HomeMy WebLinkAboutSW5240602_Stormwater Narrative_20241007 ne
LERING,IN'.
Red Bud Solar
Post-Construction Stormwater Project
Narrative
Nash County, NC
Prepared by:
NEI Electric Power Engineering, Inc.
12600 W Colfax Avenue, Suite C500
Lakewood, CO 80215
REV DATE ENG APPVD DESCRIPTION
1 05/28/24 MJG RDB Issue for Permit
2 10/04/24 MJG RDB Issue for Permit
neiengineering.corn
12600 West Colfax Ave., Suite C500, Lakewood, CO 80215
October 3,2024
RE: Red Bud Solar-Project Narrative
The Red Bud Solar project, located in Nash County, involves the improvement of approximately
320.2 acres of undeveloped land into a solar energy generation facility.The proposed construction
includes the clearing and grubbing of existing wooded land, grading of the existing contours and
the construction of a new substation, solar facility, and access roads. Access to the site will be
provided by entrance driveways on Taylors Gin Rd.
The site coordinates are 36° 4'29.14"N and 78° O'54.06"W. Red Bud Solar is in the Tar-Pamlico
River Basin.All subject parcels are wooded and located off Taylors Gin Rd.
The owner for the project is listed as follows:
Duke Energy
160 Rush St. Raleigh NC 27603
Contact: Zachary Cole (Zachary.cole®duke-energy.com)
Jurisdictional and non-jurisdictional wetlands have been identified throughout the site. No
jurisdictional wetlands are to be disturbed as part of this project.
The proposed improvements will not result in more than 15% of the project area converted to
impervious surface. In the existing condition, approximately 9.94 acres, less than 2% of the site, is
existing impervious area in the form of aggregate and compacted dirt roads. In the proposed post-
construction condition,total impervious area will increase to 3.5 acres, or approximately 2%of the
site.Therefore,the proposed project is compliant with the Tar-Pamlico nutrient reduction and peak
flow attenuation requirements. The project meets the requirements of Low Density Development
as outlined in NCAC 15a. Less than 12%of the site is classified as Built-Upon Area. Please see the
attached Supplemental EZ form for more details.
Sediment and erosion control measures will be implemented prior to the occurrence of any earth-
disturbing activities. Perimeter control BMPs will be installed prior to the mass grading of the site.
Sediment basins and skimmer basins will be the primary sediment control BMPs used during the
lifespan of all construction activities until final stabilization is reached. Once final stabilization has
been established, all sediment basins will be decommissioned and removed. No permanent
BM PS will be established on site.
Below is an overview of the project site.
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PROJECT SITE MAP
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APPROX. SITE AREA
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The project also complies with all recommendations in Part E-6 of the NCDEQ Stormwater Design
Manual. Below is a description of how each recommendation is achieved on the project.
RECOMMENDATION 1: AVOID COMPACTION OF SUBSOIL
Subsoil compaction should be minimized during and after installation of solar arrays to allow
the maximum amount of natural infiltration. If compaction occurs during construction, subsoil
should be tilled and amended to return the soil to its pre-compaction condition.
The design has kept site grading to the minimum needed to make the site constructable for the
solar arrays. Limiting the use of heavy equipment on site will also help avoid compacting the
subsoil. Installation of steel piers and solar modules will use light tracked equipment. An
additional note has been added to the Grading Plan Note 13 on Sheet CO1-02 of the plans.
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RECOMMENDATION 2: DISCONNECT RUNOFF FROM SOLAR PANEL ARRAYS
Solar arrays should be designed and installed to allow growth of vegetation under and
between the solar arrays. Rows of panels should be installed with sufficient distance
between rows to allow for capture of rainfall from at least 1.0 inch of rain (Figure 1). Where
installed on slopes greater than 8%. consider options for maintaining sheet flow and
dissipating energy at the drip edge of each row of panels.
Figure 1: Disconnection of flow path between solar panels when average slope is
less than 8%.
Solar Panel Width=X ft Disconnection Length>_X ft Solar Panel Width=X ft
Disconnection Flow Path
i.
Avg Slope • 8%
In general, the minimum disconnection length between two rows of solar panels is equal to the
width of each row, as shown in Figure 1. However, some panel layouts include horizontal gaps
between individual modules that allow stormwater to drip off the panels at intervals much
smaller than the width of each row. In these instances, the solar farm can be designed with a
smaller disconnection length, provided that they will not cause concentration of stormwater
runoff. The disconnection length should not be less than 80% of the total solar panel width.
The solar panel width is 14.74' and the disconnection length is 12.04'for this project. However,
each row uses two solar modules in portrait orientation with a horizontal gap between the rows to
allow stormwater to drip off.
12.04
= 0.81
14.84
The project complies with this recommendation by including the horizontal gap and maintaining a
disconnection length greater than 80% of the total solar panel width.The figure below was taken
directly from the manufacturer's installation manual for this product.
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Table 1
Gap between
{ modules
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RECOMMENDATION 3: AVOID CONCENTRATION OF STORMWATER
Panels should be positioned to allow stormwater to run off their surfaces; however, collection
and concentration of stormwater flow is to be avoided. Arrays should be installed on a
uniform plane such that stormwater will sheet flow off the panels and remain unconcentrated.
When considering a potential build site. it's a good idea to consider the slope of the land in
the areas of the site where the solar arrays are most likely to be installed. Areas with steep
slopes may not be suitable or may require considerable grading.
The site is designed to allow water to disperse within the array areas to avoid concentration.
There are no design features within the arrays intended to concentrate flows.
RECOMMENDATION 4: MINIMIZE USE OF HERBICIDES AND FERTILIZERS
Weed control and vegetation management is particularly important for ground-mounted solar
systems. Overuse of herbicides and fertilizers can contribute to degraded water quality. Limit
the use of fertilizers to that necessary to maintain vegetation. Use mowing for vegetation
control instead of herbicides.
A Vegetation Management Plan has been prepared for this project and is attached in the
appendix of this document for reference. Herbicides will only be used to target a specific list of
invasive species and allow for growth of the desired vegetative cover. The site will be mowed for
vegetation control.
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RECOMMENDATION 5: PLANT MIX OF WARM- & COOL-SEASON GRASSES
Large solar arrays can have the effect of creating microclimates under the panels. To help
account for this, plant a mixture of warm-season and cool-season grasses to account for
differences in temperature and shading created from the installation of large solar arrays. In
addition, use low-growing, low-maintenance grass mixtures. Planting mixtures can also
include low-growing wildflowers such as white clover and other types of vegetation that can
be attractive to pollinators. A win-win for the grass and the bees!
The plans include NCDEQ recommended seeding mixes for warm and cool seasons. The
Vegetation Management Plan also includes temporary and permanent seed mixes to be used for
the lifetime of the project.
RECOMMENDATION 6: LIMIT VERTICAL CLEARANCE TO <_ 10 FEET
Stormwater runoff falling from solar panels can cause scouring and erosion at the driplines.
Limiting the lowest vertical clearance to no greater than 10 feet will help prevent erosion and
scouring along the dripline.
No vertical clearance will be greater than 10 ft on the low edge of the panels.
