20180866 Ver 1_Final_IRT_Comment_Responses_V2_20191217

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

REPLY TO
ATTENTION OF:

CESAW-RG/Browning November 13, 2019

MEMORANDUM FOR RECORD

SUBJECT: Shaw’s Run Stream and Wetland 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: Shaw’s Run Stream and Wetland Site, Columbus County, NC

USACE AID#: SAW-2018-01169
NCDMS #: 100055
30-Day Comment Deadline: October 31, 2019

DWR Comments, Mac Haupt:

1. Table 4- DWR believes that the upper reaches of UT1 and UT2 are at risk for losing flow. The DWR
stream score provides evidence that these reaches are at risk. Thanks to DMS for recommending another
flow gauge for the upper reach of UT1. In addition, DWR questions the design for these reaches
maintaining a single thread channel.
2. Table 5.- thanks for including the taxonomic subgroup for the mapped soil series names.
3. Table 7.- Is the Angola site an appropriate reference for this stream restoration site?
4. Section 3.5.2- DWR will require more soil profiles for this site before final approval of this mitigation
plan. One soil boring with a profile is not adequate.
5. Section 8.1.1- the verbiage states all the stream restoration will be priority I type work. DWR believes
the upper reaches of UT1 and UT2 should include more headwater type restoration work. It appears there
is more slope associated with the upper UT2 reach, however, the drainage area is small, or right at the
minimum to maintain an intermittent channel from published research (25 acres).
a. Other verbiage suggests the designer may substitute rock as necessary. DWR believes very little
rock needs to be placed in the proposed restoration features.
b. Outfall Structures- DWR does not believe use of a Terracell is warranted. Why not utilize log
cross vanes as shown on the design sheets?
6. Section 8.2- what is the drainage area at the top of UT1?
7. Table 15- DWR recommends limiting Green Ash planting to no more than 5% due to the ash borer.
8. Table 17- DWR would like the proposed growing season stated/written into the Table. We realize Axiom
will monitor the soil temperature, however; we will need to know the proposed season, the location of the
soil probes and the pairing of the soil temperature with the appropriate vegetative bud burst (not red maple,
since they usually show early bud burst).
9. Table 18- the 30 day flow criteria is only for intermittent streams. DWR expects near continuous flow for
perennial streams.
10. DWR accepts and appreciates DMS’s comment regarding the wetland performance criteria.
11. Appendix A- Figures, in the future, for projects with proposed stream reaches high in the watershed, please
include a LiDAR figure.
12. In addition, it is also helpful to have pictures showing representative reaches, particularly when there has
been at least a year since the site visit.
13. Figure 6- typical riffle cross section- DWR is assuming the designer will not line the channel and up the
stream bank with rock.
14. Figure 9- DWR likes the placement of the flow gauges, however; either some of the wetland gauges may
need to be moved or other gauges added to monitor wetlands located in upper topo gradients.
15. Design sheet 2D- what is floodplain interceptor made out of and does the designer intend to install this
feature?
16. Design sheet 4- what is the line that borders the stream between the wetted perimeter line and limits of
disturbance line? Also, please put a scale on all design sheets with stream planforms.
17. Design sheet 5- DWR believes the single thread channel should start at approximately station 7+00.

Summary: before final approval of this mitigation plan, DWR would like the following:
a. Information on number and location of soil profiles, including areas in upper topo gradients,
b. Better explanation or case for starting with single thread channels at the top of the project,
c. Site pictures, particularly of the upper reach features.

WRC Comments, Travis Wilson:

1. Significant portions of the watershed shown for UT 1 and UT 2 are located north of a road and railroad
bed making it unclear how or if that area drains into those watersheds. The mitigation plan states UT 1
starts at a culvert under the roadbed but appears to still be interconnected with the roadside ditches and
drainage. With a Priority 1 approach will the drainage coming under the road access the channel or be
pushed further down the roadside ditch? There also does not appear to be any cross pipes connecting flow
from the UT 2 watershed delineated on the north side of the road to UT 2 south of the road making that
watershed significantly smaller.

