20100621 Ver 1_Mitigation Site Visit_20100507

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NC®ENR
North Carolina Department of Environment and Natural Resources
Beverly Eaves Perdue
Governor
Bill Biddlecome
U.S. Army Corps of Engineers
Washington Regulatory Field Office
P.O. Box 1000
Washington, North Carolina 27889
Re: Howell Woods Mitigation Bank
Johnston County, NC
Site Visit Comments
Dear Mr. Biddlecome:
Division of Water Quality
Coleen H. Sullins
Director
May 7, 2010
Dee Freeman
Secretary
This is in response to the prospectuses for the Howell Woods Mitigation Bank, dated January 22, 2010.
According to the prospectuses, the bank sponsor proposes to establish restoration and preservation areas to the
mitigation bank. The Division of Water Quality (DWQ) Raleigh Regional Offive has reviewed the prospectus'
(dated Janurary 22, 2010). Based on this review and the April 29, 2010 site visit, our comments are as follows:
Stream Preservation: We believe that only three of the segments of stream channel proposed for stream
perservation are viable candidates due to the fact that they are relatively undisturbed and are fairly stable
systems with old growth vegetation in the riparian areas. These stream segments include the channel
downstream of the proposed restoration reach, Mill Creek, and the northern -most channel. On the day of
the site visit, DWQ did not agree that the segment east of the proposed restoration reach demonstrated
stream characteristics and, therefore, would not be a viable candidate for stream preservation. However,
DWQ does believe that there are opportunities in this area for wetland preservation.
Although we believe these stream segments are viable options for preservation due to the fact that they are
relatively undisturbed, we don't believe that they meet the criteria listed in the Stream Mitigation
Guidelines for stream preservation (see Stream Mitigation Guidelines April 2003 page 16). We would,
however, support preservation at a lower mitigation credit ratio.
Stream Restoration: The channel that is proposed to be filled to allow water to be diverted into the
wetland slough, although once channelized, appeared to be fairly stable with relatively mature vegetation
adjacent. The wetland slough was quite expansive with matue trees and a diverse shrub and herbaceous
layer. The channel was observed to be approximately 6 feet deep while the wetland slough was
approximately 2 -4 feet deep. Currently some of the water from the channel reaches this wetland slough.
However, if all the water from the exsiting channel is diverted to the wetland slough we believe that it will
only degrade the wetland by downcutting (based on different depths in each system) and may have the
potential to drain the wetland. Based on the relative stability of these features and habitat they are
providing, DWQ does not believe that this is a viable candidate for stream restoration.
NorthCarolina
Naturally
North Carolina Division of Water Quality Raleigh Regional Office Surface Water Protection Phone [phone] Customer Service
Internet www ncwaterquality org 1628 Mail Service Center Raleigh, NC 27699 -1628 FAX [phone]
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We appreciate the opportunity to comment on the Mitigation Prospectuses. If the bank and initial project move
forward, we looking forward to reviewing a more detailed mitigation banking instrument. Please feel free to
contact Lauren Witherspoon (919) 791 -4251 if you have any questions regarding this letter or,the project.
oSincer ly,
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D anny Smi
Regional Supervisor
Surface Water Protection Section
cc: RRO file copy
Ian_McMillan — 401 Oversight and -Express Permits Unit