20190495 Ver 1_Final Daft MP_2020_20201030

This mitigation plan has been written in conformance with the requirements of the following:
• Federal rule for compensatory mitigation project sites as described in the Federal Register Title 33 Navigation and
Navigable Waters Volume 3 Chapter 2 Section § 332.8 paragraphs (c)(2) through (c)(14).
• NCDEQ Division of Mitigation Services In-Lieu Fee Instrument signed and dated July 28, 2010
These documents govern NCDMS operations and procedures for the delivery of compensatory mitigation.

Draft Mitigation Plan
Cowford Project
DMS Project #: 100095 | Contract #: 7746 | USACE Action ID: SAW- 2019-00487
DWR Project #: 2019-0495 | RFP: 16-007577
October 2020
White Oak River Basin | HUC 03030001 | Onslow County, North Carolina
Prepared By:
Resource Environmental Solutions, LLC
For Environmental Banc & Exchange, LLC
3600 Glenwood Avenue, Suite 100
Raleigh, NC 27612
919-209-1067
Prepared For:
NC Department of Environmental Quality
Division of Mitigation Services
1652 Mail Service Center
Raleigh, NC 27699-1652

MEMORANDUM

3600 Glenwood Avenue, Suite 100 Raleigh, North Carolina 27612 919.770.5573 tel. [phone] fax
TO: NCDMS
FROM: Matt Butler – RES
Brad Breslow – RES
DATE: October 12, 2020
RE: Response to DMS Comments on the Draft Mitigation Plan Cowford, Project ID #10095,
DMS Contract #0007746
Reviewers: Lindsay Crocker, Lin Xu, Periann Russel, Joe Famularuo

Specific:
1. Page 3,1.2 Project Outcomes – The draft plan indicated that the Cowford Branch and New
River are nutrient sensitive waters (NSWs). NSW is the supplemental surface water
classification. Please list the primary surface water classification as well.
Primary (Class C) has been added to this paragraph, per the comment.

2. Page 3, Table 1. Update ratios in both stream and wetland sections to show 1:1.
The ratios have been updated, per the comment.

3. Page 12, 4.1.2. The ESA section of the environmental screening process for this project
found ‘no suitable habitat’ and ‘no effect.’ Update to reflect. Also, because this was a self-
certification process, the document should not contain statements from USFWS. Remove
that portion of the sentence.
This section has been updated to reflect “no suitable habitat” and “no effect.” Additionally, the
section has been updated to clarify that the lack of response from USFWS indicates that they did not
object to the determinations made in the self-certification process.

4. Page 13, Table 7. Regulatory Considerations. Update 404 and 401 to indicate pending
permit rather than Categorical Exclusion for ‘resolved’ section.
Table 7 has been updated, per the comment.

5. Page 14, 5.1.3 Geomorphology – At the bottom of the page, the draft plan discussed that
the project would greatly reduce sediment loadings to the project stream by planting buffer
and treating offsite drainage. However, research show the biggest sediment source is bank
erosion from degraded stream. Consider including restoring the channel to its stable form
as a fact reducing sediment loading into the channel. Consider also running RUSLE to
determine actual erosion that may be reduced from direct field erosion/sediment to justify.
This section has been revised to include bank erosion as a sediment source and RUSLE2 calculations.

6. Page 17, 18, and 35. The objectives for this project should be consistent. Suggest merging to
streamline project objectives to fit all three areas rather than a similar list of various
objectives in each section. This will clarify and unify the project.
Objectives removed from page 17 and consolidated into two sections on pages 18 and 36.

7. Page 19, Section 7.1.2 refers to section 6.2 for detail discharge analysis. Section 6.2 does not
exist in the document. Update reference or remove.
This was a typo, the sentence has been updated to reference Section 7.2.2.

8. Page 19. Provide map of reference location relative to project location.
RES acknowledges that the reference reach is located in the upper Neuse River Basin. Further
description on why UT to Buffalo Creek was chosen can be found in the following comment
response.

9. Page 19, 7.1.1 Reference Characterization – The selected reference reach has a significant
larger drainage area comparing to the proposed project reaches. And the reference reach is
in upper Neuse River basin while the project site is in the lower coastal plain. Please explain
the reason why UT to Buffalo Creek was selected for comparison.
RES chose the UT to Buffalo Creek reference site for this project to better fit the topography of
Reach KJ1-C, which exhibits slopes more akin to the upper coastal plain. The reference reach
drainage area is larger than project reaches, however, RES is confident that scaling channel
dimensions to fit different drainage area sizes is a useful design technique when combined with the
other techniques outlined in the mitigation plan.

10. Page 20 Section 7.2.1 describes that a braided channel (headwater) is depicted in the plan
sheets (for KJ1-A), but this cross-section typical is just showing one flow path in the plan
sheet designs. Update to provide typical or explain.
Verbiage relating to a “braided” system has been removed to clarify the headwater valley work
being done. RES will grade and vegetate a headwater valley for Reach KJ1-A, but the channel itself
will form by natural processes. On a vegetated low gradient stream such as KJ1-A, there is potential
for braided channel formation; however, RES is not grading in braided flow paths.

11. Page 22, Section 7.2.2.3. Section 7.2.2.3 It is unclear how RES will use the Tau values
estimated from the different methods. Please add a brief explanation for this and clarify
how these values contribute to designing for capacity as well as competence.
RES has added to these sections to explain that these values are used as design QAQCs to ensure
that the design velocity and shear stress falls withing accepted ranges. The proposed HWV
Restoration at the top of this project will act as a sediment sink for the downstream reaches due to
its low transport capacity. RES anticipates that this section will see significant aggradation due to the
drastic change in transport capacity from the upstream ditches to the HWV section. This HWV
section will also have significantly less transport capacity than the proposed downstream reaches.
Therefore, RES does not anticipate any downstream capacity / aggradation issues. Competency is
not generally a concern for sand bed channels because the entire bed is designed to be mobile.

12. Page 22, Table 9 and section 7.2.2.2 Design Discharge – Discharge estimated from flood
frequency analysis and regional curves for KJ1-B and KJ1-C are very similar. Please explain
why 5 cfs was chosen for KJ1-B while the design discharger for KJ1-C is 8 cfs.
KJ1-B was slightly undersized to promote floodplain inundation through the wetland. In addition to
this the valley for KJ1-C is much steeper than the valley for KJ1-B and the KJ1-C channel was
therefore designed with slightly steeper slope. This steeper slope allowed RES to maintain the same
channel dimensions for both KJ1-B and C which will simplify construction which promotes a more
successful project.

13. Page 25. Suggest adding a statement that if planting occurs later than 3/15, provider will
seek IRT approval.
Statement added.

14. Page 27. This page describes agricultural BMPs, please explain if these are outside the
easement and/or describe /name them specifically.
This paragraph has been re-written to clarify these practices. “Agricultural BMP” has been rephrased
to “sediment load attenuation structures,” and the paragraph now better summarizes Section 7.3,
where further description of their function can be found. All of these structures will be contained
within the easement and protected in perpetuity.

15. Page 38. Long Term Stewardship. Please remove last paragraph, IRT has issue with those
statements in the past.
RES has removed this paragraph, per the comment.

Construction Plan Sheets
1. Include project IDs (DMS, CES and DWR) on the title sheet. Also include lat and long, and
the total disturbed acreage on the title sheet.
Project IDs and contract number are located on the Cover sheet in the lower left-hand corner.
Project coordinates have been added to the Cover sheet below the Vicinity Map in the upper right-
hand corner. RES will provide the total disturbed acreage with the final plan set once construction
staging has been coordinated with the contractor and land quality.

2. Show the boundaries of limited disturbance on plan sheets
Limits of disturbance will be provided with the final plan set once construction staging has been
coordinated with the contractor and land quality.

3. Label wetlands in the plan sheets as the approved JD.
The approved JD did not have wetlands. However, there was a typo in the plan sheets and Figure 8
(labeled as “WB”) and have been corrected to show as “WA”

4. Include details for treatment pool and engineered sediment pack.
A detail for the engineered sediment pack is shown on Sheet D2. A detail for the treatment pool has
been added on Sheet D6.

Digital Data
1. KJ1-A has a reported length 923 ft but the feature length is 932 ft. It is understood that
crediting is based on valley length, but please check that the valley length (913) is correct.
The DRAFT shapefile contained length within the confluence at the top of the Project that was not
claimed for credit; this length has been removed in the updated digital files. RES has also added a
valley length shape to the design map data to provide how that length was found.

2. Please include the 0-credit connecting feature for KJ1-C and KJ1-B in the shapefile
resubmittal.
This feature has been added to the updated digital files per the comment.

Appendices/Figures
16. Table 4. Regulatory Considerations. Update 404 and 401 to indicate pending permit rather
than Categorical Exclusion for ‘resolved’ section.
Table 4 lists the Mapped Soil Series. Table 7 has been updated, per the comment.

17. Appendix C. Remove the MOA and replace with recorded CE and Plat number when
recorded/complete. OK to leave the Affidavit from the landowner regarding CREP
easement.
Appendix C has been updated per the comment. The recorded easement and plat will be added when
complete.

18. Appendix K. Add full checklist from the Categorical exclusion and supporting documents.
This is now requested by IRT. The supporting docs can be minimized (EDR reduced to
outcome pages, etc).
The full Categorical Exclusion document has been added to Appendix K, per the comment.

19. Appendix L. Add the first 3 of 4 pages of the Floodplain checklist for information.
Appendix L has been updated to include these pages. RES apologizes for their initial omission.

Cowford Mitigation Plan 1 October 2020
Project #100095

Table of Contents
1 PROJECT INTRODUCTION ............................................................................................................. 3
1.1 Project Components................................................................................................................ 3
1.2 Project Outcomes.................................................................................................................... 3
2 WATERSHED APPROACH .............................................................................................................. 4
2.1 Site Selection .......................................................................................................................... 4
3 BASELINE AND EXISTING CONDITIONS ................................................................................... 6
3.1 Watershed Summary Information .......................................................................................... 6
3.2 Landscape Characteristics ...................................................................................................... 6
3.3 Reach Summary Information ................................................................................................. 8
3.4 Wetland Summary Information ............................................................................................ 11
4 REGULATORY CONSIDERATIONS ............................................................................................ 12
4.2 Clean Water Act - Section 401/404 ...................................................................................... 13
4.3 Potential Constraints ............................................................................................................. 13
5 FUNCTIONAL UPLIFT POTENTIAL ............................................................................................ 14
5.1 Anticipated Functional Benefits and Improvements ............................................................ 14
6 MITIGATION PROJECT GOALS AND OBJECTIVES ................................................................. 17
7 MITIGATION WORK PLAN .......................................................................................................... 19
7.1 Reference Stream.................................................................................................................. 19
7.2 Design Parameters ................................................................................................................ 20
7.3 Sediment Control Areas ....................................................................................................... 24
7.4 Vegetation and Planting Plan ............................................................................................... 24
7.5 Mitigation Summary ............................................................................................................. 27
7.6 Determination of Credits ...................................................................................................... 27
8 PERFORMANCE STANDARDS .................................................................................................... 30
8.1 Stream Success Criteria ........................................................................................................ 30
8.2 Wetland Success Criteria ...................................................................................................... 31
8.3 Vegetation Success Criteria .................................................................................................. 32
9 MONITORING PLAN ...................................................................................................................... 33
9.1 As-Built Survey .................................................................................................................... 33
9.2 Visual Monitoring ................................................................................................................ 33
9.3 Stream Hydrology Events ..................................................................................................... 33
9.4 Cross Sections ...................................................................................................................... 34
9.5 Wetland Hydrology .............................................................................................................. 34
9.6 Vegetation Monitoring ......................................................................................................... 34
9.7 Scheduling/Reporting ........................................................................................................... 35
10 ADAPTIVE MANAGEMENT PLAN .............................................................................................. 37
11 LONG-TERM MANAGEMENT PLAN .......................................................................................... 38
12 REFERENCES .................................................................................................................................. 39

Cowford Mitigation Plan 2 October 2020
Project #100095

List of Tables

Table 1. Cowford Project Components Summary ........................................................................................ 3
Table 2. Project Parcel and Landowner Information .................................................................................... 5
Table 3. Project Watershed Summary Information....................................................................................... 6
Table 4. Mapped Soil Series ......................................................................................................................... 7
Table 5. Summary of Existing Channel Characteristics ............................................................................... 8
Table 6. Summary of Stream Parameters ...................................................................................................... 9
Table 7. Regulatory Considerations ............................................................................................................ 13
Table 8. Functional Benefits and Improvements ........................................................................................ 18
Table 9. Peak Flow Comparison ................................................................................................................. 22
Table 10. Stable Channel Design Output .................................................................................................... 23
Table 11. Comparison of Allowable and Proposed Shear Stresses ............................................................ 23
Table 12. Comparison of Permissible and Proposed Velocities ................................................................. 24
Table 14. Cowford Project (ID-100095) - Mitigation Components ........................................................... 29
Table 15. Monitoring Requirements ........................................................................................................... 36

List of Figures

Figure 1 – Project Vicinity
Figure 2 – USGS Quadrangle
Figure 3 – Landowner Parcels
Figure 4 – Watershed Landuse
Figure 5 – Mapped Soils
Figure 6 – Historical Imagery
Figure 7 – Existing Conditions and Project Constraints
Figure 8 – Conceptual Design Plan
Figure 9 – Buffer Width Zones
Figure 10 – Monitoring Plan
Figure 11 – 1YR Inundation Map
Figure 12 – 10YR Inundation Map

Appendices

Appendix A – Plan Sheets
Appendix B – Data Analysis and Supplementary Information
Appendix C – Site Protection Instrument
Appendix D – Credit Release Schedule
Appendix E – Financial Assurance
Appendix F – Maintenance Plan
Appendix G – DWR Stream Identification Forms
Appendix H – USACE District Assessment Forms
Appendix I – Wetland JD Forms and Maps
Appendix J – Invasive Species Plan
Appendix K – Approved FHWA Categorical Exclusion
Appendix L – DMS Floodplain Requirements Checklist
Appendix M – Final Site Hydric Soils Detailed Study

Cowford Mitigation Plan 3 October 2020
Project #100095

1 PROJECT INTRODUCTION
1.1 Project Components
The Cowford Project (Project) is located within a rural watershed in Onslow County, North Carolina
approximately three and half miles northwest of Richlands, NC. The Project lies within the White Oak
River Basin, North Carolina United States Geological Survey (USGS) 8-digit Cataloguing Unit 03030001
and 14-digit hydrologic unit code (HUC) 03030001010010, a Targeted Local Watershed (TLW) and the
Division of Water Resources (NCDWR) sub-basin 03-05-02 (Figure 1). The Project proposes to restore
3,337 linear feet (LF) of stream as well as re-establish 2.991 acres of wetland that will provide water quality
benefit for 238 acres of drainage area (Figure 2). The Project is in the Carolina Flatwoods Level IV
ecoregion.