Best Regards,
Ryan Brick
rbrick®a neieng.com
12600 W Colfax Avenue, Ste C500 Lakewood, CO 80215
720-817-0321
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Appendix A: Vegetation and Soil
Management Plan
•
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CONFIDENTIAL BUSINESS INFORMATION
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Duke Energy Renewables
Red Bud Solar Phase I
Vegetation and Soil Management Plan-
DRAFT 1
Nash County, NC I DRAFT March 29, 2024
Chris Ryan
Project Manager
cryan@res.us 1843.2787.7515
Duke Energy Solar Solutions I Red Bud Vegetation&Soil Management Plan
CONFIDENTIAL BUSINESS INFORMATION
Table of Contents
1.0 Introduction 1
1.1 Overview 1
1.2 Project Description 1
2.0 Objectives 2
3.0 Existing Conditions 2
3.1 Site Conditions 2
3.2 Soil Characterization 3
3.3 Site Hydrology and Drainage 4
4.0 Integrated Vegetation Management 4
4.1 Integrated Vegetation Management Overview 4
4.2 Project Submittals 5
5.0 Construction Phase Vegetation and Stabilization Management 5
5.1 Vegetation Sequencing 5
5.2 Pre-Panel Construction Soil Management 6
5.3 Temporary Stabilization 6
5.4 Seed Bed Preparation 7
5.5 Seed Installation Methods 8
5.6 Permanent Ground Cover Seed Installation 9
5.7 Final Stabilization 11
5.8 Adaptive Management Strategies 11
6.0 Post Construction Performance Standards 12
6.1 Preliminary Acceptance 12
6.2 Final Acceptance 12
6.3 Project Vegetation Performance Standards 13
7.0 Post-Construction Short-Term and Long-Term Vegetation Maintenance and Monitoring 13
7.1 General Practices 13
7.2 Annual Maintenance Plan 13
7.3 Monitoring 14
7.4 Vegetation Control Activities 14
7.5 Remedial Seeding 15
8.0 References 16
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List of Tables
Table 1. Project Soil Types 3
Table 2. Vegetation Scope Submittals Required to Support Project IVM Objectives 5
Table 3. Temporary Seed Mix by Season 7
Table 4. Permanent Mix—Grassy Only Cover(GO). 9
Table 5. Pollinator Seed Mix for Upland (PHU) Zones Outside of Arrays 10
Table 6. Vegetation Performance Standards 13
Table 7. Vegetation Action Thresholds and Tolerance Levels within the Arrays 14
Table 8. Vegetation Action Thresholds and Tolerance Levels outside the Arrays 15
List of Appendices
Appendix A/Maps
Appendix B/ Nuisance Plant Species
Appendix C/Soils
Appendix D/ North Carolina Solar Site Habitat Planning and Assessment Form
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i.o Introduction
Li Overview
Duke Energy Corporation (Duke) plans to construct a solar energy generation facility, the Red Bud Solar Farm (Project),
situated within an approximate 477.5-acre property boundary with a solar photovoltaic (PV) generation facility planned for
approximately 322 acres.The Project's location resides in Nash County, NC.
To support project development and successful vegetation establishment, Resource Environmental Solutions, LLC (RES)was
contracted to prepare a Vegetation and Soil Management Plan (VSMP). The VSMP provides the method and materials
needed to establish permanent, naturalized vegetative cover efficiently and effectively while minimizing erosion.The VSMP
also provides a method to prevent establishment of undesirable species and outlines vegetation maintenance requirements.
The details contained in this document are intended to be prescriptive steps for vegetation and soil management prior to,
during, and after project construction and during operations. Proper establishment of permanent vegetation provides
numerous benefits, including erosion control, competition against nuisance plant species, water infiltration, water
purification, and improved soil health.
The general construction contractor ("Contractor") will be responsible for the construction of the Project's facilities and
compliance with all federal, state, and local laws and ordinances pertaining to the work described within this document. All
contract documents, designs, specifications, and direction provided by Duke Energy Corporation shall supersede this
document.
1.2 Project Description
The Project Boundary is technically located in all or portions of Castalia, NC. Specifically, it is located approximately 11 miles
west of 1-95 and 7 miles north of US-64/Nashville, NC (Appendix A, Figure 1). The Project is located on the north side of
Taylors Gin Road (State Rd S-30-399), approximately 1.5 miles to the east of Castalia, NC. Pig Basket Creek,which flows west
to east, is located in the southern portion of the property with a larger portion being to the north of the creek. Pig Basket
Creek continues for approximately 8.5 miles before reaching confluence with the Stoney Creek, which continues an
additional -A miles before reaching the confluence with the Tar River in the town of Rocky Mount.
The project is in the Eastern Slate Belt of the Piedmont Level III EPA Ecoregion. Per the EPA descriptions, it comprises a
transitional area between the mostly mountainous ecological regions of the Appalachians to the northwest and the relatively
flat coastal plain to the southeast. Its eastern border is the fall line, where erosion resistant rocks give way to the sands and
clays of the coastal plain.The historic oak-hickory-pine forest was dominated by white oak, southern red oak, post oak, and
hickory, with some shortleaf pine and loblolly pine. There is a moderate to dense network of perennial streams and rivers,
of generally moderate to low gradient. Stream drainage in the Piedmont tends to be perpendicular to the structural trend
of the rocks across which they flow. Few natural lakes but numerous large reservoirs are to be found. The ecoregion's
dominant landform is an erosional terrain of moderately dissected irregular plains with some hills, with a complex mosaic
of Precambrian and Paleozoic metamorphic and igneous rocks. Most rocks of the Piedmont are covered by a thick mantle
of saprolite, except along some major stream valley bluffs and on a few scattered granitic domes and flatrocks. Rare plants
and animals are often found on the rock outcrops. The soils are mostly Ultisols and are generally finer-textured than those
found in coastal plain regions with less sand and more clay. Mammals include white-tailed deer, black bear, bobcat, gray
fox, raccoon, gray squirrel, eastern chipmunk, pine vole. Birds include eastern wild turkey, northern cardinal, Carolina wren,
wood thrush,tufted titmouse, prairie warbler,field sparrow. Herpetofauna includes eastern box turtle,common garter snake,
copperhead, timber rattlesnake. Several major land cover transformations have occurred in the Piedmont over the past 200
years, from forest to farm, back to forest, and now in many areas, spreading urban- and suburbanization. Once largely
cultivated with crops such as cotton, corn, tobacco and wheat, most of the Piedmont soils were moderately to severely
eroded. Much of this region is now in planted pine or has reverted to successional pine and hardwood woodlands, with
some pasture in the landcover mosaic. Larger cities include Lynchburg, Greensboro, Raleigh, Charlotte, Greenville, and
Atlanta (CEC 2011).
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2.0 Objectives
The VSMP has been prepared to ensure successful and prompt establishment of permanent native vegetation for the Project
and to position for efficient vegetation maintenance during operations. The following goals and objectives have been
established for this management plan:
• Stabilize areas disturbed during construction with desired vegetation cover and meet the revegetation
requirements for NPDES construction stormwater compliance in North Carolina.
• Minimize the presence and proliferation of noxious and invasive species throughout the construction and
operational project phases.
• General adherence to the conservation practices of the National Resources Conservation Service (NRCS, Code
327).
• Incorporate and cite to the principles of the Environmental Protection Agency's (EPA) Integrated Vegetation
Management (IVM) strategy.
The VSMP provides prescriptive directives for pre-construction soil and vegetation management, recommendations for
temporary seeding and soil stabilization best management practices (BMPs)for stormwater during construction,and,finally,
directives for permanent seeding and vegetation establishment. For a full list of construction stormwater BMPs, please refer
to the Project's Erosion Control Plans (ECP). The Contractor shall be responsible for complying with the North Carolina
Construction Stormwater General Permit (CSGP) by submitting a Construction/Stormwater Pollution Prevention Plan
(SWPPP) to North Carolina Department of Environmental Quality(NCDEQ).
