of decomposition or discoloration. Crystals are bright
Slightly Weathered WS Slight discoloration inward from open fractures.
Moderately Weathered WM Discoloration throughout. Weaker minerals decomposed. Strength
somewhat less than fresh rock, but cores cannot be broken by hand or
scraped by knife. Texture preserved. Joints may contain clay.
Highly Weathered WH Most minerals somewhat decomposed. Specimens can be broken by hand
with effort or shaved with knife. Core stones present in rock mass. Texture
becoming indistinct but fabric preserved.
Completely Weathered WC Minerals decomposed to soil but fabric and structure preserved (saprolite).
Specimens easily crumbled or penetrated.
Residual Soil RS Advanced state of decomposition resulting in plastic soils. Rock fabric and
structure completely destroyed.
DISCONTINUITIES
SPACING * BANDING, BEDDING, FOLIATION FAULTS,JOINTS,and other
FRACTURES
Greater than 6.0 feet Very Thick Very Wide
2.0—6.0 feet Thick Wide
8-24 inches Medium Medium
2.5—8 inches Thin Close
3 to 2.5 inches Very Thin Very Close
SPACING* LAMINATION, FOLIATION,or FAULTS,JOINTS,and other
CLEAVAGE FRACTURES
-3 inch Intense
Less than%inch Very Intense Extremely Close
*—Spacing is the perpendicular distance between discontinuities.
TYPE of DISCONTINUITY ATTITUDE(DIP)
TERM CONDITION TERM EXISTING
ANGLE
A fracture along which no movement has
Horizontal 0 5
Joint
occurred. Low Angle 5-35
Bedding A natural plane dividing sedimentary rock layers Moderate Angle 35-55
Plane
Shear Plane A fracture along which some movement has High Angle 55-85
occurred.
Fault A zone of fractured rock containing one or more Vertical 95-90
shear plane and areas of gouge

■1MOE
•
ISM
KEY TO BORING LOG ROCK CLASSIFICATION (PAGE 2 OF 2)
ROCK GRAIN SIZE
IGNEOUS AND METAMORPHIC ROCKS SEDIMENTARY ROCKS
Coarse Grained Diameter>5 mm(3/16 in) Coarse Grained Diameter>2 mm(1/16 in)
Medium Grained 1 mm(1/32 in)—5 mm (3/16 in) Medium Grained 0.06 mm—2 mm(1/16 in)
Fine Grained <1 mm(1/32 in) Fine Grained 0.002 mm—0.06 mm
Glassy Grains not visible with unaided eye. Very Fine Grained Grains not visible with unaided eye.
VOIDS
TERM SIZE OF VOID
Pit <6 mm(1/4 inch)
Vug 6 mm—50 mm(2 inches)
Cavity 50 m—0.6 m(2 feet)
Cave >0.6 m
ROCK HARDNESS
CLASS HARDNESS FIELD TEST
II Extremely Hard Many blows with a geologic hammer required to break intact specimen.
II Very Hard Hand-held specimen breaks with hammer end of pick under more than one
blow.
III Hard Cannot be scraped or peeled with knife, hand-held specimen can be broken
with single moderate blow with pick.
IV Soft Can just be scraped or peeled with knife.
V Very Soft Material crumbles under moderate blow with sharp end of pick and can be
peeled with a knife.
ROCK QUALITY DESIGNATION ** (RQD)
ROCK QUALITY DESIGNATION **,% ROCK MASS DESCRIPTION
90-100 Excellent
75-90 Good
50-75 Fair
25-50 Poor
<25 Very Poor
** - RQD is the ratio of the cumulative length of all pieces of rock greater than or equal to four inches to
the total length drilled, expressed as a percentage

SOIL CLASSIFICATION CHART
MAJOR DIVISIONS SYMBOLS TYPICAL
GRAPH LETTER DESCRIPTIONS
•mil•'
CLEAN •�• 4• WELL-GRADED GRAVELS,GRAVEL-
GRAVEL GRAVELS IA. ��'� *1 GW SAND MIXTURES,LITTLE OR NO
AND •• 11. 0 S FINES
GRAVELLY •+ii •+•:
SOILS '4,• •4• POORLY-GRADED GRAVELS,
(LITTLE OR NO FINES) 0. e�i, 01 GP GRAVEL-SAND MIXTURES,LITTLE
•• 15 •• 15 OR NO FINES
COARSE •+"
GRAINED GRAVELS WITH 4 •1 SILTY GRAVELS, GRAVEL-SAND-
SOILS MORE THAN 50% FINES ' : GM SILT MIXTURES
OF COARSE •• •
FRACTION •
RETAINED ON NO. ,
4 SIEVE (APPRECIABLE r. GC
CLAYEY GRAVELS,GRAVEL-SAND-
AMOUNT OF FINES) ��� CLAY MIXTURES
CLEAN SANDS WELL-GRADED SANDS,GRAVELLY
MORE THAN 50% SAND SW SANDS,LITTLE OR NO FINES
OF MATERIAL IS AND
> 00000000
LARGER THAN SANDY
NO.200 SIEVE SOILS POORLY-GRADED SANDS,
SIZE (LITTLE OR NO FINES) SP GRAVELLY SAND,LITTLE OR NO
FINES
SANDS WITH - - SILTY SANDS,SAND-SILT
MORE THAN 50% FINES - - - SM MIXTURES
OF COARSE -
FRACTION J
PASSING ON NO.
4 SIEVE AMOUNT OF FINES)APPRECIABLE SC MIXTURES
CLAYEY SANDS,SAND-CLAY
INORGANIC SILTS AND VERY FINE
ML SANDS,ROCK FLOUR,SILTY OR
CLAYEY FINE SANDS OR CLAYEY
SILTS WITH SLIGHT PLASTICITY
SILTS j INORGANIC CLAYS OF LOW TO
FINE AND LIQUID LIMIT CL MEDIUM PLASTICITY,GRAVELLY
CLAYS
GRAINED LESS THAN 50 / CLAYS,SANDY CLAYS,SILTY
CLAYS,LEAN CLAYS
SOILS — — —
OL ORGANIC SILTS AND ORGANIC
SILTY CLAYS OF LOW PLASTICITY
MORE THAN 50% INORGANIC SILTS,MICACEOUS OR
OF MATERIAL IS j MH DIATOMACEOUS FINE SAND OR
SMALLER THAN SILTY SOILS
NO.200 SIEVE
SIZE
SILTS
AND LIQUID LIMIT //7 CH PLASTICITY
CLAYS OF HIGH
CLAYS GREATER THAN 50 PLASTICITY
i
OH ORGANIC CLAYS OF MEDIUM TO
HIGH PLASTICITY,ORGANIC SILTS
�`�� �'�� �`�� PEAT,HUMUS,SWAMP SOILS WITH
HIGHLY ORGANIC SOILS PT HIGH ORGANIC CONTENTS
NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS

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BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-1 (1 of 1)
Project No:63A-0012 Elevation:501± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:25.4' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/7/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth ( )blows/ft Remarks
(Classification) Blows (feet)
500.7 - 0.3 ��� \ SURFICIAL SOILS:4-inches r 3-2-5 0• Groundwater not
7 encountered above
1 FILL:Sampled as loose,brown and orange, cave-in at 18.3 feet
clayey fine SAND(SC)with little silt and trace 12.0 following drilling
I I rock fragments and organics, moist 2-3-4 7 completion.
1
i
3-5-5 3.5
10
1 5.0
i�i
495.0 - 6.0 j'
RESIDUUM:Very stiff,orange-brown and gray, 6.5
fine to medium sandy CLAY(CL)with little rock 5-15-7
fragments,moist 22
8.0
4-5-24 8.5
29 10.0
489.0 - 12.0 1
PARTIALLY WEATHERED ROCK:Sampled as very
hdense,white,red,and gray,clayey fine SAND
(SC)with Quartz fragments,moist 44-50/3 13.5
14.3 100+
484.0 - 17.0 fl -
Sampled as very dense,gray-brown,silty fine to
medium SAND(SM)with little clay and rock
fragments,moist 18.5
50/6 , 19.0
( 100+
479.0 - 22.0 ( -
f! Sampled as verydense,gray-brown,siltyfine to
pg Y �
hcoarse SAND(SM)with some rock fragments and
little clay, moist to wet 18-50/5 23.5 Wet spoon at 23.5 feet
( 24.4 100+
475.E - 25.4 11 50/0 25.4 -
Auger refusal at 25.4 feet.
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-1A (1 of 1)
Project No:63A-0012 Elevation:501± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:32.2' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/25/22
City/State:Waxhaw, NC Driller:HPC/J.Cain
Description of Materials *Sample Sample N-Value
Elevation Depth Depth(Classification) Blows (feet) (blows/ft) Remarks
— Auger only to 22.2 feet
1
1
1
1
Ii
478.8 22.2 REC=94% 22.2 refusal at 22.2 feet.
ROCK:Moderately weathered to fresh,closelyAuger
_ to medium fractured (moderate to high angle), RQD=49% Rock coring started at 22.2
fine grained,hard to very hard,fair to excellent, feet.
greenish gray,SLATE
REC=100% 25.2
RQD=100%fe UCS(26.3-26.6'):9,350 psi
REC=100% 30.2
_ RQD=100%
468.8 - 32.2 �� 32.2
Coring terminated at 32.2 feet.
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inc les in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

Rock Core Summary and Photograph
Boring B-1A: 22.2 to 25.2' — Rec = 94%, RQD = 49%
25.2 to 30.2' — Rec = 100%, RQD = 100%
30.2 to 32.2' — Rec = 100%, RQD = 100%
IN t 4 _ - - -
i 4 4`y' 1 22.2'
-/ ii, .
j10
in 2 z•... � is
li
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s I ,� tr Ay. } V
` 11 • t0. `
r ._
. J ;'ref 1 .
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re N
r 1 N
0:
ritNo N
a I 1! f
el ni
i ,I a. 1 ,
li - Jo? N
csi
N Nro.
�n
DATE: August 2022
I-8RFROEHLING ROBERTSON
SCALE: As Shown
Engineering Stability Since 1881
DRAWN: DJM 63A-0012
Hazen and Sawyer BORING NO.
12-Mile Creek WRF Expansion ROCK CORE SUMMARY
Waxhaw, North Carolina AND PHOTOGRAPH B-1A

