20190865 Ver 1_Notice of Intent to Approve SAW-2019-00835_20210127

Strickland, Bev
From:
Browning, Kimberly D CIV USARMY CESAW (USA)
<[e-mail]>
Sent:
Wednesday, January 27, 2021 2:25 PM
To:
Tugwell, Todd J CIV USARMY CESAW (US); Kim Browning; Davis, Erin B; Bowers, Todd;
Hamstead, Byron A; Wilson, Travis W.; Leslie, Andrea J; Haywood, Casey M CIV (USA)
Cc:
Smith, Ronnie D CIV USARMY CESAW (USA); McLendon, C S CIV USARMY CESAW
(USA); Ray Holz; John Hamby; Wiesner, Paul
Subject:
[External] Notice of Intent to Approve/ NCDMS Laurel Springs Mitigation Site/
SAW-2019-00835/ Avery County
Attachments:
Draft MP Comment Memo -Laurel Springs_SAW-2019-00835.pdf
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Good afternoon,
We have completed our review of the Draft Mitigation Plan for the NCDMS Laurel Springs Mitigation Project (SAW-2019-
00835). Please see the attached memo, which includes all NCIRT comments that were posted on the DIMS SharePoint
site during the review process along with additional comments provided by Wilmington District staff following our
review of the IRT comments.
We have evaluated the comments generated during the review period, and determined that the concerns raised are
generally minor and can be addressed in the final mitigation plan. Accordingly, it is our intent to approve this Draft
Mitigation Plan (contingent upon the attached comments being addressed in the Final Mitigation Plan) unless a member
of the NCIRT initiates the Dispute Resolution Process, as described in the Final Mitigation Rule (33 CFR Section
332.8(e)). Please note that initiation of this process requires that a senior official of the agency objecting to the approval
of the mitigation plan (instrument amendment) notify the District Engineer by letter within 15 days of this email (by COB
on February 10, 2021). Please notify me if you intend to initiate the Dispute Resolution Process.
Provided that we do not receive any objections, we will provide an approval letter to NCDMS at the conclusion of the 15-
day Dispute Resolution window. This approval will also transmit all comments generated during the review process to
NCDMS, which must be addressed in the Final Mitigation Plan to be submitted with the Preconstruction Notification
Application for NWP 27. All NCIRT members will receive a copy of the approval letter and all comments for your records.
Thank you for your participation.
Kim Browning
Mitigation Project Manager, Regulatory Division I U.S. Army Corps of Engineers

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
January 27, 2021
SUBJECT: Laurel Springs Mitigation Project - NCIRT Comments during 30-day Mitigation Plan
Review
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.
NCDMS Project Name: Laurel Springs Mitigation Site, Avery County, NC
USACE AID#: SAW-2019-00835
NCDMS #: 100122
30-Day Comment Deadline: January 10, 2021
WRC Comments. Andrea Leslie:
1. 9.6 acres of wetland reestablishment and rehabilitation are proposed, and the majority of our
comments focus on the planting strategy for this area.
2. The natural communities document used is the 3rd approximation (Classification of the Natural
Communities of NC, Schafale and Weakley, 1990). There is a more recent document — the 4tn
approximation (Guide to the Natural Communities of NC, Schafale, 2012) that is more
appropriate to use when identifying natural community types. Please note this for the future.
3. We are glad to see that two nearby wetland communities were identified as references. The
plan notes that these are freshwater marshes, and species found at these sites are listed in
Table 11, titled "Freshwater Marsh Ecosystem". However, both woody and herbaceous species
are included in the list. Please clarify if the list of species in Table 11 are those found at the
reference sites; if so, it seems that these sites are not freshwater marshes but more complex
communities. In addition, the text notes that plants in Table 11 will be used within the permanent
seed mix for stabilization. Are the woody plants to be used for the site as well?
4. A `reference forest ecosystem' (RFE) was used for the site, based on a forest in Stone Mountain
State park, 53 miles from the site. We question if this reference is applicable for the site, as it is
so far away from the project site and many of the RFE species are strictly upland species. Does
the RFE occur in a similar broad floodplain setting?