3.o Existing Conditions
3.1 Site Conditions
RES conducted a desktop review of the Project Area to determine the existing conditions of the soils, hydrology, and
vegetation on site. An initial site visit was conducted by RES on December 14, 2023, to confirm the results of the desktop
analysis. As described above, the Project Area is primarily comprised and managed for timber production with mature
hardwood forested areas adjacent to streams and drainages, with a small section on the south west side that looks to have
been managed for crop production.
Field observations were completed from an onsite visit,as well as windshield surveys via public roads and other public access
locations.Observable land cover units were mapped using Esri Field Maps application. Land cover units were classified using
the following categories: evergreen forest, deciduous forest, mixed forest, woody wetlands, herbaceous, hay/pasture,
cultivated crops, shrub/scrub, and developed/open space. RES observed some locations of invasive species populations
during the 2023 site visit, mostly Chinese privet (Ligustrum sinense) and Japanese honeysuckle (Lonicera japonica) in the
most recent clear cut area(s).The older timber stands had small-medium trees with a consistent mix of loblolly and sweetgum
throughout. Invasive species densities were not high enough to be mapped as many were not observable at the time of the
survey due to limited site access, plant senescence, and density of the overgrown clear cut condition in most of the Project
Area. Non-agricultural areas mapped as "wetlands" tended to be dominated by non-native invasive species and weedy-
natives such as broad-leaved cattail (Typha latifolia).
Invasive or undesirables plant species were noted in the field visit. During the field investigation, several locations of invasive
species populations were documented (Appendix A, Figure 2). Non-native invasives, noxious species, and weedy-native of
concern include Chinese privet, dogfennel (Eupatorium capillifolium), American sweetgum (Liquidambar styraciflua),
Blackberry (Rubus fruticosus), Carolina jasmine (Gelsemium sempervirens), Japanese honeysuckle, and Tropical soda apple
(Solanum viarum). Due to the survey being completed late in the season, undesirable herbaceous plant species commonly
found were not yet present. The seed bank will likely contain additional invasive and undesirable species that may be
encountered during installation and maintenance phases. Common agricultural weeds and invasive species of the region
(Appendix B) are present and will require management to minimize their growth.
Portions of the Project Area are at risk for invasion by vines and taller species arising from the agricultural area seed bank
with the conversion from agricultural use to solar panels, such as Chinese privet, dogfennel, red maple, sweet gum, and
Japanese honeysuckle.The final crop and land cover classification map of the Project Area is presented as Appendix A, Figure
2.
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The loamy and sandy loam soils in the vicinity of the Project Area are generally fine-grained and moderately permeable with
some series having slow moderate to rapid moderate permeability. One soil order, (Ultisols), makes up most of the soils in
the Project Area. "Ult" refers to ultimate, as they were seen as the ultimate product of continuous weathering of minerals in
a humid, temperate climate without new soil formation via glaciation. Georgeville and Nason soils are widely used both in
agriculture and forestry,with lower sloped series being prime farmland and slopes of 6-10% being of statewide importance
for farmland. However, due their high acidity and lack of organic matter, soil amendments are generally required each year
in order to sustain plant life. However, due to the clay content and its ability to retain nutrients, it often does not require
high amounts of fertilizer additions compared to other types of soils.
Soils with less than ten percent hydric inclusions can be generally described as being upland soils. Upland soil series are
comprised of silt loams and sand loams and range from soils on zero to two percent slopes to soils on greater than thirty-
five percent slopes. Upland soils account for eighty four percent of the Project Area.The dominant upland soil is Georgeville
loam (two to ten percent slopes) and makes up over sixty one percent of the soils on the site. Nason loam (two to ten
percent slopes) is prevalent in approximately 17% of the Project. The upland soil series historically supported mixed forest
vegetation.
Moist soils are based on their percentage of hydric soil components. Hydric soils are defined as soils that form under
conditions of saturation,flooding,or ponding for long enough time during the growing season to develop low or no oxygen
conditions. These soils are either saturated or inundated long enough during the growing season to support the growth
and reproduction of hydrophytic vegetation. Soils mapped as purple, based on NRCS data, have an eighty-seven percent or
greater hydric soil component and have few to no upland soil inclusions. Soils mapped as hydric include silt and sandy
loamy.
The only hydric soils, Wehadkee loam, are found in the Project Area along Pig Basket Creek. These hydric soils are typically
found on flat areas or on slopes that are less than two percent. Hydric soils make up sixteen percent of the Project. Hydric
soils (either drained or undrained) will require different site preparation, seeding and management approaches compared
to upland soils. However, based on preliminary site design no arrays are slated to be installed within these soils but any
proposed planting and site work in the vicinity of the proposed transmission line should be done with this in mind.
3.2 Soil Characterization
The NRCS-mapped soil classes and descriptions of the soil classes, from the NRCS Web Soil Survey, are shown in Appendix
C.The Project Area soils are mapped primarily as foams and sandy foams.The NRCS descriptions of the primary Project Area
soils indicate that topsoil depth ranges from approximately zero to ten inches across the site, with upland soils being zero
to seven inches. The Project Area soils ranged from poorly drained to well drained, with no to frequent documented
frequency of flooding, with the exception of the area adjacent to Pig Basket Creek, where no arrays are proposed for
development. The dominant soil types in the Project Area, based on the NRCS Soil Survey for Nash County are in Table 1.
Table 1. Project Soil Types
Map Unit Map Unit Name Hydric Hydrologic Frequency Frequency
Symbol Soil Group of Flooding of Ponding
GeB Georgeville loam No B None None
GeC Georgeville loam No B None None
HeB Helena coarse sandy loam No _ C None _ None
NnB Nason loam No _ B None _ None
NnC _ Nason loam No _ B None _ None
NpB _ Norfolk-Wedowee complex No A None _ None
NrB _ Norfolk, Georgeville, and Faceville soils No _ A None _ None
RaA _ Rains fine sandy loam Yes B/D None _ None
WeB Wedowee coarse sandy loam No B _ None _ None
Wh Wehadkee loam Yes B/D Frequent None
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RES collected six soil samples to establish a baseline of soil conditions. Samples were collected during the site visit to
represent sections and soil types across the Project Area. The samples were analyzed for chemical composition, organic
matter content, physical properties, and pH. The analysis determined that the organic matter content of the soils ranged
from 3.54-4.98% (Appendix C, Soil Analysis Results). In addition, soil pH ranged from 4.5-5.4.
An organic matter content of at least two percent is recommended for growing native vegetation. If organic matter is less
than two percent across the site, RES recommends soil amendments be applied in seeding areas to ensure vigorous
establishment of the designed plant mix. Amendments should be applied after final grading and site disturbance, at the
time of final seeding. Organic amendments should be inoculated with mycorrhizae to promote development of the
mycorrhizal community. Inoculated organic amendments help initiate soil regeneration and build soil organic matter in the
plant rooting zone.Organic matter also will be incorporated from the decomposition of above-ground vegetation over time.
3.3 Site Hydrology and Drainage
The wetland delineation documented eight wetlands totaling —24.5 acres within the Red Bud Solar Farm Delineation Area
(Land Management Group, Inc., 2018, Pilot Environmental, Inc.,2022). The Delineation Area covers the entirety of the 477.5-
acre Project Area and includes planned construction areas. Delineated wetlands included fringe wetland, slope wetland,and
depressional wetland areas. In addition to the delineated wetlands, there are thirteen delineated intermittent and perennial
streams totaling -14,700 feet within the Delineation Area (Land Management Group, Inc., 2018, Pilot Environmental, Inc.,
2022). The majority of the wetlands are along the floodplain of Pig Basket Creek in areas that have been maintained with
mature buffer canopy consisting of hardwoods.
