SW3191204_SHWT Report_20200515

,&
C- BRATING 15 Ywts
■/
SUMMIT
ENG I N EZRI NG, LA 6OR ATORY & TESTING, P.C_
September 6, 2019
Mr. Gene Vaughan
Barnette Store, LLC
231 Post Office Drive, Suite B-8
Indian Trail, North Carolina 28079
Email: Gvaughan cgthemosergroupinc.com
Subject: Estimated Seasonal High Water Table (ESHWT) Determination
Old Charlotte Hwy Multi -Family
4610 and 4612 Old Charlotte Highway
Monroe, North Carolina
SUMMIT Project No. 5720.500
Dear Mr. Vaughan:
SUMMIT Engineering, Laboratory and Testing, P. C. (SUMMIT) is pleased to submit this letter
summarizing our observations of the soil test borings as related to Estimated Seasonal High Water
Table Elevation (ESHWT) determinations. This report contains a brief description of the project
information provided to us, general site and subsurface conditions revealed during this study.
PURPOSE OF STUDY
The primary purpose of this study was to obtain information regarding the subsurface conditions
near the proposed stormwater ponds, assess the engineering characteristics of the subsurface
materials, and determination of the estimated seasonal high water table mark (if evident). This
report contains the following items:
ENGINEERING • LABORATORY • TESTING
3575 Centre Circle Drive I Fort Mill, South Carolina 29715 1 (704) 504 - 1717 1 (704) 504 - 1125 (Fax)
WWW. SU M M 1T-COM PAN I ES. COM

Summary of ESHWT Determination SUMMIT Project No. 5720.500
Old Charlotte Hwy Multi -Family September 6, 2019
• Photographic Logs, Site Vicinity Map and Boring Location Plan,
• Summary of Test Boring Observations, visual soil classifications and descriptions,
• A general review of the subsurface soils and estimated seasonal high water table depth
from existing ground surface (if evident),
• Groundwater level measurements.
EXPLORATION PROCEDURES
SU1VUMT visited the site on August 14, 2019 to perform two (2) soil test borings (identified as
Borings SW-1 and SW-2) in the proposed stormwater ponds. The approximate locations of the
borings were shown on Figure 2 — "Boring Location Plan" provided in Appendix 2. The client
(Barnette Store, LLC) provided SUNMUT a plan that indicated the approximate location of the
proposed stormwater ponds. The borings were located by professionals from our office using the
provided plan, recreation -grade handheld GPS, existing topography, and aerial maps as reference.
Since the boring locations were not surveyed, the location of the borings should be considered
approximate. Also, the elevations provided on the Boring Logs were interpolated from the
topographic information from the provided plan.
The soil test boring was performed using an ATV -mounted CME 550X drill rig, and Borings SW-
1 and SW-2 were extended to approximate depths of 16 and 8.1 feet below the existing ground
surface, respectively. Hollow -stem, continuous flight auger drilling techniques were used to
advance the boring into the ground. Standard Penetration Tests (SPT) were performed within the
mechanical boring at designated intervals in general accordance with ASTM D 1586. When
properly evaluated, the SPT results can be used as an index for estimating soil strength and density.
In conjunction with the penetration testing, representative soil samples were obtained from each
test location and returned to our laboratory for visual classification and potential laboratory testing.
The soil samples collected were visually examined and classified in general accordance with
ASTM D-2488. The Munsell Soil Color Charts (2009 Revision) were used to identify the hue,
value, and chroma of soil samples. Water level measurements were attempted at the termination
of drilling. The classification symbols are depicted on the "Boring Log" provided in Appendix 3.
2

