SW6200904_Report (Soils, Ksat)_20210122

Scott Cole, NCLSS
312 Copples Road Ext
Asheboro, NC 27205
[phone]
Double D Engineering, PLLC
Attn: Mr. Lee Humphrey
150 S. Page Street
Southern Pines, NC 28387
January 14, 2021
Re: Seasonal High -Water Table Identification and Soil Infiltration Rates: Timberland Ranch; Hoke County NC Parcel
594060001097
Soil conditions and infiltration rates were evaluated and measured on the above -referenced property within proposed
storm water infiltration devices. Work was conducted to satisfy requirements set forth in Parts A-2 and C-1 of the North
Carolina Department of Environmental Quality Stormwater Design Manual. Soil samples were evaluated with a hand
auger.
Stormwater infiltration trenches are designed to ensure the lowest point is at least two feet above the Seasonal High Water
Table (SHWT). Seasonal High Water Table depth is determined by field evaluation for soil wetness conditions which are
indicated by the presence of redoximorphic (redox) features with a chroma of 2 or less (in Munsell color notation) in
mottles or the horizon matrix. Colors of chroma 2 or less due to relic minerals from parent material (underlying rock),
anaerobic activity created by placement of fill material, or soil textural class transitions (perched water) are not considered
as indicators for seasonal high water. Upon determination of SHWT depth, an additional 6" will be deducted from the
observed depth to account for capillary fringe water movement above the SHWT.
Fluctuations of the groundwater table vary throughout the year; however no evidence of the SHWT were observed within
10' of the ground surface on this site. A summary of observations within each proposed trench is shown in the tables
below.
Infiltration Trench #1
Boring
Total Depth
SHWT
Munsell Color
(Elevation)
(inches below
(inches below
Notation
round surface)
2round surface
1 (385')
120" (10')
92" bgs (7.7')
2.5Y 8/1
(PERCHED
WATER
2 (385')
120" (10')
84" bgs (7')
2.5Y 8/1
(PERCHED
WATER)
Note: A zone of Clay accumulation was observed 7' below ground surface within Infiltration Trench #1. Chroma 1
colors were observed within this clay layer which was overtop of Sandy Clay Loam -textured soil.
Infiltration Trench #2
Boring
Total Depth
SHWT
Munsell Color
(Elevation)
(inches below
(inches below
Notation
round surface)
ground surface
1 (385')
120" (10')
Not Observed
N/A
2 (385')
120" (10')
Not Observed
N/A

Scott Cole, NCLSS
312 Copples Road Ext
Asheboro, NC 27205
[phone]
Infiltration Trench #3
Boring
Total Depth
SHWT
Munsell Color
(Elevation)
(inches below
(inches below
Notation
ground surface)
2round surface
1 (388')
120" (10')
96" bgs (8')
2.5Y 8/1
(PERCHED
WATER
2 (388')
120" (10')
96" bgs (8')
2.5Y 8/1
(PERCHED
WATER)
Note: A zone of Clay accumulation was observed 8' below ground surface within Infiltration Trench 43. Chroma I
colors were observed within this clay layer which was overtop of Sandy Clay Loam -textured soil.
Infiltration Trench #4
Boring
Total Depth
SHWT
Munsell Color
(Elevation)
(inches below
(inches below
Notation
round surface)
2round surface
1 388'
120" 10')
Not Observed
N/A
2 388'
120" 10'
Not Observed
N/A
Infiltration Trench #5
Boring
Total Depth
SHWT
Munsell Color
(Elevation)
(inches below
(inches below
Notation
round surface)
ground surface
1 (390')
120" 10'
Not Observed
N/A
2 (390')
120" (10')
Not Observed
N/A
Infiltration Trench 46
Boring
Total Depth
SHWT
Munsell Color
(Elevation)
(inches below
(inches below
Notation
round surface)
ground surface
1 390'
120" 10'
Not Observed
N/A
2 390'
120" 10'
Not Observed
N/A
Infiltration Trench #7
Boring
Total Depth
SHWT
Munsell Color
(Elevation)
(inches below
(inches below
Notation
round surface)
ground surface
1 398'
126" (10.51)
Not Observed
N/A
2 (398')
136" (11.3')
136" (elevation
2.5Y 8/1
386')