The Project area is comprised of a 17.20-acre easement involving one unnamed tributary within an
entrenched channel between agricultural fields, totaling 2,988 existing LF, that drain to Cowford Branch,
which eventually drains to the New River. The stream and wetland mitigation components are summarized
in Table 1. The Project is accessible from state route NC-258. Coordinates for the Project areas are
approximately 34.9233, -77.5917, at the crossing in the middle of the project.
1.2 Project Outcomes
The streams and wetlands proposed for restoration have been significantly impacted by ditching, drain
tiling, and other agricultural practices for over 50 years. The stream is currently allowing sediment,
nutrients, pesticides, and herbicides to flow freely into Cowford Branch and the New River. Both water
bodies are classified as Class C and Nutrient Sensitive Waters. The proposed wetland restoration area will
raise the local groundwater and restore a more natural hydrologic cycle to the riparian zone. Successful
construction and restoration of this tributary and headwater wetland system will provide numerous benefits
to water quality. Proposed improvements to the Project will help address impacts specifically discussed as
priorities in in the 2010 White Oak River Basin Restoration Priorities (RBRP).

Through stream restoration, headwater valley (HWV) restoration, and wetland restoration, the Project
presents 3,347 LF of proposed stream, generating 3,595.443 Warm Stream Mitigation Units (SMU) and
2.991 acres of proposed wetland, generating 2.991 Wetland Mitigation Units (WMU) (Table 1). This
mitigation plan is consistent with the June 6, 2019 Post Contract IRT Meeting Minutes and IRT response
emails (Appendix B).

Table 1. Cowford Project Components Summary
Stream Mitigation
Mitigation Approach Linear Feet Ratio Warm SMU
Restoration (HWV) 923 1:1 913.000*
Restoration 2,424 1:1 2,424.000
Total 3,347 3,337.000
Non-standard Buffer Width Adjustment 258.443**
Total Adjusted SMUs 3,595.443
*Headwater valley credits are calculated from valley length
** Credit adjustment for Non-standard Buffer Width calculation using the Wilmington District Stream Buffer Credit
Calculator issued by the USACE in January 2018. See Section 6.6 for further information
Wetland Mitigation
Mitigation Approach Area (acres) Ratio WMU
Re-establishment 2.991 1:1 2.991
Total 2.991 2.991

Cowford Mitigation Plan 4 October 2020
Project #100095

2 WATERSHED APPROACH
The Project was selected based on its potential to support the objectives and goals of the DMS 2010 White
Oak RBRP. The White Oak RBRP identified several restoration needs for the entire White Oak River Basin,
as well as for HUC 03030001, specifically. The Project watershed was identified as a TLW
(03030001010010, New River), a watershed that exhibits both the need and opportunity for stream,
wetland, and riparian buffer restoration. Approximately 44% of this project’s river basin is agricultural
land. Basin wide goals for all Catalog Units (CUs) outlined in the 2010 White Oak RBRP and CU Specific
Goals for the Upper New River Targeted Local Watershed include:

Basin wide goals for all CUs

1. Protect and improve water quality throughout the Basin by reducing sediment and nutrient inputs
into streams and river
2. Protect shellfish harvesting waters and reduce the number & frequency of Division of
Environmental Health (DEH) closures of designated shellfish growing areas
3. Support efforts to restore local watersheds in the White Oak River Basin; and
4. Support implementation plans (NC Coastal Habitat Protection Plan (Street et al, 2005) and its
associated implementation plans (NC Division of Marine Fisheries, 2007; NCDMF, 2009).

Upper New River: 03030001010010 Specific Goals

1. Planting riparian buffer zones with appropriate woody species.
2. Best management practices that offset the impacts of agriculture are also a high priority here.
3. Preservation should be considered where high-quality habitat exists and riparian corridors can be
maintained.

The Project directly supports many of these listed goals through the restoration and protection of aquatic
resources and presents an opportunity to grow the already protected catchment in the Upper New River
watershed from earlier DMS efforts in the White Oak River Basin. The lack of riparian buffer, historic
stream manipulation, ditching in the watershed and agricultural practices are significant contributing factors
to water quality impairment and habitat degradation in this watershed, and the Project will help address
these identified stressors at a localized level, as described in Section 2.1.
2.1 Site Selection
Currently, the majority of the Project area is within agricultural fields, having row crops of a corn/soybean
rotation. The lower portion of the stream has more incised banks with more of a riparian buffer in place.
The Project will directly and indirectly address stressors identified in the RBRP by reconstructing natural
channels within the agricultural field, stabilizing eroding stream banks and establishing floodplain
connectivity, reducing sediment and nutrient loads, and restoring forested wetlands and buffers. Project-
specific goals and objectives will be addressed further in Section 5. Watershed planning priority boundaries
are shown on Figure 1, and the Project’s drainage areas are shown on Figure 2.

The Project will address several goals outlined in the 2010 White Oak RBRP, one of the goals for all CUs
and two goals from the Upper New River TLW. The Project includes restoration of streams, wetlands, and
their associated buffers that will promote nutrient and sediment reduction in agricultural areas (RBRP
Basinwide Goal 1). The project also will plant riparian buffer zones with appropriate woody species (RBRP
TLW specific Goal 1) and the stream and wetland restoration and riparian buffer establishment to provide
a natural buffer between the agricultural fields and the waterways is a best management practice that helps
offset the impacts of agriculture (RBRP TLW specific Goal 2).

Cowford Mitigation Plan 5 October 2020
Project #100095

The land required for the construction, management, and stewardship of this Project includes portions of
one parcel in Onslow County with the following ownership in Table 2 & Figure 3. Once finalized, a copy
of the land protection instrument will be included in Appendix C. The Division of Mitigation Services
(DMS) Conservation Easement model template will be utilized to draft the site protection instruments.

Table 2. Project Parcel and Landowner Information
Owner of Record
PIN
Or
Tax Parcel ID#
Stream Reach
Kenneth W Jones 44220-129-3936
(Onslow County)

All

Cowford Mitigation Plan 6 October 2020
Project #100095

3 BASELINE AND EXISTING CONDITIONS
3.1 Watershed Summary Information
Drainage Area and Land Cover
The Project area is comprised of one unnamed tributary that flows east to west and drains into Cowford
Branch just downstream of a road crossing. The total drainage area for the Project is 238 acres (0.37 mi2)
(Figure 2). The surrounding land use is agricultural and undeveloped land with scattered single-family
homes. Drain tile has been constructed to drain the surrounding slopes below the gently sloping to nearly
level landscape along the edge of the interstream divide. Primary land use within the Project drainage area
consists of approximately 75% Row Crop, 21% Woods, 3.3% Residential, and 0.06% Impervious Surface
(Figure 4).

Table 3. Project Watershed Summary Information
3.2 Landscape Characteristics
Physiography and Topography
The Project is located in the Carolina Flatwoods level IV ecoregion within the Middle Atlantic Coastal
Plain level III ecoregion. This region is characterized by low-relief, wide upland surfaces on lightly
dissected marine terraces. Large areas of poorly drained soils are common, contributing to swamps,
Carolina bays, and low gradient streams with sandy and silty substrates. Artificial drainage for forestry and
agriculture is common in this region, and the Project floodplain is no different. (Griffeth et al., 2002;
Appendix M) An extensive ditch and drain-tile network rapidly removes surface water from the floodplain
and lowers what would naturally be a high groundwater table. The Project exists in a transitional area
between a broad interstream divide and the lower valley of Cowford Branch. The upper half of the project
begins the transition from a nearly level mineral flat to a headwater stream in a gradual sloping manner.
Just after the easement break, the valley becomes more defined and steepens to join with that of Cowford
Branch (Figure 2). Elevations range from 43 ft to 71 ft above mean sea level (NAD83), based on
topographic survey.
Geology and Soils
According to geology data from the North Carolina Geologic Survey, published in 1985, the Project is
within geologic map unit Tec, occurring in the Coastal Plain Belt. This map unit is associated with
sedimentary type rocks of the Comfort Member and New Hanover Member formation that formed during
the Tertiary period within the Cenozoic era between 2 and 63 million years ago. This undivided formation
may contain skeletal limestone commonly with locally-dolomitized solution cavities or phosphate-pebble
conglomerates. The Project floodplain soil appears to have been formed in minor erosional deposition from
the surrounding upland soils and is primarily characterized as sand, sandy clay, and loam. All soils on-site
are formed in loamy and sandy marine deposits and the alluvium from those deposits. (Appendix M).
Watershed Feature Designation
Level IV Ecoregion Carolina Flatwoods
River Basin White Oak
USGS Hydrologic Unit 8-digit 03030001
USGS Hydrologic Unit 14-digit 03030001010010
DWR Sub-basin 03-05-02
Project Drainage Area (acres) 238
Percent Impervious Surface 0.06%
Surface Water Classification (drains to) C and NSW

Cowford Mitigation Plan 7 October 2020
Project #100095

The Natural Resources Conservation Service (NRCS) depicts five mapping units across the Project (Figure
5). The Project area is dominated by Norfolk loamy fine sand (58%), with progressively smaller proportions
of Stallings loamy fine sand (24%), Rains fine sandy loam (11%), Goldsboro fine sandy loam (4%), and
Onslow loamy fine sand (3%). The soil characteristics of these map units are summarized in Table 4.

Rains fine sandy loam is the only soil unit on-site to be considered hydric by the NRCS. However, Norfolk
loamy fine sand may contain hydric inclusions of Woodington or Mucklee; Stallings loamy fine sand may
contain hydric inclusions of Woodington or Rains; and Onslow loamy fine sand may contain hydric
inclusions of Rains. Stallings loamy fine sand is considered farmland of statewide importance, while
Goldsboro fine sandy loam, Norfolk loamy fine sand, and Onslow loamy fine sand are all considered prime
farmland, and Rains fine sandy loam is considered prime farmland if drained (NRCS, n.d.).

Table 4. Mapped Soil Series
Map Unit
Symbol Map Unit Name Percent
Hydric Drainage Class Hydrologic
Soil Group
Landscape
Setting
GoA Goldsboro fine sandy loam,
0 to 2 percent slopes No Moderately Well
Drained A/D
Broad interstream
divides on marine
terraces
NoA Norfolk loamy fine sand, 0
to 2 percent slopes No Well Drained A
Ridges on marine
terraces, broad
interstream divides on
marine terraces
NoB Norfolk loamy fine sand, 2
to 6 percent slopes No Well Drained A
Broad interstream
divides on marine
terraces
On Onslow loamy fine sand No Moderately Well
Drained A
Broad interstream
divides on marine
terraces
Ra
Rains fine sandy loam, 0 to 2
percent slopes, Atlantic
Coast Flatwoods
Yes Poorly Drained B/D Carolina bays on marine
terraces
St Stallings loamy fine sand No Somewhat Poorly
Drained A/D Flats on marine terraces

A detailed soil survey was performed on the Project parcel by a licensed soil scientist in January 2020 to
evaluate the extent of hydric soils and the potential for wetland re-establishment for wetland mitigation
(Appendix M). Soils on site typically have a dark surface despite years of drainage and cultivation. The
typical soil surface consists of very dark gray to black sandy loam surface usually with brown or dark brown
mottles. This dark surface is underlain by a gray to dark gray horizon with mottles. The mottles are
concentrations of iron, manganese, and organic matter. Two borings appeared to have sandy deposition
over a black, gleyed horizon possibly from sedimentation or effects from long-term cultivation. Black, high-
organic soils also appear within the upper elevations of the landscape on the mineral flat. Additionally, the
presence of a clayey textured horizon as well as areas with a possible spodic horizon provide potential for
perching of a water table. In general, the soils on this site are highly variable and interpretation is difficult,
which may be a result of many soils converging towards the upper reach of the tributary (Appendix M).

Cowford Mitigation Plan 8 October 2020
Project #100095

Existing Vegetation
Vegetation at the Project is made up of mainly brush species that grow along the banks of the ditches. These
species include Muscadine (Vitis rotundifolia), Carex sp., Brazilian vervain (Verbena brasiliensis), and
Pokeweed (Phytolacca americana). The fields next to the ditches have been used as agricultural fields.
Along the downstream end of KJ1-C, a buffer was planted in 2004, funded by the United States Department
of Agriculture (USDA), Farm Service Agency (FSA), Conservation Reserve Program (CRP). Ditch and
stream buffer areas were planted but no bank stabilization took place. In this CRP zone, the vegetation
changes from small brush to larger trees. The canopy becomes more closed and includes species like
Persimmon (Diaspyros virginiana), Sawtooth Oak (Quercus acutissima), Loblolly Pine (Pinus teada),
Southern Red Oak (Quercus falcata), Sugarberry (Celtis laevigata) and Southern Crabapple (Malus
angustolfia). The herbaceous layer in this closed canopy area consists of Chinese privet (Ligustrum
sinense), Shrubby Lespedeza (Lespedeza bicolor), Smooth Sumac (Rhus glabra), and Trumpet vine
(Campsis radicans). Woody vines are also locally common and include Laurel Greenbrier (Smilax
laurifolia).
Land Use – Historic, Current, and Future
The area surrounding the project has been used for agriculture since 1950 and has steadily grown in usage
(Figure 6). The forested upstream area was cleared between 1950 and 1977, which led to an increase in the
use of row crops, mainly corn and soybean. Between 1977 and 1982, KJ1-A was straightened for
agricultural purposes. In 2004, a CRP was put in place on KJ1-C. However, this CRP easement expired by
its own term in September of 2019, as can be seen in Appendix C. Between 1982-2010, the watershed just
upstream of the project area was significantly altered by an increase in the number of ditches in the
surrounding agricultural fields (Figure 6).