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-2 (1 of 1)
Project No:63A-0012 Elevation:510± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth: 14.3' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/7/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth ( )blows/ft Remarks
(Classification) Blows (feet)
509.8 - 0.3 �j' SURFICIAL SOILS:3-inches /- 3-5-8 0.0Groundwater not
RESIDUUM:Stiff,tan and brown,fine to 13 encountered
medium sandy CLAY(CL), moist 1.5
5-4-6 2.0
10
2-5-6 3.5
11
5.0
504.0 - 6.0 -
Very stiff to hard, light gray-brown,clayey SILT 6.5
(ML)with some fine to coarse sand,dry 7-7-16
23
8.0
34-47-26 8'5
73
10.0
498.0 - 12.0_ PARTIALLY WEATHERED ROCK:Sampled as very
-I13.5')
dense
dark olive-gray ROCK FRAGMENTS(at 13.5
50/0.25
495.7 - 14.3 - 100+
Auger refusal at 14.3 feet.
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-3 (1 of 1)
Project No:63A-0012 Elevation:508± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:25.4' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/7/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth blows/ft Remarks
(Classification) Blows (feet)
( )
507.8 - 0.2 ;�;
4 \ SURFICIAL SOILS:2-inches 1-3-5 0• Groundwater not
8 encountered above
1 FILL:Sampled as loose,orange-brown and tan, cave-in at 21.2 feet
1 clayey fine to medium SAND(SC)with little silt 1.5
and rock fragments,moist 3-3-4 2.0 following drilling
completion.
i14 7
44 3-5-5 3.5
1 10
14 5.0
i
502.0 - 6.0 3;= -
I I Sampled as medium dense,orange-brown and 6.5
; 1 gray-brown,clayey fine to coarse SAND(SC)with 6-8-10
little rock fragments, moist 18
500.0 - 8.0 .v RESIDUUM:Hard,tan and light brown,clayey 8.5
SILT(ML)with some fine to medium sand,dry 18-21-15
36
10.0
496.0 12.0 f PARTIALLY WEATHERED ROCK:Sampled as
� hard,light gray-brown,clayey SILT(ML)with
l' little fine sand,dry 33 50/3 13.5
14.3 100+
491.0 - 17.0 fl I -
Sampled as very dense, brown and gray,clayey fine SAND(SC)with little rock fragments,dry
24-50/4 18.5
( 19.3 100+
486.0 - 22.0 ( -
f! Sampled as verydense, brown and gray,clayey
p Y Y
hfine to coarse SAND(SC)with some rock
fragments,moist 50/2 23.5 Wet spoon at 23 feet
I I
ll 11,
100+
i
482.6 - 25.4 50/0 25.4
Auger refusal at 25.4 feet.
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-4 (1 of 1)
Project No:63A-0012 Elevation:509± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:23.1' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/7/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth De(Classification) Blows (feett (blows/ft) Remarks
508.7 - 0.3 _j' \ SURFICIAL SOILS:4-inches r 3-5-7 0• Groundwater not
RESIDUUM:Stiff,tan and brown,silty CLAY(CL) 12 encountered
with little fine sand and rock fragments,dry 1.5
6-8-5 2.0
13
No Recovery 3.5 to 5' 8-6-4 3.5
10
5.0
No Recovery 6.5 to 8'-Very stiff 7-10-14 6.5
24
501.0 - 8.01 i' PARTIALLY WEATHERED ROCK:Samp as 8.5
hard,tan and brown,clayey SILT(ML)led with some 23-50/6
`\ fine to medium sand,drytan and brown,clayey
9•5 100+
�
497.0 - 12.0 \ Sampled as very dense,
�
fine to coarse SAND(SC)with some rock
`� fragments,dry 50/3 i
13.5
100+
50/3 i 18.5
100+
485.9 - 23.1 1 50/0 23.1
Auger refusal at 23.1 feet.
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING & ROBERTSON Boring: B-5 (1 of 1)
0
Project No: 63A-0012 Elevation: 550± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth: 29.5' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/5/22
City/State:Waxhaw, NC Driller: HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth Remarks
(Classification) Blows (feet) (blows/ft)
549.9 - 0.1 i \ SURFICIAL SOILS: 1-inch /- 6-12-18 0.0 Groundwater not
FILL:Sampled as hard, orange-brown and 30 encountered
548.0 2.0 brown,silty CLAY(CL)with little fine to coarse 1.5
\ \sand and rock fragments, moist / 14-35-50/5 2'0
PARTIALLY WEATHERED ROCK LENS:Sampled 100+
546.5 - 3.5 as hard,gray-brown, clayey SILT(ML)with little
\fine to medium sand and rock fragments, dry / 26-20-34
RESIDUUM: Hard,gray-brown, clayey SILT 54
5.0
(ML)with little fine sand, dry
544.0 6.0 PARTIALLY WEATHERED ROCK LENS:Sampled 6.5
as hard,gray-brown, clayey SILT(ML)with little fine to medium sand and rock fragments, dry 26 50/57.4 100+
542.0 8.0 RESIDUUM: Hard,gray-brown,silty CLAY(CL) 8.5
with some fine to medium sand, moist 9-42-38
80
10.0
8-27-27 13.5
54
15.0
533.0 - 17.0 I PARTIALLY WEATHERED ROCK:Sampled as
i hard, light olive-gray-brown, clayey SILT(ML)
with some fine to medium sand, dry 31-50/3 18.5
11
19.3 100+
11
Ili 1
42-50/5 23.5
24.4 100+
II
�I I 28-50/6 28.5
520.5 - 29.5 29.5 100+
Boring terminated at 29.5 feet.
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a tota of 18 inches in three 6"increments. The
sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-6 (1 of 1)
Project No:63A-0012 Elevation:551± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:28.4' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/6/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth blows/ft Remarks
(Classification) Blows (feet)
( )
550.9 - 0.1 j
\ SURFICIAL SOILS:1-inch [ 5-5-8 0• Groundwater not
13 encountered
FILL:Sampled as stiff, brown,orange,and gray, 1.5
's fine to medium sandy CLAY(CL)with some rock
549.0 - 2.0 % \fragments,moist / 11-19-20 2.0
RESIDUUM:Hard,gray-brown and 39
,
547.5 - 3.5 orangemedium brown,silmoistty
sand CLAY(CL)with some fine to / 18-15-50/4 3.5
,
PARTIALLY WEATHERED ROCK:Sampled as 4.8
100+
i hard,brown-gray,silty CLAY(CL)with some fine
j to medium sand,dry
50/3 i 6.5
i 100+
543.0 - 8.0 -
f Sampled as very dense Rock Fragments(about 8.5
50%)and brown-gray,silty CLAY(CL)with some ‘ 50/4
�� fine to medium sand,dry 100+
539.0 - 12.0 -
Sampled as very dense Rock Fragments with
some gray clayey fine to medium sand,dry
50/4 13.5
ii
( 100+
f
50/1 i 18.5
�� 100+
ii
i i� 23.5
50/2
100+
I�,
l
522.6 - 28.4 '' 50/0 28.4
Auger refusal at 28.4 feet.
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inc les in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-7 (1 of 1)
Project No:63A-0012 Elevation:550± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:23.5' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/6/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth blowsue Remarks
(Classification) Blows (feet) ( )
549.8 - 0.2 ' \ SURFICIAL SOILS:2-inches [ 4-8-10 0• Groundwater not
RESIDUUM:Very stiff,tan-brown-gray,fine to 18 encountered
medium sandy CLAY(CL), moist 2.5
14-13-11 24
546.5 - 3.5 11-12-11 3.5
Medium dense,tan-brown-gray,clayey fine to
0,01
medium SAND(SC),dry 23
5.0
544.0 - 6.0 f PARTIALLY WEATHERED ROCK:Sampled as 6.5
hhard,olive-gray-brown,fine to medium sandy 27-50/5
CLAY(CL)with little rock fragments,dry 7.4 100+
542.0 - 8.0 -
Sampled as very dense,gray-brown,clayey fine 8 5
h to medium SAND(SC)with some rock fragments, 23 35 50/4 100+
Y 9.8
13.5
18-50/5
14.4 100+
533.0 - 17.0 l' -
Sampled as very dense, light gray-brown,clayey
` fine to medium SAND(SC)with some rock
� fragments and little silt,dry 50/3 18.5
I
I ( 100+
f
526.5 - 23.5 1 1 50/0 23.5
Auger refusal at 23.5 feet.
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-7A (1 of 1)
Project No:63A-0012 Elevation:550± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:32.3' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:Offset 7 feet S of B-7 Date Drilled:7/25/22
City/State:Waxhaw, NC Driller:HPC/J.Cain
Description of Materials *Sample Sample N-Value
Elevation Depth Depth(Classification) Blows (feet) (blows/ft) Remarks
Auger only to 22.3 feet
527.7 - 22.3 22.3
ROCK:Moderately weathered to fresh,closely REC=100%RQD=10/ Auger refusal at 22.3 feet.
Rock coring started at 22.3
to medium fractured (moderate to high angle), °
fine grained,hard to very hard,very poor to feet.
excellent RQD,greenish gray,SLATE
REC=100°% 25.8 UCS(26.3-26.6'):7,130 psi
RQD=100%
REC=100% 30.8
RQD=100%
517.7 - 32.3 32.3
Coring terminated at 32.3 feet.
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inc les in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

Rock Core Summary and Photograph
Boring B-7A: 22.3 to 25.8' — Rec = 100%, RQD = 10%
25.8 to 30.8' — Rec = 100%, RQD = 100%
30.8 to 32.3' — Rec = 100%, RQD = 100%
•
22.3
1 . 1 1 ill, I w
, A
7 30.8' I °'
V
til . `i
l
O
I� .*W w
1
A
iiii
J,
N
o
10 N.,
25.8' 1
if N;
W
, .,k
, 43--
32.3' '
't
dip 1,
DATE: August 2022
I-8RFROEHLING ROBERTSONSCALE: As shown
Engineering Stability Since 1881
DRAWN: DJM 63A-0012
Hazen and Sawyer BORING NO.
12-Mile Creek WRF Expansion ROCK CORE SUMMARY
Waxhaw, North Carolina AND PHOTOGRAPH B-7A

