HomeMy WebLinkAboutsoils reportW. K=. W I <
WDICKSON
community infrastructure consultants
February 22, 2013
Mr. Brian McSwain
Harnett County Central Permitting
P.O. Box 65
108 East Front Street
Lillington, NC 27546
RE: Findings of Soil Investigation for Anderson Creek Park, Phase 1
Harnett County, NC
Project # 20110206.00.RA
Dear Mr. McSwain:
WK Dickson appreciates the opportunity to provide the Soil Investigation Services on the above
referenced site. This letter describes our findings on the property and provides general
recommendations based on the findings.
Project Information
The proposed project site is located at 1492 Nursery Road (SR 1117) approximately 1.6 miles from
Highway 27, in Harnett County, North Carolina. The subject property is 204.11 acres. This property
currently undeveloped timber land.
Methods and Materials
The investigation techniques utilized hand auger borings to sample and evaluate the soil morphology.
It is expected that the site will need to support a septic drain field for a four toilet bathroom used by
park visitors. The park design calls for a picnic shelter, restroom building, playground, disc golf, and
walking trails with 24 parking spaces. The water source will be a well located a minimum of 100 feet
from the septic system (see Exhibit). The soil evaluation follows the rules governing the treatment and
disposal of domestic type sewage from septic tank systems, privies, or other such systems set forth in
the 15A NCAC 18A .1900 - Sewage Treatment and Disposal Systems section of the North Carolina
Administrative Code.
A site evaluation was performed on July 11, 2012 in the area designated for an on -site septic system in
conjunction with development of the site plan. A total of six auger borings were placed across the area
designated for a drain field. See attached Exhibit for boring locations.
Findings
The area designated for a drain field is classified as suitable with areas of provisionally suitable. The
area is open and currently maintained in an herbaceous community. The surrounding area is mature
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pines with a shrubby understory. The evaluation was performed in the open area and in the forest
immediately downslope to provide the potential for a gravity system.
The site is mid -slope on a large ridge typical of the Sandhills region. Topography is generally uniform
across the proposed drain field with slope of 5 percent to a maximum of 8 percent slope. The surface
texture is loamy sand ranging from 25 inches to greater than 40 inches. This is underlain by sandy clay
loam across the main area. Lower on the slope below the potential drain field area, sandy clay was
found in the subsoil. These clayey texture horizons have a sub - angular blocky structure. No expansive
mineralogy was found. In a lower landscape below the proposed drain field, evidence of a seasonal
high water table was found at 33 inches and 41 inches. There are no restrictions to soil depth. Outside
of the proposed drain field, a brittle sandy clay loam was found the appeared to be potentially
restrictive. The area is currently undeveloped and no wells are located nearby.
Based upon the area evaluated, approximately 29,000 square feet of space is available that is classified
as suitable and provisionally suitable (see attached Exhibit).
Analysis and Discussion
Based upon the field evaluation, the site contains soil classified as suitable and provisionally suitable
for on -site waste disposal. Moderate limitations are present due to the predominance of Group III soils.
A long -term acceptance rate of 0.35 gallons /day /square foot is suggested for the initial system. The
repair area may require a slightly lower long -term acceptance rate. Due to the proposed land use of a
public park, the open space the drain field will present, and proximity to other available activities, the
prevention of damage from inadvertent vehicle traffic in this area can be addressed. It is recommended
that a gravel system be utilized to reduce the chance of this type of damage. There does not appear to
be design size constraints for a system adequate to meet the requirements necessary for the proposed
restroom building.
Thank you for the opportunity to provide Soil Investigation Services. Please contact us if you have
questions or need additional services.
Sincerely,
W.K. Dickson & Co., Inc.
George Lankford, LSS
Technical Project Manager
Enclosure
DICKSON