20140705 Ver 1_Final Mitigation Plan_20160718

FINAL MITIGATION PLAN
The Selma Mill Stream Mitigation Site
Johnston County, North Carolina
Neuse River Basin
CU 03020201
Prepared for:
Resource
Environmental
Solutions
EBX-Neuse I, LLC,
an entity of Resource Environmental Solutions
302 Jefferson Street, Suite 110
Raleigh, NC 27605
919-829-9909
April 2016
Prepared by:
rDICKSON
community in}rosiructur® consuifanls
WK Dickson & Co., Inc.
720 Corporate Center Drive
Raleigh, NC 27607
919-782-0495

EXECUTIVE SUMMARY
The Selma Mill Stream Mitigation Site is located within a watershed dominated by agricultural and
residential land use in Johnston County, North Carolina, immediately North of Selma. The project
streams proposed for restoration have been significantly impacted by channelization and agricultural
practices. The project will involve the restoration and protection of streams in the Neuse River
watershed. The purpose of this mitigation site is to restore and enhance a stream/wetland complex
located within the Neuse River Basin. The Selma Mill Stream Mitigation Site has been designed in
concurrence with the Selma Mill Riparian Buffer and Nutrient Offset Mitigation Bank.
The project lies within USGS Hydrologic Unit 03020201100050 (USGS, 2012) and within the North
Carolina Division of Water Quality (NCDWQ) Neuse River Sub -basin 03-04-02 (NCDENR, 2005).
The 2010 Neuse River Basin Plan identified HUC 03020201100050 as a Targeted Local Watershed.
The watershed is characterized by 37 percent agricultural land use area, including thirteen animal
operations. Approximately 52 percent of the area is developed with roughly 35 percent impervious
total. High priority projects should address buffer and wetland restoration needs and stormwater
management to offset projected increases in runoff related to development and expansion.
The proposed Selma Mill Stream mitigation Site is located within the southern portion of the TLW and
includes streams that discharge into Mill Creek. Due to its location and proposed improvements, the
site will provide numerous ecological and water quality benefits within the Neuse River Basin. While
many of these benefits are limited to the project area, others, such as pollutant removal and improved
aquatic and terrestrial habitat, have more far-reaching effects.
The Selma Mill Site consists of stream restoration on tributaries that drain directly to Mill Creek. The
project presents 6,881 linear feet of Stream Restoration generating 7,409 Stream Mitigation Units
(SMU). A combination of Priority 1 and Priority 2 restoration is proposed for Reaches A and B and
Headwater Valley Restoration is proposed for Reach C. Benefits include the storage of excess water
during flood events, preventing erosion of stream banks, reducing in -stream sedimentation, and nutrient
reductions. SMU totals were adjusted using the most recent non-standard buffer width guidance
documents.
The site consists of agricultural fields, cattle pastures and wooded areas. The total easement area is 34.2
acres. The wooded areas along the easement corridor designated for restoration activities are classified
as mixed pines and hardwoods. Invasive species are present throughout the wooded areas. Channels
proposed for restoration are degraded to a point where they no longer access their floodplain, lack
riparian buffers, allow livestock access, and aquatic life is not supported. Little aquatic habitat is
available to support aquatic life, and the riparian buffers are not maximizing their potential to filter
nutrients.
The objective for this mitigation site is to restore and design natural waterways through stream/wetland
complexes with appropriate cross -sectional dimension and slope that will provide function and meet
the appropriate success criteria for the existing streams. Accomplishing this objective entails the
restoration of natural stream characteristics, such as stable cross sections, planform, and in -stream
habitat. The floodplain areas will be hydrologically reconnected to the channels where feasible to
provide natural exchange and storage during flooding events. The design will be based on reference
conditions, USACE guidance (USACE, 2005), and criteria that are developed during this project to
achieve success. Additional site objectives, such as restoring the riparian buffer with native vegetation,
ensuring hydraulic stability, and eradicating invasive species, are listed in Section 1.
Selma Mill Mitigation Plan ii April 2016

The design approach for the Selma Mill Site is to combine the analog method of natural channel design
with analytical methods to evaluate stream flows and hydraulic performance of the channel and
floodplain. The analog method involves the use of a "template" stream adjacent to, nearby, or
previously in the same location as the design reach. The template parameters of the analog reach are
replicated to create the features of the design reach. The analog approach is useful when watershed and
boundary conditions are similar between the design and analog reaches (Skidmore, et al., 2001).
Hydraulic geometry was developed using analytical methods in an effort to identify the design
discharge.
Priority Level 2 restoration is proposed on Reaches Al, A2, B1, B2, and B3. Priority 1 Restoration is
proposed for Reach A2 below the confluence with Reach B. For the majority of the restoration reaches,
the channel will be rerouted from its current location to adjacent natural valley features. The headwater
valley restoration approach is proposed along Reach C. The existing ditch will be plugged and then
backfilled to the extent possible such that cut and fill is balanced along the reach.
The restoration approach on Reaches A and B includes relocating the channel to either side of its current
location within the natural valley. The existing channels will be plugged and filled to prevent continued
flow within the ditches. By rerouting the channel and constructing floodplain benches, the design will
allow the channel frequent access to its floodplain and the opportunity for creating small depressional
areas within the buffer to enhance habitat for wildlife and aquatic organisms. Relocating these channels
will not impact any forested areas because the buffer along the restoration reaches is currently used for
agriculture and disturbed.
After completion of all construction and planting activities, the site will be monitored on a regular basis
and a physical inspection of the site will be conducted at a minimum of twice per year throughout the
seven-year post -construction monitoring period, or until performance standards are met. These site
inspections will identify site components and features that require routine maintenance. The measure
of stream restoration success will be documented by bankfull flows and no change in stream channel
classification. Sand bed channels are dynamic and minor adjustments to dimension and profile are
expected. The measure of vegetative success for the site will be the survival of at least 210 seven-year
old planted trees per acre with an average height of 10 feet at the end of year seven of the monitoring
period.
Upon approval for closeout by the Interagency Review Team (IRT), the site will be transferred to the
North Carolina Wildlife Habitat Foundation (NCWHF). The NCWHF will be responsible for periodic
inspection of the site to ensure that restrictions required in the Conservation Easement or the deed
restriction document(s) are upheld. Endowment funds required to uphold easement and deed
restrictions will be negotiated prior to site transfer to the responsible party.
Selma Mill Mitigation Plan iii April 2016

TABLE OF CONTENTS
1 RESTORATION PROJECT GOALS AND OBJECTIVES..........................................................
7
2 SITE SELECTION.........................................................................................................................
7
2.1 Directions to Site....................................................................................................................
7
2.2 Site Selection..........................................................................................................................
7
2.2.1 USGS Hydrologic Unit Code and NC DWQ River Basin .............................................
7
2.2.2 Project Components........................................................................................................
8
2.2.3 Historical Land Use and Development Trends...............................................................
8
2.3 Soil Survey.............................................................................................................................
9
2.4 Site Photographs..................................................................................................................
11
3 SITE PROTECTION INSTRUMENT.........................................................................................
14
3.1 Site Protection Instrument(s) Summary Information...........................................................
14
4 BASELINE INFORMATION......................................................................................................
15
4.1 Watershed Summary Information........................................................................................
15
4.1.1 Drainage Area...............................................................................................................15
4.1.2 Surface Water Classification........................................................................................15
4.1.3 Endangered/Threatened Species...................................................................................15
4.1.4 Cultural Resources........................................................................................................16
4.2 Reach Summary Information...............................................................................................
17
4.2.1 Channel Classification..................................................................................................18
4.2.2 Discharge......................................................................................................................19
4.2.3 Channel Morphology....................................................................................................19
4.2.4 Channel Stability Assessment......................................................................................
20
4.2.5 Bankfull Verification....................................................................................................21
4.2.6 Vegetation.....................................................................................................................21
4.2.7 Quantitative Habitat Assessment..................................................................................22
4.3 Wetland Summary Information............................................................................................
24
4.3.1 Existing Wetlands.........................................................................................................24
4.4 Regulatory Considerations and Potential Constraints..........................................................
26
4.4.1 Property Ownership, Boundary, and Utilities...............................................................26
4.4.2 Site Access....................................................................................................................
26
4.4.3 FEMA/ Hydrologic Trespass........................................................................................26
5 DETERMINATION OF CREDITS.............................................................................................
27
6 CREDIT RELEASE SCHEDULE...............................................................................................
28
6.1 Initial Allocation of Released Credits..................................................................................
29
6.2 Subsequent Credit Releases..................................................................................................
29
7 FUNCTIONAL RATIONALE.....................................................................................................
29
8 MITIGATION WORK PLAN.....................................................................................................
31
8.1 Reference Stream Studies.....................................................................................................
31
8.1.1 Target Reference Conditions........................................................................................
31
8.2 Design Parameters................................................................................................................
35
8.2.1 Stream Restoration Approach.......................................................................................
35
8.2.2 Natural Plant Community Restoration.........................................................................40
8.2.3 Best Management Practices (BMPs)............................................................................
41
8.2.4 Soil Restoration............................................................................................................
41
8.3 Data Analysis.......................................................................................................................
42
8.3.1 Stream Data Analysis...................................................................................................
42
8.3.2 Mitigation Summary.....................................................................................................45
9 MAINTENANCE PLAN.............................................................................................................
47
10 PERFORMANCE STANDARDS................................................................................................48
Selma Mill Mitigation Plan iv April 2016

10.1 Stream Restoration Success Criteria.....................................................................................
48
10.1.1 Bankfull Events............................................................................................................
48
10.1.2 Cross Sections..............................................................................................................48
10.1.3 Digital Image Stations..................................................................................................
48
10.1.4 Surface Flow.................................................................................................................48
10.2 Vegetation Success Criteria..................................................................................................
48
11 MONITORING REQUIREMENTS............................................................................................
49
11.1 As -Built Survey....................................................................................................................
49
11.2 Visual Monitoring................................................................................................................
50
11.3 Cross Sections......................................................................................................................
50
11.4 Surface Flow.........................................................................................................................
50
11.5 Vegetative Success Criteria..................................................................................................
50
11.6 Scheduling/Reporting...........................................................................................................
50
11.7 Adaptive Management...........................................................Error!
Bookmark not defined.
12 LONG-TERM MANAGEMENT PLAN.....................................................................................
52
13 ADAPTIVE MANAGEMENT PLAN.........................................................................................
53
14 FINANCIAL ASSURANCES......................................................................................................
54
15 OTHER INFORMATION............................................................................................................
55
15.1 References............................................................................................................................
55
List of Tables
Table 1.
Selma Mill Site Project Components - Stream Mitigation......................................................
8
Table 2.
Historical Land Use and Development Trends........................................................................
9
Table3.
Mapped Soil Series.................................................................................................................10
Table 4.
Project Parcel and Landowner Information............................................................................14
Table 5.
Project Watershed Summary Information..............................................................................15
Table 6.
Federally Protected Species in Johnston County....................................................................16
Table 7.
Summary of Existing Channel Characteristics.......................................................................18
Table 8.
Reach Summary Information.................................................................................................18
Table 9.
Channel Stability Assessment Results....................................................................................
20
Table 10.
Natural Community Summary.............................................................................................
22
Table 11.
Average volume (cubic inches) of SWD structures used in the design reach ......................
23
Table 13.
Regulatory Considerations...................................................................................................
27
Table14.
Mitigation Credits.................................................................................................................28
Table 15.
Credit Release Schedule.......................................................................................................
28
Table 16.
Functional Benefits and Improvements................................................................................31
Table 17.
Tree Communities at the Reference Reach for Selma Mill Site ...........................................
34
Table 18.
Scaling Factors for Sizing Planform Design Parameters......................................................
39
Table19.
Proposed Plant List...............................................................................................................
40
Table 20.
Peak Flow Comparison........................................................................................................
43
Table 21.
Stable Channel Design Output.............................................................................................
44
Table 22.
Comparison of Allowable and Proposed Shear Stresses......................................................
45
Table 23.
Comparison of Allowable and Proposed Velocities.............................................................
45
Table24.
Maintenance Plan .................................................................................................................
47
Table 25.
Monitoring Requirements.....................................................................................................49
Selma Mill Mitigation Plan v April 2016

List of Figures
Figure 1- Vicinity Map
Figure 2- USGS Topographic Map
Figure 3- National Wetlands Inventory Map
Figure 4- 1980 Historical Conditions Map
Figure 5- Soils Map
Figure 6- FEMA Map
Figure 7- Current Conditions Map
Figure 8- LIDAR Map
Figure 9- Landowner Map
Figure 10- Conceptual Plan Map
Figure 11- Non -Standard Buffer Width Calculations
Figure 12- Watershed Landuse Map
Appendices
Appendix A
—Site Protection Instrument(s)
Appendix B
— Baseline Information Data
Appendix C
— Mitigation Work Plan Data and Analyses
Appendix D
— Site Protection Instruments
Appendix E
—Design Plan Sheets (I I"x17")
Selma Mill Mitigation Plan vi April 2016

I RESTORATION PROJECT GOALS AND OBJECTIVES
The 2010 Neuse River Basin River Basin Restoration Priorities (RBRP) identified several restoration
needs for the entire Neuse River Basin, as well as for HUC 03020201, specifically. The Selma Mill
Stream Mitigation Site ("Site") was identified as a stream restoration opportunity to improve water
quality, habitat, and hydrology within the Neuse 01 River Basin.
The project goals address stressors identified in the TLW and include the following:
• Nutrient removal,
• Sediment removal,
• Invasive species removal,
• Filtration of runoff, and
• Improved aquatic and terrestrial habitat.
The project goals will be addressed through the following project objectives:
• Exclusion of livestock,
• Elimination and control of exotic invasive species,
• Restoration of forested riparian stream buffers,
• Stabilization of eroding stream banks due to lack of vegetation and livestock hoof shear,
• Addition of large woody debris, such as log vanes, log weirs, root wads,
• Preservation and enhancement of hydrology in existing riparian wetland seeps, and
• Restoration of appropriate pattern, dimension, and profile in stream channels.
The proposed Site is located within the downstream end of HUC 03020201 and includes streams that
discharge into Mill Creek. Due to its location and proposed improvements, the Site will provide
numerous ecological and water quality benefits within the Neuse River Basin. While many of these
benefits are limited to the project area, others, such as pollutant removal and improved aquatic and
terrestrial habitat, have more far-reaching effects. Many of the project design goals and objectives,
including restoration of riparian buffers to filter runoff from agricultural operations and improve
terrestrial habitat, and construction of in -stream structures to improve habitat diversity, will address the
degraded water quality and nutrient input from farming that were identified as major watershed
stressors in the 2010 Neuse RBRP.
2 SITE SELECTION
2.1 Directions to Site
The Selma Mill Mitigation Bank is located in Johnston County immediately north of Selma, NC
(Figure 1). The latitude and longitude forthe site is 35.547353 °N and-78.282503 °W. The site extends
approximately 2,300 feet north on the west side of NC HWY 96 beginning immediately north of W
Chestnut Street. A tributary crosses NC HWY 96 approximately 1,900 feet north of W Chestnut Street
and extends approximately 1,600 feet west.
2.2 Site Selection
2.2.1 USGS Hydrologic Unit Code and NC DWQ River Basin
The Site is located in the Neuse River Basin within Cataloging Unit 03020201 (NCDWQ sub -basin 03-
04-02). The Site is located within the Neuse River Basin (8-digit USGS HUC 03020201, 14-digit USGS
HUC 03020201100050 (USGS, 2012) and the NCDWQ Cape Fear 03-04-02 sub -basin (NCDWQ,
Selma Mill Mitigation Plan 7 April 2016