BORING LOG
r8,RFROEHLING (',: ROBERTSON Boring: B-8 (1 of 1)
0
Project No: 63A-0012 Elevation: 550± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth: 16.6' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/6/22
City/State:Waxhaw, NC Driller: HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth Remarks
(Classification) Blows (feet) (blows/ft)
549.9 - 0.1 .' \ SURFICIAL SOILS:0.5-inch [ 7-11-14 0.0 Groundwater not
RESIDUUM:Very stiff, orange-brown,fine to 25 encountered
coarse sandy CLAY(CL)with little rock 1.5
548.0 - 2.0 0 I fragments, moist j'. 10-14-18 2.0
Hard,orange-brown and gray-brown,silty CLAY 32
546.5 - 3.5 (CL)with some fine to medium sand and little 3.5
`rock fragments, moist / 32 50/4
, /
PARTIALLY WEATHERED ROCK:Sampled as 4.3 100+
very dense,gray-brown,silty CLAY(CL)with
544.0 - 6.0 some fine to medium sand and little rock
I fragments, dry 50/3 6.5
Sampled as very dense, light gray-brown, clayey 100+
fine to coarse SAND (SC)with some rock
fragments, dry 8 5
50/0.5
11) 100+
538.0 12.0 -
Sampled as very dense, light gray, clayey fine to
coarse SAND (SC)with rock fragments (about
50%of sample), dry 50/2 13.5
100+
533.4 - 16.6 l' 1 50/0 16.6
Auger refusal at 16.6 feet.
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.samp er a tota of 18 inches in three 6"increments. The
sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING (',: ROBERTSON Boring: B-9 (1 of 1)
0
Project No: 63A-0012 Elevation: 550± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth: 15.0' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/5/22
City/State:Waxhaw, NC Driller: HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth Remarks
(Classification) Blows (feet) (blows/ft)
549.9 - 0.1 .' \ SURFICIAL SOILS: 1-inch [ 6-12-11 0.0 Groundwater not
RESIDUUM:Very stiff, brown,silty CLAY(CL) 23 encountered
with little fine to medium sand and rock 1.5
548.0 - 2.0 ' \fragments, dry / 16-50/2 2.0
547.0 - 3.0 I PARTIALLY WEATHERED ROCK:Sampled as 2'7 100+
I hard,gray-brown,silty CLAY(CL)with little fineJ/ 50/2 3.5
\sand,dry 100+
Sampled as hard, light gray-brown,silty CLAY
(CL)with little fine to medium sand and some
rock fragments,dry
11
50/1 , 6.5
100+
1 \ 50/4 8.5
100+
I
I' I \ 50/5 13.5
�II 100+
535.0 - 15.0
Boring terminated at 15 feet.
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.samp er a tota of 18 inches in three 6"increments. The
sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING * ROBERTSON Boring: B-10 (1 of 2)
0
Project No: 63A-0012 Elevation: 549± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:45.0' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/5/22
City/State:Waxhaw, NC Driller: HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth Remarks
(Classification) Blows (feet) (blows/ft)
548.9 - 0.1 SURFICIAL SOILS:4 inches [ 3-8-7 0.0 Groundwater
FILL:Sampled as stiff,gray-orange-brown,silty 15 encountered at
CLAY(CL)with some fine to medium sand and 1.5 approximately 39 feet
547.0 - 2.0 little rock fragments, moist j'. 5-6-10 2•0 immediately after
completion of drilling.
Sampled as very stiff, red-brown, clayey SILT 16
545.5 - 3.5 (MH), moist / 5-7-9 3.5
RESIDUUM:Very stiff to stiff, orange-brown 16
and gray-brown,silty CLAY(CL), moist 5.0
2-7-7 6.5
14
541.0 - 8.0 . 8.0
Medium dense,orange-brown and tan, clayey 8.5
fine SAND (SC), dry 9-11-11
01 22
0,A, 10.0
0
0,A,
0
0,A,
0 0
0,A, 11-14-16 13.5
30
0,A, 15.0
0
532.0 - 17.0 , 1
I PARTIALLY WEATHERED ROCK:Sampled as
II
hard,tan and light brown, clayey SILT(ML)with
little fine sand, dry 20-50/5 18.5
I, 19.4 100+
k
I, I
ill 15-32-50/6 23.5
100+
25.0
522.0 - 27.0 1"
RESIDUUM: Hard, brown and tan,fine to
medium sandy CLAY(CL)with some silt, moist
14-25-31 28.5
56
30.0
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a tota of 18 inches in three 6"increments. The
sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-10 (2 of 2)
Project No:63A-0012 Elevation:549± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:45.0' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/5/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth(Classification) Blows (feet) (blows/ft) Remarks
517.0 32.0 i PARTIALLY WEATHERED ROCK:Sampled as very
dense,brown and gray,clayey fine to coarse
� SAND(SC)with some rock fragments and little 42-50/4
33.5
silt,moist 34.3 100+
1
ii
2 i 50/3 38.5
�� 100+
ii
p�
505.5 - 43.5 I Sampled as very dense gray rock fragments,dry I 50/0.5 1 43.5
100+
504.0 - 45.0 1 -
Boring terminated at 45 feet.
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inc les in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-11 (1 of 1)
Project No:63A-0012 Elevation:549± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth: 18.7' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/5/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth (Classification) Blows Depthf (blows/ft) Remarks
)
548.9 - 0.1 - \ SURFICIAL SOILS:1-inch [ 9-13-20 0.0 Groundwater not
33 encountered
�� FILL:Sampled as hard,orange-brown,silty CLAY
6. (CL)with little fine to medium sand and rock 1.5
547.0 - 2.0 1, \fragments,moist
18-40-50/5 2.
0
PARTIALLY WEATHERED ROCK:Sampled as 100+
hard,tan and brown,clayey SILT(ML)with some 50/4 3.5
fine to medium sand and rock fragments,dry ‘ i
100+
50/5 6.5
�� 100+
541.0 - 8.0 -
Sampled hard,tan , 8.5
with some as fine to mediumand sandbrown andsilty rockCLAY(CL) 50/5) fragments,dry 100+
ll
537.0 - 12.0 , -
!� Sampled as very dense,tan and brown,clayey
fine to coarse SAND(SC)with quartz fragments
(about 50%of sample),dry 50/4 13.5
! 100+
531.0 - 18.0 1I -
Sampled as very dense Rock Fragments with 18.5
530.3 - 18.7 some tan and brown,fine to coarse clayey SILT , 50/2
\(ML),dry 100+
Boring terminated at 18.7 feet.
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inc les in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-12 (1 of 1)
Project No:63A-0012 Elevation:548± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:22.5' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/6/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N Value
Elevation Depth Depth blows/ft Remarks
(Classification) Blows (feet) ( )
547.8 - 0.37 \ SURFICIAL SOILS:3-inches ` 4-9-9 0.0 Groudwater not
,� 18 encountered
: FILL:Sampled as very stiff,orange-brown,
clayey SILT(MH)with some fine to medium sand 1.5
546.0 - 2.0 \and little rock fragments,dry / 6-11-17 2.0
RESIDUUM:Very stiff, brown and tan,fine to 28
medium sandy CLAY(CL),dry 5-11-13 3.5
24
5.0
542.0 - 6.0
PARTIALLY WEATHERED ROCK:Sampled as 6.5
I hard,orange-brown,silty CLAY(CL)with some 8-10-50/6
� fine to medium sand,moist 100+
540.0 - 8.0 f 8.0
Sampled as hard,gray-brown,clayey SILT(ML) 50/5 8.5
with some fine to medium sand and little rock /
fragments 100+
it
l� 13.5
38-22-50/5
100+
14.9
i
11
531.0 - 17.0 II -
ISampled as very dense gray rock fragments with
some fine to coarse sandy SILT(ML),dry
50/1 I 18.5
100+
'
525.5 - 22.5 11 22.5
Auger refusal at 22.5 feet. 50/0
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING (',: ROBERTSON Boring: B-13 (1 of 1)
0
Project No: 63A-0012 Elevation: 553.5± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth: 23.3' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/5/22
City/State:Waxhaw, NC Driller: HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth blows/ft Remarks
(Classification) Blows (feet) ( )
553.4 - 0.1 \ SURFICIAL SOILS:4 inches [ 4-11-9 0.0 Groundwater not
FILL:Sampled as very stiff, orange-brown and 20 encountered
tan, clayey SILT(MH)with little fine to medium 1.5
sand and rock fragments, dry 8-10-11 2.0
21
550.0 3.5 MSampled as medium dense to loose, brown and 11-16-14 3.5
tan, clayey fine to medium SAND (SC)with little 30
rock fragments,dry 5.0
4-4-4 6.5
8
8.0
3-2-2 8.5
4
10.0
541.5 12.0 RESIDUUM:Very dense, brown and gray,silty
• fine to coarse SAND (SM)with little rock
fragments and clay, moist 15 26 14 13.5
40
15.0
536.5 17.0 PARTIALLY WEATHERED ROCK:Sampled as
'' very dense, brown and gray,silty fine to coarse
SAND (SM)with some rock fragments and little 27-50/3 18.5
clay, dry 193 100+
1 ‘
pi
530.2 - 23.3 ' 50/0 23.3
Auger refusal at 23.3 feet.
100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.samp er a tota of 18 inches in three 6"increments. The
sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

BORING LOG
r8,RFROEHLING ROBERTSON Boring: B-14 (1 of 1)
Project No:63A-0012 Elevation:554± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:28.7' Hammer Type:Automatic
Project: 12-Mile Creek WRF Boring Location:See boring location plan Date Drilled:7/6/22
City/State:Waxhaw, NC Driller:HPC/Z.K.
Description of Materials *Sample Sample N-Value
Elevation Depth Depth (blows/ft)blows/ft Remarks
(Classification) Blows (feet)
553.8 - 0.3 •% \ SURFICIAL SOILS:3-inches ` 3-5-13 0.0 Groundwater not
_�;� 18 encountered
FILL:Sampled as very stiff,orange-brown and
1 tan,fine to coarse sandy SILT(ML)with little clay 1.5
�4
552.0 - 2.0 joJ
I and rock fragments,moist ' 11-13-30 2.0
-� '
�.4 Sampled as hard to very stiff,orange-brown and 43
1 tan,clayey SILT(MH)with some fine to medium 7-9-12
3.5
1 sand and trace rock fragments,moist 21
•
i 5.0
548.0 - 6.0 “ -
� Sampled as medium dense,orange-brown and 6.5
4 tan,clayey fine to medium SAND(SC)with trace 4-9-5
rock fragments, moist 14
546.0 - 8.0 '4 8.0
I Sampled as loose,orange-brown and tan, 8.5
4 clayey-silty fine to medium SAND(SC-SM)with 4-6-2
1 trace rock fragments, moist 8
i 10.0
4
542.0 - 12.0 ;_1 -
� Sampled as loose,orange-brown and tan,clayey
�.4 fine to medium SAND(SC)with trace rock
1 fragments,moist 4-3-2
13.5
4 5 1 15.0
537.0 - 17.0 PARTIALLY WEATHERED ROCK:Sampled as very
` dense,orange-brown,silty fine to medium SAND
) (SM)with little clay and rock fragments,moist 35 50/4 18.5
( 19.3 100+
50/6 23.5
24.0 100+
i
itl
525.3 - 28.7 ‘'
50/2 i 28.5 -
Boring terminated at 28.7 feet. 100+
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