4.o Integrated Vegetation Management
4.1 Integrated Vegetation Management Overview
Integrated Vegetation Management (IVM) is defined by the American National Standards Institute (ANSI A300, Part 7) as a
system of managing plant communities in which compatible and incompatible vegetation are identified; action thresholds
determined; tolerance levels established; control methods evaluated, selected, and applied to achieve management goals
and maintenance objectives. This approach to vegetation management dictates a circular approach to managing site
vegetation that can be summarized by the process flow chart below.
IVM Process Flow Chart
VSMP contains -Create annual
Vegetation maintenance plans
Conduct Yes
management progra -provide all vegetation Assessments
specifications and goals scope submittals
Adaptive 1 + Select control
management No methods
(continuous
improvement)
Write a
No statement of
iiecord data work
Yes Evaluate Schedule and CommlThicate
(QA/QC) perform work stakeholders
Source:Miller, Randall H.Best Management Practices,Integrated Vegetation Management,Third Edition,Page 5
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To conform with IVM standards, anyone that is conducting vegetation management activities will be expected to follow best
practices of vegetation assessment and recordkeeping so that all relevant management data is captured and incorporated
into an adaptive management strategy for continuous improvement.
4.2 Project Submittals
The following Project submittals in Table 2 are required to support Project IVM objectives.
Table 2. Vegetation Scope Submittals Required to Support Project IVM Objectives
Submittals • • Description
This plan, which should be developed by the construction Contractor and
submitted to the Project for approval, is an enhanced version of the annual
maintenance plan. This planning document will address all areas under Project
Preconstruction Once, in advance of control during construction so that all parties can align on responsibilities for
Site Vegetation construction maintenance in these areas. In addition to planning vegetation scope for
Plan
during construction activity, it will also confirm site nomenclature and
delineate and designate all areas under site control so that vegetation
strategies can be tailored to existing conditions.
Annually, in An annual plan, delivered in advance of the growing season, outlining known
Maintenance Plans advance of the and anticipated vegetation activities (including vegetation monitoring events)
growing season for the Project.
Operational Monthly site reports, supported by a site visit by a qualified person, to provide
Vegetation Monthly, during the scouting of undesirable vegetation and provide a qualitative assessment of
Monitoring growing season
Reports vegetation performance.
Quantitative Annually, in late An annual vegetation assessment, conducted by a qualified person, to assess
Vegetation summer/early fall site vegetation performance against the vegetation performance standards
Monitoring of each growing
Assessments season supplied in Section 6.3
6 Submittals for seed installation include seed lists as ordered (with all species
Seed Scope With every major substitutions noted), seed tags (permanent and temporary seed mixes), KMZ,
Submittals seeding shapefile, or other acceptable GIS data of seed installation, and as-built maps
mobilization
depicting final seeding conditions.
Herbicide With every control Product labels and SDS data sheets, daily field reports, KMZ, shapefile, or
Submittals event other acceptable GIS data of areas of application.
Soil Amendment With every Product labels and SDS data sheets, daily field reports, KMZ, shapefile, or
Submittals application eve other acceptable GIS data of areas of application.
Mowing With every event Daily field reports, KMZ, shapefile, or other acceptable GIS data of areas of
Submittals application, event summaries.
5.o Construction Phase Vegetation and Stabilization Management
5.1 Vegetation Sequencing
Before any seeding activities can begin, a Preconstruction Site Vegetation Plan should be submitted to the Project and
approved, as outlined in Section 4.2. This plan, which should be developed by the construction Contractor and submitted
to the Project for approval, is an enhanced version of the annual maintenance plan.This planning document will address all
areas under Project control during construction so that all parties can align on responsibilities for maintenance in these
areas. In addition to planning vegetation scope for during construction activity, it will also confirm site nomenclature, and
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delineate and designate all areas under site control so that vegetation strategies can be tailored to existing conditions.These
vegetation areas (likely, site Blocks or subblocks and areas outside of Project fence lines but under Project responsibility or
control) will be used to designate vegetation management activities and will outline the vegetation maintenance units that
will be assessed in the annual maintenance reports.
In preparation for construction and as an effort to establish vigorous perennial vegetation for soil stabilization, stormwater
management, and seeding activities may begin as early as Fall 2024. Warm season grasses are best planted from May 1 to
June 15, while cold season grasses do best when planted August 25 to October 1. Areas where disturbance has occurred
will have a cover crop installed until the permanent seed can be installed. Cover crop seeding can be through aerial seeding,
broadcast seeding, or other methods described in this document. Care will be taken to ensure seed is installed with
appropriate seed-soil contact and that proper coverage is achieved to meet the Project's goals. The final seeding of these
cover-cropped disturbed areas will be completed in the proper seeding window for permanent native vegetation.
In disturbed areas, if completion of grading and construction coincides with the proper seeding window for permanent
vegetation mixes, a cover crop will be included with the permanent seed mix as the final seeding.
In areas of cropland where no substantial grading or construction is proposed, permanent array seed mixes will be installed.
Installation methods could include aerial, broadcast, or drill seeding. This is considered the final seeding. Care should be
taken to ensure seeding methods and site conditions meet the expectations described in Sections 5 and 6 of this document.
During construction, the contractor will work to ensure that existing and newly installed vegetation is protected, managed,
and established as described in this document. Temporary or permanent seeding and stabilization measures will be
deployed following SWPPP recommendations and timelines in Section 5.
Final seeding and stabilization will occur as soon as possible once construction and disturbance activities are completed.
Schedules will follow those in the SWPPP and in Sections 5.
5.2 Pre-Panel Construction Soil Management
Soil management is a critical element for establishing perennial vegetation on large sites. In areas where intensive grading,
laydown, or site disturbances are likely, topsoil preservation will be required.Within these areas, a minimum of six inches of
topsoil will be stripped and stockpiled prior to site disturbance and grading. The Contractor will stabilize and protect all
topsoil stockpiles following SWPPP recommendations. After grading and disturbance is complete, stockpiled topsoil will be
redistributed in the disturbed areas at a minimum depth of six inches.
The Contractor will work to ensure that disturbances, haul roads, laydown areas, and grading activities are confined only to
strategic locations. This will ensure that existing and newly installed vegetation is preserved, soil structure is preserved, and
compaction minimized. In areas where compaction is excessive, decompaction activities should be employed to ensure
proper drainage and promote vegetation establishment. See Section 5.4 Seed Bed Preparation for specific metrics and
actions associated with decompaction.
5.3 Temporary Stabilization
The Contractor shall be responsible for the development of a SWPPP, application for authorization under the North Carolina
CSGP, and installation of all BMPs outlined in the ECP. All required sediment and erosion controls shall be installed prior to
the start of any grading work to ensure soil and sediment is retained onsite. The Contractor shall be responsible for
maintenance and removal of all synthetic sediment and erosion control materials once Notice of Termination of the SWPPP
permit has been received. In addition, it is critical for the Contractor to follow the steps outlined in the VSMP for soil
management and seeding to ensure success.
5.3.1 Temporary Mulch
Within all disturbed work areas that are not being actively worked for up to or exceeding seven calendar days, or as
determined by SWPPP requirements,temporary straw mulch shall be installed.Clean,weed-free wheat straw mulch shall be
applied at 1.5 tons per acre after temporary seed materials have been installed as described below. Straw mulch shall be
crimped or pressed into the soil to ensure material adheres to the soil surface.