2002) (Figure 2). This 14-digit HUC is identified as a Targeted Local Watershed (TLW) in the North
Carolina Division of Mitigation Services (NCDMS) 2010 Neuse River Basin Restoration Priorites
(RBRPs).
2.2.2 Project Components
The project area is comprised of a single easement area along three tributaries that flow into Mill Creek.
The easement is separated by a crossing at NC HWY 96. The western portion of the project originates
near the intersection of Hwy 96 W Chestnut Street and includes Reaches A1, A2, and B3. The eastern
portion of the project is located in an agricultural field to the east of NC HWY 96. This area includes
Reaches B1, B2, and C. The stream mitigation components are summarized in (Table 1; Figures 10 &
11).
Table 1. Selma Mill Site Project Components — Stream Mitigation
Mitigation
Stationing
Existing
Proposed Prop
Mitigation
Base
Adjusted
Reach
Type*
(Proposed)
Length
Length
Ratio
SMUs**
SMUs***
(LF)
(LF)
A
P2 Restoration
0+61 to 19+42
1,514
1,881
1 : 1
1,881
2,068
A
PI/P2 Restoration
19+72 to 27+30
630
758
1 : 1
758
821
A
P1 Restoration
27+60 to 34+45
571
685
1:1
685
801
B
P2 Restoration
1+94 to 10+39
741
845
1 : 1
845
903
B
P1/P2 Restoration
10+72 to 22+95
1,062
1,223
1 : 1
1,223
1,334
B
P2 Restoration
23+55 to 28+59
405
504
1 : 1
504
503
C HWV Restoration 3+00 to 8+59 584 559 1 : 1 559 559
C HWV Restoration 8+89 to 13+15 294 426 1 : 1 420 420
Total 5,801 6,881 6,875 7,409
*P1 = Priority 1; P2 = Priority 2; HWV- Headwater Valley
**Base SMUs for Headwater Valley Restoration is based on valley length and not proposed channel length
**See Appendix A- Figure 11 for SMU adjustments based on non-standard buffer widths.
2.2.3 Historical Land Use and Development Trends
Aerial imagery indicates that the subject site has been used extensively for agricultural purposes, and
that the location of the streams has not changed in over 50 years (Figure 4 and Figure 7). In the late
1990s the upstream area surrounding Reach A, which was originally wooded, was cleared. Little has
changed since 1998 in regards to the development of the project site and nearby surrounding property.
The area remains in an agricultural community with some neighboring property forested. Several
watershed characteristics, such as groundwater, vegetation, surface drainage, and potentially soil
parameters have been modified. Soil structure and surface texture have been altered from intensive
agricultural operations. Historical land use and development trends on the Selma Mill Site are
summarized in Table 2.
Selma Mill Mitigation Plan 8 April 2016

Table 2. Historical Land Use and Development Trends
Date Land Use and Development Observations*
1950 Conditions consist of agricultural fields throughout the project area, with the
exception of some wooded riparian areas on the target parcels.
1980 Land use conditions have changed very little.
1993-1998 Forested area along upstream area of Reach A cleared for pasture
1998-2010 Land use conditions have changed very little.
2010 Depicts current site conditions.
* Observations based on aerial imagery
2.3 Soil Survey
The Selma Mill Stream Mitigation Site is located in the Coastal Plain Physiographic Province. The
soils within the Coastal Plain region of Johnston County formed in sediments deposited several million
years ago by the oceans and streams. The flood plains along the Neuse River consist of relatively recent
deposits of sediments that are not as highly weathered as sediments in the Coastal Plain Region. Much
of the county is well drained; however, several areas are poorly drained. The Site is shown to straddle
two soil associations: the Rains -Goldsboro -Lynchburg and the Norfolk -Goldsboro -Rains.
The Rains -Goldsboro -Lynchburg association is found in broad, level interstream areas that are
relatively undissected by streams. The major soils are Rains, Goldsboro, and Lynchburg. The soils
range from poorly to moderately well -drained. The soils are well suited to cropland. The wetness is the
main limitation affecting agricultural uses on the Rains and Lynchburg soils. The Norfolk -Goldsboro -
Rains association is found along the edges of broad interstream areas or on moderately broad ridges in
the uplands. The major soils are Norfolk, Goldsboro, and Rains. The Norfolk and Goldsboro soils are
moderately well to well drained and are well suited to most crops and urban uses in the area. The Rains
soils are poorly drained. All soils are well suited for woodlands and most of the crops grown in the
county.
The Johnston County Soil Survey shows eight mapping units across the site. Map units include five
soil series (Figure 5). The upland soils found in this area of the county formed in sandy sediments from
marine and fluviomarine deposits or loamy alluvium. The upland soils at this site are on a river terrace
above the active floodplain. The soil series found on the site are described below and summarized in
Table 3.
Goldsboro sandy loam. This is a very deep, moderately drained soil found on uplands of the Coastal
Plain. Soils formed in fluviomarine deposits, and generally occur on slopes between 0-10%. Runoff is
negligible to medium and permeability is moderate. Major uses are cropland. Goldsboro sandy loams
occur along flats and terraces along the edges of the proposed conservation easement.
Lynchburg sandy loam. This is a very deep, somewhat poorly drained soil that occurs on terraces and
flats of the Coastal Plain. They formed in fluviomarine deposits, and generally occur on slopes between
0-5%. Runoff is negligible and permeability is moderate. Major uses are cropland, pasture, and forest.
Lynchburg sandy loam is the predominant soil throughout the project area occurring along the
streambanks and floodplains in the easement.
Selma Mill Mitigation Plan 9 Aphl 2016

Norfolk loamy sand. This is a very deep, well -drained soil that occurs on uplands of the Coastal Plain.
They formed in fluviomarine deposits, and generally occur on slopes between 0-10%. Runoff is
negligible to medium and permeability is moderate to high. This soil type is mostly cleared and used
for cropland. Norfolk loamy sands occur along the interstream areas between Reach A and B in the
target parcels of the proposed conservation easement.
Norfolk -Urban land complex. This unit consists of the well -drained Norfolk soils and urban land.
The unit is about 50% Norfolk soil and 30% urban land. Norfolk -urban land complex occurs along the
residential areas to the east of Reach A.
Rains sandy loam. This is a very deep, poorly drained soil that occurs on flats and depressions of the
Coastal Plain. They formed in fluviomarine deposits, and generally occur on slopes between 0-2 %.
Runoff is negligible and permeability is moderate. Major uses are forest and cropland. Rains sandy
loam occurs along the top of Reach B in the proposed conservation easement.
Rains -Urban land complex. This unit consists of poorly drained Rains soils and urban land in broad
upland areas on the Coastal Plain. The unit is about 55% Rains soil and 25% urban land. Rains -Urban
land complex occurs along the top of Reach A in the proposed conservation easement.
Wehadkee loam. This nearly level, poorly drained soil occurs on stream and tributary floodplains.
Most mapped areas are long and narrow, and slopes are generally 0-2%. Permeability is moderate and
the seasonally high water table is generally within 12 inches of the surface. Surface runoff is slow.
Wehadkee loam occurs at the most downstream end of the easement, near the confluence with Mill
Creek.
Table 3. Mapped Soil Series
Map
Unit
Map Unit Name
Percent
Drainage
Hydrologic
Landscape
Symbol
Hydric
Class
Soil Group
Setting
GoA
Goldsboro sandy loam
2/0 °
Moderately
B
Flats, Marine
0 — 2% slopes
well
Terraces
Ly
Lynchburg sandy loam
2%
Somewhat
C
Flats, Marine
poorly
Terraces
NoA
Norfolk loamy sand, 0
5%
Well
B
Flats, Marine
— 2% slopes
Terraces
NoB
Norfolk loamy sand, 2
2%
Well
B
Floodplains
— 6 /° slopes
NuA
Norfolk -Urban land
0/° °
Well
B
Uplands
/° complex, 0 — 3 slopes
Ra
Rains sandy loam
80%
Poorly
B/D
Flats, Marine
Terraces
Rba
Rains -Urban land
60%
Poorly
B/D
Flats, Marine
complex, 0- 2% slopes
Terraces
Wt
Wehadkee loam,
85%
Poorly
D
Depressions, Flood
frequently flooded
plains
Selma Mill Mitigation Plan 10 April 2016

2.4 Site Photographs
Facing downstream on Reach Al. 03/09/2015 Facing upstream on Reach Al. 03/09/2015
f' 1 l tip' ! • '
Slumping left bank on upper end of Reach A2. Facing downstream on lower end of Reach A2.
03/09/2015 03/09/2015
I �
L
r -
'1 r
Facing downstream on Reach B 1. 03/09/2015 Facing upstream on Reach B 1. 03/09/2015
Selma Mill Mitigation Plan 11 April 2016

MI r
fy
771.
Al
Facing upstream on Reach B2. 03/09/2015
Facing downstream on Reach B2. 03/09/2015
LJO
Facing upstream on Reach B3. 03/09/2015
Facing downstream on Reach B3. 03/09/2015
Facing downstream on Reach C. 03/09/2015
Facing upstream on Reach C. 03/09/2015
Selma Mill Mitigation Plan 12 April 2016

Y
General conditions of left bank riparian zone
General conditions Reach B2. 04/09/2014
along Reach Al and A2. 11/24/2014
s
a
General conditions of Reach A2 lower end and
General conditions of Reach B land Wetland 2
Wetland 4 (W4). 04/09/2014
(W2). 3/09/2015
General conditions of Wetland 3 (W2). 3/09/2015
Pond upstream of Reach C. 3/09/2015
Selma Mill Mitigation Plan 13 April 2016

3 SITE PROTECTION INSTRUMENT
3.1 Site Protection Instrument(s) Summary Information
The land required for the construction, management, and stewardship of this mitigation site includes
portions of the following parcels. A copy of the land protection instrument(s) is included in Appendix
A.
Table 4. Project Parcel and Landowner Information
Landowner
Pin
County
Deed Book and
Page Number
Parcel
Acreage
Protected
Acreage
HOWARD, PAUL H
261514-44-4014
Johnston
00656-0466
95.86
28.67
HOWARD, PAUL H
261514-33-0517
Johnston
00444-0216
2.19
2.45
HOWARD, PAUL H
261514-33-2842
Johnston
--
1.35
0.49
HOWARD, PAUL H
261514-33-2955
Johnston
00595- 0433
0.37
0.17
HOWARD, PAUL H
261514-34-2063
Johnston
00595- 0434
0.84
0.47
HOWARD, PAUL H
261514- 34-2163
Johnston
--
0.79
0.03
HOWARD, PAUL H
261514-34-2360
Johnston
00488-0026
1.9
0.78
EBX- NEUSE I LLC
261514-44-4614
Johnston
04534-0780
13.74
3.45
The Wilmington District Conservation Easement model template was utilized to draft the site protection
instrument. A copy of the final recorded easement is provided in Appendix A.
EBX-Neuse I, LLC (a RES entity), acting as the Bank Sponsor, will establish a Conservation Easement,
and will monitor the Site for a minimum of seven years. This Mitigation Plan provides detailed
information regarding bank operation, including long term management and annual monitoring
activities, for review and approval by the Interagency Review Team (IRT). Upon approval of the Site
by the IRT, the site will be transferred to the NCWHF. The NCWHF will be responsible for periodic
inspection of the site to ensure that restrictions required in the Conservation Easement or the deed
restriction document(s) are upheld. Endowment funds required to uphold easement and deed
restrictions will be negotiated prior to site transfer to the responsible party.
The Bank Sponsor will ensure that the Conservation Easement will allow for the implementation of an
initial monitoring phase, which will be developed during the design phase and conducted by the Bank
Sponsor. The Conservation Easement will allow for yearly monitoring and, if necessary, maintenance
of the Site during the initial monitoring phase. These activities will be conducted in accordance with
the terms and conditions of the approved Mitigation Plan for the Selma Mill Mitigation Site. The Site
will be authorized under the Neu -Con Wetland and Stream Umbrella Mitigation Bank made and entered
into by EBX-Neuse I, LLC (a RES entity), US Army Corps of Engineers, and NC Division of Water
Resources.
Selma Mill Mitigation Plan 14 April 2016

4 BASELINE INFORMATION
4.1 Watershed Summary Information
4.1.1 Drainage Area
The easement totals 34.2 acres and the project streams include three unnamed tributaries to Mill Creek.
Reach A begins at the intersection of W Chestnut Street and Hwy 96 and Reaches B and C originate in
the agricultural field to the east of Hwy 96. The total drainage area at the downstream limits of the site
is 583 acres (0.84 mi'). The land use in the site watershed is approximately 30% agricultural, 40%
residential, 10% forested, and 12% industrial/commercial.
4.1.2 Surface Water Classification
The current State classification for the Selma Mill Mitigation Site restoration reaches is undefined.
Tributaries of the site run directly into Mill Creek. Mill Creek is defined as Class WS-IV NSW
(NCDWQ 2012a). Class WS-IV waters are used as sources of water supply for drinking, culinary or
food processing purposes where a WS-1, WS-II, or WSIII classification is not feasible. These waters
are also protected for Class C uses; Class C waters are suitable for aquatic life, secondary recreation,
and agricultural usage. The NSW is a designation for nutrient sensitive waters — intended for waters
needing additional nutrient management due to being subject to excessive growth of microscopic or
macroscopic vegetation.
Table 5. Project Watershed Summary Information
Physiographic Province
Inner Coastal Plain
River Basin
Neuse
USGS Hydrologic Unit 8-digit
03020201
USGS Hydrologic Unit 14-digit
03020201100050
DWQ Sub -basin
03-04-02
Project Drainage Area (acres)
583
Percent Impervious Area
35%
4.1.3 Endangered/Threatened 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. Rare and protected
species listed for Johnston County, and any likely impacts to the species as a result of the project
construction, are discussed in the following sections.
The US Fish and Wildlife Service (USFWS) database (updated 22 September 2010) lists four
endangered species for Johnston County, North Carolina: red -cockaded woodpecker (Picoides
borealis), Tar River spinymussel (Eliptio steinstansana), dwarf wedgemussel (Alasmidonta
heterodon), and Michaux's sumac (Rhus michauxii) (Table 6). No protected species or potential habitat
for protected species was observed during preliminary site evaluations.
In addition to the USFWS database, the NC Natural Heritage Program (NHP) GIS database was
consulted to determine whether previously cataloged occurrences of protected species were mapped
within one mile of the project site. Results from NHP indicate that there are no known occurrences
within a one -mile radius of the project area. Based on initial site investigations, no impacts to federally
protected species are anticipated as a result of the proposed project.
Selma Mill Mitigation Plan 15 April 2016