Summary of ESHWT Determination SUMMIT Project No. 5720.500
Old Charlotte Hwy Multi -Family September 6, 2019
GENERALIZED SUBSURFACE STRATIGRAPHY
General subsurface conditions observed during our geotechnical study are described herein. For
more detailed soil descriptions and stratifications at a particular test location, the respective
"Boring Log" provided in Appendix 3 should be reviewed. The horizontal stratification lines
designating the interface between various strata represent approximate boundaries. Transitions
between different strata in the field may be gradual in both the horizontal and vertical directions.
Beginning from the ground surface, a layer of topsoil (surficial organic soils) was observed at the
with a thickness of approximately 2 inches. Beneath the topsoil layer, a thin approximate 6-inch
layer existing fill soils was observed in the borings that consisted of sandy silts. Beneath the
existing fill soils, residual (undisturbed) soils were encountered that consisted of lean clays and
sandy silts. Partially Weathered Rock (PWR) conditions were encountered Boring SW-1 between
the approximate depths of 6 to 14 feet and Boring SW-2 at an approximate depth of 6 feet. Auger
refusal conditions were encountered in Boring SW-2 at an approximate depth of 8.1 feet.
GROUNDWATER LEVEL MEASUREMENTS
At the time of drilling and after waiting more than 24 hours, groundwater was not observed in the
boring. Please note that groundwater levels tend to fluctuate with seasonal and climatic variations,
as well as with some types of construction operations.
ESTIMATED SEASONAL HIGH WATER TABLE
ESHWT is defined as the shallowest depth to a wet soil layer as a result of "true" or "permanent"
groundwater at any time during the year. The ESHWT is typically identified with a change in the
color of the soil layer due to water staining (typically, gray redoximorphic depletions and
mottling). Spots or blotches of different color or shades of color interspersed with a dominant color
in soil, commonly referred to as mottling. Mottling is a historic indication for the presence of
ground water caused by intermittent periods of saturation and drying, and may be indicative of
poor aeration and impeded drainage. Mottling is a "general indication of groundwater" flow
3

Summary of ESHWT Determination
Old Charlotte Hwy Multi -Family
SUMMIT Project No. 5720.500
September 6, 2019
through this layer, but it is not known whether the groundwater flow was recent.
CONCLUSIONS
Based on our observations, Estimated Seasonal High Water Table (ESHWT) indicators (water
stained soils) indicators were not evident in soils sampled in the borings. However, we did observe
some water staining in the soil stratum situated above the low permeable partially weathered rock
(PWR) stratum. The water staining most likely developed during perched water conditions.
Perched water conditions differ from the "true" or "permanent" water table. A perched water table
is water standing above an unsaturated zone and is often influenced by soil conditions, and
occurrence of less permeable soils. Where the ESHWT is defined as the shallowest depth to a wet
soil layer as a result of "true" or "permanent" groundwater at any time during the year. The BMP
designer should take into consideration that perched water conditions may exist above the low
permeable PWR stratum.
The following table summarizes the results of the boring and our observations.
Summary Table of the Boring Results and Our Observations
Auger
GW Depth
PWR
Refusal
Boring
ESHWT
GW Depth
After
Approx.
Approx.
Test
Depth
Depth
ATD
24 Hours
Depth
Depth
Location
(Feet)'
(Feet)'
(Feet)'
(Feet)'
(Feet)'
(Feet)'
SW-1
16
NE
NE
NE
6 to 14
NE
SW-2
8.1
NE
NE
NE
6
8.1
1 Depths from existing ground surface.
NE — Not Encountered in Boring.
The analyses and recommendations submitted in this report were based, in part, on data obtained
from this study. If the above -described project conditions are incorrect or changed after the issuing
of this report, or subsurface conditions encountered during construction are different from those
4

Summary of ESHWT Determination
Old Charlotte Hwy Multi -Family
SUMMIT Project No. 5720.500
September 6, 2019
reported, SUNIlMT should be notified and these recommendations should be re-evaluated based
on the changed conditions to make appropriate revisions. We have prepared this report according
to generally accepted geotechnical engineering practices. No warranty, express or implied, is
made as to the professional advice included in this report.
CLOSING
SUNMT appreciates the opportunity to provide our professional services for you on this project.
If you have any questions concerning the information in this proposal or if we may be of further
service, please contact us at 704.504.1717.
Sincerely,
SUNUMT
Todd A. Costner, E.I.
Senior Professional
LIST OF APPENDICES
1 Photographic Log
2 Figure No. 1 —Site Location Map
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Figure No. 2 — Test Boring Location Plan
3 Boring Log
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9/9/19
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Kerry C. Cooper, P.E.
Geotechnical Department Manager

Summary of ESHWT Determination
Old Charlotte Hwy Multi -Family
SUMMIT Project No. 5720.500
September 6, 2019
/ -71&
rELEBRATING 15 YEARS
SUMMIT
ENGINEERING, LABORATORY & TESTING, P.G.
APPENDIX I
Photographic Log

Summary of ESHWT Determination SUMMIT Project No. 5720.500
Old Charlotte Hwy Multi -Family September 6, 2019
Boring SW-1 Samples
(Approximate Depth = 0 to 10 feet below existing ground surface)
Boring SW-1 Samples
(Approximate Depth = 10 to 16 feet below existing ground surface)

Summary of ESHWT Determination
Old Charlotte Hwy Multi -Family
Boring SW-2 Samples
SUMMIT Project No. 5720.500
September 6, 2019
(Approximate Depth = 0 to 8.1 feet below existing ground surface)

