20201798 Ver 1_Mitigation Information_20220516

From: Davis, Erin B
To: Baker, Caroline D
Subject: FW: [External] Notice of Intent to Approve/ NCDMS Six Runs Mitigation Site/ SAW-2020-01964 / Sampson Co.
Date: Wednesday, May 18, 2022 1:10:02 PM
Attachments: Draft Mit Plan Comment Memo NCDMS Six Runs SAW-2020-01964.odf
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DWR#: 20201798 v.l
Doc Type: Mitigation Information
-----Original Message -----
From: Browning, Kimberly D CIV USARMY CESAW (USA) <Kimberly.D.Browninggausace.army.mil>
Sent: Monday, May 16, 2022 3:34 PM
To: Haywood, Casey M CIV USARMY CESAW (USA) <[e-mail]>; Tugwell, Todd J
CIV USARMY CESAW (US) -�'Todd.J.Tugwell(ousace.army.mil>; Davis, Erin B <[e-mail]>;
Bowers, Todd <[e-mail]>; [e-mail]; Wilson, Travis W.
<travis.wilson(oncwildlife.org>; Garrison, Gabriela<gabriela.garrison(oncwildlife.org>; Merritt, Katie
<katie.merritt(0ncdenr.gov>
Cc: Crocker, Lindsay<Lindsay.Crocker(0ncdenr.gov>; Crumbley, Tyler A CIV USARMY CESAW (USA)
<Tyler.A.Crumbley2(ousace.army.mil>; Brad Breslow <bbreslow(a�jres.us>; Recktenwald, Marc
<Marc.Recktenwald(oncdenr.gov>; Fennel, Tommy E CIV USARMY CESAW (USA)
<Tommy . E Fennel(ousace. army .mil>
Subject: [External] Notice of Intent to Approve/ NCDMS Six Runs Mitigation Site/ SAW-2020-01964 / Sampson
Co.
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Good afternoon IRT,
We have completed our review of the Draft Mitigation Plan for the NCDMS Six Runs Mitigation Site (SAW-2020
01964). Please see the attached memo, which includes all NCIRT comments that were received during the review
process along with additional comments provided by Wilmington District staff following our review.
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 May 31, 2022). 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. Please contact me if you have questions or wish to discuss.
Be well,
Kim (Browning) Isenhour
Mitigation Project Manager, Regulatory Division I U.S. Army Corps of Engineers 1 919.946.5107

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
May 16, 2022
SUBJECT: NCDMS Six Runs Mitigation Project - NCIRT Comments during 30-day Mitigation Plan
Review, Sampson 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-2020-01964
NCDMS #: 100170
NCDWR#: 2020-1798
30-Day Comment Deadline: March 25, 2022
DWR Comments, Erin Davis:
1. Page 3, Section 2 — Please briefly elaborate on urban development as a contributing factor for
water quality impairment and habitat degradation in this watershed.
2. Page 5, Table 3 — It would be helpful to have the proposed total planted area identified in the
Project Attribute Table.
3. Page 11, Section 3.4.7 — DWR does not consider the installation of in -stream structures to be a
temporary stream impact.
4. Pages 33-36, Section 6.2.1 —
a. Please identify which reaches include segments of Priority 2 Restoration.
b. There was an IRT meeting minute comment to "ensure DE4 and Brad's Branch are not
running parallel and are appropriately laid out for the site". Has this been achieved with
the proposed design?
c. Log sills are the only listed grade control structure for intermittent reaches BB -A, BB-B,
DE2-B, DE4-B, DE7, and DE8. DWR has observed log sills on intermittent reaches
breaking down before the end of the monitoring period. Are there any concerns with long-
term stream stability, particularly on higher slope reaches (e.g. DE2-B)?
d. Since DE3 was determined to be a jurisdictional intermittent stream and work is proposed,
please include the description of the treatment plan/design approach to convert it to an
emergency spillway channel.
5. Page 41, Table 13 — Please confirm that project reaches, all of which currently have sand or
sand/gravel substrate (Table 6), are proposed to have a gravel or cobble substrate (e.g. DE7 is
going from sand to cobble).
6. Page 42, Section 6.4 — DWR appreciates the inclusion of multiple reference wetland areas. Was
there evidence of beaver at either reference area? Was beaver presence a consideration in
developing the target wetland approach discussed in Section 6.4.1?