r&R
APPENDIX III
Material Test Reports
Proctor Reports

r8,R Froehling&Robertson,Inc.
Charlotte Office
3300 International Airport Drive,Suite 600 MaterialCharlotte,NC 28208 Test Report
Phone:[phone] www.FandR.com
Client: Hazen and Sawyer-Charlotte CC: Report No: ASM:6322-02300
9101 Southern Pine Blvd
Charlotte, NC 28273
Project: 63A0012
12-Mile Creek WRF MGD Expansion
8299 Kensington Drive
Waxhaw, NC 28173 Review Date:
Material Details
Source Sampled From
Sample Details
Sample ID 6322-02300-801 6322-02300-802 6322-02300-503 6322-02300-804 6322-02300-SO5 6322-02300-806
Field Sample ID
Date Sampled 7/14/2022
Boring No B-1 B-1 B-2 B-3 B-3 B-7
Depth 3.5-5 13.5-15 3.5-5 2-3.5 18.5-20 3.5-5
Other Testill
Descriptiog II Results Limits
Passing No.200(75 pm)(%) ASTM D1140 49 28 57 47 29 30
Procedure A A A A A A
Soaking Period(min)
Initial Dry Mass(g) 128.1 173.8 114.8 146.5 149.2 173.7
Water Content Determined No No No No No No
Water Content(%) ASTM D2216 14.3 8.6 19.3 16.1 12.7 9.9
Date Tested
Liquid Limit ASTM D4318 43 30 41 40 31 33
Plastic Limit 26 23 26 24 22 23
Plasticity Index 17 7 15 16 9 10
Tested By
Date Tested
Comments Legend
1
The results provided herein relate only to the items inspected and/or tested.This report shall not be reproduced,except in full,without the prior written approval of F&R.
Form No:18980,Report No:ASM:6322-02300 ©2000-2022 QESTLab by SpectraQEST.com Page 1 of 3

r8,R Froehling&Robertson,Inc.
Charlotte Office
3300 International Airport Drive,Suite 600 MaterialCharlotte,NC 28208 Test Report
Phone:[phone] www.FandR.com
Client: Hazen and Sawyer-Charlotte CC: Report No: ASM:6322-02300
9101 Southern Pine Blvd
Charlotte, NC 28273
Project: 63A0012
12-Mile Creek WRF MGD Expansion
8299 Kensington Drive
Waxhaw, NC 28173 Review Date:
Material Details
Source Sampled From
Sample Details
Sample ID 6322-02300-S07 6322-02300-SOB 6322-02300-SO9 6322-02300-510 6322-02300-611 6322-02300-S12
Field Sample ID
Date Sampled
Boring No B-10 B-12 B-13 B-13 B-14 B-14
Depth 8.5-10 2-3.5 3.5-5 8.5-10 6.5-8 13.5-15
Other Test.E111--
Descriptiog _d Results Limits
Passing No.200(75 pm)(%) ASTM D1140 23 57 43 30 44 30
Procedure A A A A A A
Soaking Period(min)
Initial Dry Mass(g) 187.0 183.6 174.9 187.1 174.8 160.7
Water Content Determined No No No No No No
Water Content(%) ASTM D2216 10.5 8 8.6 9.9 10.8 11.2
Date Tested
Liquid Limit ASTM D4318 38 41 33 36 36 32
Plastic Limit 22 25 23 24 21 24
Plasticity Index 16 16 10 12 15 8
Tested By
Date Tested
Comments Legend
1
The results provided herein relate only to the items inspected and/or tested.This report shall not be reproduced,except in full,without the prior written approval of F&R.
Form No:18980,Report No:ASM:6322-02300 ©2000-2022 QESTLab by SpectraQEST.com Page 2 of 3

r8,R Froehling&Robertson,Inc.
Charlotte Office
3300 International Airport Drive,Suite 600 MaterialCharlotte,NC 28208 Test Report
Phone:[phone] www.FandR.com
Client: Hazen and Sawyer-Charlotte CC: Report No: ASM:6322-02300
9101 Southern Pine Blvd
Charlotte, NC 28273
Project: 63A0012
12-Mile Creek WRF MGD Expansion
8299 Kensington Drive
Waxhaw, NC 28173 Review Date:
Material Details
Source Sampled From
Sample Details
Sample ID 6322-02300-813 6322-02300-814 6322-02300-S15
Field Sample ID
Date Sampled
Boring No B-2 B-6 B-12
Depth 2-8 2-8 2-8
Other Testilij
Descriptiog MIF Results Limits
Passing No.200(75 pm)(%) ASTM D1140 52 59 55
Procedure A A A
Soaking Period(min)
Initial Dry Mass(g) 207.2 236.0 263.7
Water Content Determined No No No
Water Content(%) ASTM D2216 14.2 11.8 11.8
Date Tested
Liquid Limit ASTM D4318 36 35 37
Plastic Limit 19 11 21
Plasticity Index 17 24 16
Tested By
Date Tested
Std.Maximum Dry Unit Weight(Ibf/ft3) ASTM D698 113.6 124.5 118.2
Std.Optimum Water Content(%) 14.0 11.5 13.4
Method C C C
Preparation Method Moist Moist Moist
Test Portion Specific Gravity Assumed
Comments Legend
1
The results provided herein relate only to the items inspected and/or tested.This report shall not be reproduced,except in full,without the prior written approval of F&R.
Form No:18980,Report No:ASM:6322-02300 ©2000-2022 QESTLab by SpectraQEST.com Page 3 of 3

r8, Froehling&Robertson,Inc.
Charlotte Office
3300 International Airport Drive,Suite 600 Proctor Report
Charlotte,NC 28208
Phone:[phone] www.FandR.com
Client: Hazen and Sawyer-Charlotte CC: Report No: PTR:6322-02300-S13
9101 Southern Pine Blvd
Charlotte, NC 28273
Project: 63A0012
12-Mile Creek WRF MGD Expansion
8299 Kensington Drive
Waxhaw, NC 28173 Review Date:
Sample Details
Sample ID: 6322-02300-S13 Date Sampled:
Sampling Method:Auger Cuttings
Source: Boring B-2
Material: Bulk Sample 2 to 8 feet
Specification:
Location: Bulk
Dry Unit Weight -Water Content Relationship Test Results
ASTM D698
— Compaction Curve Std.Maximum Dry Unit Weight(Ibflft'): 113.6
Std.Optimum Water Content(%): 14.0
115.0 Method: C
Preparation Method: Moist
114.5 Determined By: Assumed
Tested By:
114.0 Date Tested:
ASTM D4318
Liquid Limit: 36
113.5 19
M
PlasticityPlasticLimit:Index: 17
113.0 Tested By:
L Date Tested:
112.5
D 112.0
a
111.5
111.0
110.5
110.0
9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0
Water Content(%)
Comments
The results provided herein relate only to the items inspected and/or tested.This report shall not be reproduced,except in full,without the prior written approval of F&R.
Form No:110031,Report No:PTR:6322-02300-S13 ©2000-2022 QESTLab by SpectraQEST com Page 1 of 1

r&R Froehling&Robertson,Inc.
Charlotte Office
3300 International Airport Drive,Suite 600 Proctor Report
Charlotte,NC 28208
Phone:[phone] www.FandR.com
Client: Hazen and Sawyer-Charlotte CC: Report No: PTR:6322-02300-S14
9101 Southern Pine Blvd
Charlotte, NC 28273
Project: 63A0012
12-Mile Creek WRF MGD Expansion
8299 Kensington Drive
Waxhaw, NC 28173 Review Date:
Sample Details
Sample ID: 6322-02300-S14 Date Sampled:
Sampling Method:Auger Cuttings
Source: Boring B-6
Material: Bulk Sample 2 to 8 feet
Specification:
Location: Bulk
Dry nlWeightTest Results
ASTM D698
—Compaction Curve Std.Maximum Dry Unit Weight(Ibflft3): 124.5
Std.Optimum Water Content(%): 11.5
125.0 Method: C
Preparation Method: Moist
Determined By: Assumed
124.5
Tested By:
124.0 Date Tested:
ASTM D4318
Liquid Limit: 35
123.5 Plastic Limit: 11
Plasticity Index: 24
123.0 Tested By:
rn Date Tested:
122.5
122.0
121.5
121.0
120.5
120.0 -
7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0
Water Content(%)
comments
The results provided herein relate only to the items inspected and/or tested.This report shall not be reproduced,except in full,without the prior written approval of F&R.
Form No:110031,Report No:PTR:6322-02300-S14 ©2000-2022 QESTLab by SpectraQEST.com Page 1 of 1

r8, Froehling&Robertson,Inc.
Charlotte Office
3300 International Airport Drive,Suite 600 Proctor Report
Charlotte,NC 28208
Phone:[phone] www.FandR.com
Client: Hazen and Sawyer-Charlotte CC: Report No: PTR:6322-02300-S15
9101 Southern Pine Blvd
Charlotte, NC 28273
Project: 63A0012
12-Mile Creek WRF MGD Expansion
8299 Kensington Drive
Waxhaw, NC 28173 Review Date:
Sample Details
Sample ID: 6322-02300-S15 Date Sampled:
Sampling Method:Auger Cuttings
Source: Boring B-12
Material: Bulk Sample 2 to 8 feet
Specification:
Location: Bulk
Dry Unit Weight -Water Content Relationship Test Results
ASTM D698
— Compaction Curve Std.Maximum Dry Unit Weight(Ibflft'): 118.2
Std.Optimum Water Content(%): 13.4
118.5 Method: C
Preparation Method: Moist
118.0 Determined By: Assumed
Tested By:
117.5 Date Tested:
ASTM D4318
Liquid Limit: 37
117.0 Plastic Limit: 21
Plasticity Index: 16
116.5 Tested By:
Date Tested:
.73) 116.0
115.5
115.0
114.5
114.0
113.5
7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0
Water Content(%)
Comments
The results provided herein relate only to the items inspected and/or tested.This report shall not be reproduced,except in full,without the prior written approval of F&R.
Form No:110031,Report No:PTR:6322-02300-S15 ©2000-2022 QESTLab by SpectraQEST com Page 1 of 1

r&R
APPENDIX IV
Extent of Select Backfill for Retaining Walls (Drawing No. 3)

e• ' I
•
•4
• I
I I
Select Crushed
'• Stone Backfill
H
..
4
.' / /\
45c'
g'
a y d .•
• \J /1/
H/2 --
DATE: September 2022
FROEHLING Sc ROBERTSON, INC.
Engineering Stability Since 1881 SCALE: As Shown
3300 International Airport Drive,Suite 600
• Charlotte, North Carolina,28208 DRAWN: AF 63A-0012
issi T 704.596.2889 I F 704.596.3784
12-Mile Creek WRF 9.0 MGD Expansion EXTENT OF SELECT DRAWING NO.
Waxhaw, North Carolina BACKFILL FOR
Hazen and Sawyer RETAINING WALLS 3

r&R
APPENDIX V
GBA Publication "Important Information about This
Geotechnical Engineering Report"

