20161200 Ver 2_Response to Comments Final_20200619

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

CESAW -RG/Browning March 27, 2020

MEMORANDUM FOR RECORD

SUBJECT: Millstone Creek Mitigation Site - NCIRT Comments during 30-day Mitigation Plan Review

PURPOSE: The comments listed below were received during 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: Millstone Creek Mitigation Site, Randolph County, NC
USACE AID#: SAW-2019-01363
NCDMS #: 204
30- Day Comment Deadline: March 7, 2020

DWR Comments, Mac Haupt & Erin Davis:

1. Page 7, Table 1.1 – The 1:1 ratio proposed for NT R2, UTA R2 and UTB do not appear
appropriate for the outlined E1 level approaches. However, DWR appreciates that proactive
enhancement activities, such as cattle exclusion, have been implemented and are contributing
to functional uplift. DWR would support a 1.5:1 ratio for the three proposed E1 / R equivalent
reaches. DMS has revised the proposed mitigation for these reaches, per IRT input during the
4/24/2020 Millstone Mitigation Plan meeting, to restoration with a 1:1 credit ratio based on work
proposed,
2. Page 28, Section 5.1 – The USFWS website was consulted on August 27, 2007. Please revisit
this source to confirm that there have been no changes to listed species. The USFWS website
was consulted on 3/30/2020; there have been no changes to listed species; this section of the
plan has been updated with current information.
3. Page 35, Section 8.2 – Should Header be labeled as UTA R1 instead of UTA R2? This was
mislabeled and has been fixed.
4. Page 36, Section 8.2.1 – DWR is concerned that by raising the channel bed by 5-6 feet at the
top of UTA R1 and NT R1 that flow may not be maintained, and jurisdictional stream status may
be lost. Flow documentation in the upper sections of these reaches will be critical. Surface
gauges have been included in the monitoring plan to address this concern.
5. Page 39, Section 8.2.4 – Please correct UTA R2 and UT R2 to UTA R1. This comment has
been addressed.
6. Page 48, Table 8.9 – Are live stakes included in the stem counts (e.g. silky dogwood)? If not,
please include live stake species and estimated quantities. The revised document specifies live
stake quantities in Section 8.6 Re-Vegetation Plan, Table 8.9.
7. Page 52, Section 8.7 – Are sod mats still being proposed? They do not appear in the design
sheets. If proposed, please add a typical detail. Sod mats are proposed as an option in Section
8.7 of the revised Mitigation Plan, detail on page 6.1 of the plan sheets.
8. Page 53, Section 8.9 #3 – The proposed transition from perennial single thread channel to
wetland will be an area to monitor for signs of instability. Additionally, with the wetland ditch
plugged and the previously proposed log-step outfall not included in this design version,
monitoring any concentrated flow areas developing between the wetland and Mill Creek for
instability will also be important to address. The existing transition from single thread to
wetland at the bottom of Ut B is currently stable due to very low gradient at the bottom of
Ut B, the design will not cause instability. The transition between the wetland and Millstone
Creek will be visually assessed twice annually throughout the monitoring phase of the project;
the lack of excessive erosion or scour on the current ditch indicates a low energy system.
9. Page 56, Section 9.5 – The proposed wetland enhancement is based on hydrologic functional
uplift, as such DWR recommends the hydrologic performance criteria of a minimum 8 percent
hydro period. DWR also requests an additional wetland groundwater gauge, for a total of
two wetland monitoring gauges. A hydrological performance standard of 8% along with an
additional groundwater gauge has been included in the revised mitigation plan.
10. Page 56, Section 10 – Please confirm that the record drawings and baseline monitoring report
will be submitted after completion of Phase 2 construction. Phased monitoring periods are not
proposed, correct? Phased monitoring is required for the paired watershed study to document
efficacy of RSC as designed. Record drawings will need to be completed on phase I project
components upon completion of construction and planting. A complete record drawing and
baseline monitoring report including phase I and phase II project components will be submitted
for IRT review when both phases have been completed. The required seven-year monitoring
phase will begin after the finalization of the baseline monitoring report.
11. Design Sheets - Please include the following items:
a. Location of existing and proposed fencing; The fencing component of this project has been
completed; DMS funded the design and installation of the easement fencing. Construction
access will require small areas of existing fencing to be removed and replaced. The existing
and proposed locations of fencing have been included on design sheets.
b. Details: ford crossing, BMP wetland feature, ditch plug (specify minimum plug width), ditch
filling/partial filling (specify maximum depth from ground surface to be filled), live stake
installation, bare root and container planting Details have been included for the ford
crossing, BMP wetlands, ditch (to include plug and fill specifications) and plant installation.
12. Figure 10.1
a. In order to monitor the minimum 30-day consecutive flow performance standard, please
add flow gauges to NT R1 and UTA R1, within the upper one-third of each reach. Gauges
have been included in these locations on the monitoring map.
b. DWR requests an additional cross section along the lower section of MC R1 and an
additional wetland groundwater gauge. An additional cross section has been added in this
area.
c. Please show the easement boundaries. The easement boundary has been included on
maps and plan sheets.
USACE Comments, Kim Browning:

