20220450 Ver 1_Draft MP Comments

DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
69 DARLINGTON AVENUE
WILMINGTON, NORTH CAROLINA 28403-1343

CESAW-RGM/Isenhour July 14, 2023

MEMORANDUM FOR THE RECORD

SUBJECT: RES Yadkin 03 Umbrella Mitigation Bank – Falcon Ridge Mitigation Site,
Draft Mitigation Plan Review, Randolph County, NC

PURPOSE: The comments below were received from the NCIRT during the 30-day
comment period in accordance with Section 332.8(d)(7) of the 2008 Mitigation Rule

USACE AID#: SAW-2022-00424
30-Day Comment Deadline: May 10, 2023

Mac Haupt, NCDWR:
1. Section 3.2.3- Existing Wetlands- did a North Carolina Licensed Soil Scientist
verify the hydric soils on site?
2. Section 3.4 – Reach Summary Information- DWR likes the fact that there will be
no crossings on this project.
3. What previous RES projects have utilized engineered sediment packs? How do
they promote surface flow?
4. Table 6 Summary of Stream Parameters- shows that a number of these reaches
scored low intermittent for the DWR Stream Determination Scores. This project
being located in the Slate Belt further exacerbates the flow issue. In addition,
DWR will be requiring more days of consecutive flow than in years past,
therefore, careful attention will need to be paid to this issue for this project.
5. Section 6.2.3- Wetland Mitigation Approach- in the Wetland Enhancement
paragraph it is stated that the listed wetlands have sufficient hydrology. Are
wetland gauges present? It is further stated that, “wetlands may also benefit from
improved hydrology, as a byproduct of stream restoration and enhancement
activities; however, hydrology will not be monitored, nor will their success depend
on it.” DWR strongly disagrees with the previous statement. DWR will require
that gauges be present and will require wetland hydrology monitoring. Not only
should the wetlands be monitored to document the “sufficient” hydrology but also
to make sure the constructed stream channels don’t impact or affect the wetlands
by drainage. In addition, the removal of the pond on reach PR7-A will likely cause
some wetland hydrology changes that need to be documented.
6. Section 7.1.2- Performance Standards- Surface Flow- DWR will require that
reaches must maintain surface flow for a period of no less than 90 days for
anytime during the year.
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7. Section 7.2 – Vegetation and Wetlands Success Criteria- for the wetlands please
see #5. Moreover, a North Carolina Licensed Soil Scientist needs to verify hydric
soils on site and recommend or identify the soil series so the appropriate wetland
performance hydrology can be assigned as per the October 2016 Mitigation
Update.
8. Section 8.3- Stream Hydrology Events- since flow will likely be an important
factor in the success of this project, more flow gauges or different placement may
be recommended after the first of second monitoring year.
9. Design sheets- General comments:
a. DWR likes the format of RES’s design sheets
b. There will be a lot of construction through wooded areas, DWR hopes that
care will be taken to conserve as many trees as possible, DWR did note
the verbiage relative to the amount of invasive plants on site and realizes
there may be considerable cleared areas.
c. Since there will be a large number of structures installed on this site, DWR
urges RES to obtain most of the stone needed for the construction on site.
The photos of many of tributaries showed a lot of stone for the bed
material. DWR much prefers on site material to rip rap.
10. Design sheets S1 and S3- for the channel construction on these sections please
have the appropriate engineer on site for structure inspections.
11. Design sheet S9- DWR requires a wetland monitoring gauge stream right at
station 6+00.
12. Design sheet S10- does PR10 initiate upstream of the wetland? Was this reach
seen on the IRT site visit?
13. Design sheet S15- DWR requires two gauges, one 20-30 feet above the
jurisdictional determination point and “stream” left at approximately station 0+75.
DWR questions the decision to construct a channel in the wetland.
14. Design sheets S18 and S19- DWR requires the placement of wetland monitoring
gauges at stream left of PR7-A at station 11+25 and station 12+50.
15. Design sheet S20- at station 19+00 the graded floodplain is narrow,
approximately 35-40 feet. DWR would like to see the graded floodplain be at
least 50-60 feet or more.
16. Design sheet S23- DWR requires two wetland gauges, one stream right of PR8
at station 4+50 and the other on PR7A? on stream left at 635 grading marker.
17. Design sheet D5- riffle grade control- DWR requests that the designer use on site
material (stone) as much as possible for the structures.

