20090195 Ver 1_More Info Received_20090319

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TO:
FROM:
DATE:
RE:
ENVIRONMENTAL SERVICES, INC.
1022 Grandiflora Drive Suite 250
Leland, North Carolina 28451
910-383-6021 / Facsimile 910-383-6049
www.environmentalservicesinc.com
MEMORANDUM
Mickey Sugg
Matt Smith
16 March 2009
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Cypress Village Subdivision Section 404 PCN Application.
USACE Action ID 2008-02703.
In a conversation on 11 March 2009, additional clarification was requested about the proposed
mitigation for proposed wetland impacts and how hydrologic connectivity associated with
wetland impact W2 would be maintained. A discussion of hydrologic connectivity associated
with wetland impact W2 is being submitted by the design engineer separately. Below is a
detailed description of mitigation proposed for wetland impacts.
The applicant proposes to provide mitigation for the 0.27 acre of unavoidable impacts to Section
404 wetlands resulting from project construction by purchasing credits from the Hofmann Forest
Wetland Mitigation Bank at a 1:1 ratio. In addition, the applicant proposes to preserve the
remaining 7.81 acres of wetlands present on the property through a restrictive covenant. The
restrictive covenants will follow the USACE restrictive covenants guidance.
Onsite restoration or creation of wetlands was not considered to be a practicable means of
providing mitigation due to the small size of the wetland impacts and the high cost of wetland
creation/restoration on such a small scale. The Hofmann Forest Wetland Mitigation Bank was
considered to provide the best practicable means of providing mitigation for the impacts
associated with the project. This bank represents the only constructed and mature mitigation
bank located in the White Oak River Basin and while the Bank and the project site are located on
opposite sides of the White Oak River the non-riverine wet pine flatwoods and pocosin habitats
present on the bank closely resemble the wetlands associated with the project in vegetation type,
landscape position, and soil type. As such, we feel that purchasing credits from the Hofmann
Forest Wetland Mitigation Bank for 0.27 acre of unavoidable impact is the most practical means
of providing mitigation for the relatively small associated with the applicant's project.
Please feel free to call me at [phone] if you require any additional information.
Cc: Joanne Steenhuis, N.C. Division of Water Quality
OPERATIONICONSTRUCTION QA/QC
Municipal
Services
March 17, 2009

US Army Corps of Engineers
Attn: Mr. Mickey Sugg - Project Manager
69 Darlington Avenue
Wilmington, NC 28403-1343
Re: Cypress Village Subdivision
Masontown Road SR 1127
Newport, NC 28570
CIVIL/SANITARY ENGINEERS
Engineering
Company, P.A.
Dear Mr. Sugg:
It is my understanding that you are concerned over the submitted plans in regards to the potential
hydraulic isolation of the 1.5 acre wetland located to the right of the roadway at station 7+00 on Cypress
Lane and at the intersection of Cul-de-sac A. Specifically you questioned why a culvert was not proposed
at approximately station 7+00 on Cypress Lane and at the intersection of Cul-de-sac A and Cypress Lane.
The wetland in question is somewhat isolated now due to the natural topography, in general the wetland is
located in a saddle between two hills. The hilltops are at elevation 31 and slope down to elevation 25.5.
The saddle is trapped by an existing ridge line (matched with the new roadway) which is at an elevation of
27.5. The grade on the other side of the proposed road ranges in elevation from 27.0 to 28.0. 1 proposed
the new road along the existing ridge and elevated the roadway from 0 to 1.5 feet (at 7+00) from station
6.00 to station 8+00. 1 also proposed the use of roadside ditches versus curb and gutter to allow the
transfer of surface waters from one side of the road to the other via piping and an extended detention
basin. By elevating the 20' roadway in such a manor provides for minimum load transfer from the earth fill
and minimum disturbance (compaction) of the existing subgrade which now provides the hydraulic
connection from approximately elevation 25.5 to elevation 27.5. The roadway section consists of 6" of
gravel and 1.5 inches of asphalt and the soils are all Leon sands which are well drained. With the
proposed road section the roadside ditch at elevation 26.5 will cut into the existing grade only 1 foot which
will intercept surface waters and transfer them across the road via dual 24" culverts at elevation 24.5
piping. Groundwater therefore has the ability to still transfer through the roadway fill along with the ability
to intercept surface water and transfer it across the roadway to the extended detention basin (peak
attenuation).
Attached is an aerial photo of the area. The photo is intended to show that the two wetlands in question
all drain to the northwest to a 42 inch culvert at elevation 19.35 which crosses hwy 70 so all of the
wetlands drain to the same area and are interconnected.
From the above analogy the wetlands are still interconnected however if you are still concerned I can bury
a 12" hdpe pipe packed with gravel and sand under the roadway at elevation 24.5.
Please contact the undersigned should you have any additional concerns.
Sincerely,
MUNICIPAL ENGINEERING SERVICES COMPANY, P.A.
MichePL nt on, NCPE # 22670
1cc: file

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