NC Central University P3 - Chidley South - Chidley NCDEQ Stormwater Permit - SHWT Report

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February 27, 2019
Metcon, Inc.
3100 Smoketree Court, Suite 215
Raleigh, North Carolina 27604
Attention: Ms. Melanie Ziemniak
Project Manager
Reference: Stormwater Soil Evaluation Report
NCCU On -Campus Student Housing - Chidley
Durham, North Carolina
S&ME Project No. 1305-18-087 (CO-3)
Dear Ms. Ziemniak:
S&ME, Inc. (S&ME) has conducted a stormwater soil evaluation in general accordance with S&ME Change
Order Proposal 1305-18-087 (CO-3) dated February 11, 2019. Our evaluation was conducted to provide
information for the design of a Stormwater Control Measure (SCM) and a Stormwater Management
Permit Application to the North Carolina Department of Environmental Quality (NCDEQ) — Division of
Energy, Minerals, & Land Resources (DEMLR) and/or local delegated authority. A soil scientist evaluated
the soil conditions within the proposed SCM location on February 25, 2019.
Background Information
We understand that a new sand filter type Stormwater Control Measure (SCM) is proposed at the NCCU
Chidley student housing site. The enclosed Figure 1 and Figure 2 depict the site and approximate SCM
soil boring locations (SHWT-1 and SHWT-2) on a US Department of Agriculture (USDA) Natural Resource
Conservation Service (NRCS) Durham County soil survey exhibit and US Geologic Survey (USGS)
topographic exhibit respectively.
The soils on site are mapped as the White Store -Urban land complex soil series with 0 to 25 percent
slopes. About 25 percent of each mapped area is covered by houses, streets, driveways, etc. and about 40
percent is undisturbed soil, and about 30 percent is a White Store soil that has been graded or terraced. In
these graded or terraced areas, as much as two-thirds of the original soil material has been cut away or as
much as 18 inches of fill material has been added. The remaining mapped area is fill, 18 or more inches
thick and the fill material is a mixture of sand and very plastic clay. The White Store soil series formed in
material weathered from Triassic mudstone.
The soil assessment was performed with hand auger borings conducted at two locations (SHWT-1 and
SHWT-2) as shown on the attached Stormwater Soil Evaluation Exhibit (Figure 3). Our evaluation
consisted of identifying and recording the soil morphological conditions at these locations in order to
S&ME, Inc. 13201 Spring Forest Road I Raleigh, NC 276161 p 919.872.2660 1 f 919.876.3958 1 www.smeinc.com

Stormwater Soil Evaluation Report
NCCU On -Campus Student Housing - Chidley
Durham, North Carolina
S&ME Project No. 1305-18-087 (CO-3)
develop soil profile descriptions, performing seasonal high water table (SHWT) estimations and measuring
the observed water table (OWT) and depth to auger refusal if applicable.
Findings
SHWT Estimation, OWT Measurement, and Depth to Auger Refusal
S&ME estimated the SHWT by advancing hand auger borings at the two locations shown on the attached
Figure 3 and evaluating the soil for evidence of SHWT influence. This evaluation involved looking at the
actual moisture content in the soil and observing the matrix and mottle colors. Depending on the soil
texture, the soil color will indicate processes that are driven by SHWT fluctuations, such as iron reduction
and oxidation and organic matter staining.
In addition, S&ME recorded the depth that the OWT was encountered below existing ground surface
(EGS) at each soil boring location if applicable. The OWT was measured as the static water level in each of
the temporary hand auger boring locations. It should be noted that the static water level/OWT measured
in the auger holes is a measurement of the water table at that moment and does not represent an
average water level or the highest point at which the water table may rise to. Furthermore, it is expected
that groundwater elevations in the study area will likely be influenced by factors such as precipitation and
proximity to surface water discharge/recharge features.
See Table 1 below and the profile descriptions on Figure 3 for the estimated depth to SHWT, measured
depth to the OWT and auger refusal if applicable.
Table 1
Permeability/Hydraulic Conductivity Estimation
The soil profile descriptions on the attached Figure 3 show the soil morphological conditions including
soil texture, structure, soil matrix and mottle color, estimated United States Department of Agriculture
(USDA) permeability and estimated USDA hydraulic conductivity (Ksat) for the different soil horizons
found on -site.
In the area of Boring Location SHWT-1, the soil surface layer to a depth of 6 inches consisted of sandy
loam fill material which has an estimated USDA permeability range of 2 to 6 inches per hour and
February 27, 2019 2