WK Dickson submitted a request to USFWS for review and comments on the proposed Selma Mill
Mitigation Project on February 16, 2015 in regards to any potential impacts to threatened and
endangered species. A response from USFWS received on March 20, 2015 stated that the proposed
Project "is not likely to adversely affect any federally -listed endangered or threatened species, their
formally designated critical habitat, or species currently proposed for listing under the [Endangered
Species] Act". The USFWS did express concern that sedimentation resulting from the Project may
impact aquatic species. They recommend "that all practicable measures be taken to avoid adverse
impacts to aquatic species, including implementing... stringent sediment and erosion control measures".
The proposed site offers some potential to improve or create suitable habitat for several Federal Species
of Concern. Habitat may be improved or created for species that require riverine habitat by improving
water quality, in -stream and near -stream forage, and providing stable conditions not subject to regular
maintenance. Improved stream habitat may benefit the American eel (Anguilla rostrata). Terrestrial
habitat will be improved through the restoration and enhancement of bottomland hardwood
communities. Improved terrestrial habitat may benefit pondspice (Listea aestivalis), Cuthbert
turtlehead (Chelone cuthbertii), and Rafinesque's big -eared bat —Coastal Plain subspecies
(Corynorhinus rafinesquii marcotis).
Table 6. Federally Protected Species in Johnston County
Common Name
Scientific name
Federal
Status
Habitat
Present
Record
Status
Vertebrate:
Red -cockaded woodpecker
Picoides borealis
E
No
Current
Bald eagle
Haliaeetus leucocephalus
BGPA
Yes
Current
Invertebrate•
Tar River spinymussel
Eliptio steinstansana
E
No
Current
Dwarf wed emussel
Alasmidonta heterodon)
E
No
Current
Vascular Plant:
Michaux's Sumac Rhus Michauxii E No Current
4.1.4 Cultural Resources
Cultural resources include historic and archeological resources located in or near the project area. WK
Dickson completed a preliminary survey of cultural resources to determine potential project impacts.
No architectural structures or archeological artifacts have been observed or noted during preliminary
surveys of the site for restoration purposes. A review of the North Carolina State Historic Preservation
Office GIS Web Service database revealed that there are National Registered listings within a one -mile
radius of the proposed project area. The proposed project is located just outside the West Selma
Historic District QT1514) which contains several national listed and study listed sites. The proposed
project will not have any adverse effects to historical structures or viewsheds. In addition, the majority
of the site has historically been disturbed due to agricultural practices and channel modifications.
WK Dickson submitted a request to the NC State Historic Preservation Office (SHPO) to search records
to determine the presence of any areas of architectural, historic, or archaeological significance that may
be affected by the Selma Mill Mitigation Site on February 16, 2015.
Selma Mill Mitigation Plan 16 April 2016

4.2 Reach Summary Information
The Site is comprised of a contiguous easement area along three tributaries that flow into Mill Creek.
The easement is separated by a crossing at NC Hwy 96, one agricultural crossing, and two co -located
utility crossings. The western portion of the project originates at the intersection of Hwy 96 and West
Chestnut Street and includes Reach Al, Reach A2, and Reach B3. The eastern portion of the project
originates in the agricultural field to the east of Hwy 96 and includes Reach B 1, Reach B2, and Reach
C.
The Selma Mill stream channels include unnamed tributaries that eventually flow into Mill Creek
(Figure 2). The Selma Mill Mitigation Site is not located in a FEMA mapped floodway (Figure 6).
Invasive control and stabilization will be performed in select segments of the project. Stream
Classification Forms were completed at representative locations throughout the project area and stream
determinations were confirmed by NCDWR staff (Appendix B). Results of the preliminary data
collection are presented in Figure 7, Table 7 and Table 8. The Stream Morphology Table is included
in Appendix B.
Reach Al and A2 are oversized and incised perennial channels that are impacted by active cattle
grazing. The watershed that drains to this channel is primarily commercial and residential and runoff is
conveyed through a closed system that outfalls directly to the channel. Reach B 1 is an oversized channel
that has been historically channelized and is devoid of an intact buffer along the left bank. About 500
feet downstream, Reach Blruns through a small patch of bottomland hardwood forest where the
riparian buffer is fairly intact with hardwoods; invasive vegetation is common throughout the buffer
along this section. Reach B3 is an entrenched channel that has no intact buffer and the channel is
adjacent to a maintained residential property. Livestock freely access the channel. Reach C is an
intermittent drainage feature impaired by channelization. The majority of the riparian vegetation is
agricultural field with no trees located in the buffer. There is a small existing wetland along the left
bank and the headwater for this reach originates from a wooded wetland flat.
In general, all or portions of A1, A2, B1, B2, B3 and C do not function to their full potential. Current
conditions demonstrate significant habitat degradation as a result of impacts from livestock, historic
land uses, and water diversion. Having been channelized in the past and/or ditched to drain nearby
fields for agricultural activities, the streams do not access their floodplains as frequently as they
naturally would have prior to farming operations. In most cases, these streams are hydraulically
unstable and are devoid of bedform diversity. Habitat along the majority of the restoration reaches is
poor in that there is little woody debris or overhanging vegetation for fish cover or protection for other
aquatic species. Vegetative and habitat diversity is poor along the reaches, as well, and offers little
benefit to the wildlife in the area. Site photographs and morphological parameters are located in
Appendix B.
Selma Mill Mitigation Plan 17 April 2016

Table 7. Summary of Existing Channel Characteristics
Reach Drainage ABKZF' Width
Area (ac) (ft) (ft)
Mean
Depth (ft)
Width:Depth
Ratio
Sinuosity
Slope (ft/ft)
Al 267 36.8 15.0
2.4
6.8
1.0
0.0004
A2 583 20.2 12.4
1.6
7.6
1.0
0.0021
B1 138 8.7 9.2
0.9
9.9
1.0
0.0036
B2 189 8.7 7.3
1.2
6.2
1.1
0.0030
B3 189 11.4 9.4
1.2
7.8
1.0
0.0030
C 42 2.5 5.0
0.5
10.1
1.0
0.0045
'ABKF= 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)
Table 8. Reach Summary Information
Parameters
Al
A2
Bl
B2
B3
C
Length of Reach
938
1,625
1,396
278
444
921
(linear feet)
Valley
X
X
X
X
X
X
Classification
Drainage Area
267
583
138
189
189
42
(acres)
NCDWQ Stream
Identification
41
41
32.50
32.50
32.50
24.50
Score
NCDWQ Water
Quality
N/A
N/A
N/A
N/A
N/A
N/A
Classification
Morphological
Description
G5cB5
G5c
G5c
G5c
G5c
G5c
stream type)
Evolutionary
Stage II/
Stage II
Stage VI
Stage II
Stage 11
Stage 11
Trend
Stage IV
Underlying
Ly
Ra
Ly
Mapped Soils
L y
Wt
o
L y
L y
GoA
Ly
Class
poorly
poorly;
poorly -,well,
poorly
poorly
poorly; well
poorly
poorly
Slope
0.04%
0.21%
0.36%
0.30%
0.31%
0.45%
FEMA
N/A
N/A
N/A
N/A
N/A
N/A
Classification
Native
Pasture;
Pasture;
Pasture;
Vegetation
forest
pasture
hardwood
pasture
Maintained
pasture
Community
forest
open space
ition
EInats
10
10
20
10
10
10
4.2.1 Channel Classification
The streams have been classified as intermittent and perennial streams using the NCDWR Stream
Identification Form version 4.11 (Appendix B) and are G5c stream types as classified using the Rosgen
stream classification system (Rosgen, 1994). The design reaches have been separated into six distinct
sections that are described in Section 4.2.3. Channel characteristics are summarized in Table 7, and
Appendix B. Stream determinations have been verified by NCDWR staff (Appendix B).
Selma Mill Mitigation Plan 18 April 2016

4.2.2 Discharge
Estimating flows (discharge) for the Selma Mill Site is difficult due to the channelization and
agricultural impacts of the existing streams. Several models, regression equations, and the Coastal Plain
regional curves were used to estimate existing bankfull discharges. Land use and slope were considered
when the discharge calculations were developed. All hydraulic and hydrologic analyses are discussed
in Section 8.3.1. Data and analysis of the hydrologic and hydraulic models are included as Appendix
C.
4.2.3 Channel Morphology
4.2.3.1 Reach Al
Reach Al is a perennial channel located in an active pasture with a drainage area of 0.42 square miles
(267 acres). The reach is approximately 1,104 linear feet and flows in a northerly direction through
active pasture. The planform of this perennial, G-type channel is generally straight and is slightly
entrenched throughout. The approximate bankfull cross -sectional area is 36.8 square feet with
approximate dimensions of 15 feet wide and 2.4 feet deep, while the cross -sectional area of the channel
at top of bank is 111.3 square feet. The dominant bed material is coarse sand. The gradient of the reach
is approximately 0.0004 ft/ft. The reach is oversized and exhibits moderately unstable banks. The
riparian buffer is primarily comprised of pasture grasses on the left bank and a narrow corridor of pine
trees along the right bank of the channel. The channel scored 41 points on the NCDWQ Stream
Identification Form (Version 4.11).
4.2.3.2 Reach A2
Reach A2 is a perennial channel located in an active pasture with a drainage area of 0.91 square miles
(583 acres). The reach is approximately 1,610 linear feet, and flows in a northerly direction until
draining to a wetland at the northwest end of the easement. Reach A2, a G-type channel, is typically
12.4 feet wide and 1.6 feet deep near bankfull, and 25.9 feet wide with a max depth of 4.2 feet at top
of bank. The approximate bankfull cross sectional area is 20.2 square feet. The existing slope of Reach
A2 is 0.0021 ft/ft, and the dominant bed material is coarse sand. The channel scored 41 points on the
NCDWQ Stream Identification Form (Version 4.11).
4.2.3.3 Reach B1
Reach B 1 is a perennial channel located to the east of NC Hwy 96 with a drainage area of 0.22 square
miles (138 acres). This reach is approximately 1394 linear feet and has a slope of 0.0036 ft/ft. This
section is a G-type channel and has an approximate bankfull cross -sectional area of 8.7 square feet and
an area of 49.0 square feet at top of bank. The channel is typically 9.2 feet wide and 0.9 foot deep. The
riparian buffer is comprised of agricultural field and some mixed hardwoods and pines along the
channel. The channel scored 32.5 points on the NCDWQ Stream Identification Form (Version 4.11).
4.2.3.4 Reach B2
Reach B2 is a perennial channel that begins after the confluence of Reaches B 1 and C, and flows
through an agricultural field before reaching NC Hwy 96. Reach B2 has a drainage area of 0.30 square
miles (189 acres) and has an existing length of 375 linear feet. The reach is a G-type channel, has an
average cross -sectional area of 8.7 square feet, and a slope of 0.0030 ft/ft. The channel scored 32.5
points on the NCDWQ Stream Identification Form (Version 4.11).
4.2.3.5 Reach B3
Reach B3 is a perennial channel that begins after the crossing at NC Hwy 96, and runs through pasture
and maintained residential land before its confluence with Reach A. Reach B3 has a drainage area of
0.30 square miles (189 acres) and has an existing length of 405 linear feet. The reach is a a G-type
Selma Mill Mitigation Plan 19 April 2016

channel, has an average cross -sectional area of 11.4 square feet, and a slope of 0.0030 ft/ft. The channel
scored 32.5 points on the NCDWQ Stream Identification Form (Version 4.11).
4.2.3.6 Reach C
Reach C is a straightened, intermittent ditch located in an active pasture in the upstream section of the
project. The reach is approximately 852 linear feet, and flows southwest to its confluence with Reach
B. It has a drainage area of 0.07 square miles (42 acres). Reach C, a G-type channel, is typically 5.0
feet wide and 0.5 feet deep near bankfull, and 15.3 feet wide with a max depth of 1.2 feet at top of bank.
The approximate bankfull cross sectional area is 2.5 square feet. The existing slope of Reach C is 0.0045
ft/ft, and the dominant bed material is muck. The channel scored 24.5 points on the NCDWQ Stream
Identification Form (Version 4.11).
4.2.4 Channel Stability Assessment
A modified version of the channel stability assessment method (CSA) provided in "Assessing Stream
Channel Stability at Bridges in Physiographic Regions" by Johnson (2006) was used to assess channel
stability for the Selma Mill existing channels and reference reach. This method may be rapidly applied
on a variety of stream types in different physiographic regions having a range of bed and bank materials.
The original CSA method was designed to evaluate thirteen stability indicators in the field. These
parameters are: watershed characteristics, flow habit, channel pattern, entrenchment/channel
confinement, bed material, bar development, presence of obstructions/debris jams, bank soil texture
and coherence, average bank angle, bank vegetation/protection, bank cutting, mass wastingibank
failure, and upstream distance to bridge. As this method was initially developed to assess stability at
bridges, a few minor adjustments were made to remove indicators that contradict stability
characteristics of natural channels in favor of providing hydraulic efficiency at bridges. First, the
"channel pattern" indicator was altered such that naturally meandering channels scored low as opposed
to straightened/engineered channels that are favorable for stability near bridges. Secondly, the last
indicator, "upstream distance to bridge," was removed from the assessment as bridges are not a focus
of channel stability for this project. The twelve indicators were then scored in the field, and a rating of
excellent, good, fair, or poor was assigned to each project reach based on the total score. (See Appendix
B for the CSA field form.)
The CSA results (scores and ratings) for the Selma Mill Site project and reference reaches are provided
in Table 9. Project Reaches Al, A2, B1, B2, B3 and C all received "Fair" ratings. The reference reach
received a "Good" rating. All channels proposed for either restoration have been straightened and
entrenched, and some are actively maintained. These characteristics are reflected in the poor CSA
scores for channel pattern and bank vegetation/protection. Most reaches scored poorly for watershed
characteristics since the surrounding land use is dominated by agriculture activities, residential
development, and lack of riparian buffers.
Table 9. Channel Stability Assessment Results
Al A2 Bl B2 B3 C Ref.
Reach
Watershed characteristics
Selma Mill Mitigation Plan 20 April 2016

