SW3210301_Soils Report (SHWT)_20210309

May 17, 2019
Mr. Travis Manning
Kolter Homes,LLC
8913 Silver Springs Court
Charlotte, North Carolina 28215 Email:
@.com
Subject:Estimated Seasonal High Water Table (ESHWT) Determinations
Cresswind
Potter Road
Union County, North Carolina
SUMMIT Project No. 2409.02
Dear Mr. Manning:
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 detention 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:

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 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
SUMMITvisited the site onMay 8, 2019andperform soil test borings (identified as Borings B-
2, B-13 through B-18) in the proposed detention ponds. The approximate locations of the borings
areshown on Figure 2 –“Boring Location Plan” provided in Appendix 2. The client (Kolter
Homes, LLC) provided SUMMITa plan that indicated the approximate location of the proposed
detention ponds. The boring locations werenot surveyed prior to this study and should be
considered approximate.
The soil test borings wereperformed using an ATV-mounted CME 550X drill rig,and extended
to an approximate depth of 16feet below the existing ground surface. 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, theSPT 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.

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 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
“BoringLog” 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 with
approximate thicknesses ranging from3 to 5inches. Beneath the topsoil layer,residual
(undisturbed) soils were encountered thatconsisted ofelastic siltsandsandy silts. A stratum of
partially weathered rock (PWR) conditions were encountered in Boring B-13 between the
approximate depths of 6 to 10feet. Auger refusal conditions were not encountered in any of the
borings.
GROUNDWATER LEVEL MEASUREMENTS
At the time of drilling and after waiting more than 24 hours, groundwater was not observed in the
borings.It should also be noted that groundwater levels tend to fluctuate with seasonal and
climatic variations, as well as with some types of construction operations. Therefore, water may
be encountered during construction at depths not indicated in the borings performed for this
exploration.
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

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
poor aeration and impeded drainage. Mottling is a “general indication ofgroundwater” flow
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, even though
groundwater and ESHWT indicators were not observed in Boring B-13, perchedwater conditions
can develop during wet weather above low permeable stratum such as the partially weathered rock
(PWR) stratum encountered in the boring. 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 borings and our observations.
Summary Table of the Boring Results and Our Observations
Partially
GW Depth
Weathered
Boring ESHWT GW Depth After
Rock Approx.
Test Depth Depth ATD 24 Hours
1
1 1 1 1
Depth, (Feet)
Location(Feet)(Feet)(Feet)(Feet)
B-2 16NENENENE
B-13 16NENENE6 to 10
B-19 16NENENENE
1
Depths from existing ground surface.
NE – Not Encountered in Boring.

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
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
reported, SUMMITshould 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
SUMMITappreciates 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,
SUMMIT
Todd A. Cos
tner, E.I. Kerry C. Cooper, P.E.
Senior Professional Senior Geotechnical Engineer
LIST OF APPENDICES
1Photographic Log
2 Figure No. 1 –Site Location Map
Figure No. 2 – Test Boring Location Plan
3Boring Logs

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
APPENDIX 1
Photographic Log

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
Boring B-2 Samples
(Approximate Depth = 0 to 10 feet below existing ground surface)
Boring B-2 Samples
(Approximate Depth = 10 to 16 feet below existing ground surface)

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
Boring B-13 Samples
(Approximate Depth = 0 to 10 feet below existing ground surface)
Boring B-13 Samples
(Approximate Depth = 10 to 16 feet below existing ground surface)

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
Boring B-18 Samples
(Approximate Depth = 0 to 10 feet below existing ground surface)
Boring B-18 Samples
(Approximate Depth = 10 to 16 feet below existing ground surface)

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
APPENDIX 2
Figures
1

Summary of ESHWT Determination SUMMITProject No. 2409.02
CresswindMay 17, 2019
APPENDIX 3
BoringLogs