Important Information about us
(-- Gootocbnical-Enginooring
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
While you cannot eliminate all such risks, you can manage them. The following information is provided to help.
The Geoprofessional Business Association (GBA) Typical changes that could erode the reliability of this report include
has prepared this advisory to help you—assumedly those that affect:
a client representative—interpret and apply this • the site's size or shape;
geotechnical-engineering report as effectively • the function of the proposed structure,as when it's
as possible. In that way, clients can benefit from changed from a parking garage to an office building,or
a lowered exposure to the subsurface problems from a light industrial plant to a refrigerated warehouse;
• the elevation,configuration,location,orientation,or
that,for decades, have been a principal cause of weight of the proposed structure;
construction delays, cost overruns, claims, and . the composition of the design team;or
disputes. If you have questions or want more • project ownership.
information about any of the issues discussed below,
contact your GBA-member geotechnical engineer. As a general rule,always inform your geotechnical engineer of project
Active involvement in the Geoprofessional Business changes-even minor ones-and request an assessment of their
Association exposes geotechnical engineers to a impact.The geotechnical engineer who prepared this report cannot accept
wide array of risk-confrontation techniques that can responsibility or liability for problems that arise because the geotechnical
be of genuine benefit for everyone involved with a engineer was not informed about developments the engineer otherwise
construction project. would have considered.
This Report May Not Be Reliable
Geotechnical-Engineering Services Are Performed for Do not rely on this report if your geotechnical engineer prepared it:
Specific Purposes, Persons, and Projects for a different client;
Geotechnical engineers structure their services to meet the specific . for a different project;
needs of their clients.A geotechnical-engineering study conducted • for a different site(that may or may not include all or a
for a given civil engineer will not likely meet the needs of a civil- portion of the original site);or
works constructor or even a different civil engineer.Because each • before important events occurred at the site or adjacent
geotechnical-engineering study is unique,each geotechnical- to it;e.g.,man-made events like construction or
engineering report is unique,prepared solely for the client.Those who environmental remediation,or natural events like floods,
rely on a geotechnical-engineering report prepared for a different client droughts,earthquakes,or groundwater fluctuations.
can be seriously misled.No one except authorized client representatives
should rely on this geotechnical-engineering report without first Note,too,that it could be unwise to rely on a geotechnical-engineering
conferring with the geotechnical engineer who prepared it.And no one report whose reliability may have been affected by the passage of time,
-not even you-should apply this report for any purpose or project except because of factors like changed subsurface conditions;new or modified
the one originally contemplated. codes,standards,or regulations;or new techniques or tools.If your
geotechnical engineer has not indicated an`apply-by"date on the report,
Read this Report in Full ask what it should be,and,in general,if you are the least bit uncertain
Costly problems have occurred because those relying on a geotechnical- about the continued reliability of this report,contact your geotechnical
engineering report did not read it in its entirety.Do not rely on an engineer before applying it.A minor amount of additional testing or
executive summary.Do not read selected elements only.Read this report analysis-if any is required at all-could prevent major problems.
in full.
Most of the"Findings" Related in This Report Are
You Need to Inform Your Geotechnical Engineer Professional Opinions
about Change Before construction begins,geotechnical engineers explore a site's
Your geotechnical engineer considered unique,project-specific factors subsurface through various sampling and testing procedures.
when designing the study behind this report and developing the Geotechnical engineers can observe actual subsurface conditions only at
confirmation-dependent recommendations the report conveys.A few those specific locations where sampling and testing were performed.The
typical factors include: data derived from that sampling and testing were reviewed by your
• the client's goals,objectives,budget,schedule,and geotechnical engineer,who then applied professional judgment to
risk-management preferences; form opinions about subsurface conditions throughout the site.Actual
• the general nature of the structure involved,its size, sitewide-subsurface conditions may differ-maybe significantly-from
configuration,and performance criteria; those indicated in this report.Confront that risk by retaining your
• the structure's location and orientation on the site;and geotechnical engineer to serve on the design team from project start to
• other planned or existing site improvements,such as project finish,so the individual can provide informed guidance quickly,
retaining walls,access roads,parking lots,and whenever needed.
underground utilities.

This Report's Recommendations Are perform their own studies if they want to,and be sure to allow enough
Confirmation-Dependent time to permit them to do so.Only then might you be in a position
The recommendations included in this report-including any options to give constructors the information available to you,while requiring
or alternatives-are confirmation-dependent.In other words,they are them to at least share some of the financial responsibilities stemming
not final,because the geotechnical engineer who developed them relied from unanticipated conditions.Conducting prebid and preconstruction
heavily on judgment and opinion to do so.Your geotechnical engineer conferences can also be valuable in this respect.
can finalize the recommendations only after observing actual subsurface
conditions revealed during construction.If through observation your Read Responsibility Provisions Closely
geotechnical engineer confirms that the conditions assumed to exist Some client representatives,design professionals,and constructors do
actually do exist,the recommendations can be relied upon,assuming not realize that geotechnical engineering is far less exact than other
no other changes have occurred.The geotechnical engineer who prepared engineering disciplines.That lack of understanding has nurtured
this report cannot assume responsibility or liability for confirmation- unrealistic expectations that have resulted in disappointments,delays,
dependent recommendations if you fail to retain that engineer to perform cost overruns,claims,and disputes.To confront that risk,geotechnical
construction observation. engineers commonly include explanatory provisions in their reports.
Sometimes labeled"limitations;many of these provisions indicate
This Report Could Be Misinterpreted where geotechnical engineers'responsibilities begin and end,to help
Other design professionals'misinterpretation of geotechnical- others recognize their own responsibilities and risks.Read these
engineering reports has resulted in costly problems.Confront that risk provisions closely.Ask questions.Your geotechnical engineer should
by having your geotechnical engineer serve as a full-time member of the respond fully and frankly.
design team,to:
• confer with other design-team members, Geoenvironmental Concerns Are Not Covered
• help develop specifications, The personnel,equipment,and techniques used to perform an
• review pertinent elements of other design professionals' environmental study-e.g.,a"phase-one"or"phase-two"environmental
plans and specifications,and site assessment-differ significantly from those used to perform
• be on hand quickly whenever geotechnical-engineering a geotechnical-engineering study.For that reason,a geotechnical-
guidance is needed. engineering report does not usually relate any environmental findings,
conclusions,or recommendations;e.g.,about the likelihood of
You should also confront the risk of constructors misinterpreting this encountering underground storage tanks or regulated contaminants.
report.Do so by retaining your geotechnical engineer to participate in Unanticipated subsurface environmental problems have led to project
prebid and preconstruction conferences and to perform construction failures.If you have not yet obtained your own environmental
observation. information,ask your geotechnical consultant for risk-management
guidance.As a general rule,do not rely on an environmental report
Give Constructors a Complete Report and Guidance prepared for a different client,site,or project,or that is more than six
Some owners and design professionals mistakenly believe they can shift months old.
unanticipated-subsurface-conditions liability to constructors by limiting
the information they provide for bid preparation.To help prevent Obtain Professional Assistance to Deal with Moisture
the costly,contentious problems this practice has caused,include the Infiltration and Mold
complete geotechnical-engineering report,along with any attachments While your geotechnical engineer may have addressed groundwater,
or appendices,with your contract documents,but be certain to note water infiltration,or similar issues in this report,none of the engineer's
conspicuously that you've included the material for informational services were designed,conducted,or intended to prevent uncontrolled
purposes only.To avoid misunderstanding,you may also want to note migration of moisture-including water vapor-from the soil through
that"informational purposes"means constructors have no right to rely building slabs and walls and into the building interior,where it can
on the interpretations,opinions,conclusions,or recommendations in cause mold growth and material-performance deficiencies.Accordingly,
the report,but they may rely on the factual data relative to the specific proper implementation of the geotechnical engineer's recommendations
times,locations,and depths/elevations referenced. Be certain that will not of itself be sufficient to prevent moisture infiltration.Confront
constructors know they may learn about specific project requirements, the risk of moisture infiltration by including building-envelope or mold
including options selected from the report,only from the design specialists on the design team.Geotechnical engineers are not building-
drawings and specifications.Remind constructors that they may envelope or mold specialists.
GEOPROFESSIONAL
Agla GB/ BUSINESS
- ASSOCIATION
Telephone:[phone]
e-mail:[e-mail] www.geoprofessional.org
Copyright 2016 by Geoprofessional Business Association(GBA).Duplication,reproduction,or copying of this document,in whole or in part,by any means whatsoever,is strictly
prohibited,except with GBAs specific written permission.Excerpting,quoting,or otherwise extracting wording from this document is permitted only with the express written permission
of GBA,and only for purposes of scholarly research or book review.Only members of GBA may use this document or its wording as a complement to or as an element of a report of any
kind.Any other firm,individual,or other entity that so uses this document without being a GBA member could be committing negligent

FROEHLING
ROBERTSON
Engineering Stability Since 1881
NC License No. F-0266
F&R Project No.:63A-0012 28 February 2023
Mr. Michael D. Parker, PE
Hazen and Sawyer
9101 Southern Pine Boulevard,Suite 250
Charlotte, North Carolina 28273
Re: Addendum No. 1 to Report of Subsurface Exploration and Geotechnical Evaluation
Twelve Mile Creek WRF 9.0 MGD Expansion
Union County, North Carolina
Mr. Parker:
Froehling & Robertson, Inc. (F&R) is pleased to provide this Geotechnical Report Addendum No. 1 for
the above referenced project. This letter report is an addendum to our Report of Subsurface
Exploration and Geotechnical Evaluation dated 16 September 2022 (F&R Project No. 63A-0012).
As requested, we performed two additional (supplemental) soil test borings in the area of the planned
outfall. This Addendum (No. 1) letter report reviews our understanding of the project, exploration
procedures, describes general subsurface conditions for the two supplemental test borings, and
presents our conclusions with respect to construction of the outfall. Our services were performed in
general accordance with the scope of work included in the Subcontract Agreement for Professional
Services, between Hazen and Sawyer and F&R, dated 27 January 2022 and as additionally requested by
Hazen and Sawyer via an email dated 8 November 2022. At the time of this Addendum, the findings,
previous recommendations, and limitations presented in our original report are still applicable to the
project unless specifically noted otherwise.
PROJECT INFORMATION
A new effluent outfall is planned south of the facility, on the north side of Twelve Mile Creek.
Subsurface exploration of the proposed outfall area was not included in our previous study.
Project information relative to the outfall structure was provided to F&R by the project team via email
correspondence,which included the following:
• Outfall Drawings.pdf—Sheets C24, C65, C66, CD7,and CD8 dated 12 January 2023
• Plant Outfall—Structural Drawings.pdf—Sheet S680 dated December 2022
We understand the outfall end-wall will be a cast-in-place concrete structure with a footprint of about
17 feet by 16 feet. The structure has a planned bearing elevation of 484.00 feet, a bottom of key
elevation of 482.00 feet, and an outfall invert elevation of 487.15 feet. Based on the existing grades of
about 485 to 498 feet (as shown on the provided plans), excavations up to about 14 feet below existing
grade will be required to reach the planned bearing elevation of 484.00 feet.
The provided plans show that a cofferdam is proposed around the area of the outfall structure to
facilitate dewatering for construction. The cofferdam detail (on Sheet CD7) indicates that the cofferdam
will be a constructed rip-rap embankment with a polyethylene membrane on the creek side of the coffer
dam which will be held in place by stacked sandbags.
704.596.2889 3300 International Airport Drive A Minority-Owned Business
Suite 600
Charlotte, NC 28208

