SW6190504_Updated SHWT letter for Hoke County Coop_7/22/2019

July 15, 2019
Mr. Blair Pittman
Bobbitt Design Build
bpittmankbobbitt.com
Seasonal High Water Table Evaluation
Hoke County Cooperative Extension Building
Raeford, North Carolina
Our Project Number 121-19-96010
Gentlemen:
TERRATECH
E N G I N E E R S- I N C
CjeotecknicafrEngineering
rEnvironmentafConsulting
Construction Materiafs Testing
As requested, a representative of TerraTech Engineers, Inc. was present at the above referenced site
recently to evaluate the depth to the seasonal high water table (SHWT) in the area of the planned
stormwater management features. The approximate locations of our evaluation, which were provided to
us, are shown on the attached Figure 1. Our scope of services did not include surveying of the planned
stormwater feature. We determined the approximate location of the stormwater features by measuring
angles and distances from existing points, along with using online mapping programs. Our locations
should be considered approximate.
We have reviewed the Hoke County GIS Soil Survey Map for information related to the expected soil
conditions at the subject property. Based on our review, the soils at the proposed boring locations
generally consist of Norfolk (NoB) series soils. The Norfolk (NoB) soil series is described as well
drained, very deep, moderately permeable soils of the upland Coastal Plain that include sandy clays and
clayey sands. These soils have slopes ranging from 0 to 6 percent. Our borings B-1 and B-2 are in an
area that is topographically lower than borings B-3 through B-5. The reviewed soil survey indicates that
the depth to the expected SHWT in the Norfolk series is 2.5 to 3.5 feet below the ground surface.
We performed five test borings in the areas shown on Figure 1. The soils in our test borings were generally
sandy clays and clayey sands. However, sandy silts and silty sands were present in test boring B-2.
Ground water was not encountered in our five test borings. Based on our visual evaluation of the soil
samples, the soils in boring B-2 exhibited characteristics indicative of a SHWT of approximately 3 to 3.5
feet below the existing ground surface.
We reviewed the results of our previous test borings at the property. These borings indicated that ground
water was present in the higher portions of the site near our current borings B-3 through B-5 at depths of
5 to 10 feet below the ground surface.
Based on our evaluation, we recommend that the SHWT for the western stormwater management feature
(area of borings B-1 and B-2) be taken as 3.5 feet below the existing ground surface, and that the SHWT
for the eastern stormwater management feature (area of borings B-3 through B-5) be taken as 5 feet below
the existing ground surface.
The highest ground water observations generally occur in the later winter and early spring and can vary
with fluctuations in precipitation, evaporation, surface water runoff, and other factors. If long term ground
TerraTech Engineers, Inc.
NC Engineering Corporation C-1356
4905 Professional Court, Raleigh, North Carolina 27609
[phone]

TERRATECH
ENGIN E E R$• INC
Cjeotecknicaf Engineering
rEnvironmentalConsulting
Construction Materials Testing
Page 2
water levels are crucial for the planned construction, we recommend that water levels be monitored over
an extended period of time using wells or piezometers.
If you have any questions concerning this information, please contact us. , \\\ ti I I I I 1 i ///,
Sincerely,
TerraTech Engineers, Inc. (C-1356)
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Not to Scale Figure 1: Test Boring Locations
TerraTech Engineers, Inc. (C-1356) Project: Hoke County Cooperative Extension Building
4905 Professional Court
Raleigh NC 27609 Raeford, North Carolina
919-876-9799 Our Proi ect Number 121-18-96010