20090565 Ver 1_Mitigation Plan Review_20100305

A
NCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue Coleen H. Sullins Dee Freeman
Governor Director Secretary
March 5, 2010
Mr. Mickey Sugg
U.S. Army Corps of Engineers
69 Darlington Avenue
Wilmington, NC 28403-1343
Subject Project: Bachelors Delight Stream and Wetland Mitigation Bank
Mitigation plan review
Dear Mr. Sugg:
DWQ # 2009-0565
Onslow County
The Division of Water Quality (DWQ) 401 Oversight and Express Review Permitting Unit has
reviewed the Restoration Plan (dated January 2010) for the above-referenced mitigation bank. In
addition, Tammy Hill from this Unit participated in a site visit with the Local Interagency
Review Team (LIRT) on June 17, 2009. Our comments are as follows:
Wetlands
• DWQ supports the application of the Buffer Correction Factor in the calculation of final
stream credits produced by the bank. However, restored upland buffers should not be
included in the wetland mitigation acreages in Table 3.
• DWQ supports the use of on-site reference ecosystems, including the preserved areas
along HE-2 and HE-4 for stream and riparian communities. No reference was proposed
for the non-riparian wetlands. The preserved area in the headwaters of HU-1 may
provide an appropriate hydrologic reference, although the forest composition and age
probably do not offer an ideal vegetative reference. DWQ suggests that a monitoring
well be installed in a representative location within this area, or another suitable nearby
wetland, to use as a hydrology reference for the non-riparian wetland restoration.
• We support the 5:1 preservation ratio for riparian wetlands with mature canopy trees. We
suggest a higher ratio for non-riparian preservation of 20-year-old naturalized
silvicultural areas on the northern part of the project. It appears that a 10:1 ratio has been
factored into credit calculation for this area in Table 6. DWQ supports the 10:1 ratio, but
is willing to consider a somewhat more favorable ratio, based on the connectivity with
other large preserved areas, if other members of the IRT feel it is deserved.
• The proposed success criteria and credit release schedule for wetlands are acceptable.
Although monitoring reports will not be submitted after years 4 and 6 of the 7-year
monitoring period, qualitative monitoring (i.e. photographs, visual inspection of the
project) should be conducted during those years to check for any potential problems. If
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
Location: 2321 Crabtree Blvd., Raleigh, North Carolina 27604
Phone: [phone] FAX: [phone]
Internet: http://h2o.enr.state.nc.us/ncwetlands/
NorthCarohna
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An Equal Opportunity 1 Affirmative Action Employer
Bachelors Delight Mitigation Bank
Page 2 of 3
problems are identified, the Local IRT chair should be notified regarding proposed
remedial actions.
gtream s
• DWQ concurs with the proposed plans for restoration, enhancement and preservation of
stream features on the site. Based on review of the Restoration Plan and the site visit, the
site appears to be a good candidate for a mitigation site.
• The small section of zero-order stream valley restoration proposed for HU-1 A (between
HU-1 and the preserved HU-IA valley) is not present on the Site Design Map (Figure 7).
Although it will be small at the map's scale, the 171 linear feet of valley should be
visible, and including it on the map may be useful for future site visits and credit
calculations. Also, HM-IA is not labeled on this map. It is not necessary to reprint the
current plan for these clarifications, but they should be included in any revised mitigation
plans, and the attempted restored length should be evident on as-built maps.
• We appreciate the sponsor's willingness to conduct additional monitoring along BD-5
prior to determining the most ecologically-sound course of action for that reach.
• The monitoring plan and credit release schedule for streams are acceptable. There may
be limited value in measuring cross-sections in the headwater valleys, and DWQ is open
to discussing the option of their removal from the monitoring plan with the Local IRT.
We do support cross-section and longitudinal profile monitoring along the first and
second order stream restoration reaches, and feel that a success criterion should be added
regarding significant aggradation or degradation of channel stability in comparison with
the as-built. If such conditions are observed, the Sponsor would be responsible for
identifying and addressing issues prior to the associated credit release(s). We appreciate
the inclusion of pre- and post-construction (at years 3 and 5) monitoring of aquatic
macrobenthos. Although it is not necessary to attach a success criterion to those
measurements, we do look forward to seeing the results.
• DWQ does not concur with the stream credit generation proposed for the site.
Determination of mitigation credits generated at the site should be separated between
stream restoration/enhancement and stream preservation, as follows:
• For the stream restoration and enhancement reaches, where riparian buffer widths exceed
the standard 50-foot width outlined in the 2003 Stream Mitigation Guidelines, DWQ
concurs with the use of the draft Regulatory Guidance for the Calculation of Stream and
Buffer Mitigation Credit for Buffers Widths Different From Standard Widths (v. 4.4,
March 1, 2009). The 2003 Guidelines establish that additional channel mitigation credit
can be generated at sites with wider buffers, with the agreement of the permit agencies.
The draft buffer width guidance provides a science-based method for calculating the
additional stream credit. This guidance has been reviewed and approved by the
Interagency Review Team and is currently on Public Notice on the U.S. Army Corps of
Engineers website.
• With respect to the stream preservation areas, the 2003 Guidelines include a list of
criteria (Page 16) that may be used as a guide for selecting preservation sites. Based on
DWQ's review, the proposed preservation reaches do not meet any of the eight selection
criteria. In addition, the Guidelines indicate that additional buffer width may be required
at preservation sites. Based on DWQ's site visit, the preservation reaches observed were
in good, but not unique condition, and the wooded riparian areas were generally
unremarkable. DWQ concurs that there is value in including the preservation reaches to
the project, and if the preservation reaches were excluded, it would seriously limit the
Bachelors Delight Mitigation Bank
Page 3 of 3
viability of the entire project due to a lack of connectivity between the restoration and
enhancement reaches. However, it should be noted that preservation does not replace lost
stream function and values, and does not support the goal of "no net loss".
It is DWQ's position that preservation credit should be awarded at 5:1 as per the 2003
guidelines. DWQ would consider slightly more favorable credit ratios if the preservation
reaches could be demonstrated to meet HQW criteria.
Geographic Service Area
• We support the revised GSA depicted in Figure 4. We would like to verify that bank
credits would not be in-kind mitigation for tidally-influenced or barrier island resources.
The MBI should state that, on a case-by-case basis, credits from the bank may provide
compensation for impacts outside the GSA if approved by the regulatory agencies.
General
• We continue to look forward to information regarding further development of the
landowner's plans for the areas immediately surrounding the bank boundaries.
• We maintain that the project appears to be a viable candidate for providing mitigation
credits through the restoration and enhancement of a Costal Plain wetland and stream
complex. It appears that the project designers are applying restoration and enhancement
methods appropriately and thoughtfully based on the ecology of the site.
We appreciate the opportunity to visit the proposed bank site and to comment on the Mitigation
Plan. We look forward to working with the Local IRT and bank Sponsor toward a successful
mitigation bank. Please feel free to contact Tammy Hill at [phone] or
[e-mail] regarding our comments or any issues related to t?s bank.
Since ly,
Ian McMillan, Acting Supervisor
401 Oversight and Express Review Program
Cc: Ms. Joanne Steenhuis, DWQ Wilmington Regional Office
Ms. Becky Fox, US EPA, 1307 Firefly Rd., Whittier, NC 28789
Mr. Ron Sechler, NMFS, Habitat Conservation Div., 101 Pivers Island Rd., Beaufort, NC 28516
Ms. Tere Barrett, NC DCM, 400 Commerce Ave., Morehead City, NC 28557
Ms. Molly Ellwood, NC WRC
Mr. Howard Hall, US FWS