The future land use for the Project area will include 17.20 acres of conservation easement that will be
protected in perpetuity. The Project easement will have 3,347 linear feet of a functioning stream, a minimum
50-foot riparian buffer, and 2.991 acres of riparian wetlands. Outside the Project, the area will likely remain
in agricultural use.
3.3 Reach Summary Information
The Project area is comprised of one unnamed tributary, KJ1, split into three reaches based on proposed
mitigation treatment (A, B, and C), that flows east to west and drains just downstream of the project into
Cowford Branch (Figure 7). Results of preliminary data collection are presented in Table 5. Morphological
parameters are located in Appendix B.

Table 5. Summary of Existing Channel Characteristics
Reach Drainage
Area (ac)
ABKF 1
(ft2)
Width
(ft)
Mean
Depth
(ft)
Width: Depth
Ratio
Bank
Height
Ratio
Entrenchment
Ratio Sinuosity Slope
(ft/ft)
KJ1-A 115 3.8 4.1 0.9 4.3 2.5 1.8 1.00 0.004
KJ1-B 181 4.5 4.9 0.9 5.3 3.9 1.5 1.01 0.007
KJ1-C 238 6.5-8.2 6.6-6.7 1.0-1.2 5.4-6.8 1.8-4.2 1.9-2.1 1.02 0.007
1ABKF= cross-sectional area (measured at approximate bankfull stage as estimated using existing conditions data and NC
Regional Curve equations where field indicators were not present)

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Channel Classification
The Project stream has been classified as intermittent using, the NCDWR Stream Identification Form
version 4.11 (Stream ID Form) KJ1. The project stream was also rated using the North Carolina Stream
Assessment Method (NCSAM) and received an overall score of Low (Appendix H). Table 6 summarizes
these stream parameters and the Stream ID Form as well as a stream identification map, which includes
USGS and NRCS Onslow County Soil Survey mapped streams, can be found in Appendix G. Stream
determinations have been verified by the USACE (Appendix I).

Table 6. Summary of Stream Parameters
Reach Hydrology
Status
Stream Determination
Score
NCSAM
Score
Reach Length
(LF)
Rosgen Stream
Classification
KJ1 Intermittent 27.5 Low 2,988 E5 – G5c
Existing Channel Morphology
3.3.2.1 Reach KJ1
KJ1-A
Reach KJ1-A originates at an ephemeral/intermittent break, located at the confluence of 3 ditches
on the eastern boundary of the proposed conservation easement. The reach has a mild valley with
limited longitudinal slope, has been historically ditched, and no longer provides significant
ecological functions. KJ1-A flows west through row crop fields to KJ1-B. Much if not all the reach’s
morphology is currently driven by ditching instead of natural channel processes. The break between
reach A and B was selected because the valley steepens and becomes more defined downstream of
this point. Row crops are directly adjacent to both banks. Drain tiles from the adjacent fields currently
outlet directly into the reach.

KJ1-A Banks KJ1-A Banks

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KJ1-B
Reach KJ1-B originates at downstream end of KJ1-A and flows west through hydric soils to a
proposed culvert crossing and easement break. The reach has been ditched and has further degraded
such that it lacks floodplain connection, appropriate patten, and bedform diversity. There is an
existing 41 LF culvert crossing approximately in the middle of the reach. Row crops are directly
adjacent to both banks. Drain tiles from the adjacent fields currently outlet directly into the reach.

KJ1-B Banks Below the crossing on KJ1-B

KJ1-C
Reach KJ1-C originates downstream of the proposed easement break and continues west to the
downstream limits of the conservation easement. The reach has a relatively steep (~1%), defined
valley. Directly downstream of the easement, the channel flows under NC HWY 258 through a 48”
CMP. The reach has been ditched and has further degraded and entrenched such that it lacks
floodplain connection, appropriate patten, and bedform diversity. Managed forest, from an expired
CRP easement, forms an immature buffer along much of the right bank while row crops form much
of the left bank.

KJ1-C Banks KJ1-C Banks

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3.4 Wetland Summary Information
Jurisdictional Wetland Information
A survey of existing wetlands was performed on October 3, 2019. Wetland boundaries were delineated
using current methodology outlined in the 1987 U.S. Army Corps of Engineers Wetland Delineation
Manual (Environmental Laboratory 1987).

A preliminary jurisdictional determination (PJD) request was sent to the USACE on October 4, 2019 and
revised materials were submitted on November 12, 2019. The confirmed PJD package was completed by
USACE; the PJD was received on February 12, 2020. These documents and correspondence can be found
in Appendix I.

Within the boundaries of the proposed Project, no jurisdictional wetlands are present (Figure 5). The only
jurisdictional feature is the stream KJ1 (Appendix I).
National Wetland Inventory
The USFWS National Wetland Inventory Map (NWI) also depicts no wetland areas within the Project
(Figure 5). The only mapped NWI depicts palustrine forest wetlands in forested areas within a mile of the
project boundaries.
Hydric Soil Indicators
A detailed hydric soil investigation for Cowford Mitigation Site was completed in January of 2020 by a soil
scientist. A series of approximately 75 soil borings were performed to described and verify the presence
and estimate the extent of hydric soil and soils that appear to exhibit relict or historic hydric indicators
(Appendix M). Soils were characterized and classified using the Field Indicators of Hydric Soils in the
United States, Version 7.0 (USDA-NRCS 2010). Hydric indicators were found within 12 inches of the soil
surface and found in both riparian and non-riparian landscapes. The hydric soil indicators found include the
F3-Depleted Matrix, S7- Dark Surface, A11-Depleted Below Dark Surface, A12-Thick Dark Surface, S5-
Sandy Redox, and S9-Thin Dark Surface. Also present were S5-Sandy Redox, S9-Thin Dark Surface, and
F3-Depleted Matrix. The range of the indicators points to the complexity of the soils at the location, and
these can all be found on both riparian and non-riparian landscapes.
Existing Hydrology
Overbank flooding is limited by the deeply dredged and straightened channel and lowers surrounding
groundwater elevation in the floodplain. Additionally, the drain tile system lowers the ground water
elevations farther from the stream, extending to nearby portions of the contributing watershed. The smooth
cultivated surfaces and ditches also quickly remove surface water to prevent accumulation and limit
infiltration. These drainage modifications decrease both surface storage and subsurface storage. There are
two potential surface drainage patterns that have a concave topography that contribute to the watershed.
One enters along the stream channel from the northeast and one from the southeast where a ditch is located.
Due to the landscape and potential convergence of multiple soil units, this site appears to have been
historically part of a small riverine headwater system where hydric soil extends outward up into the higher
elevations of the mineral flat. This Project is located along the transition from a riparian to non-riparian
landscape where multiple soil morphologies were noted. This confluence of differing soils and the
converging landscape provide variable soil textures and hydric soil indicators providing evidence this area
supported a riparian wetland prior to drainage and conversions to agricultural use.

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4 REGULATORY CONSIDERATIONS
Environmental Screening and Documentation
To ensure that a project meets the “Categorical Exclusion” criteria, the Federal Highways Administration
(FHWA) and NCDMS have developed a categorical exclusion (CE) checklist that is included as part of
each mitigation project’s Environmental Screening process. The CE Approval Form for the Cowford
Project is included in Appendix K and was approved by DMS and FHWA in August 2019.
Threatened and Endangered Species
Plants and animals with a federal classification of endangered or threatened are protected under provisions
of Sections 7 and 9 of the Endangered Species Act of 1973, as amended. According to the United States
Fish and Wildlife (USFWS) IPAC database review tool (USFWS 2018) and the self-certification process
conducted by RES and submitted to the USFWS on August 2nd, 2019, there are sixteen endangered or
threatened species listed that may occur in proximity to the Project. However, it was determined that only
four species; Cooley’s Meadowrue (Thalictrum cooleyi), Golden Sedge (Carex lutea), Pondberry (Lindera
melissifolia), and Roughed-leaved Loosestrife (Lysimachia asperulaefolia), had the potential to have
suitable habitat on the property. After a habitat and species survey conducted on July 19th, 2019, it was
determined there was “no suitable habitat” nor species present on site. Therefore a “no effect” determination
was made for all of the listed species that were provided in the official species list. The USFWS was
consulted through the self-certification process during the CE process and no response was provided by
USFWS, which is typical as the certification letter (provided) is their official response unless they do not
concur with the determination. Supporting documentation and correspondence can be found in Appendix
K.

The Fish and Wildlife Coordination Act requires consultation with state fish and wildlife agencies when
“waters of any stream or other body of water are proposed or authorized, permitted or licensed to be
impounded, diverted…or otherwise controlled or modified. The North Carolina Wildlife Resources
Commission (NCWRC) was consulted during the CE process and the NCWRC stated that there are no
records of any state or federally listed species at the site nor any in the immediate vicinity of the site.
Documentation is included in Appendix K.
Cultural Resources
A review of North Carolina State Historic Preservation Office (SHPO) GIS Web Service (accessed 11
February 2020) database revealed five listed or potentially eligible historic or archeological resources
nearby the proposed project properties. Three of these listings are marked as gone; Billy Banks House
(ON0023), India Anna Elizabeth Jarman House (ON0318), and Lloyd Humphrey House (ON0306). The
other two documented buildings are the S. Ab Cox House (ON0104) and the William Kinsey House
(ON0342). No construction shall be completed outside of proposed easement, so these listings should be
untouched. RES consulted with the SHPO during the CE and the SHPO had “conducted a review of the
project and are aware of no historic resources which would be affected by the project.” Cultural Resources
screening met the Categorical Exclusion Criteria for FHWA and DMS projects and documentation is
included in Appendix K.
Federal Emergency Management Agency (FEMA)/ Hydrologic Trespass
According to the North Carolina Floodplain Mapping Information System, there is no part of the Project
included within the mapped FEMA 100-year floodplain (Zone AE) and no regulated floodway is mapped
(FEMA 2018) (Figure 5).

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4.2 Clean Water Act - Section 401/404
Impacts to jurisdictional streams will be unavoidable, due to the restoration activities proposed. Although
these impacts are unavoidable, the proposed stream treatment will result in an overall functional uplift of
the stream system, as described in Section 5. All of KJ1 is proposed for restoration activities. These
activities will have permanent impacts, due to stream restoration and stream realignment. No existing
wetlands will be impacted during stream restoration activities. The project does intend to reestablish
wetlands on-site. All stream impacts will be accounted for in the Pre-Construction Notification form.

Table 7. Regulatory Considerations
Regulation Applicable? Resolved? Supporting Documentation
Waters of the United States - Section 404 Yes Pending Permit Appendix I
Waters of the United States - Section 401 Yes Pending Permit Appendix I
Endangered Species Act Yes Yes Appendix K
National Historic Preservation Act Yes Yes Appendix K
Coastal Zone Management Act
(CZMA)/Coastal Area Management Act
(CAMA)
No N/A N/A
FEMA Floodplain Compliance No N/A Appendix L
Magnuson Stevens Act - Essential Fisheries
Habitat No N/A N/A
DOT Right-of-way Permit Yes No N/A
4.3 Potential Constraints
Major project constraints include an existing culvert crossing on KJ1-B, road and utility right of ways, and
multiple drainage ditches and drain tiles that outfall into the existing channel. Most of the drainage ditches
and drain tiles tie to the bottom of the existing channel somewhat limiting the potential to connect the
channel to the existing valley.

The proposed Project is located approximately 3 miles from Hell and Purgatory Airport. Hell and Purgatory
Airport has a single grass runway and no permanent structures; it is not anticipated that the Project will
interfere with the airport’s function. There is a portion of Reach KJ1-C that was enrolled in a CRP contract
which expired in 2019. The CRP program contract was for vegetated ditch buffers, which was herbaceous
vegetation, and there was no requirement to stabilize eroding banks. The CRP contract had not provided
funds for any of the tasks outlined in the RFP (RFP #16-007577). The contract ran for 15 years and it
expired on September 20, 2019 (Appendix C).

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5 FUNCTIONAL UPLIFT POTENTIAL
In order to thoroughly examine the potential functional uplift to stream systems proposed for restoration,
the Stream Functions Pyramid Framework (Framework) (Harman et. al. 2012) serves as a useful concept
to understand streams and their ecological functions. The Framework presents a logical, holistic view of
streams that describes the interrelatedness of fundamental stream functions. The Framework defines five
stream function categories, ordered into a hierarchy, that demonstrates the dependence of higher-level
functions (biology, physicochemical, and geomorphology) on lower level functions (hydrology and
hydraulics). Functions that affect the greatest number of other functions are illustrated at the base of the
Pyramid, while functions that have the least effect on other functions are illustrated at the top. Further
justifying this hierarchical concept, Fischenich (2006) found that the most critical restoration activities are
those that address stream functions related to hydrodynamic processes, sediment transport processes, stream
stability, and riparian buffers.