r&R
SCOPE OF SERVICES
The purposes of our involvement on this project were to 1) provide general descriptions of the
subsurface soil and rock conditions in the area of the planned outfall, and 2) provide geotechnical
recommendations for construction of the outfall. In order to accomplish the above objectives, we
undertook the following scope of services:
1) Reviewed readily available geologic information relative to the project site.
2) Coordinated utility clearance with NC-811.
3) Visited the site to observe existing surface conditions and features.
4) Executed the requested supplemental subsurface exploration consisting of two (2)
additional standard penetration test (SPT) borings. The borings were advanced below
auger refusal levels using rock coring techniques to depths of 23.6 feet and 32 feet below
the existing ground surface.
5) Evaluated the findings of the subsurface exploration and prepared this geotechnical
addendum letter report summarizing our work on the project. This report provides
descriptions of the subsurface conditions encountered and discusses possible difficult
excavation and dewatering considerations.
F&R's geotechnical services did not include topographic or field surveying, development of quantity
estimates, preparation of plans and specifications, or the identification and evaluation of wetlands or
other environmental aspects of the project site.
EXPLORATION PROCEDURES
Subsurface Exploration Methods
The supplemental subsurface exploration program was performed on 2 and 5 December 2022 and
consisted of two (2) test borings (designated as 0-1 and 0-2). The test borings were performed at the
approximate locations as shown on the attached Boring Location Plan (Drawing 1). The boring locations
were marked in the field using a handheld GPS. Boring elevations were interpolated from the provided
plans. In consideration of the methods used in their determination, the test boring locations shown on
the attached Boring Location Plan and elevations shown on the attached Boring Logs should be
considered approximate.
The test borings were performed in accordance with generally accepted practice using an ATV-mounted
CME-550X rotary drill rig equipped with an automatic hammer. Hollow-stem augers were advanced to
pre-selected depths and representative soil samples were recovered with a standard split-spoon
sampler(1 3/8 in. ID, 2 in. OD) in general accordance with ASTM D 1586,the Standard Penetration Test.
Utilizing an automatic hammer, a weight of 140 pounds is freely dropped from a height of 30 inches to
drive the split-spoon sampler into the soil. The number of blows required to drive the split-spoon
sampler three consecutive 6-inch increments is recorded, and the blows of the last two increments are
summed to obtain the Standard Penetration Resistance (N-value). The N-value provides a general
indication of in-situ soil conditions and has been correlated with certain engineering properties of soils.
Rock coring was performed in each boring to explore the auger refusal materials encountered. The
borings were advanced beyond auger refusal using rock-coring techniques generally following the
procedures outlined in ASTM D 2113. The rock cores were logged by a member of our professional staff
and relative hardness, rock type, percent recovery, and rock quality designation (RQD) were measured.
The percent recovery is the ratio of the sample length obtained to the total length of the core run,
Hazen and Sawyer Addendum No.1—Twelve Mile Creek WRF9.0 MGD Expn.
F&R Project No. 63A-0012 2 28 February 2023

r&R
expressed as a percent. The RQD is the percentage of the length of the core recovered in segments 4 or
more inches long, compared to the total length of the core run. Care is taken during observation of the
core to see that breaks in the core length caused by drilling or handling are ignored in the RQD
determination. The percent recovery and RQD are related to rock soundness and continuity. The
percent recovery and RQD values are shown on the attached boring logs.
Subsurface water level readings were taken in each of the borings during drilling and immediately upon
completion of the soil drilling process. By the nature of the work performed, our field exploration
activities resulted in disturbances to the site. Reasonable efforts were made to lessen potential impacts
of the field exploration. Following the completion of rock coring,the borings were backfilled with auger
cuttings. Periodic observation and maintenance of the boreholes should be performed due to potential
subsidence at the ground surface, as the borehole backfill could settle over time. F&R assumes no
responsibility for borehole subsidence after demobilizing from the site and recommends that others
occasionally observe the boring locations and provide any additional infill that may be needed.
Representative portions of the split-spoon soil samples obtained throughout the exploration program
were sealed in air-tight containers and transported to our laboratory. The collected samples were
evaluated by a member of our professional staff in general accordance with techniques outlined in the
visual-manual identification procedure (ASTM D 2488) and the Unified Soil Classification System. The
soil descriptions and classifications discussed in this report and shown on the attached Boring Logs are
generally based on visual observation and should be considered approximate. Copies of the boring logs
are provided and classification procedures are further explained in the attached appendix.
Split-spoon soil samples recovered on this project will be stored at F&R's office for a period of sixty days.
After sixty days,the samples will be discarded unless prior notification is provided to us in writing.
SUBSURFACE CONDITIONS
The subsurface conditions discussed in the following paragraphs, and those shown on the attached
Boring Logs, represent an estimate of the subsurface conditions based on interpretation of the boring
data using normally accepted geotechnical engineering judgments. The strata breaks designated on the
Boring Logs represent approximate boundaries between soil types. Actual transitions between soil
strata are generally less distinct than the immediate transitions depicted on the Boring Logs. Although
individual soil test borings are representative of the subsurface conditions encountered at the boring
locations on the dates shown, they are not necessarily indicative of subsurface conditions at other
locations or at other times.
Below the existing ground surface, the supplemental borings generally encountered existing surficial
soils underlain by residual soils, partially weathered rock, auger refusal and rock. These materials are
discussed further below:
Surficial Materials
Surficial soils were encountered in each of the borings to depths of approximately 3 to 6 inches.
Surficial soils are typically a dark-colored soil material containing roots, fibrous matter, and/or other
organic components, and are generally unsuitable for engineering purposes. We note that no
laboratory testing has been performed to determine the organic content or horticultural properties of
the observed surficial soil materials. Therefore, the term "surficial soils" is not intended to indicate
suitability for landscaping and/or other purposes. The surficial soil depths provided in this report are
based on driller observations and should be considered approximate. The transition from surficial soils
to underlying materials may be gradual and therefore the observation and measurement of surficial soil
depths is subjective. Actual surficial soils depths should be expected to vary across the site.
Hazen and Sawyer Addendum No.1—Twelve Mile Creek WRF9.0 MGD Expn.
F&R Project No. 63A-0012 3 28 February 2023

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Residual Soils
Residual soils, formed by the in-place weathering of the parent rock, were encountered in each of the
test borings below the pavement base stone. The sampled residual soils were generally described as
sandy and clayey silt (ML) and silty clay (CL). Standard penetration resistances in the sampled residuum
ranged from 5 to 46 blows per foot(bpf).
Partially Weathered Rock
Partially weathered rock (PWR) is a transitional material between soil and rock, which retains the relic
structure of the rock and has very hard or very dense consistencies. PWR was encountered at a depth of
17 feet below existing grade in boring 0-2. A possible layer of PWR was also inferred in boring 0-1 at a
depth of 12 feet based on hard drilling at that level; however, the possible PWR was not sampled.
Sampled partially weathered rock was described as silty sand (SM) with penetration resistances of 50
blows per 5 inches (50/5) of split-spoon penetration.
Auger Refusal and Rock
Auger refusal occurs when materials are encountered that cannot be penetrated by the soil auger and is
normally indicative of a very hard or very dense material, such as boulders, rock lenses, pinnacles,
impenetrable debris within fill, or the upper surface of bedrock. Auger refusal materials were
encountered at in borings 0-1 and 0-2 at depths of 14 feet and 23.5 feet below existing grade,
respectively(approximate elevations of 484 and 477 feet, respectively).
Rock coring was performed in each boring to advance the borings beyond encountered auger refusals.
Rock recovered during the coring operations was generally described as greenish gray slate and phyllite.
Specific descriptions of recovered rock are provided on the respective boring logs as well as an
accompanying Rock Core Summary and Photograph Log. The Percent Recovery and Rock Quality
Designation (RQD) of the rock core samples ranged from 37 to 97%and 0 to 7%, respectively.
Groundwater Data
Groundwater was encountered at depths of 14.1 feet and 10.7 feet during drilling in borings 0-1 and
0-2, respectively. It should be noted that groundwater levels fluctuate depending upon seasonal factors
such as precipitation and temperature.
RECOMMENDATIONS AND CONCLUSIONS
General
The following findings and conclusions are based on our observations at the site, interpretation of the
field and laboratory data obtained during this exploration, and our experience with similar subsurface
conditions and projects. Soil penetration and rock core data has been used to develop foundation
support recommendations for the outfall end-wall structure and evaluate potential excavation
conditions based on previous experience and resulting empirical correlations. Subsurface conditions in
unexplored locations may vary from those encountered.
The subsurface exploration aids the geotechnical engineer in determining the soil stratum appropriate
for structural support. This determination includes considerations with regard to both allowable bearing
capacity and compressibility of the soil and rock strata. In addition, since the method of construction
greatly affects the soils intended for structural support, consideration must be given to the
implementation of suitable methods of site preparation, fill compaction, and other aspects of
construction.
Hazen and Sawyer Addendum No.1—Twelve Mile Creek WRF9.0 MGD Expn.
F&R Project No. 63A-0012 4 28 February 2023