5.3.2 Temporary Seeding
During active construction, within all disturbed areas where work has stopped, temporary seeding should be initiated after
seven days and completed within fourteen days. Seed will be broadcast at rates in Table 3. Additionally, if outside of the
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appropriate planting window for permanent native vegetation establishment (See Section 5.5), all disturbed and/or finish
graded areas will be seeded with a temporary seed mix as needed to meet state regulations for erosion and sediment
control, as specified in Table 2.The Contractor will ensure that all temporary seed mixes are annual seed that will not persist
or affect the long-term success of the permanent native seed mixes to be installed upon site work completion. Temporary
seed should be seasonally appropriate, as outlined in the table below.
Table 3. Temporary Seed Mix by Season
Timing of Stabilization Seed Type Seeding Rate
April 15-August 25 German millet (Setaria italica) 40 lbs./acre
Summer Seeding
August 25-April 15 Rye grain (Secale cereale) 56 lbs./acre
Winter Seeding
Temporary seeding aids in stabilization of soils when work areas are not active. Millet and rye grain are annual grasses that
quickly germinate to aid in the stabilization process and will not persist or compete with the permanent native seed mixes.
Two consecutive years of a cover crop application could be needed in the early years of the seeding effort to reduce pressure
from undesirable perennial species as the permanent native species establish.
5.4 Seed Bed Preparation
5.4.1 Eradication of Undesirable Vegetation
Prior to receiving either temporary or permanent seed, an evaluation as to the presence of noxious, invasive, or undesirable
vegetation should be conducted. If species listed with the State of North Carolina' as noxious or invasive are observed, they
shall be controlled via mechanical or chemical treatment methods.A preliminary list of specific invasive species that may be
located onsite, the recommended herbicide treatment, and optimum time for application is included in Appendix B for
reference. Herbicide application shall follow label directions for the target species and site conditions and be applied by an
North Carolina licensed applicator. Where undesirable species exist within or adjacent to aquatic resources, the applicator
shall use an aquatic-approved herbicide. Herbicide application shall occur not less than two weeks before the final seeding
installation.
Vegetation control shall be confirmed and follow up herbicide applications may be necessary. Herbicide will not be necessary
as a site preparation method in areas where non-invasive existing vegetation is designated to remain in place, such as grass
swales and fence rows.
Where dense stands of undesirable vegetation exist, boom spraying, and biomass removal may be necessary for efficient
establishment of the desired vegetative cover. Additional seeding may be necessary if herbicide treatments negatively
impact vegetation establishment requirements as dictated by SWPPP recommendations.
The Project Grassy Only Array Mix(Table 4) has been designed to allow for application of broadleaf-specific herbicides within
the array footprint. Depending on the presence of agricultural weeds and other undesirable vegetation, an application of
broadleaf-specific herbicide with residual may be recommended for vegetation control after permanent seeding.
5.4.2 Rough-Cut Mowing
Prior to final seed mix installation, areas of existing vegetation within the planting areas will be mowed to a height of 4
inches. Mowing should occur approximately one week prior to seed installation. Where site conditions will not allow
equipment access due to excessive soil moisture and/or steep slopes, hand mowing may be required to ensure seed is able
to be properly installed.
'https://nc-ipc.weebly.com/uploads/6/8/4/6/6846349/invasive_plant_list_-_ranked_-_2023-11-16.pdf
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5.4.3 Disturbed Soil Prep
Within disturbed areas, harrowing may be required to ensure seed is able to adhere to the soil surface. Disturbed soils that
have developed a crust should be harrowed to rough up the soil surface and allow for adequate seed adherence. Prepared
soil will be seeded and stabilized within twenty-four hours of preparation. Stabilization measures should follow the
requirements provided in the Final Stabilization section of this document. If prepared soils are impacted by rain or other
weather events, the area will likely need to be harrowed again to ensure required conditions exist prior to seeding.
5.4.4 Soil Compaction
Soil compaction can have significant negative effects on vegetation establishment. Over-compacted soils will inhibit seed
germination, root penetration, and delay plant establishment. Under-compacted soils will not hold together and will be
easily eroded. The Contractor will test soils for compaction in seeding zones with a soil penetrometer, for confirmation by
the owner. Compaction levels should register between seventy-five and two hundred and fifty pounds per square inch (PSI)
to a minimum of twelve inches below finish grade. The Contractor will remediate compaction readings outside of these
parameters, taking efforts to preserve and protect topsoil, if not already in place.
5.5 Seed Installation Methods
Installing native seed at inappropriate times or over unsuitable soil conditions can cause delays in seed germination and
significantly reduce the viability of the plantings. For this reason, the permanent short stature and pollinator seed mix shall
be installed from October 31 to May 1 when site conditions are appropriate for equipment operation and proper seed/soil
contact. Because of weather seasonality, project scale, and construction schedule, seeding could occur outside the October
31 to May 1 seeding window as determined by the Project or Project's representative. If the timing of seeding is proposed
to occur outside the preferred window, different seeding methodologies and strategies may need to be considered.
Under any schedule, the Contractor will ensure that all equipment used onsite is clean and free of mud, dirt, vegetation, or
other seed sources prior to mobilizing.All equipment will be inspected and calibrated to meet Project-specific requirements
and ensure proper working order. Equipment will be tailored to the specific task and site conditions. Specific conditions are
listed below.
5.5.1 Disturbed Areas
Areas where grading or other soil disturbances have occurred will have seed mixes installed with an approved broadcast or
drop seeder specifically designed and calibrated to handle, distribute, and cultipack native seed species into disturbed and
prepared soils. Seed will be installed to ensure proper coverage across the entire planting area. Seeding will not occur when
excessive soil moisture prevents equipment from operating properly. Where possible, seed should be rolled with a
cultipacker or harrow to ensure adherence to the soil.
5.5.2 Undisturbed Areas
In areas where soil has not been disturbed, seed mixes will be installed with an approved no-till native seed drill designed
and calibrated to handle, distribute, and place native seed at appropriate depths and conditions. If vegetation exists within
the planting area, all undesirable vegetation will be eradicated at least two weeks prior to planting, and where possible
vegetation should be mowed to a height of four inches. Seed will be installed to ensure proper coverage and row spacing
across the entire planting area are achieved and Project performance standards are met (see Section 6). Seeding should not
occur when excessive soil moisture prevents equipment from operating properly.
5.5.3 Wet or Sloped Areas
Areas where soil moisture, slopes, site equipment or other conditions prevent access by installation equipment should be
broadcast seeded with the specified native seed mix. Seed should be distributed across the planting areas to ensure
appropriate coverage to meet the Final Success Criteria established in this document. Broadcast seeding activities should
not occur when wind speeds prevent proper seed dispersal and accurate distribution within the seeding zones, which
typically occurs when wind speeds exceed ten miles per hour.
In areas where standing water is present or soils are excessively wet, seeding will occur only during the next suitable
installation period when soils are dry enough for proper seed installation or otherwise as determined by client or client's
representative.Temporary seeding may be required when the ground is prepared outside of these installation periods. Refer
to the Temporary Seeding description in Section 5.3.2 for rates and requirements.
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5.6 Permanent Ground Cover Seed Installation
The permanent seed mix will provide vegetative cover and will ensure achievement of the performance goals for the Project.
The seed mixes will utilize the mix-specific installation directions and will be installed at various stages and locations
(Appendix A, Figure 5; Conceptual Seeding Plan). The planting plan uses short stature native grass and sedge mixes within
the solar arrays and pollinator mixes in selected locations outside of the arrays.