2
Flow habit
7
7
7
7
7
5
4
3
Channel pattern
9
9
10
10
10
10
3
4
Entrenchment/channel
9
9
8
8
8
7
3
confinement
5
Bed material
6
6
7
7
7
7
5
6
Bar development
9
9
7
7
7
9
5
7
Obstructions/debris jams
5
5
6
6
6
3
3
8
Bank soil texture and
8
8
7
7
7
8
4
coherence
9
Average bank angle
10
10
10
10
10
7
4
10
Bank vegetation/protection
10
10
8
11
11
10
3
11
Bank cutting
6
6
6
6
6
4
4
12
Mass wasting/bank failure
7
7
5
5
5
2
2
13
Upstream distance to bridge
NA
NA
NA
NA
NA
NA
NA
Score
95
95
89
92
92
80
48
Rating*
Fair
Fair
Fair
Fair
Fair
Fair
Good
Excellent (0 < Score <= 33), Good (33 < Score <= 66), Fair (66< Score <= 99), Poor (99 < Score <= 132)
4.2.5 Bankfull Verification
Bankfull is difficult and often times impossible to accurately identify on actively maintained channels
and agricultural ditches. The usual and preferred indicators rarely exist, and other factors may be taken
into consideration in order to approximate a bankfull stage. Other factors that may be used are wrack
lines, vegetation lines, scour lines, or top of a bankfull bench; however, complete confidence should
not be placed on these indicators. Along the proposed restoration reaches, the channel is generally
entrenched and actively maintained, which means bankfull indicators were very limited or non-existent.
Therefore, bankfull stage was estimated by using Coastal Plain Regional Curves and other hydrologic
analyses, existing cross -sections, and in-house spreadsheets to estimate bankfull area and bankfull
discharge.
4.2.6 Vegetation
Current land use in the vicinity of the project is primarily agricultural and residential. Along the upper
end of Reach A, the right bank stream corridor is wooded with loblolly pine and mixed hardwoods.
Exotic species are also present throughout, including Chinese privet (Ligustrum sinense) and multiflora
rose (Rosa multiflora). The rest of Reach A, and the majority of Reaches B and C, is active agricultural
field (pasture or fallow field) with either Bermuda grass or fields planted with annual rye/wheat,
depending upon the season. Other grasses and weeds are limited.
The current land use along the right bank of the top of Reach B and along portions of the stream corridor
is forest with a mix of trees, saplings, and shrubs. The common species include tulip poplar
(Liriodendron tulipifera), sweetgum (Liquidambar styraciflua), and loblolly pine (Pious taeda). The
understory mainly consists of giant cane (Arundinaria gigantea), and few other shrubs. Green briar and
Chinese privet are locally dense. All naturally vegetated areas were classified by their community type,
and their boundaries were approximately located. Detailed observations of vegetation species, soils,
and hydrology were recorded in each community type. Table 10 describes each natural community.
Selma Mill Mitigation Plan 21 April 2016

Table 10. Natural Community Summary
Existing Land Use
Percent of
Watershed
Natural Community
(Schafale and Weakley Community)
Agriculture
30
NA
Residential
40
NA
Mixed Pines/Hardwoods
10
Mesic Mixed Hardwood Forest -Coastal Plain
Open Water
< 1
NA
Roads
7
NA
Industrial/Commercial
12
NA
4.2.7 Quantitative Habitat Assessment
A quantitative habitat assessment was performed on the reference reach to measure the volume of
woody debris and fish cover. These data were used to establish a baseline for measuring functional
uplift and to determine the placement and volume of woody debris in the design reaches.
The length of each sample reach was thirty to forty times the base -flow wetted width of the channel
with a minimum reach size of 100 feet. The sample reach was divided into ten transects spaced evenly
over the entire reach. Transect length was five feet upstream and five feet downstream of the transect
midpoint, and extended the full width of the channel. Parameters measured at each transect were small
woody debris (SWD), substrate material, and riparian composition. At each transect, the channel bed
form was noted and an average width and depth recorded. The following is an analysis of the habitat
assessment data.
4.2.7.1 Small Woody Debris Methods and Results
Small woody debris was measured at the reference reach in order to design SWD habitat structures
similar to those found in the reference reach. SWD greater than 0.2 inches in diameter were measured
in each reference reach transect. Large woody debris was eliminated from analysis since these are
analogous to structures such as log vanes and log toes currently applied to most restoration designs.
Transects were identified as either shallow or pool bed form types resulting in four pools and six
shallows measured at the reference reach. Measurements of SWD were summed for each bed form type
and divided by the number of corresponding transects to get the average volume of SWD per pool or
shallow. The average volume was then divided by the average transect area to get the volume of SWD
per square foot. The average design reach bed form area was calculated by assuming a length of ten
feet (based on reference transects) and multiplying that by the average bottom cross section width. The
average volume was multiplied by the ratio of average reference reach transect area to the average area
in the design reach to obtain the volume of SWD to be installed at each fixed pool and at select locations
along the design shallows.
WK Dickson currently uses wattles, dead brush, and woody debris bundles in the design of restoration
channels. Based on the reference reach SWD analysis, these SWD structures will be concentrated in
pool habitats and throughout shallows in volumes and size classes similar to those found in the reference
reach. Wattles are woody branch structures tied together and embedded into the bank so that the free
ends stick out into the wetted channel. Dead brush structures are shrub or tree tops that are anchored to
the bottom of the channel. Woody debris bundles are bundles of sticks one to four inches in diameter
and one to four feet long that are anchored to the streambed. The average volume of each SWD structure
is presented in Table 11.
Selma Mill Mitigation Plan 22 April 2016

Table 11. Average volume (cubic inches) of SWD structures used in the design reach.
SWD Average Volume
Woody Debris Bundle 509
Dead Brush 589
Wattle 42
Root Wad 562
Leaf Pack 120
In addition to the habitat assessment conducted at the reference site, the design reaches of the project
site were visually assessed in order to measure representative habitat gains over time post -construction.
Based on these assessments, there is a disparity of SWD volume between the reference reach and the
design reaches (Chart 1). Small woody debris assessment results for all design reaches except for the
upper end of Reach B were very low compared to the reference reach results. Since most of the design
reaches flow through open agricultural fields, there is little to no woody vegetation present to contribute
to woody debris. The woody debris present is predominantly contributed from adjacent buffer with
some input from upstream reaches.
Average SWD per Reach
goo
m
= 700
600
m
500
a
v 400
= 300
200
100
Buffalo Branch
Best Site Reach A Reach B (wooded Reach B (no Reach C
buffer) buffer)
0 Reference ■ Mitigation*
Chart 1. Average volume (cubic inches) of SWD per assessed reach. This chart represents existing conditions
in all assessed reaches. *Mitigation reaches were assessed qualitatively.
Woody debris collected in streams provides habitat for macroinvertebrates, fish, and amphibians, and
increases stream productivity by retaining carbon in the channel. This quantitative habitat assessment
provides guidance for improving habitat conditions through specifically placed and sized SWD
structures, and provides a means for assessing functional gains over time. WK Dickson has included
these structures in the design plans (Appendix D).
4.2.7.2 Substrate Composition
Substrates were divided into eight classes as follows: coarse/fine particulate organic matter,
silt/clay/muck, fine sand, coarse sand, gravel, cobble, boulder, and bedrock (Chart 2). Channel width
and water depth were measured at each transect in four equally spaced intervals from bank to bank.
Substrate coverage was visually determined between widths measured at each major change in substrate
type.
Selma Mill Mitigation Plan 23 April 2016

The substrate composition analysis revealed that the reference reach has similar substrate to the reaches
at Selma Mill. Organic matter (C/FPOM) was observed during the substrate comparison but was
immeasurable and less than 0.5 percent. Macroinvertebrate abundance and diversity has been tied to
the ability of a channel to retain carbon. Several design structures and vegetation plantings can be used
to increase organic substrate composition. Constructed leaf packs will be installed in select locations
for immediate macroinvertebrate colonization. SWD bundles will serve to collect organic matter
flowing downstream increasing carbon retention. By adding sinuosity and creating a better floodplain
connection, adding SWD in select locations, and creating pool habitats, substrate composition will more
closely resemble reference reach conditions.
Comparison of Substrate Between Reference Reach
and Selma Mill Mitigation Reaches
100 -
90
so
o Reach A
70 -
■ Reach A
6❑ -
R Reach B
SO -
40 -
0 Reach C
30 -
■ Reference
1�0 -
10
L
U -
I 6M.R
CJFROM
Silt/Mud Fine Coarse Gravel Cobble
Boulder
Sand Sand
Chart 2. Comparison of substrate composition between the reference reach and the restoration reaches.
4.3 Wetland Summary Information
4.3.1 Existing Wetlands
The USFWS National Wetland Inventory Map (NWI) depicts a small area of wetlands within the site
(Figure 3). An area along the floodplain of Reach A2 is mapped as PFOIA (Palustrine Forested Broad -
Leaved Deciduous Temporarily Flooded).
A wetland delineation was performed in March 2015. Wetland boundaries were delineated using
current methodology outlined in the 1987 U.S. Army Corps of Engineers Wetland Delineation Manual
(DOA 1987) and Regional Supplement to the U.S. Army Corps of Engineers Wetland Delineation
Manual: Atlantic and Gulf Coastal Plain Region (Version 2.0) (U.S. Army Corps of Engineers 2010).
Soils were characterized and classified using the Field Indicators of Hydric Soils in the United States,
Version 7.0 (USDA-NRCS 2010). Wetland boundaries were marked with sequentially numbered
wetland survey tape (pinkiblack striped). Flag locations were surveyed under the direction of a
Professional Licensed Surveyor (PLS) with GPS and conventional survey (Figure 7; Table 12). The
JD Approval letter for the site is included in Appendix B.
Selma Mill Mitigation Plan 24 April 2016

4.3.1.1 Wetland 1 (WI)
This disturbed wetland is in an agricultural field along the left bank of Reach C. Vegetation is primarily
a mix of grasses, sedges and common rush. There is no tree cover along the upper portion of Reach C.
This wetland is seasonally saturated from high groundwater and bank overflow. The current land use
is agriculture.
4.3.1.2 Wetland 2 (W2)
This small patch of bottomland hardwood forest is located along the floodplain of Reach B 1. The nearly
level topography exhibits evidence of flooding in many places, and this wetland is seasonally saturated
from high groundwater and some bank overflow. The current land use is forest with a mix of trees,
saplings, and shrubs. The common species include tulip poplar, sweetgum, and some loblolly pine
(Pious taeda). The understory mainly consists of giant cane (Arundinaria gigantea), and few other
shrubs. Green briar and Chinese privet are locally dense.
4.3.1.1 Wetland 3 (W3)
This small patch of bottomland hardwood forest is located at the confluence of Reach C and Reach B 1.
The nearly level topography exhibits evidence of flooding in many places, and this wetland is
seasonally saturated from high groundwater and some bank overflow. The current land use is forest
with a mix of trees, saplings, and shrubs. The common species include tulip poplar, sweetgum, and
some loblolly pine. The understory mainly consists of giant cane, and few other shrubs. Green briar
and Chinese privet are locally dense.
4.3.1.2 Wetland 4 (W4)
This disturbed, bottomland hardwood forest is located at the bottom of Reach A2. The current land use
is active pasture. Vegetation is primarily a mix of pasture grasses and some small shrubs and trees.
Multifloral rose is locally dense. The nearly level topography exhibits evidence of flooding in many
places, and this wetland is seasonally saturated from high groundwater and some bank overflow. This
wetland is hydrologically connected to a large NWI mapped wetland classified as PFOIA (Palustrine
Forested Broad -Leaved Deciduous Temporarily Flooded).
A jurisdictional determination of the wetlands has not been made by the US Army Corps of Engineers
(USACE), but the USACE has visited the restoration site. Wetland forms are included in Appendix B.
Table 12. Wetland Summary Information
Wetland Summary Information
wetland
Wetland
Wetland
Wetland
Parameters
W1
W2
W3
W4
Size of Wetland
0.21
0.23
0.11
3.63
acres
Selma Mill Mitigation Plan 25 April 2016

Wetland Type
Seep
Bottomland
Bottomland
Bottomland
Hardwood Forest
Hardwood Forest
Hardwood Forest
Mapped Soil Series
GoA
Ly
Ly
Ly/Wt
Drainage Class
Moderately well
Poorly
Poorly
Poorly
Hydric Soil Group
B
C
C
C/D
Source of Hydrology
Groundwater
Groundwater
Groundwater
Groundwater
Discharge
Discharge
Discharge
Discharge
Hydrologic
Lack of
Livestock
Impairment
vegetation and
Incised channel
Incised channel
compaction
hydrology
Incised channel
Native vegetation
Pasture
Pasture
Pasture
Pasture
community
Percent composition
of exotic invasive
<5%
25%
25%
<5%
vegetation
4.4 Regulatory Considerations and Potential Constraints
4.4.1 Property Ownership, Boundary, and Utilities
There are no major constraints to construction of the Site. The watershed that drains to the upper end
of the site is approximately 260 acres, and land use is primarily commercial and residential. Currently,
runoff from this watershed is conveyed through a closed system that outfalls at the upstream end of the
project through multiple reinforced concrete pipes (RCP). An existing powerline easement crosses
Reach B and Reach C which will result in a 30-foot easement break along each reach. These easement
breaks will be co -located with potential landowner crossings. An herbaceous/shrub planting zone is
proposed in these areas to provide stability. Reach B has one additional easement break at the NC Hwy
96 right-of-way. A 60-foot easement break is proposed for Reach A near the downstream end of the
project to allow the landowner to access property; no additional crossings or easement breaks are
proposed at this time.
4.4.2 Site Access
There are no access constraints to the Selma Mill Site. To access the Site from the town of Selma, travel
north on NC HWY 96 (N Sumner Street). The site is on the left side of the road beginning immediately
north of W Chestnut Street. Reach B crosses NC Hwy 96 approximately 1,900 feet north of W Chestnut
Street. The site protection instrument can be found in Appendix A. This site is readily accessible from
NC Hwy 96 and W Chestnut Street.
4.4.3 FEMA/ Hydrologic Trespass
Hydrologic trespass is a not a concern for this project. The downstream end of Reach A is located
within the FEMA 100-year flood plain (Zone AE) of Mill Creek; however, no portions of the project
are located within a FEMA floodway or non -encroachment area. Therefore, it is not anticipated that a
No -rise or CLOMR will be required for the project. While designing the Selma Mill Site, appropriate
measures were taken to eliminate hydrologic trespass of the adjacent agricultural fields and animal
operations. The adjacent land use will not be affected by the proposed design, and the property owners
have been notified of any potential impacts from hydrologic trespass within existing ditches. No
detrimental impacts are expected beyond the easement limits.
Selma Mill Mitigation Plan 26 April 2016

Table 13. Regulatory Considerations
Regulation
Applicable?
Resolved?
Supporting Documentation
Waters of the United States -
Yes
No
Appendix B
Section 404
Waters of the United States -
Yes
No
Appendix B
Section 401
Endangered Species Act
Yes
Yes
Section 4.1.3; Appendix B
Historic Preservation Act
Yes
Yes
Section 4.1.4; Appendix B
Coastal Zone Management Act
(CZMA)/Coastal Area
No
N/A
N/A
Management Act (CAMA)
FEMA Floodplain Compliance
N/A
N/A
Section 4.4.3; Appendix B
Essential Fisheries Habitat
No
N/A
N/A
5 DETERMINATION OF CREDITS
Mitigation credits presented in these tables are projections based upon site design. SMU totals have
been adjusted and calculated using the most recent non-standard buffer width guidance documents
(Figure 11). Upon completion of site construction, the project components and credits data will be
revised to be consistent with the as -built condition.
Selma Mill Mitigation Plan 27 April 2016