2. On paper this site looks like a better wetland restoration site with some amount of headwater stream
restoration.

3. The amount of Greene ash proposed for planting should be reduced to reflect our latest guidance of <5%

USACE Comments, Kim Browning:

1. The correct USACE Action ID is SAW-2018-01169. Please correct the cover page.
2. Section 8.3- Wetland Restoration – The inclusion of ephemeral/vernal pools is acceptable, and should be
8-14” depressions that dry up yearly so that predatory species cannot colonize.
3. 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.
4. Table 17 Success Criteria—Streams, please add a statement (regarding UT3) at least 30-days continuous
surface water flow for intermittent streams.
5. Table 18—Success Criteria: Please add a section on Photo Documentation or Digital Monitoring. An
example would be that photographs should illustrate the site’s vegetative and morphological stability on
an annual basis, in fixed locations, depicted on the monitoring maps or at all cross-sections. Cross-section
photos should demonstrate no excessive erosion or degradation of the banks. Longitudinal photos should
indicate the absence of mid-channel bars or vertical incision. Grade control structures should remain
stable.
6. The upper end of UT1 will likely be intermittent and develop into more of a headwater system rather than
a single thread. Photo documentation showing defined channel features will be important.
7. When submitting the PCN, please include an estimate of the number of trees, or acres, to be cleared for
the NLEB 4(d) Rule.
8. Maintenance Plan: Will the marsh treatment area within the easement require maintenance? If so, please
discuss.
9. Please include Lidar maps.