7. Page 42, Section 6.4.1 — Please confirm that the only proposed grading in wetland credit areas
is related to the stream restoration activities as shown on the draft design sheets.
8. Page 45, Section 6.6.1 — Please note that any plant substitutions will need to be approved by
the IRT to count toward vegetative performance standards.
9. Page 47, Table 14 — Given the proposed initial planting percentages, DWR requests that green
ash not be included in any supplemental planting efforts.
10. Page 48, Section 6.6.2 — Alligator weed was mentioned in the existing vegetation Section 3.2.3.
DWR is concerned about the presence of this species onsite based on observations from other
mitigation projects. Please include a description of the proposed treatment for this invasive.
DWR recommends including additional wetland species to the proposed planting plan as seed
or herbaceous plugs that grow in similar hydrologic conditions as alligator weed (e.g. American
bur -reed, pickerelweed, arrow arum, arrowhead, Carex spp., Cyperus spp., Scirpus spp.).
11. Page 48, Section 6.7 — DWR encourages the placement of woody debris as habitat
enhancement in project wetland and floodplain areas.
12. Page 54, Section 7.3 — DWR would be ok with the listed understory/shrub species being exempt
from the vigor performance standard to encourage site diversity.
13. Page 56, Section 8.6 — DWR was very pleased at the proposed monitoring of initial supplemental
planting areas. Can you please further define "periodic" monitoring?
14. Page 58, Section 9.1 Pond Outflows — The provided Dam Inspection Memo was appreciated
and useful. Looking at Sheets 15 and F1, will the recommended tree removal and livestock
fencing also be addressed through the project?
15. Page 58, Section 9.1 Channel Aggradation — DWR was glad to see discussion point. Please
note that channel maintenance (e.g. sediment removal, in -stream veg control) should be
restricted to the first three years of monitoring, with the exception of aquatic invasive species
treatment, in order for the IRT to properly evaluate how the system is trending later in monitoring.
Also, evolution towards a braided system may effect reach crediting so further discussion of
potential adaptive management strategies could be helpful.
16. Page 58, Section 9.1 Inundation Effect — During the IRT site walk we encouraged discussion of
a mosaic wetland system. The section appears to focus solely on forested wetland
establishment. It may be beneficial to provide more information on "alternative planting
measures" and consider alternative monitoring and performance criteria. Additional planning
now could potentially avoid a worst case scenario of minimal tree survival and carpet of alligator
weed, affecting functional uplift and credit. DWR recommends considering a OBL-FACW
wetland seed mix and/or aquatic herbaceous plugs.
17. Figure 12 Monitoring —
a. DWR requests that the groundwater gauge at southern edge of the reestablishment area
be relocated near the south corner of the veg plot in the rehabilitation area (I can provide
a map mark-up if requested). DWR also recommends considering adding a reference
groundwater gauge in the preservation area.
b. Please add easement break and culvert crossing to the fixed image locations note.
18. Cover Sheet — Site Map blocks S15 & S16 should be S14 & S15.
19. Sheets S1 & S2 — No bank grading is shown; however, Sections 3.4.7 and 6.2.1 reference bank
grading along BB -A and BB-B. Please confirm whether bank grading is proposed for these
reaches, and if so please update design sheets to callout all proposed work. DWR cannot fully
support the proposed 1.5.1 ratio for 1,014 LF until we review a revised design plan.
20. Sheet S2 — DWR understands that there is a required easement break for the existing overhead
electric line and buried water line. Since no bed or bank stabilization is proposed, please confirm
that this break is not intended to be used as a livestock or vehicle crossing and that cattle will
not have access to the stream.
21. Sheet 5-15 — It appears DE3, DE8 and multiple swales will tie into Brad's Branch over a bank
toe treatment area in the middle of an outer meander bend. Are there any concerns about long
term bank stability?