Olivia Munzer, NCWRC:

1. There are no specifics on the culvert type. CMP or RCP should be used for pipe
culverts.
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2. Please separate the seed mix by habitat type. Also, RES states they will use a
pollinator-friendly seed mix, but there are only 3 flowering species in the mix - 1
FACU, 1 OBL, and 1 UPL species. I recommend adding more native flowering
herbaceous species in the mix for each of the habitat types (wetland, upland,
riparian).

Kim Isenhour, USACE:

1. Page 1: Please check the linear feet listed in the first paragraph against Table 1
for consistency.
2. Page 7 and Sheet S15: Will wetland hydrology in WF be altered when the rock
dam on PR6 is removed? The Corps will require a wetland gauge above 0+00.
3. Page 8: In reference to the NCDOT planned work in the 2029 STIP plans, will
roads or bridges adjacent to the project be affected? Please clarify in the text.
4. Page 13 and Table 6: The data presented indicates that PR10 is more of a linear
wetland rather than a channel. When using perennial stream indicator taxa to
determine whether a channel is ephemeral, doesn’t the manual require both fish
and specific macrobenthos? I don’t recall reviewing this tributary during the IRT
site visit. I think it is acceptable to propose this reach for stream credit; however,
we will expect gauge data to reflect perennial flow since that is the justification
used for including this ephemeral reach. Since you’re proposing enhancement at
5:1, I don’t expect the flow data to change like it would if stream restoration were
conducted. I think it would have been prudent to include flow data in the draft
mitigation plan to supplement the request to include ephemeral channels.
a. I have the same concerns with PR9.
5. Page 14, Section 3.5.3: Please run iPaC again to ensure that there will be no
effect on the Tricolored Bat. Please include the species conclusion table in the
final mitigation plan.
6. Page 14 & Figure 11: Three ford crossings are being installed/improved at the
top of PR4A, PR3 and PR2A. The IRT would prefer that these crossings be
internal to the easement for maintenance concerns. You do not need to re-run
the buffer tool since these crossings are at parcel lines.
7. With the number of intermittent channels on this site, I would caution against
using too many log structures. The IRT has noted numerous rotting log
structures on intermittent channels, particularly in the Slate Belt.
8. Section 6.1.1: Do you have any reference wetland sites available?
9. Section 6.2.3:
a. The text in the last paragraph of page 32 states that wetland enhancement
will improve hydrology, soils and vegetation. The Corps will require
groundwater gauges in WE and WF in order to demonstrate hydrology
uplift.
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b. Pre-gauge data should be collected as well to help demonstrate uplift.
The text states that sufficient hydrology exists, but how do you know this
without capturing hydrology data?
c. If you anticipate that wetlands will be present after the pond on PR7-B is
removed, you will need to provide gauge data there as well.
d. If the proposed wetlands are currently jurisdictional but are impacted by
agriculture, you may propose them as rehabilitation at 1.5:1 rather than
enhancement. I’m open to discuss crediting options.
e. My recollection of onsite wetlands, particularly WE & WF, were that they
could benefit from both vegetation and hydrology functional uplift so it’s
unclear why they are being proposed for enhancement. The LOW NCSAM
ratings also make me question why rehabilitation is not proposed.
10. Section 7.2:
a. Please include a detailed soils report that verifies the areas proposed for
wetland credit.
b. A separate performance standard for wetland success criteria should be
included, to include documenting uplift in vegetation and hydrology.
11. Section 7.2.1: Please include mortality data of planted understory species as
well. This information is helpful in determining the success of understory
planting.
12. Page 43: The second sentence reads, “Longitudinal images should NOT
indicate the absence of developing bars…” Please QA this sentence.
13. Figure 13: Please confirm that you excluded all wetlands that will receive credit
from the wider buffer credit calculation. The map appears to only remove
portions of WE and WF. Please update Table 15 accordingly.
14. Figure 12: Please add random veg plots where old pond dams are being
removed throughout monitoring.
15. Planting Plan, Design Sheet P1: Please add wetland indicator status to each
species.
16. Please include the JD Concurrence email.

Kim Isenhour
Mitigation Project Manager
Wilmington District Regulatory Division