Kim Browning
Mitigation Project Manager
Regulatory Division
Restoration Systems, LLC
1101 Haynes St. Suite 211
Raleigh, North Carolina
Ph: [phone]
Fx: [phone]
1101 Haynes St., Suite 211 • Raleigh, NC 27604 • www.restorationsystems.com • Ph 919.755.9490 • Fx 919.755.9492
November 26, 2019
Mrs. Lindsay Crocker
NC DEQ – Division of Mitigation Services
1652 Mail Service Center
Raleigh, North Carolina
27699-1652
Subject: Shaw’s Run - Mitigation Plan Comment Response Letter:
DMS Contract #: 7192; DMS Project ID: 100014; RFP # 16-006990
SDG Response Jason Harvey 11-25-2019
DWR Comments, Mac Haupt:
1.Table 4 – DWR believes that the upper reaches of UT1 and UT2 are at risk for losing flow. The DWR
stream score provides evidence that these reaches are at risk. Thanks to DMS for recommending
another flow gauge for the upper reach of UT1. In addition, DWR questions the design for
these reaches maintaining a single thread channel.
Section 8.1.1 (Stream Restoration) has been added to and now includes the following text. “The
Site slope in the upper reaches of UT 1 and UT 2 exceeds 0.0035 rise/run and 0.003, respectively.
The tributaries have a contributing drainage area at the top measuring 60.8 acres (0.10 sq mi) and
23 acres (0.04 sq mi). In addition, UT 2 has a drainage area characterized by drain tiled agriculture
fields that contribute hydrology in a concentrated manner, effectively forming a spring head.
Coastal plain streams with this slope and size would be expected to be characterized by single
thread channels. However, in the event that Priority 1 stream restoration fails, and a braided
headwater wetland system develops, the stream length will be modified to the down valley length
and wetland credit for 50 feet on each side of the stream will be removed, as per headwater
guidance. Stream gauges in the upper extent have been added to monitor flow duration and visual
monitoring for the maintenance of a clear channel will be conducted.”
2.Table 5 – thanks for including the taxonomic subgroup for the mapped soil series names.
RS understands the taxonomy of a soil series gives much information about the development and
mechanics of a Site.
3.Table 7 – Is the Angola site an appropriate reference for this stream restoration site?
After an extensive reference reach search, Angola was the most suitable reference reach in the
vicinity of the Site. Although it is not ideal, it offers suitable dimension parameters for a stream in
similar geology and soils.
4.Section 3.5.2 – DWR will require more soil profiles for this site before final approval of this
mitigation plan. One soil boring with a profile is not adequate.
Additional soil profiles have been collected and are included in Appendix B. The location of the soil
profiles is depicted on Figure 4.
5.Section 8.1.1 – the verbiage states all the stream restoration will be priority I type work. DWR
believes the upper reaches of UT1 and UT2 should include more headwater type restoration work. It
appears there is more slope associated with the upper UT2 reach, however, the drainage area is
small, or right at the minimum to maintain an intermittent channel from published research (25
acres).
The upper reaches of UT 1 has 60.8 acres (0.1 sq mi) and a slope exceeding 0.0035 (rise/run) which
would be expected to maintain a single thread channel. In addition, UT 2 has a drainage area of 23
acres (0.04 sq mi) characterized by drain tile in agriculture fields that concentrate the groundwater
table to the stream. This in combination with a Priority 2 tie in, that connects the channel to the
groundwater table. The slope and concentrated flow from drain tiles would lead Restoration
Systems to expected UT 2 to be a single thread stream channel.
a.Other verbiage suggests the designer may substitute rock as necessary. DWR believes very
little rock needs to be placed in the proposed restoration features.
RS concurs that very little rock needs to be placed in the proposed restoration reaches and woody
material will be the primary natural feature associated with the Site.
b.Outfall Structures – DWR does not believe use of a Terracell is warranted. Why not utilize
log cross vanes as shown on the design sheets?
The drop structure will be updated to include natural material other than Terracell.
6.Section 8.2 – what is the drainage area at the top of UT1?
60.8 acres
7.Table 15 – DWR recommends limiting Green Ash planting to no more than 5% due to the ash borer.
The planting plan has been updated with a reduction in the number of Green Ash.
8.Table 17 – DWR would like the proposed growing season stated/written into the Table. We realize
Axiom will monitor the soil temperature, however; we will need to know the proposed season, the
location of the soil probes and the pairing of the soil temperature with the appropriate vegetative bud
burst (not red maple, since they usually show early bud burst).
Table 17 has been updated to indicate that the growing season will begin no earlier than March 1.
In addition, text has been added to Figure 9 (Monitoring Plan) as follows; “The growing season is
proposed to start no earlier than March 1. The growing season will be verified with soil
temperature (continuous monitoring soil probe) and vegetative bud burst (not to include red
maple). The soil probe will be installed in an open area within the conservation easement, in the
approximate location as depicted above.”
9.Table 18 – the 30 day flow criteria is only for intermittent streams. DWR expects near continuous flow
for perennial streams.
Understood.
10.DWR accepts and appreciates DMS’s comment regarding the wetland performance criteria.
Understood
11.Appendix A – Figures, in the future, for projects with proposed stream reaches high in the watershed,
please include a LiDAR figure.
A LiDAR map has been added as Appendix L.
12.In addition, it is also helpful to have pictures showing representative reaches, particularly when there
has been at least a year since the site visit.
Appendix K has been added to the document and includes additional Site photographs.
14.Figure 9 – DWR likes the placement of the flow gauges, however; either some of the wetland gauges
may need to be moved or other gauges added to monitor wetlands located in upper topo gradients.
The Site includes 9 groundwater gauges, including 1 groundwater gauge that is monitoring a
drained hydric soil. Of the 8 groundwater gauges, 5 are located on side slopes adjacent to the
floodplain. To address this comment, we moved two of the 5 gauges in the upper extent of the Site
further up the side slope; however, we feel the intent of the IRT to monitor wetlands out of the
floodplain has been met.
15.Design sheet 2D – what is floodplain interceptor made out of and does the designer intend to install
this feature?
Text has been added to Section 8.1.1 (Stream Restoration), including the following. “A floodplain
interceptor is a depression in the stream banks that directs return flow from the floodplain back
into the stream channel at a specific location, thereby eliminating channel bank erosion. The
interceptor is constructed by creating a low point in the channel banks, lining the low point with
matting, and planting with stabilizing vegetation. In the Piedmont and Mountains rock would be
added to the interceptor; however, this is not necessary or appropriate in the Coastal Plain.
The determination of floodplain interceptor installation and/or location is expected to be made in
