20090565 Ver 1_Other Agency Comments_20090615

0R-o5?# co>
J??ZED STgr?S,
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
W REGION 4
? r ATLANTA FEDERAL CENTER
?F1Tq? pROt?19 61 FORSYTH STREET
ATLANTA, GEORGIA 30303-8960 (`? 'j
JUN 1 1 2009 v O V
JUN 1 5 2009
Mr. Mickey Sugg
U. S. Army Corps of Engineers DENR • WATER QUALITY
*%M AND STORIAWATER BRAMCFI
69 Darlington Avenue
Wilmington, NC 28403-1343
Subject: Bachelors Delight Stream and Wetland Mitigation Bank: Prospectus
Action ID Number 2009-00832
Dear Mr. Sugg:
This letter is in response to the Public Notice for the Prospectus for Weyerhaeuser
Real Estate Development Company's Bachelors Delight Stream and Wetland Mitigation
Bank, dated May 14, 2009. The U.S. Environmental Protection Agency, Region 4,
Wetlands and Marine Regulatory Section (EPA) reviewed the draft document. The Bank
Sponsor proposes to restore 15,900 linear feet of stream, 66 acres of riparian wetlands,
and 260 acres of non-riparian wetlands, enhance 5,300 linear feet of stream and 33 acres
of wetlands, preserve 11,400 linear feet of stream and 180 acres of wetlands, and provide
197 acres of upland buffers along the stream channels. The site has been historically
managed for silviculture, and agriculture. We have comments for your consideration and
the consideration of the project sponsor. In general, we believe that the site has good
potential for a mitigation bank. We look forward to seeing the site on June 17, and will
likely have more comments at that time.
1. The Geographic Service Area (GSA) should be similar to that approved for Hofmann
Forest Mitigation Bank. In other words, we recommend that the portions of the
03030001 hydrologic unit (HUC) outside of Onslow County be omitted from the primary
GSA. There are many more coastal stream resources southwest of the Onslow County
line, and EPA does not believe that it is appropriate to give blanket approval for the use
of this site for those types of stream impacts. We note that the mitigation bank template
includes a provision that will allow the use of this bank for areas outside the primary
service area on a case-by-case basis.
2. It is unclear from the Prospectus whether the Bank Sponsor intends to timber all of the
restoration areas prior to construction. Unless these areas are planned for timbering, EPA
recommends that the sponsor attempt to protect as many large (non-pine) trees (greater
than about 21 inch diameter at base height (DBH)) as possible from damage during
construction. We note that even if a tree is not removed, it may be damaged beyond its
ability to recover. Where possible, construction methods should be careful to avoid areas
within a large tree's drip-line, for compaction, fill, or excavation.
Internet Address (URL) • http://www epa.gov
Recycled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer)
3. The Prospectus does not discuss the potential use of the areas surrounding the bank on
this property. Although the Prospectus proposes preservation of significant upland
buffers and large tracts of wetlands on the site, it does not appear that the entire property
will be placed in a conservation easement. EPA recommends that the Bank Sponsor
clarify how much of the area within the property boundaries will be preserved, and what
plans may exist or are envisioned for the remaining uplands within the property
boundaries. We have noted that there are no new road crossings requested for the
streams, but there is an existing road (Maready Road) that crosses almost every stream on
the site. The Prospectus identifies many problems with the stream reaches and wetlands
in the vicinity of Maready Road, such as impoundment due to inadequate culverts, and
roadside ditches draining wetlands. Although the Prospectus proposes installing larger
culverts in some areas and filling the roadside ditches in other areas, it appears that this
road will stay, allowing access to the entire mitigation site. EPA also has concerns that
retaining the road across the site may cause continuing problems with stream stability.
4. EPA believes that the proposed planting plans and tree, shrub, and herbaceous species
are acceptable.
5. On Page 22, the Bank Sponsor proposes credit for upland buffer along the streams. A
200 linear foot buffer (100 feet on each side of the stream) is planned along every stream
reach. The Prospectus proposes 8:1 credit for these areas, on an acreage basis. However,
EPA recommends that the Bank Sponsor instead propose increased stream credit for the
additional buffers, using the method below (which has been discussed in North Carolina
Interagency Review Team (NC IRT) meetings and accepted by NC IRT members). It is
likely that the stream credit cannot be calculated until after the as-builts are completed,
because actual buffer measurements are required on each side of the stream.