Therefore, principles of the Framework are utilized to discuss and communicate the potential functional
uplift to streams at the Cowford project and to propose realistic, attainable goals and objectives. However,
the determination of credits and performance standards for the Project follow guidance put forth by the
USACE Wilmington District.

The Cowford Stream and Wetland Mitigation Project will provide numerous ecological and water quality
benefits within the White Oak River Basin by applying an ecosystem restoration approach. The restoration
approach at the reach scale of this project will have the greatest effect on the hydrology, hydraulic, and
geomorphology functions of the system and is assumed to ultimately benefit the upper-level functions
(physicochemical and biology) over time, and in combination with other projects within the watershed.
Within the Project area, functional benefits and improvements related to the Function-Based Pyramid
Framework are anticipated by realizing site-specific functional goals and objectives These goals and
objectives, as they relate to the Framework, are outlined in Table 8.
5.1 Anticipated Functional Benefits and Improvements
Hydrology
The Project will locally address several historic hydrologic disturbances including deforestation and
channelization; however, it is not anticipated that the Project will have a significant effect on hydrology at
the watershed scale.
Hydraulic
The greatest potential uplift at the Project will be achieved by providing floodplain connectivity throughout
the Project. Channels will be designed to promote stable channel hydraulics by increasing floodplain
inundation, grade control, bank stabilization. Currently, hydraulic parameters for all reaches are not
functioning due to lack of buffer, historic realignment, maintenance of agricultural drainage through the
use of drain tiles and ditching and will be functioning post restoration.
Geomorphology
The proposed design will promote a dynamic transport of sediment through the project. Due to a lack of
floodplain connection much of the current project has a high transport capacity that drastically limits the
channels ability to store sediment. By promoting floodplain inundation and headwater valley characteristics
the transport capacity will be reduced, allowing the stream to develop / utilize depositional areas (point bars
and floodplain wetlands). In addition to reducing the transport capacity RES anticipates the project will
also reduce sediment loading within the project corridor. This load reduction will be achieved through a
reduction in bank erosion, planting a riparian buffer, and treating offsite drainage before it enters the reach.

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Soil loss within the easement area is estimated to be reduced by approximately 80% through buffer planting
(using the RUSLE2 software; NRCS). The Headwater Valley restoration (Reach KJ1-A) will act as a
sediment sink for the downstream reaches. Channel stability and bedform diversity will be improved in
restoration reaches by installing wood grade control, coir matting, bank vegetation, and habitat structures
to promote a natural riffle-pool sequence. The existing channel will be filled to help raise the groundwater
within the wetland. Channel substrate of KJ1-C will be supplemented by off-site material to ensure bed
stability and habitat creation. Transport and storage of woody debris will be improved through increases in
channel roughness from plantings and structure installation. Existing riparian vegetation for reach KJ1-C
are functioning-at-risk due to lack of diversity of woody vegetation. Therefore, riparian buffers will be
planted out to a minimum of 50 feet to improve the riparian vegetation to functioning levels, while also
providing terrestrial habitat. All of these functional parameters are interconnected and depend on each other;
therefore, improving this wide range of parameters will result in long-term functional geomorphic uplift.
Physicochemical
Although this Project would support the overarching goal in the White Oak RBRP to promote nutrient and
sediment reduction in agricultural areas, it is difficult to measure nutrient and sediment reduction at this
project level because they can be affected by many variables. However, several restoration actions that will
be realized by the Project are known to reduce nutrients and sediment even though they may not be
observable at the project level. These activities include removing drain tiles and/or outletting drain tiles into
the floodplain, converting active agricultural fields into forested buffers, filtering runoff through buffer
areas, and improving denitrification and nutrient uptake through buffer zones and riparian wetlands.
Additional benefits may also come from functional uplift of the lower-level stream functions (hydraulics
and geomorphology), which will reduce sediment and nutrients in the system through channel
establishment, bank stabilization, and reforestation. Temperature regulation will also be improved through
the restoration of canopy tree species to the stream buffer areas. Oxygen regulation will occur through two
actions: first, the temperature of the water directly impacts the amount of gas held by the water. Therefore,
by planting the buffer to shade the channel, water temperature is decreased, and dissolved oxygen is
increased. Second, by constructing stable channels that include drop structures, mixing zones will form
where oxygen dissolves much faster than the current exchange rate. The processing of organic matter will
be improved once healthy riffles are shallow enough to catch twigs and branches that then retain leaves.
Many of these physicochemical benefits occur slowly and are dependent on multiple variables within the
stream ecosystem. Therefore, it is not practical or feasible to directly measure these parameters within the
monitoring time frame of this project. With that said, it is logical to use existing riparian buffer and visual
performance standards to demonstrate the positive correlation between geomorphic parameters and
physicochemical parameters. For example, as riparian buffer trees grow, as represented in annual
monitoring reports, it is anticipated that canopy cover is actively shading the stream channel and reducing
water temperature. This is not a substitute for direct physicochemical monitoring, but it is a useful tool to
help project the long-term benefits of the Project in terms of its functional uplift. Ultimately, any uplift to
physicochemical functions at the Project can only be assumed.
Biology
As mentioned for the physicochemical stream function, it will be difficult to see measurable results of the
functional uplift of the biological functions at a project scale during the monitoring time frame of the
project. However, since the life histories of many species likely to benefit from stream and wetland
restoration are depending on the lower-level functions, the functional uplift from the hydraulic and
geomorphic levels would likely have a positive effect on the biology over time and in combination with
other projects within the watershed is anticipated. Again, there is no substitute for direct biological
monitoring, but it is important to understand the hierarchy of the Stream Functions Pyramid Framework in
order to help project long-term benefits of the Project, though only categories two and three (hydraulics and

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geomorphology) will be directly measured during the seven-year monitoring period. Ultimately, any
functional uplift to biology at the Project can only be assumed.
Wetland Functional Uplift
The Project currently has no wetlands due to the incised channel and drain tile system rapidly removing
surface and groundwater. The stream is currently allowing sediment, nutrients, pesticides, and herbicides
to flow freely into Cowford Branch and the New River. Both water bodies are classified as Nutrient
Sensitive Waters. The proposed wetland restoration area will raise the local groundwater and restore a more
natural hydrologic cycle to the riparian zone. Successful construction and restoration of this tributary and
headwater wetland system will provide numerous benefits to water quality. Successful hydrologic
restoration will provide numerous soils related functional uplifts in addition to the benefits of stream
restoration. These include, re-establishment of natural oxidation reduction cycling, improved nutrient and
chemical transformations, potential immobilization of phosphorus, increased organic carbon sequestration,
improved soil structure (surface primarily), lower soil and surface water temperature after vegetative
establishment, and increases in diversity of microbial and fungal populations that are important for soil
health. Large scale benefits may include an increase of diverse wildlife habitat, and connectivity to the
natural aquatic communities of Cowford Branch.

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6 MITIGATION PROJECT GOALS AND OBJECTIVES
Through the comprehensive analysis of the Project’s maximum functional uplift using the Stream Functions
Pyramid Framework and conclusions based on a Site Hydric Soils Detailed Study (Appendix M), specific,
attainable goals and objectives will be realized by the Project. These goals clearly address the degraded
water quality and nutrient input from agricultural practices that were identified as major watershed stressors
in the 2010 White Oak RBRP. The Project will address outlined RBRP Goal one and two of the TLW
specific goals (listed in Section 2).

The Project goals are:
• Re-establish hydrology to a historical stream/wetland complex that has been impacted by historic
channel realignment, channel entrenchment, field ditching, and field drain tiling;
• To transport water in a stable, non-erosive manner and maintain a stable water table in riparian
floodplain wetlands that will also contribute to stream baseflow;
• Improve flood flow attenuation on site and downstream by allowing for overbank flows and
connection to the floodplain;
• Create diverse bedforms and stable channels that achieve healthy dynamic equilibrium and provide
suitable in-stream habitat for aquatic organisms;
• Limit sediment and nutrient inputs into stream system;
• Re-establish wetland;
• Restore native wetland and riparian vegetation;
• Indirectly support the goals of the 2010 White Oak RBRP to improve water quality and to reduce
sediment and nutrient loads; and
• To support the life histories of aquatic and riparian plants and animals through stream restoration
activities.

Anticipated functional uplift, benefits, and improvements within the Project area, as based on the Function
Based Framework are outlined in Table 8.

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Table 8. Functional Benefits and Improvements
° These categories are measured indirectly; *These categories are not quantifiably measured

Level Function Goal Objective Measurement Method
1
Hydrology°
Transport of water
from the watershed to
the channel
to transport water from the
watershed to the channel in a
non-erosive manner and
maintain a stable water table in
the riparian wetland
Convert the land-use of
streams and their
watersheds from cropland
into riparian forest

Maintain appropriate
hydroperiod for Muckalee
soil series
Percent Project drainage
area converted to
riparian forest (indirect
measurement)

Groundwater wells
2
Hydraulic
Transport of water in
the channel, on the
floodplain, and
through the sediments
to transport water in a stable
non-erosive manner
Improve flood bank
connectivity by reducing
bank height ratios and
increasing entrenchment
ratios

Maintain regular, seasonal
flow in restored,
intermittent streams
Cross sections

Stage Recorders

Bank Height Ratio

Entrenchment Ratio

Flow gauge
3
Geomorphology
Transport of wood and
sediment to create
diverse bedforms and
dynamic equilibrium
to create a diverse bedform and a
stable channel that achieves
healthy dynamic equilibrium and
provides suitable habitat for life
Limit erosion rates and
increase channel stability
to reference reach
conditions

Improve bedform diversity
(pool spacing, percent
riffles, etc.)

Increase buffer width to at
least 50 feet
As-built stream profile

Cross sections

Visual monitoring

Vegetation plots
4
Physicochemical °
Temperature and
oxygen regulation;
processing of organic
matter and nutrients
Indirectly support the goals of
the 2010 White Oak RBRP to
achieve appropriate levels for
water temperature, dissolved
oxygen concentration, and other
important nutrients including but
not limited to Nitrogen and
Phosphorus through
buffer/wetland planting and
wetland hydrologic restoration
Establish native hardwood
riparian buffer to provide
canopy shade and absorb
nutrients

Install in-stream structures
to created aeration zones

Promote sediment
filtration, nutrient cycling,
and organic accumulation
through natural wetland
biogeochemical processes

Vegetation plots
(indirect measurement)

Established a perpetual
conservation easement
(indirect measurement)

Groundwater wells
5
Biology *
Biodiversity and life
histories of aquatic life
histories and riparian
life
to achieve functionality in levels
1-4 to support the life histories of
aquatic and riparian plants and
animals through instream
Improve aquatic habitat by
installing habitat features,
constructing pools of
varying depths, and
planting the riparian
buffer and wetlands
As-Built Survey
(indirect measurement)

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7 MITIGATION WORK PLAN
7.1 Reference Stream
The restoration portions of the Project are currently characterized by agricultural practices. Physical
parameters of the Project were used, as well as other reference materials, to determine the target stream
type. The “Classification of the Natural Communities of North Carolina” was also used to narrow the
potential community types that would have existed at the Project (Schafale, 2012). An iterative process was
used to develop the final information for the Project design.

Targeted reference conditions included the following:
• Located within the physiographic region and ecoregion,
• Similar land use on site and in the watershed,
• Similar soil types on site and in the watershed,
• Ideal, undisturbed habitat – several types of woody debris present,
• Similar topography,
• Similar slope,
• Pattern common among coastal plain streams, and
• Minimal presence of invasive species.

Reference Characterization
The selected reference stream is UT to Buffalo Creek which is part of the most downstream portion of the
Buffalo Branch Stream Mitigation Project and is located in the Upper Neuse River Basin. The reach that
was surveyed and analyzed is approximately 375 feet long with a drainage area of 1.11 square miles (709
acres). The land use in the watershed is not dominated by any one land use, but has major components of
cropland, pasture, and forests, with minor components of developed area, wetlands, herbaceous, and open
water. Site photographs of the reference stream are located in Appendix B.

The current State classification for Buffalo Creek downstream of the reference reach is C and NSW
(NCDWR 2011). Class C waters are those protected for uses such as secondary recreation, fishing, wildlife,
fish consumption, aquatic life including propagation, survival, and maintenance of biological integrity, and
agriculture. Secondary recreation includes wading, boating, and other uses involving human body contact
with water where such activities take place in an infrequent, unorganized, or incidental manner. Waters
given the supplemental classification of Nutrient Sensitive Waters (NSW) are those needing additional
nutrient management due to being subject to excessive growth of microscopic or macroscopic vegetation.
Further, Buffalo Creek is listed on the 2018 303d list for impaired waters (North Carolina Department of
Environmental Quality [NCDEQ] 2018). It received a Fair Bioclassification rating for benthic ecological/
biological integrity.
Reference Discharge
Several hydrologic models/methods were used to develop a bankfull discharge along with indicators of
bankfull stage for the reference site. Existing drainage area, land use, slope, roughness, and cross-sectional
area were all factors considered when performing the calculations. Using a combination of Coastal Regional
Curves, in-house spreadsheet tools, and a project specific regional flood frequency analysis, the existing
discharge for UT to Buffalo Creek was found to be approximately 18-21 cubic feet per second (ft3/s). See
Section 7.2.2 for a more detailed description of the hydrologic analyses performed for this project.

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7.2 Design Parameters
Stream Restoration Approach
The Project will include stream and headwater valley restoration. Stream restoration will incorporate the
design of a single-thread, meandering channel, with parameters based on data taken from reference site,
published empirical relationships, regional curves developed from existing project streams, and NC
Regional Curves. Analytical design techniques will also be a crucial element of the project and will be used
to determine the design discharge and to verify the design. Based on soil type, valley slope, and drainage
area headwater valley restoration was incorporated in the design. Headwater valley restoration will include
the design of a vegetated diffuse flow system that will allow for the passive development of a headwater
stream. The USACE and DWR guidance “Information Regarding Stream Restoration with Emphasis on
the Coastal Plain” was heavily utilized in the design of this reach. A conceptual plan is provided in Figure
8 and the design plan sheets of the restoration approach is found in Appendix A.