1. When submitting the PCN, please include an estimate of the number of trees, or acres, to be
cleared for the NLEB 4(d) Rule. The PCN will include the requested information.
2. Please QA/QC this document for grammar and typos. The revised document has been reviewed.
3. There is conflicting information throughout the plan: Page 12 states that Millstone Creek is the
only perennial channel on site, while pages 22 and 39 indicate that all channels are perennial.
Page 31 states that tributaries have little to no flow. NCSAM forms indicate channels are
perennial. Please adjust the text for consistency. The revised mitigation plan clarifies that all
project reaches are currently perennial; however, UTA R1 and NT R1 were likely intermittent prior
to historic land conversion. UTA R1 and NT R1 are anticipated to be intermittent post
construction.
4. Table 1.1:
a. The 2016 NCIRT Guidance specifies that additional credit of up to 2% may be generated
for each tributary to be monitored for water quality. At a minimum, water quality and
macroinvertebrate sampling must be conducted to receive the additional credit. Additional
credit is eligible on restored and enhanced reaches of stream channels with the intent of
linking stream mitigation and functional uplift. The IRT will authorize 4% additional credits
for streams only on this site. The credit ratios proposed have been revised to reflect a 4%
credit increase on stream reaches subject to water quality monitoring only.
b. Water Quality credits are not authorized for wetlands. No Water Quality credits have been
proposed on wetland in the revised mitigation document.
c. The 2% increase proposed for success on At-Risk Tribs is not authorized. This request
has been modified to include a success metric to address IRT comment during 4/24/20
meeting. A 20% Total-N reduction on stream reaches subject to water quality monitoring
as compared to baseline Total-N is proposed.
d. Please carry out stream credits to at least two decimal places, and avoid rounding. All
stream credits have been to two decimal places.
e. Please show how the credits are being calculated by reach length, total credits, and 4%
increase per reach. For example, Reach NTR1 is proposed for 326 LF (existing 303 LF),
326 SMUs, and 13.04 additional credits at 4%. Please see example revision at the end of
this document. The project asset table has been revised to follow the requested format.