Table: Stream mitigation credit adjustments for wider or narrower buffer widths
in the piedmont or coastal plain
Width - meters (feet) Predicted percent Stream Buffer Percent
nitrogen removal Effectiveness increase or
(from Mayer, et al Correction Factor decrease in
2007) stream credit
(SCFpcp)
Less than 15 feet (4.6 N/a -100%
meters)
15 to 29 feet (4.6 to 9.1 50.7% N/a -50%
meters)
31 to 50 feet (9.1 to 56.8 N/a -25%
15.2 meters)
50 feet (15.2 meters) 61.8 N/a N/a
51 to 75 feet (15.2 to 66.1 1.07 +3.5%
22.9 meters)
76 to 100 feet (22.9 to 69.3 1.12 +6.0%
30.5 meters)
2
101 to 150 feet (30.5 to 74.0 1.20 +10.0%
45.7 meters)
151 to greater than 200 77.6 1.26 +13.0%
feet (45.7 to 61.0
meters)
Buffer width calculations should be made separately for each side of the stream and then
totaled for the entire stream reach. The stream reach should first be broken into 100 foot
segments along the thalweg length of the mitigation site. The average width of the
segment is then calculated for each segment of the stream by averaging the sum of the
buffer widths measured at each of the segment boundaries of the segment and the mid-
point of the segment. The buffer width is measured horizontally from the bankfull
elevation to the conservation easement boundary line. The stream channel between the
left and right side bankfull elevations are not included in the measurements. The
appropriate correction factor (percentage) is then applied to the averages for each
segment, according to the Table above. The credits for all segments are then summed for
each side and divided by two. Finally, the results for each side are then added to obtain
the total credits for the site.
6. EPA is pleased that the sponsor is proposing post-project monitoring of benthic
macroinvertebrates. At this time, there are no established criteria for success, but the
benthos will provide a good indicator of condition after the stream reaches are restored.
7. On Page 31, the Prospectus states that five years of monitoring will take place over a
seven-year period. EPA understands that the proposed monitoring schedule includes
monitoring in years 1,2, 3, 5, and 7. We are not opposed to this schedule, however, we
recommend that a minimum amount of monitoring be required in years 4 and 6, such as
photos from the established photo points, and a general discussion of the success of the
site (both hydrology and vegetation).
8. There are no credit release schedules proposed in the Prospectus. EPA recommends
that the credit release schedule for the wetlands be as follows:
MBI signed,
Delivery of financial assurances,
Mitigation plans approved,
Conservation easement recorded: 15%
As-builts submitted: 15%(30%)
First year success: 10%(40%)
Second year success: 10%(50%)
Third year success: 10%(60%)
Fourth year success: 10%(70%)
Fifth year success: 10%(80%)
Sixth year success: 10%(90%)
Seventh year success: 10%(100%)
3
We note that if hydrology is determined to be successful in the first five years, the IRT
may agree to discontinue hydraulic monitoring after Year 5 (although this is unlikely if
the Bank Sponsor does not propose to monitor hydrology every year). Trees must be
monitored for a minimum of seven years.
For stream portions of the project, EPA recommends the following credit release
schedule:
MBI signed,
Delivery of financial assurances,
Mitigation plans approved,
Conservation easement recorded: 15%
As-builts submitted: 15% (30%)
First year success: 10% (40%)
Second year success: 10% (50%)
Third year success: 10% (60%)
Fourth year success: 10% (70%)
Fifth year success: 15% (85%)
Documentation of two separate bankfull events* 15% (100%)
*The release of 15% is contingent upon at least two bankfull event occurrences, in
separate years, provided that the channel is stable and all other success criteria are met.
In the event that less than two bankfull events occur during the monitoring period, the
release of the final 15% credit shall be at the discretion of the NC IRT.
9. The Vegetation Success Criteria should be based upon survival and growth of the
canopy tree species. We recommend that the following requirements be included in the
mitigation plan:
Demonstrated density of planted tree species to meet or exceed 320 per acre at the end
of 3 years (post-planting), 260 trees per acre at the end of 5 years, and 210 (7-year-
old) character canopy tree species per acre at the end of 7 years. The IRT may allow
for the counting of acceptable volunteer species toward the 210-tree per acre density
upon the review and evaluation of the annual monitoring data.
No single volunteer species (most notably red maple, loblolly pine, and sweet gum)
will comprise more than 20% of the total composition at years 3, 5, or 7. If this
occurs, remedial procedures/protocols outlined in the contingency plan will be
implemented. During years 3, 5, and 7, no single volunteer species, comprising over
20% of the total composition, may be more than twice the height of the planted trees.
If this occurs, remedial procedures outlined in the contingency plan will be
implemented.
If, within the first three years, any species exhibits greater than 50% mortality, the
species will either be replanted or an acceptable replacement species be planted in its
places as specified in the contingency plan.
4
Thank you for the opportunity to comment on this project. We look forward to
the field meeting on this site. Please contact Kathy Matthews at 919-541-3062 with any
questions or comments.
Sincerely,
?' l .
Jennifer S. Derby
Chief
Wetlands and Marine Regulatory Section
cc: USFWS, Raleigh
NMFS, Beaufort
NCWRC, Wilmington
NCDWQ, Raleigh
NCDCM, Morehead City