Ver - More Info Received - 7/23/2010

WALTON ENGiNEERIN
July 22, 2010
John Dorsey
Wetlands Program Development Unit
NC DENR
1650 Mail Service Center
Raleigh, NC 27699-1650
Re: Proposed hydrology criteria for Onslow Sands, Inc
Mr. Dorney,
a ?@20W A P
jUL 2 Oz 20iu
DENR - WINTER QUAU T Y
WET LANDS AND STORMATER BRANCH
The 6.79 acres +/- of Riverine Swamp Forest surrounding the proposed Onslow Sands, Inc
project site consists of Muckalee loam (Mk). This type of soil is poorly drained to undrained
with 0-2% slopes. The water table sits 0" - 12" below ground surface with frequent flooding.
Rocky Run flows through this area permanently year-round.
The majority of sand to be mined at Onslow Sands, Inc is described as Marvyn loamy fine
sand, 6% to 15% slope (MaC). This type of soil is well drained with a moderately high to high
capacity of the most limiting layer to transmit water. The depth to water table is typically >72
inches from December to April and other wet periods. During the dry season the water table
tends to be >80 inches. Fluctuations in the water table between 2 and 3 feet are normal
throughout a year.
Water table @ 72" (ir), 45% = 8.7' showing a -2.7' to 3.0' reduction in the water table.
Water table na, 80" @ 30% = 8.7' showing a -2.7' to 3.0' reduction in the water table.
* %=percent deviation
So, taking the average percentage of deviation and applying it to the water table properties:
Water table @ 72" na, 37.5% = 8.25' - 9.0' depicts a -2.25' to 3.0' reduction in the water
table.
Water table (a, 80" @ 37.5% = 9.21' - 97 depicts a -2.51' to 3.0' reduction in the water
table.
* %=percent deviation
Tel: [phone] PO Box 895, Burgaw, North Carolina, 28425 Fax: [phone]
WALToNENaNEERjN
In the addition of using soils data provided by USDA-MRCS Official Soil Series survey, the
presence of a permanent hydrologic source, Rocky Run, and the discharges back into the
wetlands, along with typical water table measurements for the Marvyn soil series a 2.5'
deviation from the referenced wetlands water level is proposed as proper criteria.
If you have any questions, please call me at [phone]
Tel: [phone] PO Box 895, Burgaw, North Carolina, 28425 Fax: [phone]