Summary of ESHWT Determination
Old Charlotte Hwy Multi -Family
SUMMIT Project No. 5720.500
September 6, 2019
/ -71&
rELEBRATING 15 YEARS
SUMMIT
ENGINEERING, LABORATORY & TESTING, P.G.
APPENDIX 2
Figures

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Public Works a
Equipment & Supply 4t
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Carolina Brick
& Materials
SITE
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1378
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Figure 1 Old Charlotte HwyMulti-Family CEEEBRATING 15 YEARS
Site Vicinity Map 4610 and 4612 Old Charlotte Highway
Monroe, North Carolin SUMMIT
ENGINEERING, LABORATORY & TESTING, P.C.
3575 Centre Circle
Fort Mill, South Carolina 29715
SCALE: NTS SUMMIT Project No.: 5720.500 [phone]

PWR - Approx. Partially Weathered
Figure 2
Boring Location Plan
Approx. Test Pit Location
SW-1
ESHWT — NE
SW-2
ESHWT — NE
�oav
—1
Depth
Old Charlotte Hwy Multi -Family
4610 and 4612 Old Charlotte Highway
Monroe, North Carolin
//M&
SUMMIT
3575 Centre Circle
Fort Mill, South Carolina 29715
[phone]
SCALE:NTS
SUMMIT Project No.: 5720.500

Summary of ESHWT Determination
Old Charlotte Hwy Multi -Family
SUMMIT Project No. 5720.500
September 6, 2019
47
_7411L
r
�'LEBRATING 15 YEARS
SUMMIT
ENGINEERING, LABORATORY & TESTING, P.C.
APPENDIX 3
Boring Log

SUMMIT Engineering, Laboratory & Testing, P.C. KEY TO SYMBOLS
3575 Centre Circle
/
- Fort Mill, South Carolina 29715
SUMMIT 704.504.1717
­....E..... ­„.,o T- „.,,„. summitcompanies.com
CLIENT Barnette Store, LLC PROJECT NAME Old Charlotte Highway Multi -Family
PROJECT NUMBER 5720.500 PROJECT LOCATION Monroe, Union County, North Carolina
LITHOLOGIC SYMBOLS
SAMPLER SYMBOLS
(Unified Soil Classification System)
Standard Penetration Test
F-1 BLANK
® CL: USCS Low Plasticity Clay
FILL: Fill (made ground)
o �,d GP: USCS Poorly -graded Gravel
RHMH: USCS Elastic Silt
MLS: USCS Sandy Silt
TOPSOIL: Topsoil
WELL CONSTRUCTION SYMBOLS
PWR: Partially Weathered Rock
ABBREVIATIONS
LL -LIQUID LIMIT (%) TV -TORVANE
PI -PLASTIC INDEX (%) PID - PHOTOIONIZATION DETECTOR
W - MOISTURE CONTENT (%) UC -UNCONFINED COMPRESSION
DID - DRY DENSITY (PCF) ppm -PARTS PER MILLION
NP -NON PLASTIC Water Level at Time
-200 - PERCENT PASSING NO. 200 SIEVE Drilling, or as Shown
PP - POCKET PENETROMETER (TSF) Water Level at End of
1
Drilling, or as Shown
Water Level After 24
- Hours, or as Shown