Table 14. Mitigation Credits
The Selma Mill Stream Mitigation Site Mitigation Credits
Mitigation Credits
Stream
Riparian Wetland
Non -Riparian Wetland
Totals
7,989
N/A
N/A
Mitigation
Stationing Existing
ProposedMitigation
Base
Adjusted
Reach
Type
(Existing) Length
Length
Ratio
SMUs
SMUs*
(LF)
(LF)
A
P2 Restoration
0+61 to 19+42 1,514
1,881
1 : 1
1,881
2,068
A
PI/P2 Restoration
19+72 to 27+30 630
758
1 : 1
758
821
A
P1 Restoration
27+60 to 34+45 571
685
1:1
685
801
B
P2 Restoration
1+94 to 10+39 741
845
1 : 1
845
903
B
PI/P2 Restoration
10+72 to 22+95 1,062
1,223
1 : 1
1,223
1,334
B
P2 Restoration
23+55 to 28+59 405
504
1 : 1
504
503
C
HWV Restoration
3+00 to 8+59 584
559
1 : 1
559
559
C
HWV Restoration
8+89 to 13+15 294
426
1 : 1
420
420
Total 5,801
6,881
6,875
7,409
*Base SMUs for Headwater Valley Restoration is based on valley length and not proposed
channel length.
**SMU adjustments based on non-standard buffer widths.
6 CREDIT RELEASE SCHEDULE
All credit releases will be based on the total credit generated as reported by the as -built survey of the
mitigation site. Under no circumstances shall any mitigation project be debited until the necessary DA
authorization has been received for its construction or the District Engineer (DE) has otherwise
provided written approval for the project in the case where no DA authorization is required for
construction of the mitigation project. The DE, in consultation with the IRT, will determine if
performance standards have been satisfied sufficiently to meet the requirements of the release schedules
below. hi cases where some performance standards have not been met, credits may still be released
depending on the specifics of the case. Monitoring may be required to restart or be extended, depending
on the extent to which the site fails to meet the specified performance standard. The release of project
credits will be subject to the criteria described as follows:
Table 15. Credit Release Schedule
Release
Credit Release Activity
Interim
Total Released
Milestone
Release
1
Site Establishment (includes all required criteria
15%
15%
stated above)
2
Baseline Monitoring Report and As -built Survey
15%
30%
3
First year monitoring report demonstrates
10%
40%
performance standards are being met.
Selma Mill Mitigation Plan 28 April 2016

Release
Credit Release Activity
Interim
Total Released
Milestone
Release
4
Second year monitoring report demonstrates
10%
50%
performance standards are being met.
(60%**)
5
Third year monitoring report demonstrates
10%
60%
performance standards are being met.
(70%**)
6
Fourth year monitoring report demonstrates
5%
65%
performance standards are being met.
(80%**)
Fifth year monitoring report demonstrates
°
10 /°
75%
performance standards are beingmet.
85%*
8
Sixth year monitoring report demonstrates
5%
80%
performance standards are being met.
(90%**)
9
Seventh year monitoring report demonstrates
90%
performance standards are being met, and project
10%
(100%**)
has received close-out approval.
* * 10% reserve of credits to be held back until the bankfull event performance standard has been met.
6.1 Initial Allocation of Released Credits
The initial allocation of released credits, as specified in the mitigation plan can be released by the IRT
with written approval of the DE upon satisfactory completion of the following activities:
a) Approval of the final Mitigation Plan
b) Mitigation bank site must be descured
c) Recordation of the Conservation Easement, as well as a title opinion acceptable to the USACE
covering the property
d) Financial assurances.
e) 404 permit verification for construction of the site
6.2 Subsequent Credit Releases
The second credit release will occur after the completion of implementation of the Mitigation Plan and
submittal of the Baseline Monitoring Report and As -built Survey. All subsequent credit releases must
be approved by the DE, in consultation with the IRT, based on a determination that required
performance standards have been achieved. As projects approach milestones associated with credit
release, the Sponsor will submit a request for credit release to the DE along with documentation
substantiating achievement of criteria required for release to occur. This documentation will be included
with the annual monitoring report.
7 FUNCTIONAL RATIONALE
The Stream Functions Pyramid Framework (Harman et. al. 2012) uses stream functions to describe
project objectives, existing condition assessments and monitoring, performance metrics, and design
criteria. The Framework separates stream functions into five categories, ordered into a hierarchy, which
communicate the interrelations among functions and illustrate the dependence of higher level functions
(biology, physiochemical and geomorpholgy) 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 of the pyramid.
The Pyramid is illustrated below.
Selma Mill Mitigation Plan 29 April 2016

While traditional mitigation approaches have generally relied on surrogate measures of success (i.e.
linear feet of restoration) for determining SMU credit yields, a function -based approach provides a
more objective and flexible approach to quantify the expected ecological benefits of a mitigation
design. Additionally, a functional based approach broadens the reach -scale goals of a restoration project
by contextualizing the functional uplift to the watershed scale. The proposed Selma Mill Mitigation
Site will provide numerous ecological and water quality benefits within the Neuse River Basin by
applying an ecosystem restoration approach. Anticipated functional benefits and improvements within
the project area, as based on the Function -Based Framework are outlined in Table 16.
Geology CI imate
Selma Mill Mitigation Plan 30 April 2016

Table 16. Functional Benefits and Improvements
Functional
Objective
Description
A&
Level
M
EL
(1-5)
Benefit will be achieved through cattle exclusion and direct removal of fecal
Nutrient removal
inputs, filtering of runoff through buffer areas, the conversion of active farm
5
fields to forested buffers, and improved denitrification and nutrient uptake
through buffer zones.
Benefit will be achieved through the stabilization of eroding stream banks
Sediment removal
through cattle exclusion (passive) and bioremediation, bed loss will be
3,5
arrested with grade control structures, and reduction of sediment loss from re-
forested pasture.
Benefit will be achieved through the restoration of buffer areas that will
Runoff filtration
receive and filter runoff, thereby reducing nutrients and sediment
4,5
concentrations reaching aquatic resources.
Benefit will be achieved through the enhancement of floodplain connectivity
Water storage
which will store more water during precipitation events than under current
1,2
drainage conditions.
Improved
Benefit will be achieved through the increased storage of precipitation in
groundwater
floodplain wetlands. Greater storage of water will lead to improved
2
recharge
infiltration and groundwater recharge.
Restoration of
Benefit will be achieved by restoring riparian buffer and wetland buffers to
habitats
hardwood ecosystems.
4, 5
Improved substrate
Substrate will become coarser as a result of the stabilization of stream banks
and instream cover
and an overall decrease in the amount fine materials deposited in the stream.
3, 5
Addition of large
Benefit will be achieved through the addition of wood structures as part of
woody debris
the restoration design. Such structures may include log vanes, root wads, log
3, 4, 5
weirs, and log toes.
Reduced water
temperature due to
Benefit will be achieved through the restoration of canopy tree species to the
4,5
shading
stream buffer areas.
8 MITIGATION WORK PLAN
8.1 Reference Stream Studies
8.1.1 Target Reference Conditions
The restoration portions of the project site are characterized by agricultural and livestock practices.
Several ditches and stormwater pipes exist in the watershed and contribute to the project site. Physical
parameters of the site were used, as well as other reference materials, to determine the target stream
type. An iterative process was used to develop the final information for the site design.
To develop the target reference conditions, physical site parameters were reviewed. This included the
drainage area, land use, soils mapping units from the Johnston County Soil Survey for the watershed
and Site, typical woody debris and habitat available for the area, as well as general topography. The
"Classification of the Natural Communities of North Carolina" was also used to narrow the potential
community types that would have existed at the site (Schafale and Weakley, 1990).
Selma Mill Mitigation Plan 31 April 2016

Targeted reference conditions included the following:
• Located within the Physiographic Region — Inner Coastal Plain,
• Similar drainage area,
• Similar land use onsite and in the watershed,
• Similar watershed soil types,
• Similar site soil types,
• 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.
8.1.1.1 Reference Site Search Methodology
All the parameters used in Section 4.1 were used to find appropriate reference stream sites. Obtaining
property owner information and owner authorization for access was another factor in locating suitable
reference sites for the project. For this project, there was no predetermined amount of reference sites
needed as long as the site was suitable and met the parameters. Several potential reference sites were
assessed, and their characteristics were noted. It is difficult to find reference sites on the coastal plain
because many have been disturbed by farming or urban development. Most streams tend to be modified
ditches and may have some of the characteristics that are sought in a reference, but too few to make it
an ideal reference for the project site. One reference stream site that proves to be ideal in both
geomorphology and habitat is located near the intersection of Little Divine Road and Howard Road.
Located approximately 4 miles north of the project site the reference reach is in the wooded area east
of Howard Road.
8.1.1.2 Reference Watershed Characterization
The reference stream flows west to east and is the most downstream portion of an unnamed tributary
that drains to Buffalo Creek. The reach that was surveyed and analyzed is approximately 375 feet long.
The drainage area for the unnamed tributary is 0.84 square miles (540 acres). The land use in the
watershed is characterized by mostly mixed pines and hardwoods (40 percent), cultivated row crops
(29 percent), residential (18 percent), and managed herbaceous cover/pasture land (eight percent), pine
plantations (four percent), and open water (one percent). Site photographs of the reference stream are
located in Appendix B.
The current State classification for reference reach is undefined, but the tributary runs into Buffalo
Creek. Buffalo Creek is defined as Class C NSW (NCDWQ 2012a). Class C waters are suitable for
aquatic life, secondary recreation, and agricultural usage. The NSW is a designation for nutrient
sensitive waters — intended for waters needing additional nutrient management due to being subject to
excessive growth of microscopic or macroscopic vegetation. Buffalo Creek is listed on the 2012 303d
list for impaired waters (NCDWQ 2012b). It is impaired for aquatic use, receiving a Fair
Bioclassification rating for benthic ecologicalibiological integrity.
8.1.1.3 Reference Discharge
Several hydrologic models/methods were used to develop a bankfull discharge 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 Plain Regional Curves, in-house
spreadsheet tools, and a project specific regional flood frequency analysis, the existing discharge was
Selma Mill Mitigation Plan 32 April 2016

found to be around 17 cubic feet per second (ft3/s). See Section 8.3.1.1 for a more detailed description
of the hydrologic analyses performed for this project.
8.1.1.4 Reference Channel Morphology
In comparison to the restoration reaches, the reference reach is slightly smaller than Reaches A and B
when comparing pattern, dimension and profile, which is the reason for using a scaling factor for the
design. The scaling factor is based on the difference in bankfull area of the reference channel. The new
reach would then have the necessary dimensions of that of either a smaller or larger stream
corresponding to differences in drainage area. The reference stream was typically eight to ten feet wide
and one to two feet deep. The cross sectional area was typically around 11 square feet with a width to
depth ratio around 8 to 11.
8.1.1.5 Reference Channel Stability Assessment
The reference reach was stable and showed no evidence of incision or erosion in the portion that was
surveyed and analyzed. The stream appeared to maintain its slope and had sufficient amounts of
vegetation to secure its banks. Riparian buffer widths exceeded fifty feet on each side. The CSA results
(scores and ratings) for the reference reach are provided above in Table (Section 4.2.4). The reference
reach received a "Good" rating as the channel demonstrates a stable meandering pattern and a well
vegetated riparian buffer.
8.1.1.6 Reference Bankfull Verification
Typical indicators of bankfull include vegetation at the bankfull elevation, scour lines, wrack lines,
vegetation lines, benches/inner berm, and point bars. Throughout the entire length of the reference
reach, bankfull is located at the top of bank elevation. The accuracy of this bankfull stage is verified by
the Coastal Plain Regional Curves and hydrologic analyses using existing cross sections to calculate
area and discharge. Evidence that can further support the location of bankfull is the lack of any bench
or berm features within the channel, and wrack lines present within the floodplain.
8.1.1.7 Reference Riparian Vegetation
The reference reach riparian community is characteristic of a coastal plain small stream swamp
community. This community is approximately 15 to 20 years old, as evidenced by the representative
diameter at breast height (DBH) measurements. This community was determined to have had past
disturbance altering the species composition. Most of the canopy species recorded are high dispersal
species and have been observed to occur near the restoration site. The following table lists the coverage
estimates and species encountered. The right bank is denoted as RB and the left bank is denoted as LB.
It is anticipated that a local seed source for these high dispersal species is present and will disperse
across much of the mitigation site. These species are often found in early successional communities
and quickly fill disturbance gaps. Because many of these high dispersal species often become
aggressive in these sites, they are not included in the Restoration Planting List (Section 8.2.2).
Hardwood species typical of the target community were observed in adjacent and nearby communities,
and were judged to be more appropriate for this site.
Selma Mill Mitigation Plan 33 April 2016

Table 17. Tree Communities at the Reference Reach for Selma Mill Site.
Transect
Location
Coverage
Percent
Evergreen
Percent
Deciduous
Representative
DBH (in.)
Species
1
LB
80
0
100
15
Liriodendron tulipifera,
Acer rubrum
RB
90
10
90
18
Acer rubrum, Pinus taeda
2
LB
85
0
100
20
Liriodendron tulipifera, Nyssa Mora,
Quercus alba
RB
85
10
90
18
Acer rubrum, Pinus taeda
3
LB
90
0
100
17
Quercus nigra, Liriodendron tulipifera,
Nyssa biflora
RB
85
10
90
18
Acer rubrum, Pinus taeda
4
LB
85
0
100
17
Liriodendron tulipifera, Nyssa biflora,
Quercus nigra
RB
85
15
85
15
Pinus taeda, U nnis americana,
Quercus alba
5
LB
85
0
100
17
Liriodendron tulipifera, Nyssa biflora
RB
85
0
100
15
Liquidambar styraciflua
6
LB
85
0
100
17
Quercus nigra, Liriodendron tulipifera,
Nyssa Mora
RB
85
0
100
6
Nyssa biflora, Acer rubrum,
Catalpa sp.
7
LB
80
0
100
10
Quercus michauxii, U nnis americana
RB
75
0
100
6
Magnolia virginiana
8
LB
75
0
100
18
Magnolia virginiana, Quercus michauxii,
Quercus alba
RB
80
0
100
10
Nyssa biflora, Liriodendron tulipifera,
Carya sp., Acer rubrum
9
LB
70
0
100
10
Liriodendron tulipifera, Acer rubrum,
Magnolia virginiana
RB
80
0
100
10
Nyssa biflora, Acer rubrum, Catalpa sp.
10
LB
75
0
100
12
Liriodendron tulipifera, Carya sp.
RB
75
0
100
8
Liquidambar styraciflua, Acer rubrum,
Liriodendron tulipifera
Selma Mill Mitigation Plan 34 Aphl 2016