5. Reaches proposed for EI with a R Equivalent should be credited at 1.5:1, not 1:1 as proposed.
The proposed work appears to be standard Enhancement I, defined as any stream mitigation
activity that does not involve restoration of the entire stream channel. The only section that
appears to meet restoration activities is on UTB near the bend at station 16+00. Additional credit
for WQ monitoring is already being awarded on these reaches, and therefore is not justification
for a 1:1 ratio. Bank grading, in-stream structures, and buffer planting meets the criteria for EI at
1.5:1. Additionally, NTR1 is already receiving a 1:1 ratio, and the WQ treatment on that reach is
not justification to increase the ratio on other reaches. Since cattle are currently excluded from
project reaches, that is not justification for an increased ratio. The restoration level and ratios
have been revised for these reaches to reflect work proposed and completed. This approach
was discussed at the 4/24/2020 Millstone Meeting where previously undisclosed pertinent
information such as DMS having funded the design and construction of the cattle exclusion
fencing was clarified.
6. Categorical Exclusion Documents should be updated. The response letter from SHPO dated
December 12, 2003 is sufficient. However, please update the NCWRC and USFWS documents.
with current T&E species. I did receive an email response to the Public Notice from FWS on
Aug. 13, 2019 stating that they have no significant concerns with this project.
These documents have been updated as requested and appear in Appendix E of the revised
mitigation plan.
7. Page 32: Is there a WQ monitoring station downstream of the ford crossing? The only water
quality monitoring station to be located downstream of the crossing is a macroinvertebrate
sampling location; a gauge to document overbank events will also be located on this reach.
8. Table 7.1 indicates that livestock exclusion fencing will be installed. It is unclear where fencing
currently exists. Please indicate on a map or in the plan sheets. The plans sheets have been
updated to include existing livestock exclusion fencing. The only additions/changes to the
existing fencing installed by NC DMS are along the single ford crossing on Millstone, areas
where existing fencing will be removed and replaced to allow for construction access and on
terminal project boundaries across Millstone Creek.
9. Please include the water quality monitoring locations on the Monitoring Map. Water quality
monitoring stations have been included in figure 10.2 Supplemental Monitoring Map.
10. Wetland enhancement area should demonstrate functional uplift. The performance standard for
the wetland should be a minimum of an 8% hydro period, and pre-well data should be provided
in order to show uplift. Additionally, a discussion of the NCSAM functional assessment rating as
LOW for habitat might be helpful. An 8% hydrology performance standard has been included in
the revised mitigation plan, all existing wetland data has been included in Appendix E, and a
pre-construction gauge will be installed in the wetland. The NC WAM rating has been included
in Section 3.2.5 Wetland 1 discussion.
a. Please add a vegetation monitoring plot to the wetland area to ensure that with increased
hydrology the vegetation is not negatively impacted. A vegetation monitoring plot has
been included in the wetland. The wetland is not to be planted per IRT guidance.

11. Please address how fescue will be treated/removed. Fescue has been addressed in Section
8.6. Re-Vegetation plan; fescue will be treated with herbicide prior to planting.
12. It appears that the majority of the site has buffer widths that exceed the minimum 50 feet. Since
there is only one crossing on the site and you are capturing the terminal ends of the tributaries,
you may want to consider running the Buffer Tool on the project to see if you can get the additional
2% buffer credit. The crossing and the wetland area will need to be clipped from the buffered
area for credit. If it turns out to be beneficial, please include the GIS map and corresponding
table.
13. Design sheets: Several sheets are upside down and out of order, and there are three sheets
labeled page 4.5. Please correct. The document has been corrected.
a. Please include a ditch plug detail. A ditch plug detail has been included in the plan
sheets.
14. There is concern for hydrologic trespass to occur since the ditch entering the wetland will be
plugged and there is no planned outlet for the wetland. Site topography limits hydrologic
trespass potential to the southern easement boundary. The site will be monitored for hydrologic
trespass on the southern boundary of the easement between phase 1 phase 2 of the project
and if necessary a remediation plan will be developed and implemented during phase 2.
15. Page 39, Section 8.2.4: Please QA/QC this paragraph for stream labeling. Also, to be clear about
phased construction over a two-year period, the initial credit release will not occur until the
Record Drawing/As-Built is received and approved. Stream labeling has been corrected.
Millstone Creek is not subject to annual credit release due to date of project institution.
16. Ford Crossing: There is some concern with the amount of sediment coming into the system.
Without seeing the design detail it’s difficult to discern whether the structure will have an
upstream and downstream sill to hold elevation and retain substrate in place. Will it be designed
to incorporate reinforcing underlying material? Sediment load has been considered in the
design for the project, both on and off-site sources are being addressed. A ford detail has been
included in the plan sheets.
17. Page 53, #1: with the amount of sediment coming into the system, is there a concern that the pools will
fill in over time, decreasing bedform diversity?
The pools as designed contain log and boulder structures which mimic the functioning pools
located upstream and downstream of the project reach. A note to address this has been included in
the risk/ uncertainties section of the revised mitigation plan.