Seed shall be shipped and stored in the supplier's original, labeled packaging until installed. Seed quantities should be on
a Pure Live Seed (PLS) basis. PLS is a measure used by the seed industry to describe the percentage of a quantity of seed
that will germinate, which has been determined by a laboratory for specific seed lots. Bulk seeding rates do not consider
that a given batch of seed contains a variable quantity of inert seed that will not germinate.
Seed shall be stored in a manner to protect from moisture, heat, or other conditions that would jeopardize viability or cause
germination prior to installation. Seed for individual mixes shall be categorized, blended, and packaged by small, large, and
fluffy seed to accommodate for installation implements. All legume seed shall be inoculated by the supplier prior to
shipment.
5.6.i Permanent Grass Only Cover Upland(GO)
A permanent short stature seed mix has been developed by Taylor Creek Restoration Nurseries for use throughout the
Project (Table 4). This seed mix is to be installed across array areas, depicted as the panel zone (Appendix A, Figure 5;
Conceptual Seeding Plan), where significant grading is not required.The seed mix is designed to provide stabilization using
short stature diverse blend of reliable turfy naturalized and native grass and sedge species adapted to the Carolina Piedmont
and the physical and chemical soil conditions to provide quick covers with reliable clover cover crop. Several non-native
species and cover crops are included to provide temporary site stabilization during construction and site establishment.The
Grass Only Mix (GO) has been designed for non-hydric soil conditions and will be installed over most of the Project array
footprint.
The GO Seed Mix can be installed where vegetation has not successfully established during or after panel installation.
Depending on seeding timing and seed availability,an additional modified permanent seed mix(es) may need to be designed
to provide short stature species not included in Table 4. They will need to be adapted to North Carolina's Piedmont climate
and soil conditions. If needed, these or other substitutions will be approved by the Project or the Project's representative.
Table 4. Permanent Mix-Grassy Only Cover(GO).
Scientific Name Common Name NC Native Max Height Quantity Seed/ft2 Lbs/Acre
Permanent Mix,Grassy Only Cover
Lolium multiflorum Annual rye No 3-4' 62.54 12.00
Avena sativa Seed oats No 2-4' 13.36 30.00
Festuca rubra Creeping Red fescue Yes 12-15" 7.83 0.62
Festuca rubra commutata Chewings Red Fescue Yes* 1-2' 5.74 0.50
Festuca ovina Sheep fescue No 6-12" 7.81 0.50
Poa pratens Kentucky bluegrass Yes 18-25" 16.07 0.50
Agrostis alba Redtop No 2-3' 34.37 0.30
Elymus trachycaulus Slender wheatgrass Yes 2' 2.53 1.00
Carexbicknellii Copper-shouldered oval sedge No 1-3' 0.94 0.15
Carex brevior Fescue sedge No 12" 1.07 0.10
Carex shortiana _ Short's sedge No 2' 0.62 0.10
Carex vulpinoidea Fox sedge, Brown fox sedge Yes 1-3' 7.71 0.21
Bouteloua curtipendula Side oats grama Yes 1-3' 4.41 2.00
Juncus dudleyi Dudley's rush No 6-24" 11.75 0.01
Juncus tenuis Path rush Yes 18-24" 3.67 0.01
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Scientific Name Common Name NC Native Quantity Seed/ft2 Lbs/Acre
Schizachyrium scoparium Little bluestem Yes 1-3' 5.51 1.00
Trifolium repens White clover/white Dutch clover No 6" 17.81 1.00
Total Permanent Mix-Grass Only 203.74 Seed/ft2 50.00 lbs/Acre
*Introduced
5.6.2 Permanent Pollinator Habitat(PH)Zones
The North Carolina Pollinator Conservation Alliance (NCPCA) North Carolina Solar Site Pollinator Habitat Planning and
Assessment Form scorecard is an industry- and stakeholder-driven tool for solar developers to determine if their solar site
is pollinator-friendly. The scorecard assesses ten points including native species, vegetative buffers, site preparation, and
site management. The complete North Carolina Solar Site Pollinator Habitat Planning and Assessment Form scorecard is
included in Appendix D. Pollinator Seed Mixes have been designed to be installed in select buffer zones of the solar
development (Appendix A, Figure 4; Conceptual Seeding Plan). This mix is intended to provide plant diversity, visual buffer,
and wildlife and pollinator insect species habitat. The proposed pollinator habitat seed mix (PH) contains species that are
well-adapted to general site conditions (Table 5). Perennial seeds should comprise grasses and early, middle, and late
blooming forbs. Cover crops are to be included in the pollinator mix and installed at rate of forty-two lbs. of seed per acre.
Grass, sedge, and pollinator species will be installed at the rates in Table 5. Due to seed availability of species and quantities,
substitutions may be necessary. These or other substitutions will be approved by the client or client's representative.
Table 5. Pollinator Seed Mix(PH)Zones Outside of Arrays
Botanical Name Common Name Bloom NC Quantity Lbs/acre
Season Native Seed/ft2
Cover Crops
Lolium multiflorum Annual rye NA No 27.77 12
Avena sativa Seed oats_ NA No 11.02 30
Total Cover Crops 75.90 42
Grasses, Sedges& Pollinators _ _
Allium cernuum Nodding wild onion Middle Yes 0.40 0.10
Asclepias tuberosa Butterfly weed Middle Yes 0.16 0.10
Bouteloua curtipendula Side oats grama Late Yes 4.41 2.00
Carex bicknellii Copper-shouldered oval sedge Middle Yes 0.62 0.10
Carex vulpinoidea Fox sedge, Brown fox sedge Early-Middle Yes 3.67 0.10
Chamaecrista fasciculata Partridge pea Middle-Late Yes 0.10 0.10
Coreopsis lanceolata Sand coreopsis Early-Middle Yes 0.59 0.10
Dalea purpurea Purple prairie clover Early-Late No 0.66 0.10
Echinacea purpurea Broad-leaved purple coneflower Middle Yes 0.24 0.10
Elymus canadensis Canada wild rye Middle Yes 1.91 1.00
Heliopsis helianthoides False sunflower Middle-Late Yes 0.46 0.20
Heuchera richardsonii Prairie alum root Early-Middle No 2.57 0.01
Liatris spicata Marsh blazing star Middle Yes 0.40 0.10
Monarda fistulosa Wild bergamot Middle Yes 2.57 0.10
Oligoneuron album Stiff aster(goldenrod) Middle-Late Yes 2.35 0.10
Penstemon digitalis Foxglove beard tongue Early-Middle Yes 4.78 0.10
Potentilla arguta Prairie cinquefoil Middle- Late No 1.69 0.02
Pycnanthemum virginianum Virginia mountain mint Middle-Late No 0.81 0.01 -
Ratibida pinnata Yellow or Grey headed coneflower Middle-Late Yes 1.65 0.15
Rudbeckia hirta Black-eyed Susan Middle-Late Yes 8.45 0.25
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Botanical Name Common Name Bloom NC Quantity Lbs/acre
Season Native Seed/ft2
Schizachyrium scoparium Little bluestem Late Yes 11.02 2.00
Solidago nemoralis Old-field goldenrod Middle-Late Yes 11.02 0.10
Symphyotrichum laeve Smooth blue aster Late Yes 2.02 0.10
Tradescantia ohiensis Spiderwort Early-Middle Yes 0.29 0.10
Trifolium repens White clover/white dutch clover Early-Middle No 4.45 0.25
Zizia aurea Golden alexanders Early-Middle Yes 0.40 0.10
Total Grass, Sedges& Pollinators 67.71 7.49
5.7 Final Stabilization
Following the installation of permanent and temporary stabilization seed mixes, additional measures will be required to
stabilize the final graded soils while the seeding and plantings become established. RES has provided descriptions of typical,
primary stabilization measures below. However, these measures are not intended to be all-inclusive. If specific engineering
and site solutions warrant, additional measures should be considered.