8.2 Design Parameters
8.2.1 Stream Restoration Approach
Stream restoration efforts along the tributaries at the Site will be accomplished through analyses of
geomorphic conditions and watershed characteristics. The design approach applies a combination of
analytical and reference reach based design methods that meet objectives commensurate with both
ecological and geomorphic improvements. Proposed treatment activities may range from minor bank
grading and planting to re-establishing stable planform and hydraulic geometry. For reaches requiring
full restoration, natural design concepts have been applied and verified through rigorous engineering
analyses and modeling. The objective of this approach is to design a geomorphically stable channel that
provides habitat improvements and ties into the existing landscape.
The Site will include Priority Level 1 and 2 restoration and headwater valley restoration. Priority 1 and
2 restoration reaches will incorporate the design of a single -thread meandering channel, with parameters
based on data taken from the reference site described in Section 8.1 above, published empirical
relationships, NC Coastal Plain Regional Curves, and hydrologic and hydraulic analyses. As a result of
the restoration of planform and dimension, frequent overbank flows and a restored riparian buffer will
provide the appropriate hydrology and sediment transport throughout this coastal plain watershed. A
conceptual plan view is provided in Figure 10.
Headwater valley restoration will follow current regulatory guidance and published research. This
restoration approach will result in a fully vegetated valley bottom following natural existing contours.
Any ditches or channels present will be backfilled and stabilized. Vegetation will be restored across the
entire headwater valley.
Current stream conditions along the proposed restoration reaches demonstrate significant habitat
degradation as a result of impacts from livestock, channelization performed to promote agricultural
activities, and impervious watershed conditions. Additionally, the riparian buffer is in poor condition
throughout most of the project area. Much of the riparian buffer is devoid of trees or shrubs and active
pasture is present up to the edge of the existing channel.
The Site design approach began with a thorough study of existing conditions, including the onsite
streams, valleys, and watershed. Design parameters, including active channel, habitat and floodplain
features were developed from analyses performed at the reference site. Analytical design techniques
were used to determine the design discharge and to verify the design as a whole.
Engineering analyses were performed using various hydrologic and hydraulic models to verify the
reference reach based design. A combination of methods (including Hydraflow Hydrographs, regional
curves and flood frequency analysis) were used to calculate flows received by the channel for bankfull
and other significant storm events. Through this hydrologic analysis, the design discharge (typically
referenced as bankfull or dominant discharge) was determined, and the subsequent design was based
on this calculated discharge. Design parameters developed through the analyses of reference reach data
and hydrologic and hydraulic modeling were confirmed using the Stable Channel Design function
components within HEC-RAS and through spreadsheet tools.
Engineering analyses were performed concurrently to geomorphic and habitat studies. While the stream
design was verified by simulations of hydrology and fluvial processes, analogs of desirable habitat
features were derived from reference sites and integrated into the project design. Both riparian habitat
features and in -stream structures such as log grade controls, brush toes, log vanes, log toes, log drops
were used throughout the project to act as grade control and for bank stabilization by dissipating and
redirecting the stream's energy. Bank stability will also be enhanced through the installation of live
Selma Mill Mitigation Plan 35 April 2016

stakes that include native species (e.g. black willow (Salix nigra) and silky dogwood (Cornus
amomum)).
In -stream habitat is highly dependent on available cover and organic material. A quantitative habitat
assessment method was used to measure type, location, and quantity of habitat in the reference streams.
During design, the habitat assessment results were scaled appropriately to the design parameters such
that the quantity and placement of the habitat features along the restored channel mimics reference
conditions. This process provides a natural channel design that addresses aquatic function
improvements in addition to stability.
Sections of abandoned stream channel will be backfilled to the elevation of the floodplain in areas
adjacent to the new channel with material excavated onsite and by installing channel plugs where
necessary. The floodplain will be planted with native species creating a vegetated buffer, which will
provide numerous water quality and ecological benefits. Stream banks will be stabilized using a
combination of grading, erosion control matting, bare -root plantings, native material revetment
techniques (i.e. bioengineering), structure placement, and sod transplants where possible. The stream
and adjacent riparian areas will be protected by a minimum 50-foot permanent conservation easement,
which will be fenced as needed to exclude livestock.
The Site has been broken into the following design reaches:
Reach A (STA 0+61 to STA 27+30; STA 27+90 to STA 34+45) — Reach beginning at
southwest corner of project totaling 3,324 linear feet of Priority 1 and 2 restoration. Pasture
and disturbed wetlands are located adjacent to the reach.
• Reach B (STA 1+94 to STA 10+39; STA 10+72 to STA 22+95; STA 23+55 to STA 28+59)
— Reach beginning in agricultural field just west of HWY 301 and flows west until its
confluence with Reach A totaling 2,572 linear feet of Priority 2 Restoration. Pasture and
disturbed wetlands are located adjacent to the reach.
• Reach C (STA 3+00 to STA 8+59; STA 8+89 to STA 13+15) — Reach beginning at farm
pond outlet within an agricultural field east of Hwy 96 that drains to Reach B. Pasture and
disturbed wetlands are located adjacent to this reach totaling 979 linear feet in Headwater
Valley Restoration.
Reach A
A combination of Priority 1 and 2 restoration is proposed for Reach A to address existing impairments,
particularly the channelized and oversized channel and lack of bedform diversity. The watershed that
drains to the upper end of the project is approximately 260 acres, is nearly fully developed, and land
use is primarily residential. Runoff from the watershed is conveyed through a closed system that outfalls
through multiple RCP pipes just downstream of the intersection of W Chestnut St and Hwy 96. The
primary 72-inch stormwater pipe has the lowest invert elevation of the existing pipes, and therefore
controls the upstream elevation of the project. Since the pipe invert elevation is at a minimum of 6 feet
below existing ground surface, Priority 1 restoration is not possible. If the proposed channel bed were
to be raised, the increase in water surface elevations would result in hydrologic trespass on properties
upstream. To account for the increased flows along Reach A due to a developed watershed, the design
approach will include constructing a nested channel to accommodate multiple design flows. Proposed
activities will include constructing a meandering channel within the natural valley, excavating a
floodplain bench at the elevation of the proposed channel, and backfilling the existing stream.
Selma Mill Mitigation Plan 36 April 2016

Two 30-foot easement breaks are proposed along the reach; one near the middle of the reach, the other
near the downstream end. Each break will allow for the installation of a culvert crossing consisting of
twin 48 inch HDPE pipes. One of the pipes will be buried 1.0 foot to allow for fish passage and to
convey baseflow, while the invert of the adjacent pipe will be set 2.0 to 3.0 inches above the channel
bed elevation. Priority 1 Restoration is proposed for the reach downstream of the second easement
break. The existing ditch will be backfilled, and the channel will be relocated such that it meanders
within the existing valley to the east. A minimum 100 foot buffer will be established along the entirety
of the reach and planted with native riparian vegetation. Livestock will be excluded with fencing
installed along the easement boundary. All areas within the proposed buffer will be planted with native
riparian vegetation.
Reach B
A combination of Priority 1 and 2 restoration is proposed for Reach B to address existing impairments,
particularly the channelized and oversized channel and lack of bedform diversity. Priority 1 restoration
is not possible along the upper end of this reach due to elevation constraints at the culverts under Pollock
Street (HWY 301). If the proposed channel bed were to be raised, the increase in water surface
elevations would result in hydrologic trespass on properties upstream of Pollock St. The design
approach will include meandering the proposed channel within the natural valley, excavating a
floodplain bench, and backfilling the existing stream.
There are two easement breaks proposed along the reach. The first is a 30-foot break to accommodate
an existing powerline easement located approximately 750 feet west of Pollock St; future landowner
access will be co -located in this crossing. The second is a 60-foot break for the HVVY 96 crossing. A
minimum 50 foot buffer will be established and planted with native riparian vegetation. Because the
buffer is devoid of significant woody vegetation, woody debris will be installed along the bed to
improve in -stream habitat. All areas within the proposed buffer will be planted with native riparian
vegetation.
Reach C
Headwater valley restoration is proposed for Reach C. The construction of a wide, shallow channel is
proposed to provide a hydrologic connection between the reach and an existing pond located upstream
of the reach. Restoration will involve redirecting channel flow to the natural valley, plugging and
backfilling the existing ditch such that cut and fill is balanced, and planting the buffer with native
vegetation. A 30 foot easement break is proposed to accommodate an existing powerline easement;
future landowner access will be co -located in this crossing. A minimum 100 foot buffer will be
established along the entirety of the reach and planted with native riparian vegetation.
8.2.1.1 Design Discharge
Based upon the hydrologic analyses described below and in Section 8.3.1.1, design discharges were
selected that fall between model results for the 1.1-year and 1.5-year flood frequency analysis for each
reach. The selected flows for the restoration reaches are 27ft3/s for Reach A and 15ft3/s for Reach B.
These discharges will provide frequent inundation of the adjacent floodplain.
The design discharges were selected based on the following rationale:
• The calculated bankfull discharge for the analog/reference reach closely matches both the
results of the 1.1-year flood frequency analysis and the Hydraflow Hydrographs model for the
1-year storm,
The results of the 1.1-year flood frequency analysis matched well with the NC regional curve
(Doll et al., 2003),
Selma Mill Mitigation Plan 37 April 2016

• Frequent flow indicators were observed along Reach A that coincided with flows that fell
between the 1.1-year and 1.5-year flood frequency analysis results, and
• Selecting design discharges around the 1.1-year storm events allows frequent inundation of the
adjacent floodplain.
8.2.1.2 Design Methods
There are three primary methods that have demonstrated success in stream restoration: analog,
empirical, and analytical. All three methods have advantages and limitations, and it is often best to
utilize more than one method to address site -specific conditions or to verify the applicability of design
elements. This is particularly true in developed watersheds where existing conditions do not always
reflect current inputs and events, and sediment and hydrologic inputs may remain unstable for some
time. Combinations of analytical and analog methods were used to develop the stream designs for the
Selma Mill site.
Analytical Approach
Analytical design is based on principles and processes considered universal to all streams, and can
entail many traditional engineering techniques. The analytical approach utilizes continuity, roughness
equations, hydrologic and hydraulic models, and sediment transport functions to derive equilibrium
conditions. Since the project is located within a rural watershed, restoration designs are based on
hydrologic and hydraulic analyses, including rainfall -runoff models to determine design discharges
coupled with reference reach techniques.
Analog Approach
The analog method of natural channel design involves the use of a "template" or reference stream
located near the design reach, and is particularly useful when watershed and boundary conditions are
similar between the design and analog reaches (Skidmore et al., 2001). In an analog approach, the
planform pattern, cross -sectional shape, longitudinal profile, and frequency and locations of woody
debris along the analog reaches are mimicked when developing the design parameters for the subject
stream. A scaling factor was calculated from the survey data in order to correctly size the planform
design parameters for the project site. The scaling factors for each design reach were derived from the
design cross -sectional area and topwidth of each reach as follows:
1. The appropriate bankfull cross -sectional area (CSA) of each design reach was calculated using
an in-house spreadsheet based on Manning's Equation. The input parameters included the
design discharge as determined by the hydrologic analysis described above, and proposed slope
based on site conditions and the sinuosity measured for the analog reach.
2. The cross -sectional shape was adjusted within the spreadsheet to replicate the width -depth
ratios and side slopes surveyed along the analog reach, while also maintaining the CSA
necessary to convey the design discharge.
3. The scaling factor is determined from the ratio of the design topwidth to the analog topwidth
(Table 18). For this project, several cross -sections and planform geometry were measured at
the analog site, resulting in an average width of 9.4 feet.
4. Pool cross -sectional areas were calculated using both typical reference reach techniques and
the analog approach. Design CSA areas were determined using the measured analog ratios of
shallow/ripple CSA to pool CSA as applied to the design CSAs. The pool cross -sectional shape
was adjusted within the in-house spreadsheet as described above in step 2.
Selma Mill Mitigation Plan 38 April 2016

Table 18. Scaling Factors for Sizing Planform Design Parameters
Reach Drainage Proposed Bankfull Design Analog Reach Scaling
Area (ac) CSA (ft2) Topwidth (ft) Topwidth (ft) Factor
A 583 16.5 13.0 9.1-9.6 1.4
B 189 9.4 10.0 9.1-9.6 1.1
8.2.1.3 Typical Design Sections
Typical cross sections for shallows and pools are shown on the design plan sheets in Appendix D. The
cross-section dimensions were developed for the three design reaches by using a WK Dickson in-house
spreadsheet described in Section 8.2.1.2 of this report. The cross -sections were altered slightly to
facilitate constructability; however, the cross -sectional area, width to depth ratio, and side slopes were
preserved. Typical pool sections include pools located on straight reaches and pools on meander bends.
8.2.1.4 Meander Pattern
The design plans showing the proposed channel alignment are provided in Appendix D. The meander
pattern was derived directly from the analog reach and sized using the scaling factors described in
Table 18. The analog meander pattern was altered in some locations to provide variability in pattern,
to avoid onsite constraints, to follow the valley pattern, and to make the channel more constructible.
The morphologic parameters summarized in the Appendix C were applied wherever these deviations
occurred.
8.2.1.5 Longitudinal Profiles
The design profiles are presented in Appendix C. 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 existing 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.
8.2.1.6 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. Additionally, rock structures will be utilized within the upstream portion of Reach A
to provide increased stability due to high velocities and in -stream stresses resulting from the closed
system outfall at the upstream limits of the project. Typical rock structures that will protect the channel
bed and/or banks will include riffle grade controls, cross -vanes, and meander boulder toes.
Woody debris will be placed throughout the channel at locations and at a frequency that is similar to
those mapped in the analog reaches. The analog reach has woody debris throughout the length of the
channel, providing grade control for shallows and forcing scour pools. Woody habitat features installed
will include dead brush, woody debris bundles, root wads, brush toes, and log vanes. To provide
additional bank stability, sod mats harvested onsite will be installed along stream banks during
construction if and when feasible. Sod mats will only be harvested and used if comprised of appropriate
vegetation. The use of sod mats that include aggressive turf grasses will be avoided. Sod mats are
natural sections of vegetation taken from the banks when they were cut during construction, and are
about nine inches thick. Before installation, proposed banks are graded lower than specified to
accommodate the thickness of the mat. The mats are placed on top of the bank to act as a natural
Selma Mill Mitigation Plan 39 April 2016

stabilizer of native species, and they grow much faster than the combination of coir fiber matting and
seeding. Other bank stability measures include the installation of live stakes, log sills, log drop
structures, and log toes. Typical details for proposed in -stream structures and revetments are in
Appendix D.
8.2.2 Natural Plant Community Restoration
8.2.2.1 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 at the reference reach, species present in the forest
surrounding the restoration site, and what is typically native to the area. Several sources of information
were used to determine the most appropriate species forthe restoration project. The reference stream is
located within a disturbed Coastal Plain Small Stream Swamp. Dominant species included sweetgum,
red maple (Acer ruburm), tulip poplar, swamp tupelo (Nyssa biflora), and various oak species (Quercus
sp.) in the canopy. Shrubs included sweetbay (Magnolia virginiana) and American holly (Ilex opaca).
The absence of bald cypress (Taxodium distichum) likely indicates past logging with poor regeneration
at the site. The reference site was chosen due to the stability of the channel, the physical structure of
the forest community, and to evaluate stream habitat. The species present are indicative of early
successional species that have high dispersal rates. The mitigation site also supports many species
typical of this community type due to its past disturbance history. Typically, a Coastal Plain Small
Stream Swamp would occur along the stream banks and adjacent floodplain of the proposed restoration
site.
Coastal Plain Small Stream Swamp will be the target community type and will be used for all areas
within the project, as well as for buffer around the site. The plant species list has been developed and
can be found in Table 19. Species with high dispersal rates are not included because of local occurrence,
adjacent seed sources, and the high potential for natural regeneration. The high dispersal species include
red maple, tulip poplar, and sweetgum.
The restoration of plant communities along the Selma Mill Site will provide stabilization and diversity.
For rapid stabilization of the stream banks (primarily outside meanders), silky dogwood, buttonbush
(Cephalanthus occidentalis), silky willow (Salix sericea), and black willow 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, and they stabilize the stream banks. Willows will
also be quicker to contribute organic matter to the channel. When the other species are bigger, the black
willows and silky willows will slowly stop growing or die out because the other species would 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 three feet from the top of bank, creating a three-foot section along the top
of bank. The live stakes will be spaced one per linear foot with alternate spacing vertically. See
Appendix D for a detailed planting plan.
After construction activities, the subsoil will be scarified and any compaction will be deep tilled/ripped
before the topsoil is placed back over the site. Any topsoil that is removed during construction will be
stockpiled and placed over the site during final soil preparation. This process should provide favorable
soil conditions for plant growth. Rapid establishment of vegetation will provide natural stabilization
for the site.
Table 19. Proposed Plant List
Tree Species- Zone 1 - Lower Floodplain Bench and Wetland
Common Name Scientific Name Wetland Indicator* Growth Rate
Selma Mill Mitigation Plan 40 April 2016

