20201865 Ver 1_Draft Mit Plan Comment Memo AW-2020-02051_20221209

DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
69 DARLINGTON AVENUE
WILMINGTON, NORTH CAROLINA 28403-1343
REPLY TO
ATTENTION OF:
CESAW-RG/Browning
MEMORANDUM FOR RECORD
November 22, 2022
SUBJECT: NCDMS Cornbread Valley Mitigation Site - NCIRT Comments during 30-day Mitigation
Plan Review, Macon County, NC
PURPOSE: The comments listed below were received during the 30-day comment period in
accordance with Section 332.8(g) of the 2008 Mitigation Rule in response to the Notice of NCDMS
Mitigation Plan Review.
USACE AID#: SAW-2020-02051
NCDMS #: 100175
NCDWR#: 2020-1865
30-Day Comment Deadline: October 15, 2022
NCWRC Comments, Andrea Leslie:
• We are very glad to see a mitigation site in this part of the Little Tennessee basin and to know that
there is another site just downstream. We think that these two sites could have a significant positive
impact on Cartoogechaye Creek, which supports a diverse aquatic community, including rare and
listed species. As such, it'll be very important to use excellent erosion and sediment control on the
project.
• As noted in our response to Wildlands' scoping request, there are wild Brown Trout and Rainbow
Trout in the project vicinity, and in -stream activities should be avoided during the trout moratorium
of October 15 to April 15.
• We appreciate Wildlands' efforts in developing a planting plan with a rich list of woody and
herbaceous plants. Kudos to them for this!
o We are supportive of the plans to plant smaller zones with the rapid self -seeding herbaceous
plants in the `supplemental wetland zone'. Monitoring is definitely needed to track the
progress of this effort.
o The planting plan is geared to establish a forested wetland. We recommend allowing for
flexibility via adaptive management so that pockets of different wetland types (e.g., shrub -
scrub, herbaceous) can be allowed if they develop.
o It is noted that River Cane is found offsite. We recommend incorporating this species into
the planting plan.
• DOT will eventually be replacing bridges on the site, as they were built in the 1960s. While they
may end up using off -site detours, we suspect they will be using wider structures than cannot fit the
right-of-way (ROW), which is probably not recorded anyway but just a maintenance
assumption/standard width. We recommend staying back at least 10 feet either side from the ROW
with the easement to accommodate later bridge replacements. This also may incentivize later
bridge design work (use off -site detour and avoid mitigation, state property encroachment).

• It is noted that the start of the mitigation reach on UT2A is currently a perched culvert under a DOT
road. The mitigation plan (MP) notes that this perch will be reduced but not eliminated. Please
describe what this means — what is the current and anticipated future perch be?
• We caution Wildlands to avoid some problems seen on recently built sites with poor culvert
choice/installation and structure drops:
o It appears that the proposed culverts are corrugated metal (CMP), which is good; be sure not
to substitute this material with high density polyethylene. Culverts must be buried
appropriately.
o Crossing 12 is at about a 5% with no outlet grade control, which is probably asking for
trouble. We recommend that Wildlands at least try to promote the backwatering of that pipe
with a structure.
o Avoid installing structures that are too high and regular. Instead of regular structures that
result in planar flows over the top of them (e.g., a single log set across the channel or a large
boulder resulting in a perpendicular drop), we recommend installing messy structures that
allow for diversity of flow patterns and `sneak' channels for animals with varied swimming
and crawling abilities. Although the plans do not show maximum elevation changes on the
typicals for structures, it appears that some of the structures will have a 1-ft drop from the
structure to pool bed — we caution Wildlands in structure design and placement, as scour can
result in even higher drops. We recommend considering embedding the bottom of pools with
larger stone/mix (to resist scour) and adding a messier transition at the head, maybe
doubling -up the logs/rocks and carrying cascade riffle transition from upstream of the
structure down into the pool.
• Please put a note in specifications to verify during installation that some small gaps be
retained between the fence bottoms (if woven wire is used) and ground to allow for wildlife
scooching.
USACE Comments, Kim Isenhour:
1. It will be important to have extra boundary markings in the utility crossings, perhaps "No Mow"
signs, so that it's clear where the CIE boundaries are compared to the utility line maintenance
areas. I would also recommend extra signage on the DOT easement border to prevent
encroachments if/when bridges are replaced.
2. Please include the Internal Crossing and Utility Justification that was emailed to the Corps
October 25, 2022. 1 agree that the smaller utility lines have the potential to be removed in the
future, which would leave the easement exposed if it was external to the CIE, and I understand
the dilemma of not being able to enforce cattle exclusion without the backing of the CIE.
3. Appendix 5:
a. Cherokee Nation THPO: Please confirm that the two locations that are labeled as
Protected Archeological Sites 31 MA873 and 31 MA877 are the only areas that will be
avoided during construction. Were other areas that were identified with positive shovel
tests the areas that will receive shaded bare root planting? There was a lot of
correspondence, so I just want to make sure that the two additional bare root planting
areas are identified on Figure 10.
b. USFWS: Just to confirm that Wildlands has committed to NLEB special conditions in the
404 permit that will include no night work, no artificial lighting will be added to the action
area, and trees will be removed from Oct 15 — Apr 1 outside of the bat active season for
tree -roosting species. A may affect not likely to adversely affect call has been determined.
4. Design Sheet 2.8.1: A fiber roll BMP is planned on UT3131. It appears that this is planned in a
jurisdictional area, Wetland O. BMPs cannot be placed in jurisdictional areas. Is it possible to
shift this to where the old spring box is being removed? Or perhaps note that this will just be a
temporary impact until the dense vegetation establishes.