The Project has been broken into the following design reaches:
7.2.1.1 Reach KJ1-A (HWV)
A headwater valley restoration approach is proposed for this reach to address historic ditching and buffer
impacts. Restoration activities will include:
- Grading a headwater valley,
- Installing wood structures to provide grade control and habitat,
- Installing live stakes to stabilize the bed and banks,
- Riparian planting.
7.2.1.2 Reach KJ1-B
An offline restoration approach is proposed for this reach to address historic ditching and buffer impacts.
Restoration activities will include:
- Grading a new, single-thread channel in the existing floodplain,
- Installing log structures to provide grade control and habitat,
- Establishing a riffle-pool sequence throughout the new channel,
- Installing toe protection on meander bends,
- Installing live stakes to stabilize the banks and provide channel shading,
- Riparian planting.
7.2.1.3 Reach KJ1-C
An inline, P2 restoration approach is proposed for this reach to address historic ditching, channelization,
and buffer impacts. Restoration activities will include:
- Grading a new, single-thread channel in an excavated floodplain,
- Installing log structures to provide grade control and habitat,
- Establishing a riffle-pool sequence throughout the new channel,
- Installing toe protection on meander bends,
- Installing live stakes to stabilize the banks and provide channel shading,
- Filling the existing channel,
- Riparian planting, and
- Invasive vegetation treatment.

7.2.1.4 Typical Design Sections
Typical cross sections for riffles and pools are shown on the design plan sheets in Appendix A. All cross-
section dimensions were developed from the analog reach but were altered based on existing site conditions,
hydraulic modeling, and observations from other mitigation sites in the area.

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7.2.1.5 Meander Pattern
The design plans showing the proposed channel alignment are provided in Appendix A. The meander
pattern was derived directly from the analog reach and was altered in some locations to provide variability
in pattern, to avoid on Project constraints, to improve constructability, and to promote wetland hydrology.
The morphologic parameters summarized in the Appendix B were applied wherever these deviations
occurred.
7.2.1.6 Longitudinal Profiles
The design profiles are presented in Appendix A. These profiles extend throughout the entire project for
the proposed channel alignment. The profiles were designed using the analog reach bed features that were
sized with the scaling factors. The bed slopes and bankfull energy gradients were determined for each
design reach based on the valley slope and the sinuosity of the design reach. Log structures will be utilized
in the design to control grade, divert flows, and provide additional habitat diversity and stability.
7.2.1.7 In-Stream Structures
Structures will be incorporated into the channel design to provide additional stability and improve aquatic
habitat. Native materials and vegetation will be used for revetments and grade control structures where
applicable. Typical structures that will protect the channel bed and/or banks will include riffle grade
controls, log sills, and brush bed sills.

Woody debris, including log sills, riffle material, and brush bed sills, will be placed throughout the channel.
Bank stability measures include the installation of live stakes, brush toes, and hay bale toes. Typical details
for proposed in-stream structures and revetments are in Appendix A.
Data Analysis
7.2.2.1 Stream Hydrologic Analysis
Hydrologic evaluations were performed for the design reaches using multiple methods to determine and
validate the design bankfull discharge and channel geometry required to provide regular floodplain
inundation. The use of various methods allows for comparison of results and eliminates reliance on a single
model. Peak flows (Table 9) and corresponding channel cross sectional areas were determined for
comparison to design parameters using the following methods:

• Regional Flood Frequency Analysis,
• AutoCAD’s Hydraflow Hydrographs, and
• NC Regional Curves for the Rural Coastal Plain.

Regional Flood Frequency Analysis
A flood frequency analysis was completed for the study region using historic gauge data on all nearby
USGS gauges with drainage areas less than 6,400 acres (10 mi2) which passed the Dalrymple homogeneity
test (Dalrymple, 1960). This is a subset of gauges used for USGS regression equations. Regional flood
frequency equations were developed for the 1.1-, 1.5-, and 2-year peak discharges based on the gauge data.
Discharges were then computed for the design reach. These discharges were compared to those predicted
by the discharge regional curve and USGS regional regression 2-year discharge equations.

AutoCAD’s Hydraflow Express
Hydraflow Express was used to simulate the rainfall-runoff process and establish peak flows for the
watersheds. This model was chosen over the U.S. Army Corps of Engineers model HEC-HMS because it
allows the user to adjust the peak shape factor. Rainfall data reflecting both a 284 and 100 peak shape factor
were used along with a standard Type II distribution, and NRCS hydrology (time of concentrations and
runoff curve numbers), to simulate the rainfall-runoff process.

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Regional Curve Regression Equations
The North Carolina Rural Coastal regional curves by Doll et al. (2003) and Sweet and Geratz (2003) for
discharge were used to predict the bankfull discharge for the Project. The regional curves predicted flows
that are similar to those predicted by the 1.1-year flood frequency, while the Hyrdaflow values were much
higher. The regional curve equations for NC discharges by Doll et al. (2003):

(1) Qbkf=16.56*(DA)0.72 (Doll et al., 2003)
(2) Qbkf=8.79*(DA)0.76 (Sweet and Geratz, 2003)

Where Qbkf=bankfull discharge (ft3/s) and DA=drainage area (mi2).

Table 9. Peak Flow Comparison
Reach Drainage
Area (Ac)
FFQ
Q1.1 FFQ Q1.5 NC Regional
Curve Q (1)
NC Regional
Curve Q (2)
Hydraflow
Q1
Hydraflow
Q2 Design Q
KJ1-A 115 5 16 5 2 9 14 -
KJ1-B 181 8 22 7 3 21 31 5
KJ1-C 238 9 26 8 4 30 44 8

7.2.2.2 Design Discharge
Based upon the hydrologic analyses described above, design discharges were selected that fall just below
the FFQ 1.1 and the NC Regional Curve revised values. The selected flows for the restoration reaches are
5 ft3/s for KJ1-B and 8 ft3/s for KJ1-C. These discharges will provide frequent inundation of the adjacent
floodplain.
7.2.2.3 Sediment Transport Analysis
An erosion and sedimentation analysis was performed to confirm that the restoration design creates a stable
sand bed channel that neither aggrades nor degrades over time. Typically, sediment transport is assessed to
determine a stream’s ability to move a specific grain size at specified flows. Various sediment transport
equations may be easily applied when estimating entrainment for gravel bed streams; however, these
equations are not as effectively applied to sand bed channels where the entire bed becomes mobile during
geomorphically significant flows. Therefore, more sophisticated modeling techniques were used to analyze
the stream design for this project. The following methods and functions were utilized during the sediment
transport analysis:

• HEC-RAS Stable Channel Design
• Permissible Shear Stress Approach, and
• Permissible Velocity Approach.

Stable Channel Design
Design cross-section dimensions were evaluated using the stable channel design functions within HEC-
RAS. These functions are based upon the methods presented in the SAM Hydraulic Design Package for
Channels developed by the USACE Waterways Experiment Station. The Copeland Method was developed
specifically for sand bed channels (median grain size restriction of 0.0625 mm to 2 mm). The method sizes
stable dimensions as a function of slope, discharge, roughness, side slope, bed material gradation, and the
inflowing sediment discharge. Results are presented as a range of widths and slopes, and their unique
solution for depth, making it easy to adjust channel dimensions to achieve stable channel configurations.

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RES uses these results as a QAQC of the proposed channel dimension. The stable design output parameters
are listed in Table 10.

Table 10. Stable Channel Design Output
Reach Q (ft/s3) Bottom
Width (ft) Depth (ft) Energy
Slope (ft/ft)
Composite
n value
Velocity
(ft/s)
Shear Stress
(lbs/ft2)
KJ1-B 5 2 0.85 0.0025 0.04 1.3 0.13
KJ1-C 8 2 1.1 0.0015 0.03 1.4 0.10

The recommended channel characteristics showing in Table 10 are relatively close to the proposed channel
dimensions and were used to help validate the proposed design.

Shear Stress Approach
Shear stress is a commonly used tool for assessing channel stability. Allowable channel shear stresses are
a function of bed slope, channel shape, flows, bed material (shape, size, and gradation), cohesiveness of
bank materials, vegetative cover, and incoming sediment load. The shear stress approach compares
calculated shear stresses to those found in the literature. Critical shear stress is the shear stress required to
initiate motion of the channels median particle size (D50).

RES uses the table below to further validate the design by confirming that the proposed bed shear stress at
bank full is between the critical shear stress and maximum allowable shear stress.

Table 11. Comparison of Allowable and Proposed Shear Stresses
Reach
Proposed Bed Shear
Stress at Bankfull Stage
(lbs/ft2)
Existing Critical
Shear Stress
(lbs/ft2)
Allowable Shear Stress1
Sand/Sily/Clay
(lbs/ft2)
Coarse
Gravel
(lbs/ft2)
Vegetation
(lbs/ft2)
KJ1-B 0.19 0.02 0.03 to 0.26 0.33 to 0.67 0.7 to 1.7
KJ1-C 0.21 0.02 0.03 to 0.26 0.33 to 0.67 0.7 to 1.7
1(Fischenich, 2001)

Review of the above table shows that the proposed bed shear stresses for the Project design reaches are
consistent with the allowable shear stresses for native substrate. Proposed riffles for KJ1-B will incorporate
native materials and will be supplemented with woody debris. KJ1-B riffles will be supplemented with a
mixture of gravel and woody debris to provided increased stability in the more confined valley until
vegetation can be established. This supplemental gravel is larger than the material naturally supplied by the
watershed. RES anticipates that this material will eventually mobilize and leave the site as sand fills in the
voids and the channel bed transitions from framework supported to matrix supported (Wilcock, 2009).

Velocity Approach
Published data are readily available that provide entrainment velocities for different bed and bank materials.
A comparison of calculated velocities to these permissible velocities is a simple method to aid in the
verification of channel stability. Table 12 compares the proposed velocities calculated using Manning’s
equation with the permissible velocities.

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Table 12. Comparison of Permissible and Proposed Velocities
Reach Manning’s “n”
Value
Design Velocity
(ft/s)
Proposed Bed
Material
Permissible Velocity1
(ft/sec)
KJ1-B 0.045 1.3 Sand/Fine Gravel 1.75 – 2.5
KJ1-C 0.045 1.4 Coarse Gravel 2.5 - 6
1(Fischenich, 2001)

Table 12 shows that the design velocity falls below the permissible velocity further validating the proposed
design.
Wetland Restoration
The Cowford Project offers a total ecosystem restoration opportunity. As such, the wetland restoration is
closely tied to the stream restoration and drain tile interruption. The Project will provide 2.991 WMUs
through wetland re-establishment. Wetland re-establishment is only proposed in areas that have been
determined appropriate for wetland restoration by a licensed soil scientist due to the presence of hydric soils
and potential hydrology (Appendix M). Re-establishment activities will include; a successful restoration
that raises the local groundwater elevation and allows frequent flooding, the plugging of ditches, removing
all drain tiles within the easement, and creating shallow depression features in the wetland. A 2D model of
the proposed stream restoration was run in HEC-RAS to evaluate the effectiveness of the design at
increasing wetland flooding. Inundation maps from this model of the 1- and 10-year design storms are
provided in Figures 11 and 12, respectively, and demonstrate that the proposed design will function in this
capacity. These activities will help raise the local groundwater and have a more natural hydrologic cycle in
the riparian zone. Surface roughening through shallow soil ripping will improve infiltration and slow runoff
through the floodplain. Surface roughening will also create microtopography and shallow depressional
areas, re-establishing more natural conditions and establishing habitat diversity. Historic land-use impacts
will be addressed through the planting of a native hardwood wetland community.
7.3 Sediment Control Areas
A suite of sediment load attenuation structures in the form of treatment pools and engineered sediment
packs (Appendix A, Details) will be installed within Swale A and B (Figure 8). Swale A will tie the flow
from Ditch A to reach KJ1-B and Wetland WA, while picking up its bed elevation and treating agricultural
runoff through the use of a treatment pool and planted vegetation. Swale B will tie the flow from Ditch B
into reach KJ1-C while picking up its bed elevation and treating agricultural runoff through the use of a
treatment pool, an engineered sediment pack, and planted vegetation. These structures will be installed
within the conservation easement so that they are protected. Catastrophic failure or maintenance of the
structures is not anticipated as they will be installed in a low-gradient area, and all treatment pools and
swales will be well vegetated.
7.4 Vegetation and Planting Plan
Plant Community Restoration
The restoration of the plant communities is an important aspect of the restoration Project. The selection of
plant species is based on what was observed in the forest surrounding the restoration Project and what is
typically native to the area. Specifically, species identified in forested areas adjacent to the Project along
with species described in the 2012 Guide to the Natural Communities of North Carolina, Fourth
Approximation (Schafale, 2012) for coastal plain wetland-type communities were used to determine the
most appropriate species for the restoration project.

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A Coastal Plain Small Stream Swamp (Schafale, 2012) will be the target community along the Project
reaches and wetlands. This community type represents a diverse group of species with differing flood
tolerances, able to grow in close association with one another along stream and wetland features.
Additionally, as tree species are able to survive less frequently flooded conditions than shown for their
tolerance class, the planting plan selected takes into account the species that are best suitable for the most
flooded zone of the project with the intention that they will likely survive both the wetland area and the
more upland conditions (Stanturf, 2004). While reforestation is an important goal of this Project, it is
expected that some open water and/or marsh pockets may persist in depressions within the swamp areas.
These microtopographic features will further enhance community complexity and habitat diversity. The
target community will be used for the planting areas within the Project, shown in Appendix A. The plant
species list has been developed and can be found in Table 13. Hardwood species typical of the target
community were observed in adjacent and nearby communities and were judged to be appropriate for this
site. The whole project will be planted (16.35 acres). The trees within the previous CRP easement will be
mostly removed during construction, so a new buffer will be planted (Figure 10).