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Foundation Recommendations
As previously stated,we understand the outfall end-wall will be a cast-in-place concrete structure with a
footprint of about 17 feet by 16 feet. The structure has a planned bearing elevation of 484.00 feet and a
bottom of key elevation of 482.00 feet. Based on the existing grades of about 485 to 498 feet shown on
the provided plans, excavations up to about 14 feet below existing grade will be required to reach the
planned bearing elevation of 484.00 feet.
Borings 0-1 and 0-2 were performed at distances of about 40 feet and 25 feet from the proposed outfall
structure, respectively. The subsurface conditions encountered at the foundation bearing elevation of
484.00 feet varied between borings 0-1 and 0-2. Based on the conditions encountered in boring 0-2,
we recommend an allowable design bearing pressure of 3,000 pounds per square foot (psf) for the
outfall end-wall structure. Based in the available project information and the subsurface soils
encountered in boring 0-2, an allowable bearing pressure of up to 3,000 psf should yield less than 1/2
inch of total settlement for the outfall structure.
Rock was encountered in boring 0-1 at a depth of 14 feet below existing grade (approximate elevation
of 484 feet). Therefore, rock may be present at or above the foundation bearing elevation. The
structure may bear on rock; however, should rock and soil be present at the foundation bearing
elevation, some over-excavation of the rock may be required to mitigate potential issues with
differential settlement and uneven pressures. If soil is also present,we generally recommend that rock
is over-excavated to a depth of at least 12 inches below foundation bearing and backfilled with
compacted structural fill.
All foundation subgrades should be observed, evaluated, and verified for the design bearing pressure by
a representative of the geotechnical engineer after excavation and prior to reinforcement steel
placement. Depending on the results of the above recommended foundation subgrade verification,
some undercutting, in-place densification, and/or subgrade materials replacement may be required.
The actual need for, and extent of, undercutting or in-place stabilization or subgrade materials
replacement should be based on field observations made by a representative of the geotechnical
engineer at the time of construction.
Excavations for footings should be made in such a way as to provide bearing surfaces that are firm and
free of loose, soft, wet, or otherwise disturbed soils. Foundation concrete should not be placed on
frozen or saturated subgrades. If such materials are allowed to remain below foundations, settlements
will increase. Foundation excavations should be concreted as soon as practical after they are excavated.
If an excavation is left open for an extended period, a thin mat of lean concrete should be placed over
the bottom to minimize damage to the bearing surface from weather or construction activities. Water
should not be allowed to pond in any excavation.
Lateral Earth Pressures
See Section 4.5 in the Report of Subsurface Exploration and Geotechnical Engineering Services prepared
by F&R dated 16 September 2022 provides general commentary and recommendations on Lateral Earth
Pressures; however, the following paragraphs and table provide some structure-specific
recommendations for the outfall structure.
Based on the subsurface exploration, available on-site backfill materials for outfall end-wall will
predominately consist of silty clay (CL), sandy silt (ML) and clayey silt (ML). If encountered during
construction or if an off-site source for materials is required, we do not recommend the use of highly-
plastic clays and silts(CH and MH) behind below grade walls.
The following table provides lateral earth pressure parameters for a mixture of the onsite silty clay (CL),
sandy silt(ML) and clayey silt(ML) soils.
Hazen and Sawyer Addendum No.1—Twelve Mile Creek WRF9.0 MGD Expn.
F&R Project No. 63A-0012 5 28 February 2023

r&R
ON-SITE SOILS MIXTURE (CL/ML)
Earth Pressure Conditions Coefficient
Recommended Equivalent Fluid
Pressure (pcf)
Active(Ka) 0.39 47
At-Rest(Kr) 0.56 67
Passive (Kr) 2.77 ---
*A compacted moist soil unit weight of 120 pounds per cubic foot should be used for design calculations.
Excavation Conditions
The structure has a planned bearing elevation of 484.00 feet and a bottom of key elevation of 482.00
feet. Rock was encountered in boring 0-1 at a depth of 14 feet below existing grade (approximate
elevation of 484 feet). Therefore, rock may be present in excavations for the outfall end-wall structure,
particularly the key that extends to elevation 482.00 feet.
See Section 5.7 in the Report of Subsurface Exploration and Geotechnical Engineering Services prepared
by F&R dated 16 September 2022 for further details on Excavation Characteristics.
Groundwater Conditions
Groundwater was encountered in borings 0-1 and 0-2 at depths of 14.1 feet and 10.7 feet, respectively
(approximate elevations of 484 and 483 feet, respectively). We envision that the levels that
groundwater was encountered at during this study will lower following the installation of the planned
cofferdam and water has been pumped out of the work area inside of the dam. However, some water/
groundwater and wet soils should be anticipated.
Groundwater levels fluctuate depending upon seasonal factors such as precipitation and temperature.
Additionally,groundwater measurements made in predominantly cohesive and fine-grained soils are not
necessarily indicative of the actual static subsurface water level due to the low permeability of such
soils. As such, soil moisture and groundwater conditions at other times may vary or be different from
those described in this report.
LIMITATIONS
This letter report has been prepared for the exclusive use of Hazen and Sawyer for the specific
application to the proposed Twelve Mile Creek WRF 9.0 MGD Expansion project located in Union
County, North Carolina, in accordance with generally accepted geotechnical engineering practices. No
other warranty, express or implied, is made. Our recommendations are based on design information
furnished to us at the time the work was performed; the data obtained from the previously described
subsurface exploration program, and generally accepted geotechnical engineering practice. The findings
and recommendations do not reflect variations in subsurface conditions, which could exist in
unexplored areas of the site. In areas where variations from the available subsurface data become
apparent during construction, it will be necessary to re-evaluate our recommendations based upon on-
site observations of the conditions.
Regardless of the thoroughness of a subsurface exploration, there is the possibility that conditions in
other areas will differ from those at the boring locations, that conditions are not as anticipated by the
designers, or that the construction process has altered the soil conditions. Therefore, our experienced
geotechnical engineers should evaluate foundation construction to verify that the conditions anticipated
in design actually exist. Otherwise, we assume no responsibility for construction compliance with the
design concepts, specifications, or recommendations. In the event that changes are made in the design
or location of the proposed structures, the recommendations presented in this report shall not be
Hazen and Sawyer Addendum No.1—Twelve Mile Creek WRF9.0 MGD Expn.
F&R Project No. 63A-0012 6 28 February 2023

r&R
considered valid unless the changes are reviewed by our firm and recommendations of this report
modified or verified in writing. If this report is copied or transmitted to a third party, it must be copied
or transmitted in its entirety, including text, attachments, and enclosures. Interpretations based on only
a part of this report may not be valid.
CLOSURE
We appreciate the opportunity to provide continued services for this project. Please contact us if you
have any questions regarding this report addendum.
Sincerely,
FROEHLING &ROBERTSON, INC. ,,'(H,CARO,,
+O.64SS/Ni.
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;-fyN.NGNE G1,,,,
EAIT.
AlexanderT. Kuczero, P.E. ''',,F,,k,,,,,, R Frank,P.E.
Geotechnical Engineer Regional Senior Geotechnical Engineer
Email Distribution: [e-mail]; [e-mail];
Attachments: Boring Location Plan (Drawing No. 1)
Key to Boring Log Soil Classification
Key to Boring Log Rock Classification
Soil Classification Chart
Boring Logs(0-1 and 0-2)
Rock Core Summary and Photograph (0-1 and 0-2)
F:\Projects 63A\63A-0012(Hazen and Sawyer-12-Mile Creek WRF 9.0 MGD Expansion)\Report\63A-0012(Hazen and Sawyer-12-Mile Creek WRF 9.0 MGD Expansion)Geo Report.Addendum No.I.DOC
Hazen and Sawyer Addendum No.1—Twelve Mile Creek WRF9.0 MGD Expn.
F&R Project No. 63A-0012 7 28 February 2023

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Soil Test Boring Locations
0' 20' 40'
DATE: February 2023
r&RFROEHLING ROBERTSON
Engineering Stability Since 1881 SCALE: As Shown
DRAWN: ATK 63A-0012
Hazen and Sawyer DRAWING NO.
12-Mile Creek WRF Expansion BORING LOCATION PLAN
Waxhaw, North Carolina 1

MOB
IBM
KEY TO BORING LOG SOIL CLASSIFICATION
Particle Size and Proportion
Visual descriptions are assigned to each soil sample or stratum based on estimates of the
particle size of each component of the soil and the percentage of each component of the soil.
Particle Size Proportion
Descriptive Terms Descriptive Terms
Soil Component Particle Size Component Term Percentage
Boulder > 12 inch Major Uppercase Letters >50%
Cobble 3 - 12 inch (e.g., SAND,CLAY)
Gravel-Coarse 3/4-3 inch
-Fine #4-3/4 inch Secondary Adjective 20% - 50%
Sand-Coarse #10-#4 (e.g., sandy, clayey)
-Medium #40-#10
-Fine #200-#40 Minor Some 15% -25%
Silt(non-cohesive) <#200 Little 5% - 15%
Clay(cohesive) <#200 Trace 0% -5%
Notes:
I. Particle size is designated by U.S. Standard Sieve Sizes
2. Because of the small size of the split-spoon sampler relative to the size of gravel,the true percentage of gravel
may not be accurately estimated.
Density or Consistency
The standard penetration resistance values (N-values) are used to describe the density of
coarse-grained soils (GRAVEL, SAND) or the consistency of fine-grained soils (SILT, CLAY).
Sandy silts of very low plasticity may be assigned a density instead of a consistency.
DENSITY CONSISTENCY �I
Term N-Value Term N-Value
II II II
Very Loose 0-4 Very Soft 0- 1
Loose 5 - 10 Soft 2-4
Medium Dense 11 -30 Firm 5 -8
Dense 31 -50 Stiff 9- 15
Very Dense >50 Very Stiff 16-30
Hard >30
Notes:
I. The N-value is the number of blows of a 140 lb.Hammer freely falling 30 inches required to drive a standard
split-spoon sampler(2.0 in.O.D., 1-3/8 in.I.D.) 12 inches into the soil after properly seating the sampler 6
inches.
2. When encountered,gravel may increase the N-value of the standard penetration test and may not accurately
represent the in-situ density or consistency of the soil sampled.
L
F:\Branch 62\GEOWORD\REPORTS\kcyblsc.cnc.doc

SOIL CLASSIFICATION CHART
MAJOR DIVISIONS SYMBOLS TYPICAL
GRAPH LETTER DESCRIPTIONS
•mil•'
CLEAN •�• 4• WELL-GRADED GRAVELS,GRAVEL-
GRAVEL GRAVELS IA. ��'� *1 GW SAND MIXTURES,LITTLE OR NO
AND •• 11. 0 S FINES
GRAVELLY •+ii •+•:
SOILS '4,• •4• POORLY-GRADED GRAVELS,
(LITTLE OR NO FINES) 0. e�i, 01 GP GRAVEL-SAND MIXTURES,LITTLE
•• 15 •• 15 OR NO FINES
COARSE •+"
GRAINED GRAVELS WITH 4 •1 SILTY GRAVELS, GRAVEL-SAND-
SOILS MORE THAN 50% FINES ' : GM SILT MIXTURES
OF COARSE •• •
FRACTION •
RETAINED ON NO. ,
4 SIEVE (APPRECIABLE r. GC
CLAYEY GRAVELS,GRAVEL-SAND-
AMOUNT OF FINES) ��� CLAY MIXTURES
CLEAN SANDS WELL-GRADED SANDS,GRAVELLY
MORE THAN 50% SAND SW SANDS,LITTLE OR NO FINES
OF MATERIAL IS AND
> 00000000
LARGER THAN SANDY
NO.200 SIEVE SOILS POORLY-GRADED SANDS,
SIZE (LITTLE OR NO FINES) SP GRAVELLY SAND,LITTLE OR NO
FINES
SANDS WITH - - SILTY SANDS,SAND-SILT
MORE THAN 50% FINES - - - SM MIXTURES
OF COARSE -
FRACTION J
PASSING ON NO.
4 SIEVE AMOUNT OF FINES)APPRECIABLE SC MIXTURES
CLAYEY SANDS,SAND-CLAY
INORGANIC SILTS AND VERY FINE
ML SANDS,ROCK FLOUR,SILTY OR
CLAYEY FINE SANDS OR CLAYEY
SILTS WITH SLIGHT PLASTICITY
SILTS j INORGANIC CLAYS OF LOW TO
FINE AND LIQUID LIMIT CL MEDIUM PLASTICITY,GRAVELLY
CLAYS
GRAINED LESS THAN 50 / CLAYS,SANDY CLAYS,SILTY
CLAYS,LEAN CLAYS
SOILS — — —
OL ORGANIC SILTS AND ORGANIC
SILTY CLAYS OF LOW PLASTICITY
MORE THAN 50% INORGANIC SILTS,MICACEOUS OR
OF MATERIAL IS j MH DIATOMACEOUS FINE SAND OR
SMALLER THAN SILTY SOILS
NO.200 SIEVE
SIZE
SILTS
AND LIQUID LIMIT //7 CH PLASTICITY
CLAYS OF HIGH
CLAYS GREATER THAN 50 PLASTICITY
i
OH ORGANIC CLAYS OF MEDIUM TO
HIGH PLASTICITY,ORGANIC SILTS
�`�� �'�� �`�� PEAT,HUMUS,SWAMP SOILS WITH
HIGHLY ORGANIC SOILS PT HIGH ORGANIC CONTENTS
NOTE: DUAL SYMBOLS ARE USED TO INDICATE BORDERLINE SOIL CLASSIFICATIONS