5. A soils report by a licensed soil scientist would have been preferable for this site. With the
amount of earth moving involved to grade to the target floodplain elevations, it would be
beneficial to know if hydric soil indicators are found at 12-24". Soil profiles will be important to
provide during monitoring.
6. Section 6.7, wetlands along UT1: Typically, grading over 12" would be credited as creation at
3:1; however, since it is only about 0.1 acres that will be graded greater than 12", 1 accept the
proposed 2:1 ratio because of the uplift from planting, livestock exclusion, and raising the
streambed. Priority 1 restoration would have been preferred, with wider buffers, and would have
likely eliminated some of the floodplain grading.
7. Figure 10:
a. In addition to visually monitoring the shaded planting zones, please provide information
in the monitoring report on the survival of planted understory species. A recent discussion
with Wildlands indicated that on a different project, none of the understory plantings
survived.
b. Please also plan to add mobile vegetation plots to the wetland enhancement area on UT1
and the reestablishment area on UT3.
c. I'd like to see random veg plot data for UT2A and the restoration reach of Jones Creek at
least once during monitoring
d. Please indicate the location of benthic monitoring on UT3A after it's conducted in MY2 or
MY3.
8. Jones Creek Reach 4: It's understood that livestock will be excluded from the bridge crossing,
but will cattle be accessing the other side of N. Jones Creek Road under the bridge? I was not
able to be at the site visit so I just want to confirm that the area will be adequately stabilized for
livestock crossing, similar to the crossing under the road on the Wyant Lands project.
9. 1 would encourage Wildlands to follow up with the landowner regarding livestock waterline
installation prior to construction so they are aware that even if watering facilities are not installed
by the time construction is complete, the ford crossings cannot be used for livestock watering.
10.It would be helpful to include a wetland grading figure that shows areas that will be graded
greater than 12", and those under 12". The figures are very busy and it's difficult to determine
how much grading is planned. I appreciate the explanation in the response to DMS comments.
11. Section 3.5: Did the Cherokee Nation request to be present during construction/planting?
12. Section 6.0: Where bankfull benches are being cut, please plan to provide visual observations
and/or veg transect data since vegetation establishment in these areas has proven difficult in
the past.
13. Section 6.5: Do you plan to apply a heavy herbaceous seed mix along Jones Creek Reaches 4
and 5? I'm concerned that water cresting the levies will cause floodplain scour/erosion as it re-
enters Jones Creek.
14. Section 8.0: Detailed soil profile descriptions should be recorded within restored and created
wetlands where gauges are installed. These profile descriptions should be a record of the soil
horizons present, and the color, texture, and redoximorphic features present. Representative
soil profiles should be gathered for the baseline monitoring report and during monitoring years
3, 5 and 7.
15. Table 24: It would have helped expedite the review if the NCWAM scores were included in this
table.
16. Section 6.1: The existing ditches that will remain on Jones Creek Reaches 3 and 4 should be
included in this section. I understand that they're vegetated outside the easement, but what is to
prevent the landowner from clearing or dipping them out? Would BMPs inside the easement be
a better alternative than ditches?
a. Sheet 2.1.5: It's unclear to me whether the ditches remain open in the easement and
connect to the channel, or will there be diffuse flow?
17. Section 6.7.2: Were wetland gauges installed to gather pre -construction data?
18. The existing drain tiles should be shown on Figure 2.