The restoration of plant communities along the Project will provide stabilization and diversity. For rapid
stabilization of the stream banks (primarily outside meanders), silky dogwood (Cornus amomum),
Cottonwood (Populus deltoides) and black willow (Salix nigra) were chosen for live stakes along the
restored channel because of their rapid growth patterns and high success rates. Willows grow at a faster rate
than the species planted around them, providing faster bank stabilization and contribution of organic matter
to the channel than the other planted woody species. As the community matures, the willows will slowly
stop growing or die out as the other species outgrow them and create shade that the willows do not tolerate.
The live stake species will be planted along the outside of the meander bends to three feet from the top of
bank, creating a three-foot section along the top of bank. The live stakes will be spaced at least one per
three linear feet with alternate spacing vertically.

The floodplain will also be planted with a seed mix that will promote a healthy ecosystem. RES plans on
planting a seed mix with combination of temporary and permanent species, that prefer a coastal plain soil
and are tolerant to wetland areas. This mix was created with a focus on the North Carolina Coastal Plain
species but also considered the potential availability and cost of various species. This seed mix includes
different wetland species which will promote growth and help the wetland re-establish. The non-wetland
species will be planted in the proper areas within the project and will help the project reach the targeted
community.

It is anticipated that vegetation planting will be conducted no later than March 15th, and there will be at
least 180 days until the initiation of the first year of monitoring. Furthermore, any replanting that may occur
throughout the monitoring phase of the Project will occur between November 15 and March 15, per the
October 2016 USACE/NCIRT monitoring guidance. However, if the Project completes construction after
March 15, the site will be planted no later than April 30.

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Table 13. Proposed Plant List
Bare Root Planting Tree Species
Species Common Name Spacing (ft) Unit Type
% of Total
Species
Composition
Betula nigra River birch 9x6 Bare Root 15
Taxodium distichum Bald cypress 9x6 Bare root 10
Quercus nigra Water oak 9x6 Bare root 10
Quercus phellos Willow oak 9x6 Bare root 10
Quercus lyrata Overcup oak 9x6 Bare Root 10
Nyssa biflora Swamp tupelo 9x6 Bare root 10
Platanus occidentalis American Sycamore 9x6 Bare root 10
Cephalanthus occidentalis Buttonbush 9x6 Bare root 10
Quercus falcata Southern Red Oak 9x6 Bare root 10
Fraxinus pennsylvanica Green Ash 9x6 Bare root 5
Live Staking and Live Cuttings Bundle Tree Species
Species Common Name % of Total Species Composition
Salix nigra Black willow 40
Cornus ammomum Silky dogwood 30
Populus deltoides Cottonwood 30

On-Site Invasive Species Management
Treatment for invasive species will be required within all grading limits associated with stream restoration.
Invasive species will require different and multiple treatment methods, depending on plant phenology and
the location of the species being treated (Appendix J). All treatment will be conducted as to maximize its
effectiveness and reduce chances of detriment to surrounding native vegetation. Treatment methods will
include mechanical (cutting with loppers, clippers, or chain saw) and chemical (foliar spray, cut stump, and
hack and squirt techniques). Invasive or aggressive plants containing mature, viable seeds will be removed
from the Project and properly disposed. All herbicide applicators will be supervised by a certified ground
pesticide applicator with a North Carolina Department of Agriculture and Consumer Services (NCDA&CS)
license and adhere to all legal and safety requirements according to herbicide labels, and NC and Federal
laws. Management records will be kept on the plant species treated, type of treatment employed, type of
herbicide used, application technique, and herbicide concentration and quantities used. These records will
be included in all reporting documents.
Soil Restoration
After construction activities, the subsoil will be scarified and any compaction will be deep tilled before the
topsoil is placed back over the Project. Any topsoil that is removed during construction will be stockpiled
and placed over the Project during final soil preparation. This process should provide favorable soil
conditions for plant growth. Rapid establishment of vegetation will provide natural stabilization for the
Project.

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7.5 Mitigation Summary
Natural channel design techniques have been used to develop the restoration designs described in this
document. The combination of the analog and analytical design methods was determined to be appropriate
for this Project because the watershed is rural, the causes of disturbance are known and have been abated,
and there are minimal infrastructure constraints. The original design parameters were developed from the
measured analog/reference reach data and applied to the subject stream. The parameters were then analyzed
and adjusted through an iterative process using analytical tools and numerical simulations of fluvial
processes.

The designs presented in this report provide for the restoration of natural coastal plain channel features and
stream bed diversity to improve benthic habitat. The proposed design will allow flows that exceed the
design bankfull stage to spread out over the floodplain and into adjacent wetlands. Native organic material
will be installed throughout the restored reaches to reduce bank stress, provide grade control, and increase
habitat diversity.

Forested riparian buffers of at least 50 feet on both sides of the channel will be established along the Project
reaches. An appropriate riparian plant community (Coastal Plain Small Stream Swamp) will be established
to include a diverse mix of species. The plant species list has been developed and can be found in Table
13. Within the planting zones, certain targeted species will be planted in the appropriate target community
location. Replanting of native species will occur where the existing buffer is impacted during construction.

Wetland re-establishment will be accomplished through stream restoration and drain tile interruption at the
easement boundary. Stream restoration efforts will re-establish surface-groundwater connections that will
provide retention and storage within this riparian wetland and drain tile interruption will further lift
groundwater elevations. The restored wetland area will be planted with a native Coastal Plain Small Stream
Swamp vegetation.

A combination of sediment load attenuation structures will be used on site; engineered sediment packs
coupled with treatment pools and a treatment swale. These structures will be installed within the easement
and will ultimately lead to the functional uplift of the site by reducing peak sediment loads and nutrient
inputs while allowing for the continuation of agricultural production outside of the conservation easement.

Due to the nature of the project, complete avoidance of stream and buffer impacts is not possible. Proposed
stream impacts, including stream relocation and crossing relocation, is a necessary restoration practice that
will contribute to the functional uplift of the Project’s aquatic resources. Stream restoration will also impact
existing buffers, though all these areas will be replanted with a diverse tree community. All impacts will be
accounted for in the Pre-Construction Notification (PCN) form.
7.6 Determination of Credits
Mitigation credits presented in Table 14 are projections based upon site design (Figure 8 and Appendix
A). Upon completion of site construction, the project components and credit data will only be revised to be
consistent with the as-built condition if there is a large discrepancy. Any deviation from the mitigation plan
post approval, including adjustments to credits, will require a request for modification. This will be
approved by the USACE. All credits will be released in accordance with credit release schedules outlined
in the 2016 Wilmington District Stream and Wetland Compensatory Mitigation Update (Appendix D).

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Credit Calculations for Non-Standard Buffer Widths
To calculate functional uplift credit adjustments, the Wilmington District Stream Buffer Credit Calculator
from the USACE in January 2018 was utilized. To perform this calculation, GIS analysis was performed to
determine the area (in square feet) of ideal buffer zones and actual buffer zones around all streams within
the project. Minimum standard buffer widths are measured from the top of bank (50 feet in Piedmont and
Coastal Plain counties or 30 feet in Mountain counties). The ideal buffers are the maximum potential size
(in square feet) of each buffer zone measured around all creditable stream reaches, calculated using GIS,
including areas outside of the easement. The actual buffer is the square feet in each buffer zone, as measured
by GIS, excluding non-forested areas, all other credit type (e.g., wetland, nutrient offset, buffer), easement
exceptions, open water, areas failing to meet the vegetation performance standard, etc. Additional credit is
given to 150 feet in buffer width, so areas within the easement that are more than 150 feet from creditable
streams were not included in this measurement. Non-creditable stream reaches within the easement are
removed prior to calculating this area with GIS (for both ideal and actual). The stream lengths, mitigation
type, ideal buffer, and actual buffer are all entered into the calculator. This data is processed, and the
resulting credit amounts are totaled for the whole project (Table 14 & Figure 9).

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Table 14. Cowford Project (ID-100095) - Mitigation Components
Project
Component
(reach ID)
Wetland
Position and
Hydro Type
Existing
Footage or Acreage Stationing
Mitigation
Plan
Footage or Acreage
As-Built
Footage
Restoration
Level
Approach
Priority
Level
Mitigation
Ratio (X:1)
Mitigation
Credits Notes/Comments

KJ1-A

913 1+42 to 10+65 923 TBD R P1 1:1 913.000
Headwater valley
restoration,
riparian planting
KJ1-B

688 10+65 to 19+17 852 TBD R P1 1:1 852.000
Channel
restoration,
riparian planting
KJ1-C

1,428 19+85 to 35+57 1,572 TBD R P2 1:1 1,572.000
Channel
restoration,
riparian planting
Total 3,347 3,337.000
Non-Standard
Buffer Width
Adjustment
258.443
Total Adjusted
SMU’s 3,595.443

WA RR 0.000 2.991 TBD R 1:1 2.991
Stream
restoration, drain
tile interruption,
native planting

Length and Area Summations by Mitigation Category Overall Assets Summary
Restoration
Level
Stream Riparian Wetland Non-riparian Wetland Overall
(linear feet) (acres) (acres) Asset Category Credits
Riverine Non-Riverine Restoration 3,347.000 2.991 Stream 3,595.443
Enhancement RP Wetland 2.991
Enhancement I NR Wetland NA
Enhancement II Creation
Preservation High Quality
Pres

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8 PERFORMANCE STANDARDS
The success criteria for the Project will follow the 2016 USACE Wilmington District Stream and Wetland
Compensatory Mitigation Update and subsequent agency guidance. Specific success criteria components
are presented below.
8.1 Stream Success Criteria
Bankfull Events
Four bankfull flow events must be documented within the seven-year monitoring period. The bankfull
events must occur in separate years. Otherwise, the stream monitoring will continue until four bankfull
events have been documented in separate years.
Surface Flow
Intermittent stream reaches being restored will be monitored to document intermittent or seasonal surface
flow. This will be accomplished through direct observation and the use of automatic-logging pressure
transducers with data loggers (flow gauge). Reaches must demonstrate a minimum of 30 consecutive days
of flow.
Cross Sections
There should be little change in as-built cross sections. If changes do take place, they should be evaluated
to determine if they represent a movement toward a less stable condition (for example down-cutting or
erosion) or are minor changes that represent an increase in stability (for example settling, vegetative
changes, deposition along the banks, or decrease in width/depth ratio). Cross sections shall be classified
using the Rosgen stream classification method, and all monitored cross sections should fall within the
quantitative parameters defined for channels of the design stream type. Bank height ratio shall not exceed
1.2, and the entrenchment ratio shall be no less than 2.2 within restored riffle cross sections.
Digital Image Stations
Digital images will be used to subjectively evaluate channel aggradation or degradation, bank erosion,
success of riparian vegetation, and effectiveness of erosion control measures. Longitudinal images should
not indicate the absence of developing bars within the channel or an excessive increase in channel depth.
Lateral images should not indicate excessive erosion or continuing degradation of the banks over time. A
series of images over time should indicate successional maturation of riparian vegetation.
Headwater Valley Success Criteria (KJ1-A)
The above mentioned performance standards do not apply to channels constructed in accordance with the
Information Regarding Stream Restoration With Emphasis on the Coastal Plain, Version 2, dated April 4,
2007, referred to here as the Headwater Stream Guidance. Since Reach KJ1-A is being proposed as
headwater valley restoration the success criteria for this reach will be more specific to the reestablishment
of appropriate hydrology and hydraulics, which leads to the passive development of headwaters stream
geomorphology over time.

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Channel formation must be documented using indicators consistent with RGL 05-05 in accordance with the
following schedule:
a. During monitoring years 1 through 4, the preponderance of evidence must demonstrate a
concentration of flow indicative of channel formation within the topographic low-point of the
valley or crenulation as documented by the following indicators:
• Scour (indicating sediment transport by flowing water)
• Sediment deposition (accumulations of sediment and/or formation of ripples)
• Sediment sorting (sediment sorting indicated by grain-size distribution within the primary
path of flow)
• Multiple observed flow events (must be documented by gauge data and/or photographs)
• Destruction of terrestrial vegetation
• Presence of litter and debris
• Wracking (deposits of drift material indicating surface water flow)
• Vegetation matted down, bent, or absent (herbaceous or otherwise)
• Leaf litter disturbed or washed away

b. During monitoring years 5 through 7, the stream must successfully meet the requirements of
standard 2(a) above and the preponderance of evidence must demonstrate the development of
stream bed and banks (i.e., an ordinary high water mark) as documented by the following
indicators:
• Bed and banks (may include the formation of stream bed and banks, development of
channel pattern such as meander bends and/or braiding at natural topographic breaks,
woody debris, or plant root systems)
• Natural line impressed on the bank (visible high water mark)
• Shelving (shelving of sediment depositions indicating transport)
• Water staining (staining of rooted vegetation)
• Change in plant community (transition to species adapted for flow or inundation for a long
duration, including hydrophytes)
• Changes in character of soil (texture and/or chroma changes when compared to the soils
abutting the primary path of flow)
8.2 Wetland Success Criteria
Wetland Hydrology Criteria
The Natural Resources Conservation Service (NRCS) has a current WETs table (1990-2019) for Onslow
County upon which to base a normal rainfall amount and average growing season. The closest comparable
data station was determined to be the WETS station for New River MCAF, NC. The growing season for
Onslow County is 269 days long, extending from March 10 to December 4, and is based on a daily minimum
temperature greater than 28 degrees Fahrenheit occurring in five of ten years.

