20080511 Ver 1_Mitigation Plan Review_20080317

~oS-i
o~~~ W AT ~9pG
r
Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Cazolina Department of Environment and Natural Resources
Coleen H. Sullins, Director
Division of Water Quality
March 17, 2008
Mr. Jeff Becker
Greene Environmental Services, LLC
90 Ham Produce Road
Snow Hill, NC 28580
Re: Contentnea/Little Contentnea Creek Riparian Buffer Bank (CLCBB)
Greene County
Dear. Mr. Becker:
Thank you for your interest in developing a riparian buffer mitigation bank in Greene County. The
Division of Water Quality (DWQ) received your letter dated March 11, 2008 requesting information on
DWQ buffer mitigation bank policies. Please note our responses to your specific questions below:
1) Primary service area of buffer mitigation banks being limited to the hydrologic unit (HUC) in
which the bank is located.
The policy of limiting the primary service area of a buffer bank to the HUC in which the bank is
located is based on a number of factors. From an overall standpoint, limiting mitigation credit to
the HUC in which the impact occurs minimizes the spatial losses of riparian buffers (e.g., avoid
losses of buffers in the Triangle area from being mitigated by credits from Greene County).
15A NCAC 02B .0242 (4) states that "The mitigation effort shall be the same distance from the
Neuse River estuary as the proposed impact, or closer to the estuary than the impact, and as close
to the location of the impact as feasible. DWQ has interpreted this to be within the same HUC,
which actually allows for a greater distance from the impact are to the specific mitigation site.
Finally, the requirement for mitigation within the same HUC as the impact is consistent with
other federal and state guidance on mitigation. Guidance on mitigation plan development from
the U.S. Army Corps of Engineers (USAGE) Wilmington District (see
httn://www.saw.usace.armv.mil/WETLANDS/Miti~ation/mitblan.html) states that "A
compensatory mitigation project, at a minimum, should be located within the 8-digit USGS
Hydrologic Unit (HUC) within which the impact is located".
N~ehCarolina
~atura!!y
401 OversighUExpress Review Permitting Unit
1650 Mail Service Center, Raleigh, North Cazolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
[ntemet: http://h2o.enr.state.nc.us/ncwetlands
An Equal OpportunitylAff'irmative Action Employer - 50% Recycledl10% Post Consumer Paper

Mr. Becker
CLCBB
Page 2 of 2
Similarly, the Stream Mitigation Guidelines (U.S. Army Corps of Engineers, N.C. Division of
Water Quality, U.S. Environmental Protection Agency, Natural Resources Conservation Service,
and the N.C. Wildlife Resources Commission, Apri12003) states in Section 6, Selection of
Mitigation Sites "Selection Criteria 1. Mitigation should be accomplished within one stream
order of the impacted stream, within the same subbasin (8 di itg_HUC) and as close to the
impacted stream as possible".
Therefore, limiting the service area to the HUC where the bank is located is supported by the
buffer rules, as well as being consistent with other federal and state agencies' mitigation policies.
2) Buffer mitigation credit is limited to restored areas within SO feet of the stream.
15A NCAC 02B .0233(4) defines the protected buffer as consisting of Zone 1 (30 feet) and Zone
2 (20 feet). 15A NCAC 02B .0242(9)(c) states that the buffer restoration or enhancement site
shall have a minimum width of 50 feet. Clearly, the regulated buffer is 50 feet wide.
Providing credit for protected buffer impacts with square footage outside 50 feet does not
constitute an equivalent offset, as areas outside of 50 feet are not considered "protected riparian
buffer" under the rules. Existing research also shows that buffers greater than 50 feet do not
remove additional nutrients in a linear fashion; rather, nutrient removal rates increase more
slowly with increasing distance from the stream, especially beyond 50 feet. Therefore, buffer
credit generated from areas further than 50 feet from the stream would not be functionally
equivalent, on a square foot basis, to riparian buffer within the protected 50-foot zone.
Guidance is currently being developed, using existing data on ~lutrent removal of riparian
buffers, to provide reduced credit for buffer areas beyond; 50 feet. Until'such guidance is
approved, mitigation credit beyond 50 feet will not be allowed. This policy is supported by the
October 10, 2007 memo from Tom Reeder that was forwarded to your consultant.
I hope this information is suitable to answer you questions. If you have any further questions, please
feel free to contact Amy Chapman or Eric Kulz at [phone].
Sincerely,
~/~
G~~
Cy di B. Karoly, Program Manager
401 Oversight and Express Review Program
cc: File Copy (Eric Kulz)
Central Files
Kyle Barnes - DWQ WaRO
Sean Doig - RGJ&A, 1221 Corporation Parkway, Suite 100, Raleigh, NC 27610
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
Internet: htto://h2o.enr.state.nc.us/ncwetlands
NorthCarolina
~atura!!y
An Equal OpportunitylAffirmativeAaion Employer- 50% Recycled/10% Post Consumer Paper