SUMMIT Engineering, Laboratory & Testing, P.C. BORING NUMBER SWA
Centre Circle
11AM1k
Fort Mill, South Carolina 29715 PAGE 1 OF 1
Fort
SUMMIT 704.504.1717
summitcompanies.com
CLIENT Barnette Store, LLC PROJECT NAME Old Charlotte Highway Multi -Family
PROJECT NUMBER 5720.500 PROJECT LOCATION Monroe, Union County, North Carolina
DATE STARTED 8/14/19 COMPLETED GROUND ELEVATION 660 ft HOLE SIZE 6 inches
DRILLING CONTRACTOR SUMMIT GROUND WATERICAVE-IN:
DRILLING METHOD Hollow Stem Auger AT TIME OF DRILLING --- GW NE ATD
LOGGED BY D. Smith CHECKED BY T. Costner AT END OF DRILLING --- GW> > 24 Hrs NE
NOTES See Figure 2 "Boring Location Plan" for Approx. Boring Location AFTER DRILLING ---
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MATERIAL DESCRIPTION
Lu
�Lu
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Lu
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UZ
A SPT N VALUE A
0 20 40 60 80 100
PL MC LL
0 20 40 60 80 100
El FINES CONTENT (%)
0 20 40 60 80 100
660.0
Approx. 2" of Topsoil
SPT
1
5-8-10-13
(18)
(ML) FILL: (Cultivated Fill Soils)
Light Gray (10YR, 7/1) Slightly Clayey Slightly Sandy SILT
(CL) RESIDUUM:
Very Stiff Yellow (10YR, 8/8) and Light Gray (10YR, 7/1) Lean
:.......:........:................
CLAY
----------------------------J
(CL) Hard Yellow (10YR, 8/8) and Light Gray (10YR, 7/1) Lean
CLAY with a trace of Rock Fragments
SPT
10-17-18-18
2
(35)
5.0
SPT
3
10-16-16-19
(32)
............. ..:........ :........ :........
655.0
�>
(ML) Partially Weathered Rock (PWR) when sampled becomes
Gray (10YR, 6/1), Yellow (10YR, 8/8) and Light Gray (10YR, 7/1)
SPT
4
38-50
50/2"
Sandy SILT with Rock Fragments
.,
»
Tj SPT
5
25-50
50/2"
10.0
-
l'
.....
>>
650.0
„-. .:
— — — — — — — — — — — — — — — — — — — — — — — — — — — —
(ML) Partially Weathered Rock (PWR) when sampled becomes
Bluish Gray (GLEY 2, 6/1) Sandy SILT with Rock Fragments
SPT
6
50
50/5"
---------------------------
(ML) Partially Weathered Rock (PWR) when sampled become—s
Greenish Gray (GLEY 1, 6/1) Sandy SILT with Rock Fragments
............................................
»
SPT
7
26-50
(50/4")
(ML) Hard Greenish Gray (GLEY 1, 6/1), White (White,
15.0
7.5YR9.5/1) and Yellowish Red (5YR, 5/8) Sandy SILT with Rock
Fragments
SPT
8
19-19-19-22
(38)
645.0
Bottom of Boring at 16 feet bgs, Boring Terminated
20.0

SUMMIT Engineering, Laboratory & Testing, P.C.
BORING NUMBER SW-2
Centre Circle
11AM1k
Fort
Fort Mill, South Carolina 29715
PAGE 1 OF 1
SUMMIT 704.504.1717
summitcompanies.com
CLIENT Barnette Store, LLC PROJECT NAME Old Charlotte Highway Multi -Family
PROJECT NUMBER 5720.500 PROJECT LOCATION
Monroe, Union County, North Carolina
DATE STARTED 8/14/19 COMPLETED GROUND
ELEVATION
663 ft HOLE SIZE 6 inches
DRILLING CONTRACTOR SUMMIT GROUND
WATERICAVE-IN:
DRILLING METHOD Hollow Stem Auger
AT TIME OF DRILLING --- GW NE ATD
LOGGED BY D. Smith CHECKED BY T. Costner
AT END OF DRILLING --- GW> > 24 Hrs NE
NOTES See Figure 2 "Boring Location Plan" for Approx. Boring Location
AFTER DRILLING
---
Lu
o
A SPT N VALUE A
p
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w
0 20 40 60 80 100
PL MC LL
_
Q
a O
MATERIAL DESCRIPTION
�Lu
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Lu
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0
a
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U�
m O>
0 20 40 60 80 100
El FINES CONTENT (%)
w
�Z
<
Lu
UZ
0 20 40 60 80 100
663.0
Approx. 2" of Topsoil
(ML) FILL: (Cultivated Fill Soils)
Light Gray (10YR, 7/1) Slightly Clayey Slightly Sandy SILT
SPT
6-12-12-16
1
(24)
(CL) RESIDUUM:
Very Stiff Yellow (10YR, 8/8) and Light Gray (10YR, 7/1) Lean
:.......:........:................
CLAY
----------------------------J
(CL) Very Stiff Yellow (10YR, 8/8) and Light Gray (10YR, 7/1)
Lean CLAY with a trace of Rock Fragments
SPT
9-13-15-15
2
(28)
5.0
SPT
3
7-8-10-18 ............... :........ :........ :... .....
(18)
658.0
- (ML) Partially Weathered Rock (PWR) when sampled becomes
SPT
50
Yellow (10YR, 8/8) and Light Gray (10YR, 7/1) Sandy SILT with
4
50/5"
Rock Fragments
Bottom of Boring at 8.1 feet bgs, Auger Refusal
SPT
......................................... .
50
5
50/1 "
10.0
653.0
15.0
648.0
20.0