20130739 Ver 1_Viability Letter_20171128

Water Resources
ENVIRONMENTAL QUALITY
January 7, 2016
PAT MCCRORY
Governor
DONALD R. VAN DER VAART
Secretary
S. JAY ZIMMERMAN
Director
Kristin Miguez DWR# 2013-0739
DEQ -Division of Mitigation Services
1652 Mail Service Center
Raleigh, NC 27699-1652
(via electronic mail)
Re: Site Viability for Buffer Mitigation — St. Clair Creek Headwater Stream Site
off Peoples Road, Bath, NC
Beaufort County
Dear Ms. Miguez,
On October 5, 2015, Katie Merritt, with the Division of Water Resources (DWR), received a
request from Jake Byers with Michael Baker Engineering, for a site visit at the St. Clair Creek
Restoration Site located off Peoples Road in Bath, NC to determine the potential for Tar -Pamlico
Neuse riparian buffer mitigation. On December 3, 2015, Ms. Merritt performed a site
assessment of the subject site. Karen Higgins and Mac Haupt with the DWR along with you and
Mr. Byers were also present. If approved, mitigating this site could provide riparian buffer
mitigation credits within the 8 -digit Hydrologic Unit Code 03020104 of the Tar -Pamlico River
Basin and as allowed under 15A NCAC 02B .0295 (f).
Ms. Merritt's evaluation of the site as an alternative buffer mitigation option for buffer
mitigation pursuant to Rule 15A NCAC 02B .0295 (o) (1) and (2) (effective November 1, 2015)
is provided below:
UT2
• UT2 was approved as part of a Coastal Headwater Stream Mitigation Site (DWR# 2013-
0739) by the IRT in 2013 and is in its second year of monitoring. A copy of the approved
mitigation plan has been provided to the DWR.
• Preliminary site conditions along with the onsite visit in December 2015 suggests that the
entire area along UT2 (0-100') is viable for riparian restoration and suitable for buffer
mitigation credit at 1:1. Preliminary photos and documentation have been provided to the
DWR.
• The buffer must be measured perpendicular to the length of the valley being restored.
Approximately 8.35 acres (363,577 ft2) have been planted and restored. A copy of the
proposed restoration site has been provided to DWR.
• An agricultural ditch is present within the proposed riparian restoration and isn't planned
to be removed. The presence of this ditch does not comply with the diffuse flow
requirement of Rule .0295. However, DMS can apply Clarification Memo #2008-019 to
State of North Carolina I Environmental Quality I Water Resources
1617 Mail service Center I Raleigh, North Carolina 27699-1617
919 807 6300

St. Clair Creek Restoration Project
Buffer Mitigation Viability
January 7, 2015
Page 2 of 2
this project in order to calculate the deduction of buffer credit where diffuse flow cannot
be attained.
According to the St. Clair Creek Restoration Project Year 1 Monitoring Report submitted
in April 2015, all 6 vegetative monitoring plots within the riparian areas are meeting the
success criteria identified in Rule .0295. A copy of the Year 1 Monitoring Report has
been provided to the DWR.
A conservation easement of the proposed area, dated June 241', 2013 has been provided
to the DWR and is more accurately described as CE -1 and containing 11.55 acres, more
or less. The easement document is located in the Beaufort County Register of Deeds,
Book 1821, Pages 53-64.
A map showing the project site and the buffer mitigation areas assessed is provided and signed
by Ms. Merritt on January 6, 2016. DWR did not assess this site for viability of nutrient offset
and therefore only buffer mitigation is approved. DMS shall provide an annual monitoring
report to Ms. Merritt for review and approval each year for four more years and until the
performance standards have been met. The performance standards for buffer mitigation under
Rule .0295 are the following:
(n) (2) (B) - A minimum of four native hardwood tree species or four native hardwood tree and
native shrub species, where no one species is greater than 50 percent of the stems.
(o) (2) All success criteria specified in the approval of the stream mitigation site by the Division
shall be met.
Please provide an As -Built survey verifying the acreage proposed for buffer mitigation credit and
a buffer credit ledger for this site to Ms. Merritt within 30 days from receipt of this letter. If you
have any questions regarding this correspondence contact Katie Merritt at (919)-807-6371.
Sincerely,
Karen Higgins, Supervisor
401 and Buffer Permitting Unit
KAH/km
Attachments: Site Aerial Map, DWR Clarification Memo #2008-019
cc:File Copy (Katie Merritt)