Scott Cole, NCLSS
312 Copples Road Ext
Asheboro, NC 27205
[phone]
SATURATED HYDRAULIC CONDUCTIVITY (K,,t)
Soils evaluated on this property are typical of those within the Candor Sand series. Candor Sands are very deep,
excessively drained with moderate permeability. Soil conditions across the study area of this project have consistent
structure, mineralogy and depth. The typical soil profile observed on this site consists of 60-70 inches of Sand / Loamy
Sand overtop 50 inches or greater of Sandy Clay Loam. Zones of Clay accumulation, approximately 12-18 inches thick,
were observed between the Sand and Sandy Clay Loam horizons, primarily within the proposed infiltration trenches
directly adjacent to Calloway Road. Infiltration rates were measured to determine if soil conditions were suitable for the
installation of stormwater infiltration trenches. Infiltration rates were measured using a Johnson Constant Head
Permeameter. Measurements were recorded at varying intervals until equilibrium was reached.
A summary of the Ksat equivalent values in inches per hour for each location is shown below.
Infiltration
Trench
Soil Texture
Depth (inches
below ground
surface
K�at Equivalent Value (inches / hour)
1
Sand / Loamy Sand
60" 5'
39" / hour
2
Sandy Clay Loam
114" (9.5')
2.17" / hour
3
Sandy Clay Loam
114" 9.5'
2.17" / hour
4
Sandy Loam /
Sandy Clay Loam
114" (9.5')
43" / hour
5
Sandy Clay Loam
114" 9.5'
5.5" / hour
6
Sandy Clay Loam
114" 9.5'
2.17" / hour
7
Sandy Clay Loam
114" 9.5'
2.17" / hour
CONCLUSION
Field evaluation of hydraulic conductivity provides estimations of soil infiltration rates; however, methods used to
measure these rates can influence the results. Side walls of the bore hole are "smeared" by the soil auger as the hole is
prepared and loose soil in the bottom of the hole is placed in suspension when water is applied; both of these factors
negatively influence water infiltration rates. To help overcome these issues, after excavation of each infiltration trench, it
is recommended the trench bottom and sidewalls be raked and dusted with pulverized limestone. These are practices that
have been in place within the on -site wastewater industry to help loosen the soil and aid in restoration of soil structure.
I am pleased to be of service in this matter and can be contacted at your convenience should you have any questions
concerning information within this report.
Thank ou,
Scott Cole
North Carolina Licensed Soil Scientist
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1
Trench 2
Infiltration @ 114" bgs (95)
Soil Texture: Sandy Clay Loam (heavy)
Infiltration Rate: 2.17" / hour
Boring # 1
Elevation: 385'
Depth: 120" (10')
SHWT: Not Observed
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Boring # 2
Elevation: 385'
Depth: 120" (10
SHWT: Not Obs
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�b Depth: 120"
Perched Water: 84" bgs (7')
Boring # 1
Elevation: 385'
Depth: 120" (10')
Perched Water: 92" bgs (7.7')
Trench 1
Infiltration @ 60" bgs (5')
Soil Texture: Sand / Loamy Sand
Infiltration Rate: 39" / hour
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Boring # 2
Elevation: 390'
Depth: 120" (10')
SHWT: Not Observed
Trench 5
Infiltration @ 114" bgs (9.5')
Soil Texture: Sandy Clay Loam
Infiltration Rate: 5.5" / hour
Boring # 1
Elevation: 388'
Depth: 120" (10')
SHWT: Not Observed
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1 � 386
1 inch = 200 feet
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388
390
Boring # 1
Lvation: 390'pth: 120" (10')
WT: Not Observed
Trench 44
Boring # 1
Elevation: 388'
Depth: 120" (10')
Perched Water: 96" bgs (8')
Boring # 2
Elevation: 388'
Depth: 120" (10')
SHWT: Not Observed
Trench 4
Infiltration @ 114" bgs (9.5')
Soil Texture: Sandy Loam / Sandy Clay Loam
Infiltration Rate: 43" / hour
Boring # 2
Elevation: 388'
Depth: 120" (10')
Perched Water: 96" bgs (8')
Trench 3
Infiltration @ 114" bgs (9.5")
Soil Texture: Sandy Clay Loam
Infiltration Rate: 2.17" / hour
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Elevation: 398' t
6 Depth: 136" (11.3')
SHWT: 136" (Elevation 386')
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Trench CD
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v Trench 7 we,
Infiltration @ 114" bgs (9.5')
Soil Texture: Sandy Clay Loam t Boring # 1 398'
Infiltration Rate: 2.17" / hour
Depth: 126" (10.5'),
ii SHWT: Not Observed n-
w m
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390 Trench 46
Boring # 2
Elevation: 390'
Depth: 120" (10')
�-- ...... Boring # 1 "'• ••�•'" SHWT: Not Observed
Elevation: 390' ��'��`��'~ """" '••• ......«`
Depth: 120" (10')
SHWT: Not Observed f 39 /
jTrench 6
h / Infiltration @ 114" bgs (9.5") 388
sr / Soil Texture: Sandy Clay Loam
Infiltration Rate: 2.17" / hour
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