Based upon field observation across the site the NRCS mapping units show a good correlation to actual site
conditions in areas of the site. Mitigation guidance for soils in the Coastal Plain suggests a hydroperiod for
the Muckalee soil of 12-16 percent of the growing season. The hydrology success criterion for the Site is
to restore the water table so that it will remain continuously within 12 inches of the soil surface for 9-12
percent of the growing season (approximately 29 days) at each groundwater gauge location. Due to the
extensive drainage efforts, it may take at least a year for the site to become completely saturated and reach
the target hydroperiods.

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8.3 Vegetation Success Criteria
Specific and measurable success criteria for plant density within the riparian buffers on the Project will
follow IRT Guidance. The interim measures of vegetative success for the Project will be the survival of at
least 320 planted three-year old trees per acre at the end of Year 3, 260 five-year old trees at seven feet in
height at the end of Year 5, and the final vegetative success criteria will be 210 trees per acre with an
average height of ten feet at the end of Year 7. Volunteer trees that are listed on the approved planting list
will be counted, identified to species, and included in the yearly monitoring reports, and may be counted
towards the success criteria of total planted stems. Moreover, any single species can only account for up to
50 percent of the required number of stems within any vegetation plot. Any stems in excess of 50 percent
will be shown in the monitoring table but will not be used to demonstrate success.

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9 MONITORING PLAN
Annual monitoring data will be reported using the DMS Monitoring Report Template dated June 2017 and
NC IRT monitoring template. The monitoring report shall provide a project data chronology that will
facilitate an understanding of project status and trends, research purposes, and assist in decision making
regarding project close-out. Monitoring reports will be prepared annually and submitted to DMS.
Monitoring of the Project will adhere to metrics and performance standards established by the USACE’s
April 2003 Wilmington District Stream Mitigation Guidelines and the NC IRT’s October 2016 Wilmington
District Stream and Wetland Compensatory Mitigation Update. Table 15 outlines the links between project
objectives and treatments and their associated monitoring metrics and performance standards within the
context of functional uplift based on the Stream Functions Pyramid Framework and a Site Hydric Soils
Detailed Study. Figure 10 depicts the proposed monitoring plan, including approximate numbers and
locations of monitoring devices for the Project.
9.1 As-Built Survey
An as-built survey will be conducted following construction to document channel size, condition, and
location. The survey will include a complete profile of thalweg, water surface, bankfull, and top of bank to
compare with future geomorphic data. Longitudinal profiles will not be required in annual monitoring
reports unless requested by USACE.
9.2 Visual Monitoring
Visual monitoring of all mitigation areas will be conducted a minimum of twice per monitoring year (MY)
by qualified individuals. The visual assessments will include vegetation density, vigor, invasive species,
and easement encroachments. Visual assessments of stream stability will include a complete streamwalk
and structure inspection. Digital images will be taken at fixed representative locations to record each
monitoring event, as well as any noted problem areas or areas of concern. Fixed image locations will exist
at each cross section, each vegetation plot, each stage recorder, and each groundwater well. Results of
visual monitoring will be presented in a plan view exhibit with a brief description of problem areas and
digital images. Photographs will be used to subjectively evaluate channel aggradation or degradation, bank
erosion, success of riparian vegetation, and effectiveness of channel structures. Longitudinal photos should
indicate the absence of developing bars within the channel or an excessive increase in channel depth. Lateral
photos should not indicate excessive erosion or continuing degradation of the banks over time. A series of
photos over time should indicate successional maturation of riparian vegetation.
9.3 Stream Hydrology Events
Continuous stage recorders, devices that utilize automatic-logging pressure transducers that are capable of
documenting the height, frequency, and duration of bankfull events will be installed on Priority 2
Restoration reaches. A minimum of one stage recorder will be installed on each tributary that is greater than
1,000 feet in length, with one gauge required for every 5,000 feet of length on each tributary and a maximum
of five gauges per tributary. Additionally, where restoration activities are proposed for intermittent streams,
monitoring flow gauges should be installed to track the frequency and duration of stream flow events. There
will be one flow gauge installed on KJ1-A and one stage recorder installed on KJ1-C.

Cowford Mitigation Plan 34 October 2020
Project #100095

Headwater Valley Specific Monitoring Plan (KJ1-A)
Headwater stream monitoring will be conducted for 7 years, with monitoring events occurring every year.
Surface water flow will be documented using a flow gauge. The flow gauge will be located within the
anticipated primary path of flow within the low point of the valley to ensure all flow events are captured
and placed along the topographic low point of the valley as necessary to document the upstream end of
channel forming flows. The number of gauge stations to be installed should be based on relevant factors,
including pre and post-construction site conditions, valley slope and length, watershed size, adjacent
wetlands, etc., and should be sufficient to document the upper end of stream formation when considered
with the required field indicators listed in the performance standards as is required in the October 2016
Wilmington District Stream and Wetland Compensatory Mitigation Update. Channel formation within the
valley or crenulation will be documented through the identification of field indicators consistent with those
listed in Regulatory Guidance Letter No. 05-05. Identified field indicators (listed in the performance
standards above) must be documented using data sheets and photographs, and their location must be shown
on a plan view of the site to be included with the annual monitoring report. Additional monitoring and/or
analysis may be necessary in the event of abnormal climactic conditions.
9.4 Cross Sections
Permanent cross sections will be installed at an approximate frequency of one per 20 bankfull widths with
half in pools and half in riffles on all Restoration reaches. Morphological data will be measured and
recorded for all cross-sections; however, only riffle cross sections will include bank height ratio and
entrenchment ratio measurements. Cross sections will be monitored in Years 1, 2, 3, 5, and 7. The initial
plan is to install three cross sections on KJ1-A, four on KJ1-B, and eight on KJ1-C.

9.5 Wetland Hydrology
Wetland hydrology will be monitored to document hydrologic conditions in the wetland re-establishment
areas. This will be accomplished with automatic recording pressure transducer gauges installed in
representative locations across the re-establishment area. The gauges will be downloaded quarterly and
wetland hydroperiods will be calculated during the growing season. Gauge installation will follow current
NCIRT guidance. Visual observations of primary and secondary wetland hydrology indicators will also be
recorded during quarterly site visits. Three wetland gauges will be installed in the wetland to measure these
conditions.
9.6 Vegetation Monitoring
Vegetation monitoring plots will be a minimum of 0.02 acres in size and cover a minimum of two percent
of the planted area. There will be 14 plots within the planted area (16.35 acres). Plots will be a mixture of
fixed and random plots, with ten fixed plots and four random plots (Figure 10). Planted area indicates all
area in the easement that will be planted with trees. The following data will be recorded for all trees in the
fixed plots: species, height, planting date (or volunteer), and grid location. For random plots, species and
height will be recorded for all woody stems. The location (GPS coordinates and orientation) of the random
plots will be identified in the annual monitoring reports. As discussed in Section 7.2.3, it is expected that
some open water/marsh pockets may persist in localized areas within the Project area. Therefore, RES will
attempt to avoid establishing vegetation plots in these potential areas. In the event that these areas become
too large (greater than 0.1 acres) or more widespread throughout the Project, RES will document and map
the areas to determine if any adaptive management is necessary. Vegetation will be planted and plots
established at least 180 days prior to the initiation of the first year of monitoring. Monitoring will occur in
Years 1, 2, 3, 5, and 7 between July 1st and leaf drop. Invasive and noxious species will be monitored so
that none become dominant or alter the desired community structure of the Project. If necessary, RES will
develop a species-specific treatment plan.

Cowford Mitigation Plan 35 October 2020
Project #100095

9.7 Scheduling/Reporting
A baseline monitoring report and as-built drawings documenting stream restoration activities will be
developed within 60 days of the planting completion on the Project. The report will include all information
required by DMS mitigation plan guidelines, including elevations, photographs and sampling plot locations,
gauge locations, and a description of initial species composition by community type. The report will also
include a list of the species planted and the associated densities. Baseline vegetation monitoring will include
species, height, date of planting, and grid location of each stem. The baseline report will follow DMS As-
Built Baseline Monitoring Report Template June 2017, USACE guidelines, and the October 2017
Mitigation Credit Calculation Memo.

The monitoring program will be implemented to document system development and progress toward
achieving the success criteria. The restored stream morphology will be assessed to determine the success
of the mitigation. The monitoring program will be undertaken for seven years or until the final success
criteria are achieved, whichever is longer.

Monitoring reports will be prepared in the fall of each year of monitoring and submitted to DMS. The
monitoring reports will include all information and be in the format required by USACE.

Cowford Mitigation Plan 36 October 2020
Project #100095

Table 15. Monitoring Requirements
Treatment Objective Monitoring Metric Performance Standard
Convert land-use
of Project reaches
from row-crop to
riparian forest and
wetland
Improve the transport of
water from the watershed
to the channel in a non-
erosive manner and
maintain appropriate
wetland hydrology for
Muckalee soil series
Groundwater wells with
pressure transducers:
Downloaded quarterly
Water table within 12 inches of the
ground surface for 9-12% of growing season
Reduce bank
height ratios and
increase
entrenchment
ratios by
reconstructing
channels to mimic
reference reach
conditions
Improve flood bank
connectivity by reducing
bank height ratios and
increase entrenchment
ratios
Stage recorders:
Inspected semiannually Four bankfull events occurring in separate years
Flow gauges:
Inspected quarterly
30+ days of continuous flow along the headwater
valley
Cross sections
monitored annually
Yearly photos taken and
data sheets used to mark
changes
Identify sediment sorting, scouring, sediment
deposition and observe multiple flow events
Identify bed and bank development, visible high-
water marks, shelving, water staining, change in
plant community and changes in soil character
Cross sections:
Surveyed in
MY 1, 2, 3, 5 and 7
Entrenchment ratio shall be no less than 2.2 within
restored reaches
Bank height ratio shall not exceed 1.2
Establish a riparian
buffer to limit
erosion and
sediment input to
Project streams.
Establish stable
banks with
livestakes, erosion
control matting,
and other in stream
structures.
Limit erosion rates and
maintain channel stability
Improve bedform diversity
(pool spacing, percent
riffles, etc.)
Increase buffer width to
50 feet
As-built stream profile N/A
Cross sections:
Surveyed in
MY 1, 2, 3, 5 and 7

Entrenchment ratio shall be no
less than 2.2 within restored
reaches
Bank height ratio shall not exceed
1.2
Visual monitoring:
Performed at least
semiannually
Identify and document significant
stream problem areas; i.e.
erosion, degradation,
aggradation, etc.
Vegetation plots:
Surveyed in
MY 1, 2, 3, 5 and 7
MY 1-3: ≥320 trees/acre
MY 5: ≥260 trees/acre (7 ft. tall)
MY 7: ≥210 trees/acre (10 ft. tall)
Restore wetland
hydrology and
plant and protect
riparian buffer and
riparian wetland

Promote sediment
filtration, nutrient cycling,
and organic accumulation
through natural wetland
biogeochemical processes
Groundwater wells with
pressure transducers:
Downloaded quarterly
(indirect measurement)
Water table within 12 inches of the
ground surface for 12% of growing season
Establish native hardwood
riparian buffer and high-
functioning riparian
wetland.

Vegetation plots:
Surveyed in
MY 1, 2, 3, 5 and 7
(indirect measurement)
MY 1-3: ≥320 trees/acre
MY 5: ≥260 trees/acre (7 ft. tall)
MY 7: ≥210 trees/acre (10 ft. tall)
Protect aquatic resources
in perpetuity
Visual assessment of
established fencing and
conservation signage:
Performed at least
semiannually
(indirect measurement)
Inspect fencing and signage.
Identify and document any
damaged or missing fencing
and/or signs

Cowford Mitigation Plan 37
October 2020
Project #100095

10 ADAPTIVE MANAGEMENT PLAN
In the event the mitigation project or a specific component of the mitigation project 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. Additionally, routine
maintenance activities for the Project are outlined in Appendix F.

Cowford Mitigation Plan 38
October 2020
Project #100095

11 LONG-TERM MANAGEMENT PLAN
The Project will be transferred to the NCDEQ Stewardship Program (or 3rd party if approved). This party
shall serve as conservation easement holder and long-term steward for the property and will conduct
periodic inspection of the site to ensure that restrictions required in the conservation easement are upheld.
Funding will be supplied by the responsible party on a yearly basis until such time an endowment is
established. The NCDEQ Stewardship Program is developing an endowment system within the
nonreverting, interest‐bearing Conservation Lands Conservation Fund Account. The use of funds from the
Endowment Account will be governed by North Carolina General Statute GS 113A‐232(d)(3). Interest
gained by the endowment fund may be used for the purpose of stewardship, monitoring, stewardship
administration, and land transaction costs, if applicable.

Cowford Mitigation Plan 39
October 2020
Project #100095

12 REFERENCES

Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification of Wetlands and Deepwater
Habitats of the United States. U.S. Fish and Wildlife Service, Office of Biological Services,
FWS/OBS-79/31. U.S. Department of the Interior, Washington, DC.

Dalrymple, T. 1960. Flood Frequency Analyses. U.S. Geological Survey Water Supply Paper 1543-A.

Doll, B.A., A.D. Dobbins, J. Spooner, D.R. Clinton and D.A. Bidelspach. (2003). Hydraulic Geometry
Relationships for Rural North Carolina Coastal Plain Streams. NC Stream Restoration Institute,
Report to N.C. Division of Water Quality for 319 Grant Project No. EW20011.

Environmental Laboratory. 1987. U.S. Army Corps of Engineers Wetlands Delineation Manual, Technical
Report Y-87-1. U.S. Army Engineer Waterways Experiment Station, Vicksburg, Mississippi.

Fischenich, C. 2001. ‘‘Stability thresholds for stream restoration materials.’’ ERDC Technical Note No.
EMRRP-SR-29, U.S. Army Engineer Research and Development Center, Vicksburg, Miss.