Water tupelo
Nyssa Mora
OBL
moderate
Bald Cypress
Taxodium distichum
OBL
rapid
Oak, Overcup
Quercus lyrata
OBL
moderate
River Birch
Betula nigra
FACW
rapid
Oak, Willow
Quercus phellos
FACW
rapid
Oak, Swamp Chestnut
Quercus michauxii
FACW
moderate
American sycamore
Platanus occidentalis
FACW
Rapid
Tree Species-
Zone 2 — Upper Floodplain
Bench and Riparian Zone
Common Name
Scientific Name
Wetland Indicator*
Growth Rate
Oak, Water
Quercus nigra
FAC
rapid
Oak, Willow
Quercus phellos
FACW
rapid
Oak, Swamp Chestnut
Quercus michauxii
FACW-
moderate
River Birch
Betula nigra
FACW
rapid
American sycamore
Platanus occidentalis
FACW-
rapid
Water tupelo
Nyssa biflora
OBL
moderate
Live Staking and Live Cuttings Bundle Tree Species
Common Name
Scientific Name
Wetland Indicator*
Silky dogwood
Cornus amomum
FACW
rapid
Silky Willow
Salix sericea
OBL
rapid
Black Willow
Salix nigra
OBL
rapid
Buttonbush
Cenhalanthus occidentalis
OBL
rabid
*National Wetland Indicator Status from Draft Rating 2012-Atlantic Gulf Coastal Plain
8.2.2.2 On -Site Invasive Species Management
Control 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. All treatment will be conducted so as to maximize its
effectiveness and reduce chances of detriment to surrounding native vegetation. Treatment methods
will include mechanical control (cutting with loppers, clippers, or chain saw and chemical control
(foliar spray, cut stump, and hack and squirt techniques). Plants containing mature, viable seeds will be
removed from the site and properly disposed of. 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.
8.2.3 Best Management Practices (BMPs)
Diffuse flow structures will be applied at locations where ditches or other forms of concentrated flow
enter the conservation easement. All diffuse flow structures will be installed within the conservation
easement so that landowners will not have access to the structures. Failure or maintenance of the
structures is not anticipated as these structures will be installed in low -gradient areas, and the areas
proposed to diffuse flow will be well vegetated and matted.
During a site visit in 2014, the COE indicated that the site could greatly benefit from a BMP because
of the poor quality of incoming water. Therefore, EBX/RES studied the feasibility of a 2.5 acre in -line
stormwater wetland to address water quality issues and generate approximately 3,475 SMUs. However,
a meeting on March 18, 2015 with the IRT determined that too many SMUs credits were being
requested for the BMP. The required credits were based on estimated costs for design, construction,
and maintenance. Due to the size of the expected flows and culvert arrangement a stand-alone trash
separator is not feasible and the Town of Selma lacks the proper equipment and funding to maintain
such a device. The stormwater wetland BMP was the only feasible way to address this issue and was
ultimately determined financially infeasible. Assessments of the project reaches and downstream
Selma Mill Mitigation Plan 41 April 2016

reaches have not indicated trash to be limiting factor for overall stream function. See Appendix B for
documentation.
Stormwater management issues resulting from future development of adjacent properties will be
governed by the applicable state and local ordinances and regulations. It is recommended that any future
stormwater entering the site maintain pre -development peak flow. Any future stormwater diverted into
the project should be done in a manner as to prevent erosion, adverse conditions, or degradation of the
project in any way.
8.2.4 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 site. Any topsoil that is removed during construction will be
stockpiled and placed over the site during final soil preparation. This process should provide favorable
soil conditions for plant growth. Rapid establishment of vegetation will provide natural stabilization
for the site.
8.3 Data Analysis
8.3.1 Stream Data Analysis
8.3.1.1 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 20) 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,
• NC and VA/MD Regional Curves for the Coastal Plain, and
• USGS regional regression equations for rural conditions in the Coastal Plain.
Regional Flood 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 mi') 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-1 because it
allows the user to adjust the peak shape factor for the Coastal Plain conditions. Rainfall data reflecting
both a100 and 284 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.
Selma Mill Mitigation Plan 42 April 2016

Calibration studies across the State of North Carolina have been developed by the National Resources
Conservation Service (NRCS) that show the standard 484 peak shape factor found in HEC-1 and HEC-
HMS are too conservative. The NRCS recommends using a value that ranges between 100 and 284 for
those areas on the eastern side of the state.
Regional Curve Regression Equations
The North Carolina Coastal Plain regional curves by Doll et al. (2003) and Sweet and Geratz (2003)
and the Virginia/Maryland (Krstolic et al., 2007) Coastal Plain regional curves for discharge were used
to predict the bankfull discharge for the site. The NC regional curves predicted flows that are similar to
those predicted by the 1.1-year flood frequency, while the VA/MD curves are comparable to flows
predicted by the 1.5-year flood frequency equation. The regional curve equations for NC discharges by
Doll et al. (2003) (1) and Sweet and Geratz ( 2003) (2) and VA/MD (3) discharges are:
(1) QbkJ=16.56*(DA)0.71 (Doll et al., 2003)
(2) Qbkj=8.49*(DA)076 (Sweet and Geratz, 2003)
(3) Qbkj= 28.3076*(DA)o.19114 (Krstolic et al., 2007)
Where Qbkf=bankfull discharge (ft3/s) and DA=drainage area (mi')
USGS Regional Regression Equations
USGS regression equations estimate the magnitude and frequency of flood -peak discharges (Gotvald,
et al., 2009). The regression equations were developed from gauge data in different physiographic
regions of the Southeastern United States. For this analysis, there was only concern for the 2-year return
interval. The equation for the rural Coastal Plain (Hydrologic Region 4) is:
(4) Q2=60.3 * (DA)0.649
Table 20. Peak Flow Comparison
Reach
Drainage
Area
(Ac)
Hydraflow
Qi
FFQ
Qi'i
FFQ
Qi'e
NC
Regional
Curve Q (1)
NC Regional
Curve Q (2)
VA/NM
Regional
Curve Q (3)
Regional
Regression
Eqns. Qz
Design/
Calculated
Q
Reference
540
20
19
23
15
8
26
54
15-20
A
583
59
20
47
15
8
27
57
27
13
189
11
8
22
7
4
14
27
15
C
42
2
2
8
2
1
6
10
NA
Summary and Conclusions
Because the Hydraflow Express model accounts for the urbanized watershed above Reach A; the model
results were significantly higher than both the regional curves and the 1.1-year and 1.5-year flood
frequency analysis. To account for these increased flows, a nested channel approach was implemented
along Reach A. The design discharge for the primary/low flow channel was selected to match the 1.1-
year and 1.5-year flood frequency analysis results, while the upper channel/low bench was sized such
that it will convey flows that range between the Hydraflow Express model results for the 1-year and 2-
year storm events. This will allow smaller storms to inundate the adjacent floodplain bench more
frequently, resulting in lower in -stream stresses.
Selma Mill Mitigation Plan 43 April 2016

8.3.1.2 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 forthis project. The following methods and functions
were utilized during the sediment transport analysis:
Stable Channel Design Function — Copeland Method (HEC-RAS),
Shear Stress, and
Velocity.
Stable Channel Design
Design cross-section dimensions as determined from the analog approach 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 min to 2 mm) and was selected for application at the Selma Mill Site.
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. The stable design output parameters are listed in Table 21. The results
are acceptable and match closely with the design reach parameters.
Table 21. Stable Channel Design Output
Reach Q (ft/s3) Bottom
Depth (ft) Energy
Composite
Velocity
Shear Stress
Width (ft)
Slope (ft/ft)
n value
(ft/s)
(lbs/ft )
A 27 6
1.6 0.002
0.041
1.8
0.21
B 15 5
1.2 0.003
0.041
1.8
0.22
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, and vegetative cover. The shear stress approach compares calculated
shear stresses to those found in the literature. Shear stress is the force exerted on a boundary during the
resistance of motion as calculated using the following formula:
(1) i = yRS
i = shear stress (lb/ft')
y = specific gravity of water (62.4 lb/ft3)
R = hydraulic radius (ft)
S = average channel slope (ft/ft)
Selma Mill Mitigation Plan 44 April 2016

Table 22. Comparison of Allowable and Proposed Shear Stresses
Proposed Shear Stress
Allowable Shear Stress'
Reach at Bankfull Stage
Critical Shear Stress
(Ibs/ft)
Sand/Silt/Clay
Vegetation
z
Obs/ft)
(lbs/ft2)
(lbs/ft2)
A 0.15
>0.003
0.03 to 0.26
0.2 to 0.95
B 0.17
>0.003
0.03 to 0.26
0.2 to 0.95
'(Fischenich, 2001
Review of the above table shows that the proposed shear stresses for the Selma Mill Site design reaches
fall between the critical shear stress (shear stress required to initiate motion) and the allowable limits.
Therefore, the proposed channel should remain stable.
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 23 compares the proposed velocities calculated using
Manning's equation with the permissible velocities presented in the Stream Restoration Design
Handbook (MRCS, 2007).
Table 23. Comparison of Allowable and Proposed Velocities
Reach Manning's "n" Design Velocity (ft/s) Allowable Velocity' (ft/s)
value Fine Sand Coarse Sand
A 0.05 1.5 2.0 4.0
B 0.05 1.5 2.0 4.0
'(ARCS, 2007)
8.3.2 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 largely dominated by agricultural and residential
Selma Mill Mitigation Plan 45 April 2016

landuse, 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 sand -bed 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, restoring a portion of the hydrology for the
existing wetlands.
A large portion of the existing stream will be filled using material excavated from the restoration
channel. However, many segments will be left partially filled to provide habitat diversity and flood
storage. Native woody material will be installed throughout the restored reach to reduce bank stress,
provide grade control, and increase habitat diversity.
Forested riparian buffers of at least fifty feet on both sides of the channel will be established along the
project reach. An appropriate riparian plant community, a Coastal Plain Small Stream Swamp, will be
established to include a diverse mix of species. Replanting of native species will occur where the
existing buffer is impacted during construction.
The Selma Mill Stream Mitigation Site is being built in conjunction with the Selma Mill Buffer/Nutrient
Offset Site. Reductions in nutrients and other pollutants will be achieved with the buffer restoration
work, providing substantial benefits to the watershed. The Buffer/Nutrient Offset site will only generate
credits on the first 50 feet of buffer in the easement per USACE consultation.
Due to the nature of the project, complete avoidance of stream and wetland impacts is not possible.
Proposed stream impacts, including stream relocation and culverts, total 5,801 linear feet, and will be
replaced on site. The proposed site will result in 6,881 LF of stream with three stream crossings.
Wetland impacts associated with restoration efforts total 1.12 acres of temporary impact. Creating a
new stream channel and enhancing existing channels will only temporarily impact wetlands and will
provide an overall increase in wetland function with the addition of native trees and shrubs along the
stream banks, and restored hydrology. All stream and wetland impacts will be accounted for in the Pre -
Construction Notification (PCN) form.
Selma Mill Mitigation Plan 46 April 2016

9 MAINTENANCE PLAN
The site will be monitored on a regular basis and a physical inspection will be conducted a minimum
of once per year throughout the post construction monitoring period until performance standards are
met. These site inspections may identify site components and features that require routine maintenance.
Routine maintenance should be expected most often in the first two years following site construction
and may include the following:
Table 24. Maintenance Plan
Component/Feature
Maintenance through project close-out
Stream
Routine channel maintenance and repair activities may include chinking of
in -stream structures to prevent piping, securing of loose coir matting, and
supplemental installations of live stakes and other target vegetation along
the channel. Areas where stormwater and floodplain flows intercept the
channel may also require maintenance to prevent bank failures and head -
cutting. Stream maintenance activities will be documented and reported in
annual monitoring reports. Stream maintenance will continue through the
monitoring period.
Vegetation
Vegetation shall be maintained to ensure the health and vigor of the targeted
plant community. Routine vegetation maintenance and repair activities may
include supplemental planting, pruning, mulching, and fertilizing. Exotic
invasive plant species shall be controlled by mechanical and/or chemical
methods. Any vegetation control requiring herbicide application will be
performed in accordance with NC Department of Agriculture (NCDA) rules
and regulations. Vegetation maintenance activities will be documented and
reported in annual monitoring reports. Vegetation maintenance will
continue through the monitoring period.
Site Boundary
Site boundaries shall be identified in the field to ensure clear distinction
between the mitigation site and adjacent properties. Boundaries will be
marked with signs identifying the property as a mitigation site, and will
include the name of the long-term steward and a contact number.
Boundaries may be identified by fence, marker, bollard, post, tree -blazing,
or other means as allowed by site conditions and/or conservation easement.
Boundary markers disturbed, damaged, or destroyed will be repaired and/or
replaced on an as -needed basis. Easement monitoring and staking/signage
maintenance will continue in perpetuity as a stewardship activity.
Road Crossing
Road crossings within the site may be maintained only as allowed by
Conservation Easement or existing easement, deed restrictions, rights of
way, or corridor agreements. Crossings in easement breaks are the
responsibility of the landowner to maintain.
Livestock Fencing
Livestock Fencing is to be placed outside the easement limits. Maintenance
of fencing is the responsibility of the landowner.
Beaver
Routine site visits and monitoring will be used to determine if beaver
management is needed. If beaver activity poses a threat to project stability
or vegetative success, RES will trap beavers and remove impoundments as
needed. All beaver management activities will be documented and included
in annual monitoring reports. Beaver monitoring and management will
continue through the monitoring period.
Selma Mill Mitigation Plan 47 April 2016