5. The planting list specifies 3 community types — acidic cove forest, montane alluvial forest, and
streamside assemblage. Montane alluvial forest is specified for most of the proposed wetland
area, with the exception of 20% of the wetland to be seeded in herbaceous and shrub species.
Many of the species included in the montane alluvial forest are clearly upland species — e.g.,
white oak, white pine, red spruce. These and additional species specified may not withstand a
hydroperiod of 12% (the wetland hydrology success criterion) or more. Given that the baseline

well monitoring data already shows some sustained soil saturation and drain tile removal will
further wet the site, we believe that the site has good potential to be very wet. We recommend
reevaluating the community types and plant species specified for the wetland restoration area.
Should a swamp forest bog system be more dominant on the site?
6. Please note that sycamore and river birch are more typical of larger stream systems; we
recommend eliminating these species in favor of other species more typical of smaller systems
(please use local references to inform the planting list). As much of the Eastern hemlock
specimens across western NC are infected with hemlock wooly adelgid, we recommend limiting
the number planted to 5% or less.
7. The shrubby herbaceous openings that are projected to become swamp forest bog are only
being seeded with herbaceous and shrub seed. We recommend including some bare root or
containerized plantings of woody species. Presumably, these openings would be in wetter areas
on the site, but their placement is not at topographic low points; instead, there seems to be no
difference topographically between where they are placed and the surrounding montane alluvial
forest.
8. We recommend that additional mid -story species be added to the planting list, as Amelanchier
is the only lower story species included.
9. We recommend eliminating the dissipator pad specified on page C8.09 in favor of an armored
scour hole. Please note that C8.09 notes that specifications for the dissipator pad are included
on C8.08, but they are not there.
DWR Comments, Erin Davis:
1. Page 1, Section 1.3 — Please include a discussion of past/historic onsite and adjacent area
land use.
2. Page 7, Section 2 — This section mentions potential development trends and land use
changes. Have local/regional agencies and/or planning documents been consulted? Are there
any anticipated land use changes adjacent to the project site?
3. Page 8, Section 3 — Please include a subsection on existing vegetation cover. Only 16.2 acres
of the 29.19-acre easement is proposed for planting and "disturbed forest" was mentioned
under land use. Please include a list of invasive species observed onsite.
4. Page 11, Section 3.5 — Please provide more detail on existing stream conditions. While Table
4 provides an overall summary, it doesn't identify why multiple approaches are proposed for
each stream (e.g. UT3 broken into four reaches ranging from restoration to preservation
quality).
5. Page 11, Section 3.5.2 — Are all site reaches classified as unstable? Also, reach substrate
ranges from sand to what?
6. Page 14, Section 3.6.3 — Please provide a brief description of the wetland preservation area.
7. Page 18, Section 7 — DWR considers easement breaks as project constraints to be listed in
this section as they fragment the project site and reduce the potential uplift. DWR appreciates
that the utility corridor and road crossing were collocated to a single easement break, and that
a setback for potential future DOT roadway maintenance was a planning consideration.
8. Page 24, Section 8.1.1 — Areas of good instream habitat were noted during the 2019 IRT site
walk. Can you briefly discuss if/how you will be relocating and reusing onsite bed material.
9. Page 25, Marsh Treatment Area — Please confirm that no long-term maintenance is needed for
this feature. Also, if feasible please discuss alternatives to a riprap outlet.
10. Page 25, Drop Structure — Please finalize the structure design in order to eliminate the "may
be" in the final mitigation plan. Please make sure the description matches both Detail Sheet
C8.03 and Figure 8B.

11. Page 27, Section 8.3 — Is any wetland grading proposed? If so, please identify areas that will
be excavated beyond 12 inches. Also, ephemeral pools are noted in the text but not shown on
the draft design sheets. If construction of ephemeral pools is proposed, a typical detail (with
max. depth indicated) and approximate locations should be included in the final mitigation plan.
12. Page 27, Section 8.4 — DWR appreciates the inclusion of this subsection, but requests a
sentence addressing soil compaction.