22. Sheet 15 — It appears the riprap pad extends into the conservation easement. Will this feature
require periodic long-term maintenance? If so, was access and the scope of allowable
maintenance activities discussed with NC Stewardship?
23.Appendix B — The full habitat section and overall score are cut off of the NC SAM rating sheets.
24.Appendix J — Please update to include alligator weed.
25. General comment — I noticed multiple topics the IRT have been bringing up were captured in the
plan. I liked the site -specific discussions in the land use (including references) and project risk
& uncertainties sections, as well as the detail provided in the existing vegetation and reference
wetland sections. Tables 7 and 8, along with all of the reach photos, were helpful in this review.
Overall, DWR believes this project has the potential for substantial resource functional uplift.
USACE Comments, Kim Browning:
1. Figure 11: It appears that not all areas that are generating wetland credit were clipped from the
buffer calculation. For example, the wetlands along DE4-A and the confluence of DE4-B with
Brad's Branch. Please confirm. Also, from what I can gather from figure 3, there should be 7
exempt terminal ends. I'm happy to discuss prior to the final plan submittal.
a. Do more than 5% of the stream reaches not meet the 50' minimum buffer? Section 6.8.1
indicates a 30-ft minimum buffer.
2. Section 3.4.4: Please reference the NLEB 4(d) rule and the approximate number/acres of trees
that will be removed as a result of the project.
3. Section 3.4.7: If in -stream structures are installed, wouldn't they be considered a permanent
impact, not temporary as indicated on the enhancement I reaches?
4. Page 17: Are you suggesting that DE8 was the original stream channel prior to the pond being
installed and that DE3 is only there as a result of the pond spillway construction? More
discussion should be included in the text to explain why a jurisdictional feature is being
eliminated.
5. Please confirm that no placement of fill associated with the dam rehab will occur in the wetlands
below the dam (WG).
6. Do you anticipate that the pasture north of WC-1 will be too wet for cattle access, or cause
wallowing areas to form that add a sediment source to WC-1?
7. All of the existing vegetation and wetland summary were very helpful, particularly Table 8.
8. Are there any concerns with the log sills on intermittent reaches degrading/rotting over time?
This is an observation the IRT has made on several close-out sites recently.
9. Section 6.6.3: Please add a discussion of how the Priority 2 cut areas will be addressed.
10. Section 4.1: The functional pyramid is cited to show existing conditions for each category and
was used to describe the functional uplift potential of the project, which is fine; however, these
principles of the Pyramid Framework are tied to the goals and objectives of this mitigation plan.
The text states that it's not practical or feasible to directly measure the physiochemical or
biological uplift, and that these benefits are assumed. It's unclear why NCSAM and NCWAM
were not addressed in this section, nor were their functional assessments used to target areas
for functional uplift. This would be particularly beneficial for the wetlands on -site.
11. Section 4.1.1: This section is contradictory to section 4.1 above where it discusses "The
restoration approach at the reach scale of this project will have greatest effect on the
hydrology..." Doesn't the Stream Functions Pyramid Framework refer to hydrology on the larger
watershed scale?
12. Figure 12: Please ensure that all crossings and culverts are included in photo stations.
13. There is some concern with sediment contributions from the agricultural field above BB -A.
14. Section 9.1: From what I understand, the culvert at E Darden Rd is currently perched. Will it
remain as such until NCDOT replaces this?
15. Page 58: I'm glad you considered the effects of inundation on tree growth; however, it seems
more appropriate to plant these inundated areas with species that are found in the adjacent

reference area. You may want to consider more herbaceous species and propose alternate
performance standards, such as percent cover and species diversity. I would suggest adding an
adaptive management section that addresses the potential for a mosaic system, moisture
regimes, and beaver management, especially at the bottom of Brad's Branch.
16. Figure 12: At some point during monitoring, please add random vegetation plots or transects in
the supplemental planting areas in WA, WB, and WE-1 & 2. WE-2 will be important to document
functional uplift (veg monitoring) since hydrology is already at 27%.
17. Surface Flow: The text states that intermittent streams will be monitored using pressure
transducers and data loggers to demonstrate a minimum of 30 days consecutive flow. The 30-
day metric was established to show success in the Coastal Plain Headwater guidance and was
not intended to demonstrate success for intermittent flow. Intermittent streams only dry
seasonally and therefore should have flow or the presence of water for periods much longer than
30 days. It is recommended that cameras are also used to monitor flow for both consecutive
days and cumulative days.
18. 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.
19. Section 9.1: Should beaver management be addressed in this section?
Kim Browning
Mitigation Project Manager
Regulatory Division