10 PERFORMANCE STANDARDS
The success criteria for the Site will follow accepted and approved success criteria presented in the
USACE Stream Mitigation Guidelines and subsequent agency guidance. Specific success criteria
components are presented below.
10.1 Stream Restoration Success Criteria
10.1.1 Bankfull Events
Two bankfull flow events must be documented within the seven-year monitoring period. The two
bankfull events must occur in separate years. Otherwise, the stream monitoring will continue until two
bankfull events have been documented in separate years.
10.1.2 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 reaches.
Channel stability should be demonstrated through a minimum of two bankfull events documented in
the seven-year monitoring period.
10.1.3 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.
10.1.4 Surface Flow
Headwater valley restoration reaches will be monitored to document intermittent or seasonal surface
flow. This will be accomplished through direct observation, photo documentation of dye tests, and the
use of stream gauge transducers with data loggers. Reaches must demonstrate a minimum of 30
consecutive days of flow.
10.2 Vegetation Success Criteria
Specific and measurable success criteria for plant density within the riparian buffers on the site will
follow IRT Guidance. Vegetation monitoring plots will be a minimum of 0.02 acres in size, and cover
a minimum of two percent of the planted area. Vegetation monitoring will take place annually between
July 15 and leaf drop. The interim measures of vegetative success for the site 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 the
end of Year 5, and the final vegetative success criteria will be 210 trees per acre with an average
height of 10 feet at the end of Year 7. The site will include 25 monitoring plots to monitor the 29.8
planted acres (See Drawing M1 in Appendix D). Volunteertrees will be counted, identified to species,
and included in the yearly monitoring reports, but will not be counted towards the success criteria of
total planted stems.
Selma Mill Mitigation Plan 48 April 2016

11 MONITORING REQUIREMENTS
Annual monitoring data will be reported using the 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. The success criteria for
the Site will follow current accepted and approved success criteria presented in the USACE Stream
Mitigation Guidelines, and subsequent agency guidance. Specific success criteria components are
presented in Table 25. Monitoring reports will be prepared annually and submitted to the IRT. Sheet
M1 in the design plan set (Appendix D) depicts the proposed location of monitoring devices.
Table 25. Monitoring Requirements
Required
Parameter
Quantity
Frequency
Notes
As per April 2003
USACE Wilmington
Additional surveys will be performed if
Pattern
District Stream
Baseline
monitoring indicates instability or
Mitigation
significant channel migration
Guidelines
As per April 2003
Baseline,
USACE Wilmington
Years
Dimension
District Stream
1,2,3,5,
Surveyed cross sections and bank pins
Mitigation
and
Guidelines
As per April 2003
USACE Wilmington
Additional surveys will be performed if
Profile
District Stream
Baseline
monitoring indicates instability
Mitigation
Guidelines
As per April 2003
Crest gauges and/or pressure
Surface
USACE Wilmington
transducers will be installed on site; the
Water
District Stream
Annual
devices will be inspected on a quarterly
Hydrology
Mitigation
basis to document the occurrence of
Guidelines
bankfull events
Vegetation
Annual
Vegetation will be monitored per IRT
guidelines
Exotic and
Nuisance
Annual
Locations of exotic and nuisance
Vegetation
vegetation will be mapped
Project
Semi-
Locations offence damage, vegetation
Boundary
annual
damage, boundary encroachments, etc.
will be mapped
Stream
Visual
Annual
Semi-annual visual assessments
11.1 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. Stream channel stationing will be marked with stakes
placed near the top of bank every 200 feet.
Selma Mill Mitigation Plan 49 April 2016

11.2 Visual Monitoring
Visual monitoring of all mitigation areas will be conducted a minimum of twice per monitoring year
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. 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 erosion control measures. 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.
11.3 Cross Sections
Permanent cross -sections will be installed at a minimum of one per 20 bankfull widths with half in
pools and half in shallows. All cross-section measurements will include bank height ratio and
entrenchment ratio. Cross -sections will be monitored annually. There should be little change in as -built
cross -sections.
11.4 Surface Flow
Headwater valley restoration areas will be monitored to document intermittent or seasonal surface flow.
This will be accomplished through direct observation, photo documentation of dye tests, and surface
flow gauges.
11.5 Vegetative Success Criteria
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 25 plots within the planted area (29.8 acres). Planted area
indicates all area in the easement that will be planted with trees. Existing wooded areas (e.g. top of
Reach A and Reach B) are not included in the planted area. The following data will be recorded for all
trees in the plots: species, height, planting date (or volunteer), and grid location. Monitoring will occur
each year during the monitoring period. Invasive and noxious species will be monitored and controlled
so that none become dominant or alter the desired community structure of the site. If necessary, RES
will develop a species -specific control plan.
11.6 Scheduling/Reporting
A mitigation plan and as -built drawings documenting stream restoration activities will be developed
within 60 days of the planting completion on the mitigation site. The report will include all information
required by IRT 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 USACE guidelines.
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.
Selma Mill Mitigation Plan 50 April 2016

Monitoring reports will be prepared in the fall of each year of monitoring and submitted to the IRT.
The monitoring reports will include all information, and be in the format required by USACE.
Selma Mill Mitigation Plan 51 April 2016

15 OTHER INFORMATION
15.1 References
Johnston County, North Carolina. Available online at http://www.fNvs.gov/raleigh/. [Accessed 25
October 2011.]
Amoroso, J.L., ed. 1999. Natural Heritage Program List of the Rare Plant Species of North Carolina.
North Carolina Natural Heritage Program, Division of Parks and Recreation, North Carolina
Department of Environment and Natural Resources. Raleigh, North Carolina.
Chow, Ven Te. 1959. Open -Channel Hydraulics, McGraw-Hill, New York.
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, Barbara 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.
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.
Johnson PA. 2006. Assessing stream channel stability at bridges in physiographic regions. U.S.
Department of Transportation. Federal Highway Administration. Report Number FHWA-HRT-05-
072.
Krstolic, J.L., and Chaplin, J.J. 2007. Bankfull regional curves for streams in the non -urban, non -tidal
Coastal Plain Physiographic Province, Virginia and Maryland: U.S. Geological Survey Scientific
Investigations Report 2007-5162, 48 p. (available online at http://pubs.water.usgs.gov/sir2007-5162)
LeGrand, H.E., Jr. and S.P. Hall, eds. 1999. Natural Heritage Program List of the Rare Animal
Species of North Carolina. North Carolina Natural Heritage Program, Division of Parks and
Recreation, North Carolina Department of Environment and Natural Resources. Raleigh, North
Carolina.
Natural Resources Conservation Service (MRCS). 2007. Stream Restoration Design Handbook (NEH
654), USDA
Selma Mill Mitigation Plan 55 April 2016

NCDENR 2012a. "Water Quality Stream Classifications for Streams in North Carolina." Water
Quality http://portal.ncdenr.org/web/wg/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).
North Carolina Ecosystem Enhancement Program (NCEEP). "Neuse River Basin Restoration
Priorities 2010." (September 2014).
Peet, R.K., Wentworth, T.S., and White, P.S. (1998), A flexible, multipurpose method for recording
vegetation composition and structure. Castanea 63:262-274
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.
Rosgen, D. (1996), Applied River Morphology, 2nd edition, Wildland Hydrology, Pagosa Springs, CO
Schafale, M.P. and A.S. Weakley. 1990. Classification of the Natural Communities of North
Carolina, Third Approximation. North Carolina Natural Heritage Program, Division of Parks and
Recreation, NCDENR, Raleigh, NC.
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.
Tweedy, K. A Methodology for Predicting Channel Form in Coastal Plain Headwater Systems.
Stream Restoration in the Southeast: Advancing the Science and Practice, November 2008, Asheville,
NC. Unpublished Conference Paper, 2008.
http://www.bae.ncsu.edu/programs/extension/wgg/sp2/2008conference/tweedy paper.pdf
US Army Corps of Engineers (USACE), 2002. Regulatory Guidance Letter. RGL No. 02-2,
December 24, 2002.
US Army Corps of Engineers (USACE), 2003. April 2003 NC Stream Mitigation Guidelines
United States Department of Agriculture (USDA), Natural Resources Conservation Service (MRCS),
1994. Soil Survey of Johnston County, North Carolina.
U.S. Army Corps of Engineers (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.
United States Department of Agriculture (USDA), Natural Resources Conservation Service (MRCS),
Web Soil Survey; hiip://websoilsurvey.nres.usda.gov (September 2014).
United States Department of Agriculture, Natural Resources Conservation Service. 2010. Field
Indicators of Hydric Soils in the United States, Version 7.0. L.M. Vasilas, G.W. Hurt, and C.V. Noble
(eds.). USDA, NRCS, in cooperation with the National Technical Committee for Hydric Soils.
Selma Mill Mitigation Plan 56 April 2016

United States Environmental Protection Agency, (USEPA, 1999) 1999. EPA Manual. Quantifying
Physical Habitat in Wadeable Streams.
United States Fish and Wildlife Service. "Threatened and Endangered Species in North Carolina."
North Carolina Ecological Services. http://www.fivs.gov/raleigh/. (September 2014).
USDA-NRCS. 1986. Urban Hydrology for Small Watersheds. Technical Release 55.
Selma Mill Mitigation Plan 57 April 2016

Figure 11e. Non Standard Buffer Width Calculations
Reach
Base SMUS
Multiplier
Calculated Total*
Al-RB
183
0%
92
A2-RB
167
12%
94
A3-RB
709
20%
425
A4-RB
587
7%
314
A5-RB
235
0%
117
A6-RB
336
0%
168
A7-RB
339
7%
181
A8-RB
84
0%
42
A9-RB
294
16%
171
A10-RB
390
20%
234
Al -LB
112
0%
56
A2-LB
137
20%
82
A3-LB
339
7%
181
A4-LB
280
0%
140
A5-LB
1013
12%
567
A6-LB
147
12%
82
A7-LB
278
16%
161
A8-LB
333
12%
186
A9-LB
203
12%
114
A10-LB
415
20%
249
All -LB
66
0%
33
Reach A Total
3690
Bl-RB
223
0%
112
B2-RB
622
12%
348
B3-RB
926
12%
519
B4-RB
296
12%
166
B5-RB
503
0%
252
Bl-LB
254
0%
127
B2-LB
591
7%
316
B3-LB
141
12%
79
B4-LB
476
7%
254
B5-LB
248
0%
124
B6-LB
358
7%
192
B7-LB
503
0%
252
Reach B Total
2740
Cl-RB
559
0%
279.5
C2-RB
559
0%
279.5
Cl-LB
426
0%
213
C2-LB
426
0%
213
Reach C Total
985
Project Total
7415
* Calculated Total formula = (Base SMU x Multiplier)/2
Methodology
Reach breaks were drawn at 90 degree angles from the edge of outside meanders,
Reach breaks must incorporate entire wavelength to simplify the number of breaks.
Smaller multiplier was always used in areas of overlap
At confluences, credits were not given for the same area twice
0 one reach was chosen for the multiplier (as shown with the confluence break lines)
o the other reach was given no multiplier
Only first 50 feet of buffer are generating NCDWR buffer mitigation credits

M E M O R A N D U M
302 Jefferson Street, Suite 110 Raleigh, North Carolina 27605 919.209.1056 tel.
TO: Andrea Hughes- USACE
FROM: Brad Breslow, Daniel Ingram- RES
DATE: July 18, 2016
RE: Response to Selma Mill Mitigation Plan Comments
Selma Mill Draft Mitigation Plan, SAW-2015-00710
fires
919.829.9913 fax
Listed below are comments provided by the USACE the Selma Mill Mitigation Plan and RES' responses:
1. The linear feet of restoration areas should be consistent throughout the document. In one section Reach
C indicates 929 LF, in another 979, and the chart (Section 5.0) it still indicates adjustment for extra
buffers.
The document and figures have been updated to be consistent throughout.
2. I recognize that the CE has been recorded so I am not requesting that you make changes. For future
reference, the 60 day notification also applies to transfer of the property. Also, the CE should reference
the Action ID number for the mitigation plan (in this case SAW-2015-00710).
Updated
3. JD approval letter is required.
JD Approval letter included in Appendix B and referenced on Page 25.
4. Please make the required changes to Section 6.1 per the response to comments memo.
Section highlighting requirements for initial allocation of released credits has been updated.
5. Page 36, please revise the paragraph for Reach C to reflect changes to the design.
Paragraph has been updated.
6. Page 37, the description of Reach C states "just upstream of Reach C" — should this be corrected to
state Reach B?
Description has been updated.
7. Sections 11.3 and 11.5 are monitoring descriptions but success criteria is included (this was provided
in the Performance Stds section). I suggest removing any duplication.
Redundancies from sections 11.3 and 11.5 were removed from the document.

8. Page 51, the monitoring period is 7 years (not 5).
Text was updated to read 7 years.
9. Adaptive Management — Section 11.7 should be combined with 13.0.
Combined sections into 13.0.
10. Financial Assurances — this section should provide information related to how the monies will be
handled in the event of default (the CE holder has agreed to receive the funds and ensure the work is
successfully completed).
Text was added to this section stating, In the event of sponsor default, the NCWHF has agreed to receive
the funds and ensure the work is successfully completed. "
11. Page 2 should reflect changes in design.
Updated
12. The HWV restoration is based only on valley length. The length should be measured in a straight line
down the valley. According to page E4 of the plans, the beginning should be at approximately station
1+40 and extend to approximately station 10+00. Therefore the length, adjusted for the 30 foot easement,
should be approximately 860 LF. The length associated with connecting to a pond outlet is not included
because it is not within the (straight line) valley.
Updated

k
'S
a
Reach B
Powerline-
Easement Break
I
■ +4 ft:ti
Existing Proposed Mitigation Base Adjaested
* Reach Mitigation Type Length (LE) Length (LE) Ratio SMUs SMUs*
A Pl/P2 Restoration 2,145 2,646 1 : 1.0 2,646 3,005
A Pl Restoration 540 654 1 : 1.0 654 762
B P2 Restoration 728 832 1:1.0 832 927
B Pl/PZ Restoration 1,062 1,223 1 : 1.0 1,223 1,376
B P2 Restoration 405 504 1 : 1.0 504 535
r C Headwater Valley Restoration 658 779 1 : 1.0 779 873
C Headwater Valley Restoration 294 426 1 : 1.0 426 481
f' Total 5,832 7,064 7,064 7,959
•f*SMUadiushnentsbased onnon-standard bufferwidths.
Figure G. Priority 1 Restoration
Resource Conceptual Design Plan Priority 2 Restoration
Environmental Selma Mill Mitigation Site Headwater Valley Restoration
Solutions 0 175 350 700 Crossing
Feet Existing Wetlands
1 Inch = 350 feet Q Proposed Easement