13. Page 28, Table 18 —
a. Please check botanical name spelling and be consistent with common names (e.g.
serviceberry/shadbush, sweet birch/cherry birch). It would be helpful to include a
column with the wetland indicator status. Also, please indicate if any of the species will
be installed as live stakes.
b. DWR appreciates the species diversity provided, both in incorporating RFE species and
not exceeding 20 percent per species in each planting zone. It appears the 9-acre
Montane Alluvial Forest planting zone overlaps the 9.8 acres of proposed wetland area.
Is this community type characteristic for wetland habitat? We question the
appropriateness of planting white pine in a wetland restoration area. Also, we request
that hemlock be capped at 5% due to woolly adelgid concerns with potential tree
mortality. And were woody stem plantings of shrub species considered for the site?
14. Page 29, Section 8.5.2 — DWR appreciates the discussion of the potential herbaceous
dominated wetland. DWR generally supports mosaic communities, if appropriate for the site
and with an area cap (which was noted at 20 percent). Please confirm whether the seed mix
provided will be applied site wide. If not, please include a separate riparian seed mix for less
saturated wetland and upland areas in the final plan.
15. Page 29, Section 9 — DWR recommends adding a sentence to this section stating that success
criteria and monitoring will be completed in accordance with the 2016 NCIRT Guidance.
16. Page 31, Table 21 —
a. Please clarify that the wetland hydrology is an annual criterion.
b. DWR requests a species diversity success criterion for areas that establish as
herbaceous dominated wetland areas.
17. Page 30, Table 20 — Please confirm whether the one surface water gauge and one crest
gauge proposed is the same monitoring device/location.
18. Page 31, Section 9.2 — DWR appreciates the inclusion of this section, especially the site
specific detail provided for easement encroachment. Please note that some of the listed
actions will require IRT review as adaptive management and may need USACE/DWR permit
authorizations.
19. Page 33, Section 9.2.2 — As noted, IRT consultation and approval will be necessary if any
future earthwork is proposed. Depending on the depth of proposed ephemeral pools, the credit
ratio may change to reflect wetland creation.
20. Page 33, Section 9.2.3 — Again, DWR appreciates this discussion. We recommend an
additional sentence addressing any identified cause for observed veg issue(s) (e.g. beaver
trapping, soil amendments).
21. Page 35, Section 10 — Please specify DMS as the point of contact to notify the IRT of any site
issues.
22. Figure 4 — Please shown existing utility lines. Also, can a property boundaries layer please be
added to this figure or another figure.
23. Figure 8A — Please make sure information provided in figures is consistent with design sheets
(e.g. log vane detail).
24. Figure 8C, Reinforced Riffle Step — Please identify where this feature is proposed on the plan
view drawings. Please specify stone size. And what necessitates stone placement to top of
bank? DWR is concerned whether bank armoring is warranted.
25. Figure 9 — DWR appreciates the level of detail provided with multiple planting zones.

26. Figure 10 — DWR requests a minimum of two veg plots within the mapped potential freshwater
marsh areas. DWR requests the UT2 downstream cross section be shifted south due to
concerns of UT2 maintaining channel features within the Fork Creek floodplain. Also, please
label reaches.
27. Figures — DWR would welcome the inclusion of LiDAR and historic aerial figures, as well as
drone and ground photos of existing site conditions. All of these items are helpful in our review.
28.Appendix B —
a. Please include available pre -construction groundwater well data in the final plan.
b. In the future, DWR would like more detail included in the site soil investigation, including
a map indicating all soil check locations. (Note that Appendix D did not include wetland
determination forms with soil data.)
29. Detail Sheets — Please add typical details for (1) bare root & live stake planting and (2)
channel/ditch backfill & plugs. If partial backfilling is proposed, please specify the max depth
from ground surface to fill. For channel plugs, please specify the minimum length.
30. Sheet C8.07, Marsh Treatment Area — Please provide the max. depth proposed for the deep
pools. Please provide stone size and percent composition of riprap outlet, if an alternative non -
hardened stabilized outlet is not feasible.
31. Sheet C8.09 — Please clarify whether the proposed aluminum box culvert will be a bottomless
span, as called out on Sheet C5.01.
32. Sheet C8.11 —
a. Please confirm the temporary seed species are annual rye and winter wheat.
b. Under construction sequence note #22, does stabilization include soil de -compaction
and topsoil placement?
c. Please include the permanent seed mixes.