5.7./Straw Mulch
Straw mulch should be applied to disturbed bare soil that is not stabilized by other measures. Straw mulch provides soil
stabilization, moisture holding capacity, and plant protection during the early stabilization period. Clean, weed-free wheat
straw mulch should be applied at 1.5 tons per acre after seed materials have been installed as described above. Straw mulch
should be crimped or pressed into the soil to ensure material adheres to the soil surface.
5.7.2 Hydromulch
Hydromulch should be considered where site conditions make straw mulch impractical, such as under panels, in areas where
mulching equipment cannot access, or where slopes warrant an engineered product for stabilization. Hydromulch products
and installation methods should be submitted to the Owner for review to ensure appropriate materials and installation
methods are implemented. Native seed does not establish well when installed by the hydromulch method and cannot be
included in the hydromulch solution. Native seed must be installed as described in the Seed Installation section above.
5.7.3 Erosion Control Blanket
Erosion control blanket will be installed on all slopes steeper than 3:1. Additionally, erosion blankets will be installed along
the flow line of minor drainageways. Erosion blanket materials should be North American Green's SC150BN product or
approved equal and be installed per the manufacturer's specifications. Equivalent materials may be considered for approval
but must be comprised of an organic mesh so as not to endanger wildlife. Materials including plastic netting will not be
acceptable.
5.7.4 Coir Mat
Coir matting will be installed within the channel and side slopes of all major primary drainageways. Mats will be installed
parallel to the flow of the channel and topography.Coir matting will be Rolanka International, Inc's BioD-Mat 70 or approved
equal. Mats will be secured using twelve-inch U pins, eighteen inches on center along the edges of the blanket and spaced
on three-foot centers through the center of the blanket. Straw mulch, per the section above, should be placed within coir
mat areas prior to installation of the mat materials. Mats should be crimped and/or trenched into the soil a minimum of six
inches along all mat area boundaries.
5.7.5 Riprap Scour Protection
Scour protection should be considered in drainage areas where concentrated flows or steep outflows are anticipated. Rock
materials and scour protection design should be sized and placed to prevent erosion, reduce sediment transport,and ensure
safe and stable site conditions throughout the life of the facility.
5.8 Adaptive Management Strategies
As construction progresses and plans and site conditions evolve, implementation of additional or different stabilization
measures may be necessary. Alternative strategies should be considered when the typical treatments listed above do not
provide adequate stabilization or engineering needs.
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To support Adaptive Management Strategies throughout the operational lifespan of the Project, it is imperative that the
IVM process and submittals outlined in Section 4.0 are followed so that accurate Project vegetation information can be
assessed, archived, and utilized to drive optimum Project outcomes.
5.8.1 Stabilization and Engineering Solutions
As construction progresses and Project conditions evolve,additional stabilization measures should be considered to address
specific instances. Alternative strategies should be considered when the typical treatments listed above do not provide
adequate stabilization or engineering needs.Alternatives should be explored when major drainageways,slopes steeper than
2:1, or unstable soils require additional stabilization measures. References for alternatives exploration include the
Environmental Protection Agency (EPA) and Natural Resources Conservation Service (NRCS) best practices.
5.8.2 Seed Mix and Site Suitability
The scale and scope of this VSMP analyzes the project on a macro scale. Adaptive management will be required to install
the appropriate seed mix based on existing or evolving site conditions, especially soil moisture. Small wet pockets may exist
within fields, and construction traffic and disturbance, and drain tile disruptions may create additional wet areas due to soil
compaction or changes in site hydrology. These conditions may not be obvious during significant portions of the year and
thus minor remedial overseeding may be required to ensure adequate vegetative cover of the appropriate seed mixes.
6.o Post Construction Performance Standards
6.1 Preliminary Acceptance
Upon completion of permanent seed and final stabilization installation, the Contractor shall be responsible for
maintaining the site until the Notice of Termination of the NPDES permit can be submitted.At least 90 days following
the installation of these measures, the Contractor shall request an inspection by Duke or their representative.
Inspections shall review site conditions for the following criteria:
Cover Crop Establishment: Cover crops may be present and vigorous throughout all planting areas.Areas with
insufficient vegetation growth will be remediated with nurse and permanent seed mixes, per initial installation,
prior to acceptance. Duke will inspect that the planned vegetation is in good condition and distributed evenly
throughout the Project.
Permanent Vegetation Establishment: It is unlikely that substantial evidence of permanent seedlings will be present at
this point in the vegetation establishment process. However, inspections should review seedlings for even
distribution across the Project. If uneven distribution of final seed is observed, corrective action may be required
by drill seeding additional final seed mixes prior to acceptance.
Stabilization Measures:All stabilization measures shall be installed as described in this document, or per manufacturer
specifications and properly healed in.Any deficiencies shall be remedied prior to acceptance. All incidental erosion
features shall be remediated to ensure stable site conditions prior to acceptance. All soil disturbances, erosion
remediations, or adaptive management shall be seeded with final seed mixes as planned prior to acceptance.
Partial Acceptance: It is anticipated areas of the Project will receive permanent seeding and stabilization at various
times throughout the Project construction. Duke may reserve the right to refuse acceptance of sub-areas within
the Project prior to the overall Project completion.
6.2 Final Acceptance
Upon completion of installation acceptance, the vegetation will enter the establishment period as described in the
Monitoring and Maintenance section of this document. Monitoring and Maintenance shall focus on establishing and
maintaining the planned vegetation throughout the Project. Success criteria shall follow the standards established below
and in Table 6:
Planned Vegetation:The planned specified plant species will be the predominate vegetation present within the
planting zones. Monitoring will evaluate vegetation cover and diversity to ensure planting matrix remains robust
in a variety of climatic and site conditions. All seeded areas will have at least seventy-five percent cover by planted
perennial species within four years after installation. In addition, seventy percent of the installed species should be
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present after the four-year establishment period.The Contractor will remediate by installing additional seed to
ensure diversity requirements are met.
Noxious and Invasive Species: Noxious and Invasive species will not make up more than fifteen percent coverage of the
site or any defined maintenance area.All listed species, according to NC Invasive Plant Council Pest List and
species, (https://nc-ipc.weebly.com/uploads/6/8/4/6/6846349/invasive_plant_list_-_ranked_-_2023-11-16.pdf),
shall be eradicated upon identification. In areas where substantial plant populations are removed, additional over-
seeding may be required to ensure site vegetation coverage.
Soil Stabilization: Monitoring will be used to review soil conditions across the site to ensure no major erosion features
form and that all soils are stabilized by the planned vegetation.Where erosion features are noted, corrective
action is required to stabilize soils and establish planned vegetation.
6.3 Project Vegetation Performance Standards
Table 6. Vegetation Performance Standards
Category Performance Standards
Permanent Vegetation Goals Total Cover (%) of Planted Perennial Species
Based on years since seed installation
Year 1 20%
Year 2 40%
Year 3 60%
Year 4 75%
Final Acceptance
75% cover of installed species by the end of the fourth seeding year's
Planted Vegetation Performance Standards growing season
70% of the installed species present by the fourth year after seeding
Undesirable Species (Noxious and Invasive) < 15 % coverage of the site
Soil Stabilization No major erosion features form, all soils are stabilized by the planned
vegetation
7.o Post-Construction Short-Term and Long-Term Vegetation Maintenance and Monitoring
7.1 General Practices
Proper management during the vegetation establishment (Establishment Period) and beyond is critical to realize the long-
term cost benefits associated with a native vegetation community. Typically, the Establishment Period for native plants can
last up to four years while they develop extensive root systems and often germinate over multiple years. For the purposes
of this VMSP, it should be assumed that the Establishment Period is four full growing seasons after permanent seed
installation to align with the performance standards listed in Section 6.3.
