SW6230805_Soils/Geotechnical Report_20230831

Scott Cole,NCLSS
312 Copples Road Ext
Asheboro,NC 27205
[phone]
D&L Engineering,PLLC March 28,2023
Attn: Mr. Lee Humphrey
150 S. Page Street
Southern Pines,NC 28387
Re: Seasonal High-Water Table Identification and Soil Infiltration Rates: Turnberry, Hoke County NC
parcel 494560301008
Soil conditions and infiltration rates were evaluated and measured on the above-referenced property within
the proposed storm water BMP device. Work was conducted in accordance with 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.
SEASONAL HIGH WATER TABLE IDENTIFICATION
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 chroma colors of 2 or less (in Munsell
color notation) in mottles or the horizon matrix, and at times, saturated soil conditions and/or free water
within the soil profile. 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. Stormwater infiltration trenches are designed to ensure the lowest point is at least two
feet above the Seasonal High Water Table(SHWT).
SATURATED HYDRAULIC CONDUCTIVITY(Ksat)
Soils evaluated on this property are typical of those within Blaney Loamy Sand Soil series. These soils are
well drained to moderately well drained soils with varying rates of permeability. Infiltration rates are
measured to determine if soil conditions are suitable for the installation of stormwater infiltration devices.
Infiltration rates are measured using a Johnson Constant Head Permeameter. Measurements are recorded
at varying intervals until equilibrium is reached.
The SHWT and Infiltration rates for the stormwater BMP devices are reported in the table below.
BMP Device Site#1
Test Location SHWT Munsell Color Ksat#1 Ksat#2
(feet below Notation
ground surface)
Not observed 0-5' 7-15'
Elevation 232' within 15'of N/A Sandy Clay Sandy Clay
surface Loam/Sandy Loam(sap)
(Elevation 217') Clay Not
2.5"/hour Measured

Scott Cole,NCLSS
312 Copples Road Ext
Asheboro,NC 27205
[phone]
BMP Device Site#2
Test Location SHWT Munsell Color Ksat#1 Ksat#2 Ksat#3
(feet below Notation
ground surface)
Observed 0-2' 2-10' 10-13"
Elevation 218' within 13'bgs 2.5Y 7/1 Sandy Clay Sandy Clay Clay
(Elevation 205') Loam Loam/Sandy Expansive
5"/hour Clay Not
2.5"/hour Measured
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 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 you,
n 5ait so
Scott Cole 1":0 J►
North Carolina Licensed Soil Scientist ""� �,�i' .al
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BMP Site#1(Elevation 232')
SHWT: Not Observed
SHWT Elevation: NA
Ksat 0-5'SCL/SC: 2.5"/hour
Ksat 7-15'SCL(sap): Not Measured
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BMP Site#2(Elevation 218')
` '� SHWT: 13'bgs
SHWT Elevation: 205'
Ksat 0-2'SCL: 5"/hour
Ksat 2-10'SCLISC: 2.5"/hour
Ksat 10-13'C(exp): Not Measured
ilk \.13'heavy wetness/free water: SHWT
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