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19, 2008
Buffer Interpretation !C larification 42008-019
MEMORANDUM
Michael f. Easley
Sinvernor
William G. Ross. Jr., Secretary
Department of Environment and Natural Resources
Coleco. It. Sullins. Director
Division of Water Quality
l he IM ision of Water Quality's (DWQ's) stance on whether diffuse flow of stormwater through the newly restored buffers on
miti,.!a6on sites should be a requirement. Diffuse flow- is a requirement for buffer restoration or enhancement in the Neuse River
Basin Buffer Rule 15A NCAC 02B.0242(9)(d)(iii), the Tar -Pamlico River Basin Buffer Rule 15A NCAC 02B.0260(9)(d)(iii), and the
Catawba River Basin Buffer Rule 15A NCAC 028.0244 (9)(d)(iii).
Diffuse flow is a requirement for all sites in a buffered basin for buffer mitigation and for for sites providing nutrient offset credit as
well.
Current Palic _ According to the Mitigation rules in the Neuse. Tar -Pamlico and Catawba buffer rules, a grading plan must be
provided for buffer mitigation sites. In addition, those rules state that "The site shall be graded in a manner to ensure diffuse flow
through the riparian buffer".
Problem: The question has been raised as to whether stormwater carried by lateral ditches that enter buffered streams should provide
diffuse flow prior to that stormwater entering the restored buffers.
Soltnion: the Neuse, Tar -Pamlico and Catawba buffer rules with respect to buffer mitigation sites contain a very clear requirement
that states that diffuse flow of stormwater must be maintained through the buffer. Unless otherwise approved by DWQ, all buffer
mitigation sites must provide diffuse flow of stormwater from ditches and similar conveyances through the restored buffer.
Where such diffuse flow cannot be attained and where DWQ agrees that such treatment is not possible, deduction of'buffercredit will
he calculated as follows:
SCENARIO 1
�Ac-
401
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Jol Wetlands ( ertilication (;nil
1050 Mail Scmce Center. Raleigh. North Carolina 27699-1050
_'12 1 CYahtree lioulekard. Suite 250. Raleigh. Ninth Carolina 27004
Phone [phone] ' FAX [phone] ! Internet: hts:/lh2o.enr.state.nc.us/ttc%vetlends
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Page 2 of 4
A, B and C are angles. a, b, and c are distances (lengths)
DWQ believes that using an immediate drainage area extending at a 60 -degree angle from the point of discharge to the stream is a
reasonable approach to the issue of determining the area which is not draining through the restored buffer. To calculate the area of
buffer being "short-circuited" by the ditch, the area of the right triangles shown in the figure above must be determined.
a=50'
A = 30°
B = 60°
b=acot A
b = 50 (1.732)
b = 86.6' (87')
The area to be excluded from credit would be the area of the two right triangles:
Area = (a x b)/2
Area = (50 feet x 87feet)/2
Area = 2,175 SF
Total deducted area = 2,175 x 2 = 4,350 SF or 0.1 acres.
The example shown above assumes a buffer width of 50 feet from the top of bank (riparian buffer mitigation site). For nutrient offset
sites, credit can be generated out to 200 feet from the top of bank. The policy applies to sites with larger buffers as follows:
SCENARIO 2
NorthCarolina
401 Wetlands Certification Unit �atllrll11l� 1
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] / FAX [phone] / Internet: kittyWh2o.enr.state.tic.us/ncwedands
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Page 3 of 4
Ifa ditch leading to a buffered stream is buffered, then no credit is deducted from the stream buffer. If the upstream origin of the ditch
is "ithin the buffer. no credit is deducted. If the upstream origin of the ditch is not buffered (e.g. if the ditch begins upstream offsite),
tl1e credit deduction is applied to the most upstream portion of the ditch on the property.
SCENARIO 3
CRFAIT t*WCMb
r
Where a network of interconnecting ditches occurs on a site. and all of the ditches are buffered, the only credit deduction would be at
the point where an unbuffered ditch enters the project.
SCENARIO 4
401 N cdamN Ceni ication Unh
I6�fl \1;111 SO iCe ('enter. Raleigh. Nonh Carolina 27(i49-I6i(1
23
X21 ( shore lioulcaard. Surto ?50. Raleigh. ,Nonh Carolina 27604
Phone i I1)-7?3-1786 ; I AN 919-733-6843 i Internet. ht :il iLo enr.state nc.uslncwetlands
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Page 4 of 4
Where a natural stream enters the project site, no deduction of credit will occur. Also, when a natural stream or a modified natural
stream flow into a buffered stream, no deduction of credit will occur. The modified natural stream must be subject to the buffer rules,
and must be verified to be a modified natural stream (as opposed to a ditch) through an on-site determination by DWQ personnel.
SCENARIO 5
Q0 ba
I'M MIWIAL CrA j l?
beb I 04
For any additional questions or clarifications on this issue, please contact Eric Kulz or Amy Chapman at [phone].
Signature:
'-)yO ��
L-pI4 e
Date:
E
Signature:
Date:
401 Wetlands Certification Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] / FAX [phone] / Internet: htIP;jWo,cnr,state.nc.us/ncwetlnnfic
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