18. Beaver were mentioned in the document, please add this to the Risks/Uncertainties
section. A discussion about effects of future beaver colonization has been added to the
risks/ uncertainties section.
19. Page 54, Section 9: Please remove the statement “If all performance standards have been
successfully met, NCDMS may propose to terminate stream, wetland and/or veg monitoring after MY5.” 7
years of monitoring is required. This statement has been removed.
20. Section 9.4: There will be no loss of credits if this performance standard is not met; however, the
additional 2% for NTR1, NTR2, UTAR1 and UTB are not approved. DMS has revised the proposal based
on IRT input to include a measurable metric for the additional 2% credit proposed on water quality
monitoring reaches.
21. Table 10.1: The section that discusses exclusion of livestock from channels is unclear whether
fencing is existing or planned. The treatment for this section should be to install or maintain livestock
exclusionary fencing. The discussion of the conservation easement establishment should be under site
protection. The document has been revised to clarify that fencing had been previously installed by DMS.
22. Section 10.4: Please see the end of the document for example phrasing for the Adaptive
Management section. The document has been revised to include an adapted version of the example
provided.
23. Section 11: Please revise based on correct ratios. The document has been revised as requested.
24. General note: It’s helpful when all maps and figures are located in one section of the plan.
Example of how to revise Table 1.1:

Reach Existing
Length
Approach Proposed
Length
Mitigation
Ratio
Proposed
Credit
4% WQ
Monitoring
NTR1 303 R 326 1:1 326.00 13.04
NTR2 103 EI 103 1.5:1 68.67 2.75
UTAR1 505 R 523 1:1 523.00 20.92
UTAR2 100 EI 100 1.5:1 66.67 2.67
UTB 529 EI 529 1.5:1 352.67 14.11
MCR1 1462 EI 1462 1.5:1 974.67 38.99
MCR2 553 R 533 1:1 533.00 21.32
TOTAL 3555 3576 2844.68 113.80

W-1 1.323 E 1.320 2:1 0.660 0

EXAMPLE Project Risks and Uncertainties

Listed below are identified project risks and uncertainties that have been evaluated in the
development of design plans for the site, along with methods that have been/will be used to address
these concerns. Methods to address may be presented as adaptive management.
1. Land use development: There is potential for increased land development around the site in
the future that could lead to additional runoff and changes to watershed hydrology.
• Methods to Address: The project area has seen little development in recent years and it is
unlikely that development will threaten the site in the foreseeable future. Restoration of the
site to reconnect streams to their floodplains will reduce the likelihood of future degradation
from watershed changes, as increased flows will spread over a wider floodplain. Grade
control (in the form of constructed in-stream structures and natural bedrock outcrops) will
decrease the chances of future channel incision.

2. Easement Encroachment: Any encroachment to the conservation easement. (Including road
widening, culvert maintenance, utility easements, etc.)
• Methods to Address: The sponsor has had considerable discussions with the landowner
regarding the project requirements and limitations of easement access and is confident that
the landowner fully understands and will maintain the easement protections. The easement
boundaries will be fenced with barbed wire fencing and clearly marked per NRCS
standards. Any encroachments that do occur will be remedied by the sponsor to address
any damage and provide any other corrections required by the IRT.

