20170537 Ver 1_Draft Mitigation Plan IRT Comments_20170911

SAW -2015-01799
Hannah Bridge Mitigation Site — Neu -Con UMBI
EBX-Neuse I, LLC
Draft Mitigation Plan IRT Comments
September 11, 2017
U.S. AM Copts of Engineers Comments:
1. According to the Jurisdictional Determination issued on August 18, 2016, the site
contains 24.29 acres of existing wetlands. Table 2 on Page 8 indicates 3.27 wetland re-
establishment acres, 13.18 wetland high enhancement acres, 3.46 low enhancement acres,
and 7.27 preservation acres. The Public Notice identified 10.25 acres of high
enhancement wetland, 6.40 acres of low enhancement acres, and 7.27 preservation acres.
Please explain any discrepancies between the wetland treatment acreages listed in the
Public Notice and the current plan. Also please explain the difference between the
wetland acreages listed in Table 8 on page 22 of the current plan and the wetland
acreages submitted and approved with the JD.
2. Page 23, Section 4.4.1 states a utility crossing exists at the top of tributary HB 1. The
maps depict an easement break at the upper end of HB I and Table I indicates a road
crossing for HB 1. Please clarify.
3. Page 23, Threatened and Endangered Species: Please provide an estimate of vegetation
clearing for the project in acres. Also, please provide the number of trees that will be
removed for the restoration and enhancement activities. This information must be
submitted with the permit application.
4. Page 27, Section 7 states the total credits generated will be based on the as -built survey.
Please be aware that the total credits generated will be based on the approved mitigation
plan.
5. Page 27, Section 7.1: Please revise this section to state that initial allocation of credits is
contingent upon execution of the financial assurance document and issuance of the 404
permit.
6. Page 29, Section 8.1.1.2 states the reference stream is HB2. Figure 2 indicates that HB2
is proposed for restoration and enhancement activities and therefore, does not appear
suitable for use as a reference stream.
7. Please provide additional information regarding the proposed restoration and
enhancement activities for streams and wetlands:
a. Approximately 392 linear feet of HB2 is proposed for EII at a 2.5:1 ratio.
According to the design plans, and Figure 10, approximately 30-35 linear feet of
channel will have work conducted along one streambank to address bank erosion
and the buffer is undisturbed forest. This does not appear to support the proposed
2.5:1 ratio.
b. Approximately 579 LF of HB4 is proposed for restoration at a 1:1 ratio.
However, the design sheets indicate that the work proposed includes some
grading along the left bank and installation of 3 brush bed sills. This does not

appear to support a 1:1 ratio. Also, the lower end of HB4 is proposed for
enhancement at a 5:1 ratio. The existing conditions map depicts this area as
undisturbed forest and sheet P2 of the design plans indicates that the 50 foot
buffer and adjacent wetlands are not included in the 26.4 acres of planting. A
more appropriate ratio for the lower section of HB4 would be 10:1.
c. Wetlands adjacent to tributary HFI are depicted as forested, undisturbed wetlands
on the existing conditions map. Page 33 indicates that the buffer is intact but
invasive species are present throughout. Since the buffer is intact and undisturbed
and it is expected that all sites will be treated for invasive species throughout the
monitoring period, a more appropriate ratio for the existing stream is 10:1.
d. Table 11 indicates that 246 linear feet of stream channel will be created below the
existing HFI and through an existing wetland. It appears that the channel is being
created to accommodate the proposed restoration activities on Reach HB 1 and
may result in adverse and unnecessary impacts to the existing wetlands. For this
reason, we do not support generating credits associated with the proposed stream
creation.
e. According to the existing conditions map, HF2 is a ditch adjacent to and through
wetlands. According to Table 11, the sponsor proposes 149 LF as EIII at a 5:1
ratio. Page 34 states that a combination of headwater valley restoration and EII is
proposed for this reach. While a ditch feature is shown on the design sheets, the
feature is not labeled and no work is shown for this reach. Since the wetlands
adjacent to the upper portion of HF2 are proposed for enhancement at a 2:1 ratio,
we assume that the ditch will be filled to enhance the hydrology of the wetlands.
Please provide a map depicting all ditches that will be filled on the mitigation site.
f. Reach TH3 is proposed for enhancement Il at a 1:1 ratio. According to the design
sheets, the only work that will be conducted consists of some grading along —50%
of the right bank and the addition of log sills. This does not support the proposed
1:1 ratio.
g. The wetland area below and adjacent to the farm pond is proposed for
enhancement at a 2:1 ratio. On the existing conditions map, this area is depicted
as disturbed forest. There is one vegetation plot proposed for a small upland area
east of the pond. Figure 12 does not depict hydrology gauges or vegetation plots
in the wetland areas and the wetlands are not included in the 26.4 acres proposed
for planting. Please explain the rationale for the 2:1 ratio.
h. No information was provided on removal of the farm pond. Please provide a
description/plans regarding the process for pond removal and wetland restoration.
8. Page 45, Section 11: The plan states a detailed monitoring plan is provided in Figure 11.
Figure 11 depicts the location of vegetation plots, wetland gauges, and crest gauges.
Please revise the map to include proposed cross section locations. Also, please identify
vegetation plots associated with 404 credit generating areas versus state buffer nutrient
credit generating areas.
9. Page 45, Section 11: The plan states that success criteria is presented in Table 19. Table
19 provides information related (only) to monitoring.