33. General Design — There are no meander bend bank treatments proposed for stabilization or
habitat (e.g. brush toe, boulder toe, vegetated/live lift). Are there any concerns about long-term
bank stability? Is sufficient instream habitat enhancement expected from proposed step and
vane structures?
34.Overall, DWR believes this project has the potential for substantial resource functional uplift
due in part by the inclusion of wider buffers.
USACE Comments, Kim Browning:
1. The correct USACE Action ID for this project is SAW-2019-00835. Please correct the cover
page.
2. Figure 10: Please label the reaches.
a. At least two freshwater marsh areas should be represented in veg monitoring.
b. A flow gauge should be installed on UT2 due to the small drainage area and the concern
that this tributary will not maintain channel characteristics. Photo documentation will also
be helpful.
3. Figure 11: Buffer Width Zones- Without being able to review the actual data spreadsheet, it's
difficult to determine whether terminal ends were accounted for. In the table provided it appears
you used the old version of the buffer tool. The new version allows terminal ends where the
project enters or exits the property to be exempt from counting against you. Please re -run the
buffer tool to account for the crossing terminal ends, clip creditable wetlands from the actual
buffer, and correct the length entered in the spreadsheet. Please provide a printout of the actual
spreadsheet. Also, please provide a map that depicts the idea buffers. I'm happy to meet with
you if you need additional explanation. Please provide this information for review prior to
submitting the final mitigation plan and 404 permit to avoid review delays.
a. Table 1 should be updated accordingly.
4. 1 appreciate the marsh treatment areas planned; however, these treatment areas should not be
placed in existing or proposed wetlands. On Figure 6A it appears that one of these BMPs is

located in a proposed jurisdictional area in Wetland GI. Please confirm that these treatment
areas will not be constructed in proposed wetlands.
5. Appendix D: Supplemental groundwater gauge data provided January 11, 2021 indicates that
gauges 1 & 4 malfunctioned so it's difficult to determine accurate current hydrology conditions,
and gauge 3 in Wetland GB currently meets hydrology performance standards with 68 days.
Given that wetland gauge 3 already meets hydrology performance standards, rehabilitation is
not appropriate in this location since hydrologic functional uplift cannot be demonstrated. Please
change this area to wetland enhancement. It's understood that this area is not being proposed
for wetland credit and is proposed for buffer credit.
6. Section 3.5: This section should be expanded to include a narrative with more detail (similar to
the detail given in Table 17) of existing conditions, and broken out to describe each reach
separately. Photos of existing conditions would also be beneficial.
7. Section 3.6: This section should also be expanded to include a more detailed narrative of existing
wetland conditions, particularly those proposed for preservation.
8. Table 14 discusses the functional uplift potential and references NCSAM/WAM, including the
water quality and habitat uplift. These are benefits that are presumed and will not be measured
by monitoring. Unless you intend to demonstrate actual uplift in these areas, I recommend that
this section be reworded that uplift in these areas is implied. It is appreciated that RS used
NCSAM/WAM to establish current conditions of the site and the potential for functional uplift.
9. It would be beneficial to add some coarse woody debris to the depressional areas in the buffers
and throughout the adjacent wetlands for habitat, and to help store sediment, increase water
storage/infiltration, and absorb water energy during overbank events.
10. Table 21:
a. The wetland hydrology performance standard should be measured annually.
b. Any volunteer species on the approved planting list must be established for at least 2
years to count towards success and will be subject to the average height standard.
c. Given that 20% of the site is expected to be herbaceous, please add a performance
standard proposing a diversity of at least 4 species and over 75% cover.
d. Please add a performance standard that intermittent streams will demonstrate at least
30-days consecutive flow.
11. Section 8.3: Ephemeral pools should be 8-14" depressions that dry up yearly so that predatory
species cannot colonize, and should not be so numerous that trees do not grow in large areas
of the buffer. Additionally, please indicate the number and location of these areas.
BROWNING.KIMBER Digitally signed by
LY.DANIELLE.15276 BROWN ING.KIMBERLY.DANIELLE.
1527683510
83510 Date: 2021.01.27 14:12:28-05'00'
Kim Browning
Mitigation Project Manager
Regulatory Division