Fischenich, J.C., 2006. Functional Objectives for Stream Restoration, EMRRP Technical Notes Collection
(ERDC TN-EMRRP-SR-52), US Army Engineer Research and Development Center, Vicksburg,
Mississippi. (available online at http://el.erdc.usace.army.mil/elpubs/pdf/sr52.pdf)

Griffith, G.E., J.M.Omernik, J.A. Comstock, M.P. Schafale, W.H.McNab, D.R.Lenat, T.F.MacPherson,
J.B. Glover, and V.B. Shelburne. 2002. Ecoregions of North Carolina and South Carolina, (color
Poster with map, descriptive text, summary tables, and photographs): Reston, Virginia, U.S.
Geological Survey (map scale 1:1,500,000).

Harman, W., R. Starr, M. Carter, K. Tweedy, M. Clemmons, K. Suggs, C. Miller. 2012. A Function-Based
Framework for Stream Assessment and Restoration Projects. US Environmental Protection
Agency, Office of Wetlands, Oceans, and Watersheds, Washington, DC EPA 843-K-12-006.

NCDENR 2012a. “Water Quality Stream Classifications for Streams in North Carolina.” Water Quality
http://portal.ncdenr.org/web/wq/home. (February 2012).

NCDENR 2012b. “2012 North Carolina 303(d) Lists -Category 5.” Water Quality Section.
http://portal.ncdenr.org/web/wq/home. (August 2012).

NCDWQ (North Carolina Division of Water Quality). 2011. A Guide to Surface Freshwater Classifications
in North Carolina. Raleigh. http://portal.ncdenr.org/c/document_library/
get_file?p_l_id=1169848&folderId=2209568&name=DLFE-35732.pdf; accessed March 2020.

North Carolina Division of Mitigation Services (NCDMS). “White Oak River Basin Restoration Priorities
2010.

North Carolina Geological Survey, 1985, Geologic map of North Carolina: North Carolina Geological
Survey, General Geologic Map , scale 1:500000.

Radford, A.E., H.E. Ahles and F.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. The
University of North Carolina Press, Chapel Hill, North Carolina.

Cowford Mitigation Plan 40
October 2020
Project #100095

Rosgen, D. (1996), Applied River Morphology, 2nd edition, Wildland Hydrology, Pagosa Springs, CO

Schafale, M.P. 2012. Guide to the Natural Communities of North Carolina, Fourth Approximation. North
Carolina Natural Heritage Program, Division of Parks and Recreation, NCDENR, Raleigh, NC.

Stanturf, J. A., et al. “Recognizing and Overcoming Difficult Site Conditions for Afforestation of
Bottomland Hardwoods.” Ecological Restoration, vol. 22, no. 3, Jan. 2004, pp. 183–193.

Sweet, W. V. and Geratz, J. W. 2003. Bankfull Hydraulic Geometry Relationships And Recurrence
Intervals For North Carolina's Coastal Plain. JAWRA Journal of the American Water Resources
Association, 39: 861–871.

United States Army Corps of Engineers (USACE). 2003. April 2003 NC Stream Mitigation Guidelines.

USACE. 2005. Regulatory Guidance Letter; SUBJECT: Ordinary High Water Mark Identification. No.
05-05.

USACE. 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Atlantic and
Gulf Coastal Plain Region (Version 2.0), ed. J. S. Wakeley, R. W. Lichvar, and C. V. Noble.
ERDC/EL TR-10-20. Vicksburg, MS: U.S. Army Engineer Research and Development Center.

USACE. 2016. Wilmington District Stream and Wetland Compensatory Mitigation Update.

USACE. 2007. INFORMATION REGARDING STREAM RESTORATOIN With Emphasis on the
Coastal Plain (Version 2)

USDA NRCS. 1994. Soil Survey of Onslow County, North Carolina.

USDA NRCS. n.d. Water Erosion (RUSLE2). Retrieved from
https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/technical/tools/rusle2/

USDA NRCS. n.d. Web Soil Survey; http://websoilsurvey.nrcs.usda.gov (January 2020).

USDA NRCS. 2018. Field Indicators of Hydric Soils in the United States, Version 8.2. L.M. Vasilas, G.W.
Hurt, and J.F Berkowtiz (eds.). USDA, NRCS, in cooperation with the National Technical
Committee for Hydric Soils.

United States Fish and Wildlife Service. “Threatened and Endangered Species in North Carolina.” North
Carolina Ecological Services. http://www.fws.gov/raleigh/. (February 2020).

Wilcock, Peter; Pitlick, John; Cui, Yantao. 2009. Sediment transport primer: estimating bed-material
transport in gravel-bed rivers. Gen. Tech. Rep. RMRS-GTR-226. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research Station. 78 p.
0 2,0001,000
Feet
Figure 1 - Project Vicinity
CowfordMitigation Project
Onslow County, North C arolina
Legend
Proposed Easem ent
White Oak River Basin - 03030001
TLW - 03030001010010
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Cowford MitigationProject
34.9233, -7 7.5 917
0 2,0001,000
Feet
Figure 2 - USGS
Richlands (1981)
CowfordMitigation Project
Onslow County, North Carolina
Legend
Proposed Easem ent
KJ1-A - 115 ac
KJ1-B - 181 ac
KJ1-C - 238 ac
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P
P
JONES KENNETH W442201293936
0 600300
Feet
Figure 3 - Landowner Parcel
CowfordMitigation Project
Onslow County, North Carolina
Legend
Proposed Easement
Project Parcel
P Parking Spot
Parcel Access
Parcel
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0 600300
Feet
Figure 4 - Land-use
CowfordMitigation Project
Onslow County, North Carolina
Legend
Proposed Easement
Drainage Area
Landuse
Row Crop - 75%
Woods - 22%
Residential - 3.3%
Impervious Surface - 0.06%
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St
Ra
NoA
NoB
Mk
Wo
On
Ra
NoA
On
Ra
On
Ly
GoA
CrC
Pn
Wo
GoA
GpB
On
CrC
Pn
GoA
NoB
W
NoB
Pn
NoB
NoB
0 600300
Feet
Figure 5 - Mapped Soils
CowfordMitigation Project
Onslow County, North Carolina
Legend
Proposed Easement
Hydric (100%)
Predominantly Hydric (66-99%)
Predominantly Hydric (33-65%)
Predominantly Nonhydric (1-32%)
Nonhydric (0%)
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Map Unit Symbol Map Unit Name
GoA Goldsboro fi ne sandy loam, 0% to 2% sl ope s
NoA Norfol k l oamy fi ne sand, 0% to 2% slopes
NoB Norfol k l oamy fi ne sand, 2% to 6% slopes
On Onslow loamy fi ne sand
Ra Rains fine sandy l oam, 0% to 2% slopes
St Stalli ngs loamy fi ne sand
Document Path: R:\Resgis\dropboxgis\projects\NC\Cowford\MXD\4_Mitigation Plan\Figure 7 - Historical Imagery - Cowford.mxd1950
1982 2010
Legend
Proposed Easment
Figure 6 - Historic Imagery
CowfordMitigation Project
Onslow County, North Carolina
©Date: 8/24/2020
Checked by: MDE01,000500
Feet
1 inch = 1,000 feet
1977
Source: USGS Earth Explorer
Source: NC OneMap
Source: USGS Earth Explorer
Source: USGS Earth Explorer
Drawn by: GDS
K J 1 -C
K J1-A
KJ1-B
PFO4B
PFO1/4A
PFO3/4Bd
PFO1A
PUBHh
0 600300
Feet
Figure 7 - Existing Conditions
CowfordMitigation Project
Onslow County, North C arolina
Legend
Proposed Easem ent
Expired FSA CRP Land (6.56 ac)
Hydric Soil Layer
NWI Wetlands (USFWS 10/29/2018)
FE MA Zone AE (None)
Stream Determ ination
Intermittent
6 6 Existing D itches
Existing D rain Tile
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Ex isting C ros sing
S
wa
l
e
BS
wale A
WA
KJ1-B KJ1-A
K J 1 -C
0 600300
Feet
Figure 8 - Conceptual
CowfordMitigation Project
Onslow County, North Carolina
Legend
Proposal Easement (17.20 ac)
Mitigation Approach
Re-establishment
Restoration
Restoration (HWV)
Project Swale
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Relocate Culvert Crossing
Add Crossing
Remove ExistingCrossing Remove seven DrainTiles
Proposed Treatm entPool
Proposed ESP
Reach Mitigation Type Proposed Length (LF)Mitiation Ratio SMUs
KJ1-A Res toration (HWV)*923 1:1 913.000
KJ1-B Res toration 852 1:1 852.000
KJ1-C Res toration 1,572 1:1 1,572.000
3,347 3,337.000
-124.432
382.875
3,595.443
Proposed Wetland Mitigation Type Total Acres Mitigation Ratio W MUs
WA Re-es tablis hm ent 2.991 1:1 2.9912.991 2.991
Cowford Wetland Credits
Total
Total
Total Adjusted SMUs
Cowford Project Credits
**Credit Loss in Required Buffer
**Credit Gain for Additional Buffer
**Stream Credit adjustments for additional buffer were not calculated on any HWV reach (USACE, 2018)
*Headwater valley restoration length is calculated from valley length
KJ1-C
KJ1-B
©
0 400200
Feet
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Cowford MitigationProject
Onslow County,North Carolina
1 in = 400 feet
KJ1-C
KJ1-B
Ideal Buffers Actual Buffers
Legend
Proposed Easement
Ineligible Area
Buffer Width Zone
0-15 feet
16-20 feet
21-25 feet
26-30 feet
31-35 feet
36-40 feet
41-45 feet
46-50 feet
51-75 feet
76-100 feet
101-125 feet
126-150 feet
Project StreamBuffer Zones less than 15 feet >15 to 20 feet >20 to 25 feet >25 to 30 feet >30 to 35 feet >35 to 40 feet >40 to 45 feet >45 to 50 feet >50 to 75 feet >75 to 100 feet >100 to 125 feet >125 to 150 feetMax Possible Buffer (square fe et)100,110 33,370 33,370 33,370 33,370 33,370 33,370 33,370 166,850 166,850 166,850 166,850Ideal Buffer (square fe et)73,975 24,360 24,219 24,210 24,217 23,943 23,857 23,838 120,047 122,584 125,658 128,943Actual Buffer (square fe et)72,568 23,412 23,029 22,777 22,582 22,430 22,327 22,259 90,184 91,047 52,051 27,220Zone Multiplie r 50%10%10%10%5%5%5%5%7%5%4%4%Buffe r Cre dit Equivale nt 1,669 334 334 334 167 167 167 167 234 167 133 133Percent of Ide al Buffe r 98%96%95%94%93%94%94%93%75%74%41%21%Credit Adjustm e nt -32 -13 -16 -20 -11 -11 -11 -11 175 124 55 28
Total Base line Credit
3,337.000
Buffe r Width Zone (fee t from Ordinary High Wate r Mark)
Cre dit Loss in Re quire d Buffe r
-124.432
Credit Gain for Additional Buffer
382.875
Ne t Change inCredit from Buffers
258.443
Total Credit
3,595.443
t
t
t
v
ª
Esri, HERE, Garmin, (c) OpenStreetMap contributors
©
0 300150
Feet
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Figure 10 - Monitoring Plan
CowfordMitigation Project
Onslow County, North Carolina
Note: There will be 10 fixed vegetation plots, and 4 will berandomly placed each monitoring year and reported to theIRT. Monitoring device locations are proposed and are subjectto change based on as-built conditions.
Legend
Proposed Easement -
17.20 ac
Proposed Wetland
Planted Area - (16.35 ac)
Monitoring Devices
Fixed Plot
Random Plot
Proposed Stream
HWV Restoration Stream
v Flow Gauge
ªStage Recorder
t Wetland Well
Cross Section
Fixed image locations will exist at each cross section,each vegetation plot, each stage recorder and each flow gauge.
0 10050
Feet
Figure 11 - 1YR Innudation Map
CowfordMitigation Project
Onslow County, North Carolina
Legend
Proposed Easement
Proposed TOB
Proposed Wetland
Depth
2.00 ft
1.90 ft
1.80 ft
1.70 ft
1.60 ft
1.50 ft
1.40 ft
1.30 ft
1.20 ft
1.10 ft
1.00 ft
0.90 ft
0.80 ft
0.70 ft
0.60 ft
0.50 ft
0.40 ft
0.30 ft
0.20 ft
0.10 ft
0.00
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0 10050
Feet
Figure 12 - 10YR Innudation Map
CowfordMitigation Project
Onslow County, North Carolina
Legend
Proposed Easement
Proposed TOB
Proposed Wetland
Depth
3.50 ft
3.40 ft
3.20 ft
3.00 ft
2.80 ft
2.70 ft
2.50 ft
2.30 ft
2.20 ft
2.00 ft
1.80 ft
1.60 ft
1.40 ft
1.30 ft
1.10 ft
0.90 ft
0.70 ft
0.50 ft
0.40 ft
0.20 ft
0.00
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ID#* 20190495 Version* 1
Select Reviewer:*
Erin Davis
Initial Review Completed Date 11/02/2020
Mitigation Project Submittal-10/30/2020
Is this a Prospectus, Technical Proposal or a New Site?* O Yes a No
Type of Mitigation Project:*
rJ Stream rJ Wetlands [Buffer ❑ Nutrient Offset
(Select all that apply)
Project Contact Information
Contact Name:*
Lindsay Crocker
Project Information
..................................................................................................................................................................
ID#:* 20190495
Existing IDI
Project Type: r DMS r Mitigation Bank
Project Name: Cowford
County: Onslow
Document Information
Email Address:*
[e-mail]
Version: * 1
Existing Version
Mitigation Document Type:*
Mitigation Plans
File Upload: Cowford_100095_FDMP 2020.pdf 19.21 MB
Rease upload only one PDF of the complete file that needs to be subrritted...
Signature
Print Name:* Lindsay Crocker
Signature:*