3. Drought and Floods: There is potential for extreme climatic conditions during the monitoring
period of the project.
• Methods to Address: The sponsor will apply adaptive management techniques as
necessary to meet the site performance criteria. Such adaptive management may include
replanting, channel damage repair, irrigation, or other methods. If adaptive management
activities are significant, additional monitoring may be required by the IRT.

4. Beavers: While there was no evidence of recent beaver activity during recent assessments,
there is potential for beavers to colonize the site during the monitoring period of theproject.
• Methods to Address: Due to the watershed size, beaver colonization is unlikely. However,
the sponsor will take steps to trap and remove beaver if they colonize the Site during the
monitoring period.
5. Hydrologic Trespass: There is potential for the stream restoration to create conditions under
which hydrologic trespass on adjoining landowners is more likely.
• Methods to Address: The majority of the project has been designed and will be
constructed utilizing a priority 2 restoration approach, which will greatly reduce the potential
of hydrologic trespass outside of the conservation easement boundary. Along UT1 Reach
3 where the stream transitions to a priority 1 restoration approach, the conservation
easement boundary is located up the adjacent hill slopes. The ground elevations along the
conservation easement boundary in this area are approximately 2 to 3 feet above the
bankfull elevation. Based on Manning’s equation, the cross section from easement
boundary to easement boundary along UT1 Reach 3 will convey approximately 689 cubic
feet per second (cfs). Using USGS regression equations, which utilize drainage areas and
impervious surface, the estimated discharge from the 500-year recurrence interval is 185
cfs. Based off this information, the possibility of hydrologic trespass is extremely unlikely
and is not expected to be an issue.

6. Invasive/Nuisance Species: Numerous invasives, such as kudzu and Chinese privet
currently exist in the easement area. There is potential for these species to jeopardize buffer
vegetation establishment.
• Methods to Address: The sponsor will locate invasive vegetation. It will be visually
assessed, photographed, and mapped. These areas will be treated by mechanical or
chemical methods, so that invasive species are no more than 5% of the easement acreage,
and zero tolerance for kudzu. Any vegetation requiring herbicide application will be
performed in accordance with NC Department of Agriculture rules and regulations.

EXAMPLE Adaptive Management
An integral part of a successful compensatory mitigation project is early detection of problems during
implementation, determining the cause(s) of those problems, and attempting to correct those
problems so that the compensatory mitigation project achieves its objectives and ecological
performance standards. Interim performance standards are crucial to ensuring compensatory
mitigation performance follows a trajectory to attain final compensatory mitigation success.
In the event the mitigation site or a specific component of the mitigation site fails to achieve the
necessary performance standards as specified in the mitigation plan, the sponsor shall notify the
members of the IRT and work with the IRT to develop contingency plans and remedial actions. Large
scale corrective measures may require an Adaptive Management Plan. Large scale corrective
measures may include, but are not limited to, re-grading part of the mitigation site, replanting more
than 20% of the site to improve composition or species diversity, or the addition of stabilization
structures. The Adaptive Management Plan review will follow Section 332.8(o)(9) of the 2008
Mitigation Rule, part of the streamlined review process, which requires an IRT review period of 15
calendar days.
Once the Adaptive Management plan is prepared, the sponsor will:
1. Notify the USACE as required by the Nationwide Permit 27 general conditions.
2. Notify NCDWR if necessary for 401 conditions.
3. Revise performance standards, maintenance requirements, and monitoring requirementsas
necessary.
4. Obtain other permits as necessary.
5. Submit the Adaptive Management Plan for IRT review and approval.
6. Implement the Adaptive Management Plan.
7. Provide the IRT a Record Drawing/As-Built of corrective actions.
The Final Mitigation Plan should include:
1. Identify responsible parties who will identify problems.
2. Potential problems that may arise during the monitoring period, particularly if performance
standards are not met.
3. Potential causes of those problems.
4. Identify a process for determining measures to correct deficiencies in compensatory mitigation
projects, such as site modifications, design changes, revisions to maintenance requirements,
and revisions to monitoring requirements (see 33 CFR § 332.7(c)(3))