DWR Comments, Erin Davis:
1. DWR requests that responses to DMS comments dated September 2, 2022, be included in the
final mitigation plan appendices. There are several discussion points that could be helpful to
refer back to if questions/concerns arise during IRT credit release reviews.
2. Page 26, Section 3.5 — DWR appreciates the thorough coordination with Duke Power. To
confirm, all project utility crossings will be helicopter maintained?
3. Page 29, Table 27 — Why is Biology asterisked in the Functions Supported column?
4. Page 42, Section 6.6 — Since a Priority 2 restoration approach typically limits the potential
function uplift compared to Priority 1, DWR prefers it be limited to confluences and transition
zones. Our recommendation for reducing the risk of hydrologic trespass is wider buffers, not a
Priority 2 design.
5. Pages 43-44, Section 6.6 — In this section, the natural levy design is only mentioned along
Jones Creek Reach 4, however, Reach 2 and Reach 5 are discussed in Section 3.5. Please
clarify.
6. Page 47, Section 6.7 — While not strictly required, DWR has come to appreciate and expect a
hydric soil investigation report when project wetland restoration credit is being proposed. In
particular it is helpful to have a Licensed Soil Scientist evaluate drained hydric soil for
reestablishment credit suitability.
7. Page 49, Section 6.8 — The wattle type could affect the longevity of the BMP function and
potential maintenance. What type of wattle is proposed (e.g., straw vs. coir fill, fiber vs. plastic
netting)? Also, please monitor for signs of erosion from any concentrated flow around the
wattle.
8. Page 50, Section 6.9 — As part of Land Management, please provide a brief description of
proposed soil restoration to address equipment/haul road compaction, low nutrients/organics,
pH, etc. for planting medium suitability.
9. Page 52, Table 40 — DWR is ok with the proposed modified vigor performance standard for
wetland planting zones. Regarding table note 4, DWR requests that in addition to visual
assessment of the shaded planting zones, trends on planted stem survival be reported (e.g.,
general survival observations, which species are establishing well, and which aren't).
10. Page 53-55, Table 41 —
a. The proposed project is comprised of more lumping than splitting of reaches based on
construction activities to represent a more "holistic restoration" approach. To confirm,
performance standards, monitoring and adaptive management applies to restoration
and enhancement credited areas sitewide. In -stream structures and bank treatments
along enhancement reaches should be assessed for stability throughout the monitoring
period. Due to proposed streambed work, DWR requests additional an cross-section
along Jones Creek Reach 4 and UT3A Reach 2.
b. While macroinvertebrate sampling requested by the IRT isn't required to have a specific
performance standard, please provide more information on the proposed sampling
methodology and schedule. Please note that if sampling efforts are unsuccessful at
demonstrating stream biology, credits for this reach may be at -risk.
11. There are several design sheets where existing trees are specifically called out to be saved or
removed, while other trees have no callouts. Please be consistent with callouts throughout the
plan. Maybe add a plan note that only trees over a certain DBH will have save/remove callouts.
Also, please revisit/reevaluate areas shown both as stream bank grading and tree protection
(e.g., Sheets 2.1.4, 2.1.5, 2.1.7).
12. Multiple ditches that flow towards the project easement and stream are to remain open to
continue positive drainage. Understanding that field changes may occur due to site conditions

during construction, please assess the potential need for stone placement within any ditches or
stream tie-in points during this planning phase and include on final design plans as necessary.
13. Sheets 2.1.1 — 2.1.7 — Please add callouts to any areas proposed to be graded as natural
levees as discussed in the plan narrative.
14. Sheet 2.1.5 — To confirm, the existing ditch transitions to diffused flow within the easement?
15. Sheet 2.2.1 —Section 6.6.6 mentions the construction of an outlet/headwall. If this is proposed,
please show on plan sheet. DWR's preference is to fully remove existing infrastructure from
the project easement. However, if any infrastructure is left or built within the easement, please
clearly identify in the as -built and MYO report, including coordination with Stewardship and
changes to the standard easement agreement (e.g., maintenance activity allowance).
16. Sheet 2.3.1 — Is the UT1A culvert located on the easement boundary? If so, DWR requires an
offset to the start of crediting to allow for future structure maintenance. DWR's preference
would be to have a setback between the project easement and the existing structure.
17. Sheet 2.4.2 — To clarify, the existing ditch is a wetland feature? Also, the narrative mentions
remnant road roughening along UT2. Please show the approximate road footprint.
18. Sheet 2.6.1 — Please include the brush pack icon to the plan legend sheet. Also, does the
proposed vernal pool outlet to the stream? If so, will the outlet be vegetated or stone lined?
19. Sheet 2.6.3 — What is the hatched feature on the left floodplain between Sta. 10+50 — 11 +00?
20. Sheets 2.7.1 & 2.7.2 — Please add reach callouts (e.g., reach name, credit start/end station
and approach). Why does the proposed thalweg icon change to arrows? Assuming the "w" line
is a water line, please add it to the legend and callout it's removal from the easement.
21. Sheet 2.8.1 — While not a credited stream, please add a callout and show the footprint of
UT3131 within the project easement, as well as any proposed work.
22. Sheet 2.8.2 — Please briefly describe how riffles will be built into existing tree roots.
23. Sheet 2.9.1 — The narrative mentions the UT3C Reach 1 culvert is undersized and that
headwall is eroding. Is replacement of this structure proposed? If so, please callout. If not,
please discuss any potential adverse impacts the existing structure may have on the project
reach. Also, to confirm no constructed riffles are proposed along UT3C Reach 1 or Reach 2?
24. Sheet 4.1.1 & 4.1.2 — DWR appreciates the level of detail provided for the different planting
zones and the proposed species diversity, including herbaceous wetland plugs. The inclusion
of potential substitutes is helpful to review at this stage.
25. Sheet 7.3 — For consistency, please use either vernal pool or floodplain pool for both the
legend icon and detail.
Digitally igned byKimberlyT. KimberlyT. Isenhou
r
Isenhour Date: 2022.11.22 1 1:44:19
05,00,
Kim Isenhour
Mitigation Project Manager
Regulatory Division