10. Page 46, Section 11.3: Please revise the last sentence to state 4 bank full events in
separate years.
11. Page 46, Section 11.5: It appears that the lower end of TH3 is undisturbed forest and will
not require planting.
12. Page 47: Section 11.7 does not include any information and should be deleted.
13. Page 48, Section 11.8: Please delete this section. Adaptive management is addressed in
Section 13.
14. Page 48, Long Term Management Plan (LTM): The Rule requires that the mitigation
plan must provide a LTM plan that includes an itemized list of long term management
activities, an annual cost accounting, the amount of funding (endowment) that will be
provided, and the terms of the funding for these activities. Please provide this
information. Also, the plan indicates that the easement holder intends to hold the funds
in an investment account combined with other endowment funds. In order to ensure that
the LTM activities for the site have adequate funding, we discourage combining
mitigation site endowments in the same account.
15. Page 49, Adaptive Management Plan: In the event the IRT determines that corrective
actions are necessary, the sponsor should prepare a Corrective Action Plan for review and
approval by the IRT prior to beginning work.
16. Page 50, Financial Assurances. This section must provide specific information regarding
the process to be followed in the event of default including who will serve as obligee (the
Corps cannot direct the use of funds), the party that will serve standby trust or other
designee, and this section should specify that all proposed use of the funds and work
plans must be reviewed and approved by the Corps and IRT. The party agreeing to
receive funds and ensure the work is done must provide a signed statement to this effect
and a copy of this statement should be included in the mitigation plan. Also, we
recommend inclusion of a draft copy of the performance bond(s) with the draft mitigation
plan.
17. Please use the attached conservation easement template for mitigation sites that will
generate both 404 and DWR buffer nutrient credits.
18. Please provide a map depicting areas that will generate DWR buffer/nutrient credits.
19. All existing wetlands should be depicted and labeled on Figure 10 and the design plans.
Also, please explain why the boundaries of Wetland 9 (below the road crossing) as
depicted on Figure 10, do not match the boundaries depicted in the soil scientist report.
NC Division of Water Resources Comments:
1. In google earth aerials the 1993 aerial shows forested, and in 1999 several project areas
had been cleared.
2. Section 2.1.1- disagree with statements made, see above comment (google earth).
3. Pictures on page 14 refer to different wetlands, however, they are not identified in any of
the "primary" figures. Ultimately found map in Appendix B, DWR requests that if

pictures and a Table are referring to wetlands in the main body of the text, a map should
be listed with the other primary figures in the main document.
4. Wetland hydrology criteria -The wetland performance criteria for wetland hydrology will
be as stated in the October 2016 Mitigation Guidance (Bibb- 12% of the growing season),
the IRT will consider a year 1 and/or 2 exception as noted in the current Guidance.
5. Table 19-1 believe the Mitigation Guidance is from October of 2016.
6. DWR would recommend installing a few gauges adjacent to reach HBI and around the
proposed wetland enhancement area. In addition, adjacent to the filled ditch above reach
HF2 as well.
7. Typically, wetland gauges should downloaded monthly. Downloading at a quarterly
interval risks losing valuable data which may extend the monitoring period beyond 7
years for wetlands.
8. DWR recommends installing groundwater gauges adjacent and around reach HBI to
demonstrate that the wetlands are not impacted and in fact show that they will be
enhanced.
9. On design sheet S6 there are two diffuse flow structures planned to be installed at the
easement edge, however, after these structures a topo swale appears to channel flow back
toward the stream channel. These flow paths end up draining into a meander bend.
DWR recommends altering the design of the swale so it empties into a riffle, or construct
a floodplain pool that accepts flow from both swales and has one outlet directed at a
riffle. In fact, on design sheet S7 another flow path was diverted away from the initial
flow path but directed at a meander bend. DWR would recommend these confluences
occur a riffle, preferably that has some hardening associated with it (ie, constructed riffle
typical).
10. DWR does not believe the lower portion, below the crossing( sheet S9), of reach HB4
warrants restoration credit, nor does the EIII portion of HB4 warrant 5:1 credit.
11. DWR questions the credit ratio for the following project areas:
a. Wetland enhancement (3:1) above reach TH3,
b. Stream reaches HF 1 and HF2,
c. Any wetland enhancement at 2:1 located (>100 feet) away from the restored
stream channel, including the enhancement area located west of HB4.