•u s.
us'
KEY TO BORING LOG ROCK CLASSIFICATION (PAGE 1 OF 2)
Classification of rock is based on the following characteristics: Weathering, Discontinuities, Color and
Grain Size, Hardness,Voids, Geologic Lithology, and Rock Quality Designation (RQD).
WEATHERING
TERM SYMBOL DESCRIPTION
Fresh F No visible sign of decomposition or discoloration. Crystals are bright
Slightly Weathered WS Slight discoloration inward from open fractures.
Moderately Weathered WM Discoloration throughout. Weaker minerals decomposed. Strength
somewhat less than fresh rock, but cores cannot be broken by hand or
scraped by knife. Texture preserved. Joints may contain clay.
Highly Weathered WH Most minerals somewhat decomposed. Specimens can be broken by hand
with effort or shaved with knife. Core stones present in rock mass. Texture
becoming indistinct but fabric preserved.
Completely Weathered WC Minerals decomposed to soil but fabric and structure preserved (saprolite).
Specimens easily crumbled or penetrated.
Residual Soil RS Advanced state of decomposition resulting in plastic soils. Rock fabric and
structure completely destroyed.
DISCONTINUITIES
SPACING * BANDING, BEDDING, FOLIATION FAULTS,JOINTS,and other
FRACTURES
Greater than 6.0 feet Very Thick Very Wide
2.0—6.0 feet Thick Wide
8-24 inches Medium Medium
2.5—8 inches Thin Close
3 to 2.5 inches Very Thin Very Close
SPACING* LAMINATION, FOLIATION,or FAULTS,JOINTS,and other
CLEAVAGE FRACTURES
-3 inch Intense
Less than%inch Very Intense Extremely Close
*—Spacing is the perpendicular distance between discontinuities.
TYPE of DISCONTINUITY ATTITUDE(DIP)
TERM CONDITION TERM EXISTING
ANGLE
A fracture along which no movement has
Horizontal 0 5
Joint
occurred. Low Angle 5-35
Bedding A natural plane dividing sedimentary rock layers Moderate Angle 35-55
Plane
Shear Plane A fracture along which some movement has High Angle 55-85
occurred.
Fault A zone of fractured rock containing one or more Vertical 95-90
shear plane and areas of gouge

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s
KEY TO BORING LOG ROCK CLASSIFICATION (PAGE 2 OF 2)
ROCK GRAIN SIZE
IGNEOUS AND METAMORPHIC ROCKS SEDIMENTARY ROCKS
Coarse Grained Diameter>5 mm (3/16 in) Coarse Grained Diameter>2 mm (1/16 in)
Medium Grained 1 mm(1/32 in)—5 mm (3/16 in) Medium Grained 0.06 mm—2 mm (1/16 in)
Fine Grained <1 mm(1/32 in) Fine Grained 0.002 mm—0.06 mm
Glassy Grains not visible with unaided eye. Very Fine Grained Grains not visible with unaided eye.
VOIDS
TERM SIZE OF VOID
Pit <6 mm(1/4 inch)
Vug 6 mm—50 mm(2 inches)
Cavity 50 m—0.6 m(2 feet)
Cave >0.6 m
ROCK HARDNESS
CLASS HARDNESS FIELD TEST
II Extremely Hard Many blows with a geologic hammer required to break intact specimen.
II Very Hard Hand-held specimen breaks with hammer end of pick under more than one
blow.
III Hard Cannot be scraped or peeled with knife, hand-held specimen can be broken
with single moderate blow with pick.
IV Soft Can just be scraped or peeled with knife.
V Very Soft Material crumbles under moderate blow with sharp end of pick and can be
peeled with a knife.
ROCK QUALITY DESIGNATION ** (RQD)
ROCK QUALITY DESIGNATION **,% ROCK MASS DESCRIPTION
90-100 Excellent
75-90 Good
50-75 Fair
25-50 Poor
<25 Very Poor
** - RQD is the ratio of the cumulative length of all pieces of rock greater than or equal to four inches to
the total length drilled, expressed as a percentage

BORING LOG
r&RFROEHLING ROBERTSON Boring: 0-1 (1 of 1)
Project No:63A-0012 Elevation:498± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:23.6' Hammer Type:Automatic
Project: 12-Mile Creek WRF Outfall Boring Location:See Boring Location Plan Date Drilled: 12/5/22
City/State:Waxhaw, NC Driller: HPC:J. Cain
Elevation Depth Description of Materials *Sample Sample
ep h N-Value Remarks
(Classification) Blows (feel) (blows/ft)
497.8 - 0.3 -"'"\SURFICIAL SOIL:3 inches ` 1-4-9 0 Groundwater was
RESIDUUM:Stiff to very stiff, brown, clayey 13 encountered at 14.1 feet
SILT(ML)with trace organics, moist 2.5 during drilling.
2.0
10-12-9
- 21
494.5 - 3.5 Stiff,tan,fine to medium sandy SILT(ML), moist 4-5-4 3.5
-
- 9
— 5.0
492.0 - 6.0 / 2-2-3 6.0
Firm, brown and gray,silty CLAY(CL), moist
5
7.5
1-2-3 8.5
5
10.0
486.0 - 12.0
i PARTIALLY WEATHERED ROCK: Not Sampled Hard drilling 12 to 14 feet
484.0 - g14.0 ROCK: Highly weathered to fresh, closely REC=37% 14.0 Auger refusal at 14 feet.
fractured (high angle), hard to very hard,fine RQD=0% Rock coring started at 14
-j grained,greenish gray,SLATE feet.
--,j
J/ REC=97% 18.6
-;/ RQD=23%
i,%
474.4 - 23.6 23.6
Coring Terminated at 23.6 feet
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

Rock Core Summary and Photograph
Boring 0-1: 14.0 to 18.6' — Rec = 37%, RQD = 0%
18.6 to 23.6' — Rec = 97%, RQD = 23%
'll il ' Atr---- - ---,..........._ , -------
mix 1,
• t 14.0' ;3
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i . >;� 18.6 QD w,
is
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DATE: February 2023
p FROEHLING ROBERTSON
r8cR SCALE: As Shown
Engineering Stability Since 1881
DRAWN: DJM 63A-0012
Hazen and Sawyer BORING NO.
12-Mile Creek WRF Expansion ROCK CORE SUMMARY
Waxhaw, North Carolina AND PHOTOGRAPH 0-1

BORING LOG
r&RFROEHLING ROBERTSON Boring: 0-2 (1 of 1)
Project No:63A-0012 Elevation:494± Drilling Method: HSA
Client: Hazen and Sawyer Total Depth:32.0' Hammer Type:Automatic
Project: 12-Mile Creek WRF Outfall Boring Location:See Boring Location Plan Date Drilled: 12/2/22
City/State:Waxhaw, NC Driller: HPC:J. Cain
Elevation Depth Description of Materials *Sample Sample
ep h N-Value Remarks
(Classification) Blows (feet) (blows/ft)
493.5 - 0.5
.'A,7' \SURFICIAL SOIL:6 Inches 2-9-2 0.0 Groundwater was
- RESIDUUM:Stiff, brown red,fine to medium 11 encountered at 10.7 feet
sandy SILT(ML)with trace organics and rock 1•5 during drilling
fragments, moist 4-4-5 2.0
9
490.5 - 3.5 6 10 14 3.5
- Very stiff, brown and tan,fine to medium sandy
- SILT(ML), moist 24
5.0
9-10-16 6.0
26
7.5
486.0 - 8.0 - Hard,tan,fine to medium sandy SILT(ML), 8.5
- moist 16-23-23
46
10.0
SZ -
482.0 - 12.0 1-
- Stiff, red brown,fine to medium sandy SILT(ML) 12.7
- with some rock fragments, moist 27-8-6
14
14.2
477.0 - 17.0- PARTIALLY WEATHERED ROCK:Sampled as very
` dense, brown gray,silty fine to coarse SAND
� (SM), moist 50/5 18.5
100+
20.0
_)
470.5 - 23.5 23.5 Auger refusal at 23.5 feet.
ROCK: Moderately weathered to fresh, closely REC=96% Au g
fractured (high angle), hard,fine grained, RQD=36% Rock coring started at
-4 greenish gray and white,SLATE 23.5 feet.
REC=94% 28.0
465.0 - 29.0 _ RQD=0%
Lightly weathered to fresh, closely fractured
(high angle), hard to very hard,fine grained,
greenish gray and white, PHYLLITE
462.0 - 32.0 - '' 32.0
Coring Terminated at 32.0 feet
*Number of blows required for a 140 lb hammer dropping 30"to drive 2"O.D.,1.375"I.D.sampler a total of 18 inches in three 6"increments.
The sum of the second and third increments of penetration is termed the standard penetration resistance,N-Value.

Rock Core Summary and Photograph
Boring 0-2: 23.5 to 28.0' — Rec = 96%, RQD = 36%
28.0 to 32.0' — Rec = 94%, RQD = 0%
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DATE: February 2023
I-8RFROEHLING ROBERTSON
� SCALE: As Shown
Engineering Stability Since 1881
DRAWN: DJM 63A-0012
Hazen and Sawyer BORING NO.
12-Mile Creek WRF Expansion ROCK CORE SUMMARY
Waxhaw, North Carolina AND PHOTOGRAPH 0-2