the field. During construction the field manager will identify if concentrated flow is occurring across
the floodplain, or down the valley walls. The field manager will direct the installation of a floodplain
interceptor, if necessary, and will include the floodplain interceptor in red-line drawings for the as-
built construction documents. “
17.Design sheet 5 – DWR believes the single thread channel should start at approximately station 7+00.
Section 8.1.1 (Stream Restoration) has been added to and now includes the following text. “The
Site slope in the upper reaches of UT 1 and UT 2 exceeds 0.0035 rise/run and 0.003, respectively.
The tributaries have a contributing drainage area at the top measuring 60.8 acres (0.10 sq mi) and
23 acres (0.04 sq mi). In addition, UT 2 has a drainage area characterized by drain tiled agriculture
fields that contribute hydrology in a concentrated manner, effectively forming a spring head.
Coastal plain streams with this slope and size would be expected to be characterized by single
thread channels. However, in the event that Priority 1 stream restoration fails, and a braided
headwater wetland system develops, the stream length will be modified to the down valley length
and wetland credit for 50 feet on each side of the stream will be removed, as per headwater
guidance. Stream gauges in the upper extent have been added to monitor flow duration and visual
monitoring for the maintenance of a clear channel will be conducted.”
13.Figure 6 – typical riffle cross section – DWR is assuming the designer will not line the channel and up
the stream bank with rock.
Rock will not be used to line the channel, as this is a sand-bed stream. Figure 6 in the detailed plan
has been updated. Typical Riffle Cross Section has been updated with removal of rip rap stone.
16.Design sheet 4 – what is the line that borders the stream between the wetted perimeter line and
limits of disturbance line? Also, please put a scale on all design sheets with stream planforms.
The design sheets have been updated. Label “Limits of Construction” has been added for
clarification.
Summary: before final approval of this mitigation plan, DWR would like the following:
a.Information on number and location of soil profiles, including areas in upper topo gradients,
Axiom has collected additional soil profiles and included them in the Detailed Mitigation Plan.
The location of the profiles is depicted on Figure 4.
b.Better explanation or case for starting with single thread channels at the top of the project,
See answers to question 1 and 17
c.Site pictures, particularly of the upper reach features.
Additional Site photographs have been included as Appendix K.
WRC Comments, Travis Wilson:
1.Significant portions of the watershed shown for UT 1 and UT 2 are located north of a road and
railroad bed making it unclear how or if that area drains into those watersheds. The mitigation plan
states UT 1 starts at a culvert under the roadbed but appears to still be interconnected with the
roadside ditches and drainage. With a Priority 1 approach will the drainage coming under the road
access the channel or be pushed further down the roadside ditch? There also does not appear to be
any cross pipes connecting flow from the UT 2 watershed delineated on the north side of the road
to UT 2 south of the road making that watershed significantly smaller.
Piped culverts occur beneath a rail line and road in the upper watershed for UT 1. Roadside ditches
drain towards the culvert and access the upper reaches of UT 1; therefore, a marsh treatment area
is intended to capture stormwater pulses prior to the initiation of the UT 1 channel. The drainage
area for UT 1 is correct in Mitigation Plan figures as the ditches drain towards UT 1.
WRC is correct that the UT 2 drainage area is split by the road and no culverts cross beneath the
road, effectively splitting the drainage area. However, drain tile in the field offsets this by
attenuating storm flow, providing slow release of hydrology similar to a spring fed tributary. In
addition, the upper reaches of UT 2 have a short section of Priority 2 restoration further
maintaining contact with the groundwater table. The high slope of UT 2, spring like flow of UT 2
headwaters, and continuous contact with the groundwater table would be expressed as a lower
perennial, single thread channel.
2.On paper this site looks like a better wetland restoration site with some amount of headwater
stream restoration.
RS feels there is adequate evidence to support the proposed stream restoration proposal including
the soils in the lower reaches of the Site are mapped as Muckalee (a fluvial soil type), the Site is
contained within an alluvial valley which matches the Coastal Plain guidance for the existence of a
stream, the drainage area at the upper extent of the Site measures over 60 acres (Coastal Plain
guidance suggests streams initiate at approximately 25 acres, and during the PJD Site visit the
stream was called jurisdictional by the USACE and NCDWR.
3.The amount of Greene ash proposed for planting should be reduced to reflect our latest guidance of
<5%
The planting plan has been updated with a reduction in the number of Green Ash.
USACE Comments, Kim Browning:
1.The correct USACE Action ID is SAW-2018-01169. Please correct the cover page.
The USACE Action ID has been updated.
2.Section 8.3 – Wetland Restoration – The inclusion of ephemeral/vernal pools is acceptable, and should
be 8-14” depressions that dry up yearly so that predatory species cannot colonize.
Understood and agreed.
3.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.
Woody debris will be spread across the Site instead of burned.
4.Table 17 Success Criteria – Streams, please add a statement (regarding UT3) at least 30-days continuous
surface water flow for intermittent streams.
Table 17 includes the parameters to be measured. Table 18 includes success criteria and has a
statement that “continuous surface flow must be documented each year for at least 30 consecutive
days”.
5.Table 18 – Success Criteria: Please add a section on Photo Documentation or Digital Monitoring.
An example would be that photographs should illustrate the site’s vegetative and morphological
stability on an annual basis, in fixed locations, depicted on the monitoring maps or at all cross-sections.
Cross-section photos should demonstrate no excessive erosion or degradation of the banks.
Longitudinal photos should indicate the absence of mid-channel bars or vertical incision. Grade
control structures should remain stable.
Table 18 has been updated to include a Visual Assessment section outlining the above referenced
information.
6.The upper end of UT1 will likely be intermittent and develop into more of a headwater system rather
than a single thread. Photo documentation showing defined channel features will be important.
The upper reaches of UT 1 will be monitored for maintenance of channel developing flow.
7.When submitting the PCN, please include an estimate of the number of trees, or acres, to be cleared
for the NLEB 4(d) Rule.
We will include the number of acres to be cleared with the PCN.
8.Maintenance Plan: Will the marsh treatment area within the easement require maintenance? If so,
please discuss.
Marsh treatment areas will not require maintenance and are expected to fill with sediment and
naturalize over time.
9.Please include Lidar maps.
We added a LiDAR map as appendix L.
Sincerely,
Raymond Holz
Restoration Systems