Stormwater Soil Evaluation Report
NCCU On -Campus Student Housing - Chidley
Durham, North Carolina
S&ME Project No. 1305-18-087 (CO-3)
estimated USDA Ksat range of 1.4 to 14 inches per hour. The underlying soil material consisted of a sandy
clay loam fill material from a depth of 6 to 36 inches which has an estimated USDA permeability range of
0.6 to 2 inches per hour and estimated USDA Ksat range of 0.14 to 1.4 inches per hour, and sandy clay fill
material from a depth of 36-56 inches which has an estimated USDA permeability range of 0.06 to 0.2
inches per hour and estimated USDA Ksat range of 0.014 to 0.14 inches per hour, and sandy loam fill
material from a depth of 56 to 108+ inches which has an estimated USDA permeability range of 2 to 6
inches per hour and estimated USDA Ksat range of 1.4 to 14 inches per hour. The observed (apparent)
apparent water table was encountered at 100 inches (8.3 feet) below existing ground surface (EGS).
In the area of Boring Location SHWT-2, the soil surface layer to a depth of 10 inches consisted of sandy
loam fill material which has an estimated USDA permeability range of 2 to 6 inches per hour and
estimated USDA Ksat range of 1.4 to 14 inches per hour. The underlying soil material consisted of a mix
clay fill and clay soil material from a depth of 4 to 38 inches which has an estimated USDA permeability
range of 0.06 to 0.2 inches per hour and estimated USDA Ksat range of 0.014 to 0.14 inches per hour.
Auger refusal on rock/brick debris was encountered at 38 inches (3.2 feet) below EGS.
Please refer to the enclosed figures and soil profile descriptions for more information. These estimates
were obtained from one or more of the following: Durham County Soil Survey "Physical & Chemical
Properties of the Soil - Permeability'; and/or USDA-NRCS (United States Department of Agriculture -
Natural Resource Conservation Service) official series description, and/or "NRCS Field Book for Describing
& Sampling Soils". The permeability estimates were converted to conductivity on the profile description
tables.
Conclusion
The soil material encountered at both hand auger boring locations SHWT-1 and SHWT-2 consisted of fill
material with various amounts of debris. The fill material contained relic mottling that we do not believe is
indicative of the current SHWT. Therefore we recommend that the OWT depth of 100 inches (8.3 feet) at
location SHWT-1 be used as the SHWT depth for the sand filter type SCM design.
Limitations
Data and conclusions presented herein are based on materials encountered at the hand auger boring
locations only. Conditions may vary between hand auger boring locations and in other areas of the
proposed SCM. The reported depths are based upon the ground surface locations of the borings at the
time of our evaluation.
February 27, 2019

Stormwater Soil Evaluation Report
NCCU On -Campus Student Housing - Chidley
Durham, North Carolina �f
S&ME Project No. 1305-18-087 (CO-3)
Closing
S&ME appreciates the opportunity to provide soil evaluation services for this project. If you have any
questions please contact Walter Cole at 919-872-2660 or wcolePsmeinc.com.
Sincerely,
S&ME, Inc.
/�Q SOIL SO
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NORTH
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Walter Cole, LSS, REHS Thomas P. Raymond, PE
Senior Project Manager Environmental Area Manager
Enclosed: Figure 1: USDA-NRCS Durham County Soil Survey Exhibit
Figure 2: USGS Topographic Exhibit
Figure 3: Stormwater Soil Evaluation Exhibit
February 27, 2019 4

Figures

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� REFERENCE: 2
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GEODATABASE AND THE 2017 NCONEMAP AERIAL ORTHOIMAGERY LAYER THIS MAP IS SOILS:
m FOR INFORMATIONAL PURPOSES ONLY. ALL FEATURE LOCATIONS DISPLAYED ARE WwC: White Store -Urban land complex, 0-10% slopes
F APPROXIMATED. THEY ARE NOT BASED ON CIVIL SURVEY INFORMATION, UNLESS STATED WwE: White Store -Urban land complex, 10-25% slopes
OTHERWISE.
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SCALE: FIGURE NO.
USDA-NRCS SOIL SURVEY EXHIBIT 1 " = SO'
DATE:
III E 2-27-19 1
NCCU ON -CAMPUS STUDENT HOUSING PROJECT NUMBER
DURHAM, DURHAM COUNTY, NORTH CAROLINA 130S-18-087

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REFERENCE:
GIS BASE LAYERS WERE OBTAINED FROM THE USGS NATIONAL TOPO MAP VIEWER. THIS
MAP IS FOR INFORMATIONAL PURPOSES ONLY. ALL FEATURE LOCATIONS DISPLAYED ARE p
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SCALE: FIGURE NO.
USGS TOPOGRAPHIC EXHIBIT 1 " = 500 '
DATE:
III 8-21-18 2
NCCU ON -CAMPUS STUDENT HOUSING PROJECT NUMBER
DURHAM, DURHAM COUNTY, NORTH CAROLINA 1305-18-087

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Boring SHWT-1 Chidley, Alston Avenue
SBME Project Number:: 1305-18-087 Boring Date: February 25, 2019 Landscape Position: Sideslope / Cut -Filled Area
Color
USDA
USDA
Estimated
Estimated
Moist
Permeability
Conductivity
Horizon
Depth (in)
(Mtri ax)
(Mottles)
Texture
Grade
Structure
Consistence
Notes
(in/hr)
(in/hr)
fill
0-6
10YR 3/2
sandy loam
weak
granular
eery friable
2-6
1.4- 14
fill
6-12
10YR 4/4
sandy clay
weak
subangular
friable
glass fragments
0.6-2
0.14-1.4
loam
blocky
10YR 4/4
sandy clay
subangular
fill
12-26
75YR 3/4
5Y 511
loam
weak
blocky
friable
clay inclusions
0.6-2
0.14-1.4
fill
26-36
10YR 6/4
10YR 7/1
sandy clay
weak
subangular
friable
clay inclusions
0.6-2
0.14-1.4
10YR 6/6
loam
blocky
subangular
fill
36-56
10YR 6/4
10YR 6/6
sandy clay
weak
blocky
firm
0.06-0.2
0.014-0.14
7.55/8
sandy clay
fill
56-108+
2.5Y 7/3
5/1
SY 5
sandy loam
weak
granular
eery liable
loam inclusions
2 6
1 4 14
Estimated SHWT depth from EGS: 100 inches (8.3 feet)
Measured OWT depth from EGS: 100 inches ( 8.3 feet )
Auger refusal depth from EGS: >108 inches (>9.0 feet)
Boring SHWT-2 Chidley , Alston Avenue
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Colo
USDA
USDA
Estimated
Estimated
Moist
Permeability
Conductivity
Horizon
Depth (in)
tri
(Max)
(Mottles)
Texture
Grade
Structure
Consstence
Notes
(in/hr)
(in/)
fill
0-10
10YR 312
sandy loam
weak
granular
eery friable
2-6
1.4 - 14
angular
fill
4-20
7.5YR 513
clay
weak
blocky-
eery fine
masshe
0.06-0.2
0.014-0.14
angular
fill
20-26
2.5YR 4/8
2.5YR 4/3
clay
weak
blocky-
eery firm
masshe
0.06-0.2
0.014-0.14
Bt
26-38
SYR 4/4
2.5YR 6/2
clay
massiee
eery firm
2.SYR 5/1
0.06-0.2
0.014-0.14 �
R
38+
rock/brick
auger refusal
N/A
N/A
o Estimated SHWT depth from EGS: >38 inches (>3.2 feet)
-o Measured OWT depth from EGS: >38 inches (>3.2 feet)
E Auger refusal depth from EGS: 38 inches ( 3.2 feet )
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a REFERENCE:
GIS BASE LAYERS WERE OBTAINED FROM THE 2017 NCONEMAP AERIAL ORTHOIMAGERY Hand Auger Boring Location
LAYER. THIS MAP IS FOR INFORMATIONAL PURPOSES ONLY. ALL FEATURE LOCATIONS
5 DISPLAYED ARE APPROXIMATED. THEY ARE NOT BASED ON CIVIL SURVEY INFORMATION, Proposed Sand Filter
UNLESS STATED OTHERWISE.
0
SCALE: FIGURE NO.
STORMWATER SOIL EVALUATION EXHIBIT 1 " = 7S '
DATE:
III = 2-27-19 3
NCCU ON -CAMPUS STUDENT HOUSING PROJECT NUMBER
DURHAM, DURHAM COUNTY, NORTH CAROLINA 130S-18-087