It should be anticipated that permanent seeding and stabilization measures will be installed in phases throughout the Project
as portions of the Project are completed by the Contractor. Once final permanent seeding and stabilization measures have
been accepted by the owner, the Contractor will begin maintenance and monitoring protocols as described below.
Below are listed specific management activities to be implemented during both the Establishment Period, defined as the
first four years after installation, as well as Long Term Management, beginning after Year 4.
7.2 Annual Maintenance Plan
Before the start of each growing season (March-October), an annual maintenance plan should be drafted and submitted for
Project approval containing a review of last season's control activities, a tentative schedule of monitoring and control events,
and an action plan addressing known issues and containing points of focus for the upcoming growing season.This plan will
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be used to set an annual agenda with the acknowledgement by all parties that additional control events will be conducted
based on the action thresholds established by this VSMP.
7.3 Monitoring
Monitoring vegetation and site condition should be completed in coordination with SWPPP inspection requirements to
ensure proper establishment of the desired vegetation. Monitoring will be conducted by a qualified person that is able to
identify installed vegetation and recognize undesirable plant species for treatment. A qualified person should hold a
certification as an approved botanical professional specializing in native vegetation and ecological restoration. Operational
vegetation monitoring should occur monthly during the growing season to collect vegetation data and determine the need
for control events. The monthly operational assessment report should include a summarization of vegetation activities
conducted, a compilation of notes and field observations as received from operational crews, and as well as a site visit to
confirm identification of potential invasive species by site personnel and provide data on seed establishment and vegetation
coverage on a qualitative basis.
A quantitative vegetation assessment should occur in the late summer/early fall, before the growing season is over,to assess
vegetation performance against the performance standards outlined in Section 6.3. A qualified person will conduct a
vegetation assessment throughout the site, with a minimum of three assessment points taken in all vegetation units as
defined by the Annual Maintenance plan, so that the species makeup and estimated vegetation coverage can be recorded
and assessed. Species' areal cover and adventive status should be recorded at each point, as well as presence or absence of
major erosional features within visual range of the point. This data should be summarized to allow comparison of ground
conditions to performance standards.
Seed mixes should be compared annually to actual species cover measurements, to facilitate determinations on whether
poorly performing species should be replaced as part of the adaptive management strategy. Consideration should be made
for late successional species which may not establish within the first several years.
7.4 Vegetation Control Activities
Per IVM Protocol,vegetation control activities are conducted based on vegetation triggering action thresholds that threaten
the tolerance levels outlined in Table 7 below. Action thresholds have been established based on economic and ecological
risk factors to the Project. Proposed control activities should be based on site conditions as established by the monitoring
protocol established in Section 7.4.General expectations for control activities have also been provided to aid the drafting of
annual maintenance plans through the vegetation establishment period and into long-term management.
Table 7. Vegetation Action Thresholds and Tolerance Levels within the Arrays
Possible Control
Vegetation Factor Action Threshold Tolerance Level
Activities
Mowing,sterilant
herbicide spray(in areas
Vegetation Height 18 inches 24 inches
where mowing is difficult
or dangerous to conduct)
Presencel0% Mowing, herbicide
Undesirable Species 15%coverage
coverage treatments, reseeding
Bare Soil 1 square meter 3 square meters Reseeding,erosion control
Duke Energy Solar Solutions I Red Bud Vegetation&Soil Management Plan
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Table 8. Vegetation Action Thresholds and Tolerance Levels outside the Arrays
Possible Control
Vegetation Factor Action Threshold Tolerance Level
Activities
Mowing, herbicide
Undesirable Species 10%coverage 15%coverage
treatments, reseeding
Bare Soil 1 square meter 3 square meters Reseeding,erosion control
7.4.1 Mowing
Mowing will occur in panel array areas having vegetation height restrictions, adjacent to Project facilities, and adjacent to
driveways when vegetation approaches the eighteen-inch action threshold. Due to the practical constraints of mobilizing
equipment and personnel to perform maintenance,a minimum of two site mows per year(an initial sitewide mow beginning
in May, and a follow-up mow in July-August, as vegetation conditions warrant) should be assumed and prearranged as part
of the annual maintenance plan To ensure no impacts to facility operations, maximum grow heights within the array areas
must not exceed twenty four inches. Within the areas and in all pollinator buffer areas, vegetation should be mowed down
to a target height of eight to ten inches. Outside of the array areas, regular mowings for control of undesirable species
should be expected during the establishment period, but once buffer areas are fully established, expected mowings can be
reduced to once every year, occurring as a dormant mowing between November 1 and March 1. If substantial undesirable
annual vegetation persists within the buffer areas, mowing regimens should continue to follow the array area mowing
schedule. In areas where fires caused by combines working in areas outside the arrays could pose a risk to the Project, a
firebreak of fifteen feet along the outside of the Project fence lines may need to be mown and blown clean as part of the
final mowing event of the season.
7.4.2 Herbicide Treatments
The first year of maintenance should primarily focus on mowing and mechanical control of vegetation. However, if perennial
noxious or invasive species are identified during monitoring or maintenance, chemical control should be employed.
Herbicides should be applied on a spot application basis, focused on target plants. If large stands of undesirable vegetation
are identified, boom spraying with a species-specific herbicide (e.g., broadleaf) can be discussed with the owner. Re-seeding
of the planned seed mixes should be implemented at least two weeks after undesirable vegetation is treated with herbicide.
Herbicide application will be conducted by trained and certified professionals and follow label guidelines.A preliminary list
of specific invasive species identified onsite, the recommended herbicide treatment, and optimum time for application is
included in Appendix B. Where undesirable species exist within or adjacent to aquatic resources, the applicator shall use an
aquatic-approved herbicide.Where dense stands of undesirable vegetation exist, boom spraying, and biomass removal may
be necessary to maintain the desired vegetative cover. The use of herbicides and application dates must be approved by
Project and/or Project's representative.
7.5 Remedial Seeding
Installation of additional seed should be anticipated in areas where seed mixes are underperforming or areas where planting
densities fall below the plan specified success criteria. Consideration should be given to why the previously installed seed
mix is underperforming to determine if an alternate mix is warranted.
If deemed necessary,over-seeding will be performed by installing the appropriate permanent seed mix. Seeding rates lower
than those indicated in the initial installation tables can be considered, provided specific performance goals are agreed to
by the client or their representative. Any bare soil larger than one square meter will be re-seeded to ensure site coverage,
vegetation maintenance, and undesirable species do not establish within the facility. Broadcasting seed can be effective for
small areas in need of repair. Larger areas should be installed with a seed drill. Straw mulch or wildlife-friendly erosion
blanket should be installed if substantial erosion concerns are noted.
Duke Energy Solar Solutions I Red Bud Vegetation&Soil Management Plan
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8.o References
Environmental Protection Agency (EPA). Level III and IV Ecoregions by State.Available for download at
https://www.epa.gov/eco-research/level-iii-and-iv-ecoregions-state
Environmental Protection Agency (EPA) August 28, 2020. National Menu of Best Management Practices (BMPs) for
Stormwater.Available for download at https://www.epa.gov/npdes/national-menu-best-managementpractices-
bmps-Stormwater.
Geo Hydro Engineers. 2022. Report of Subsurface Exploration and Geotechnical Engineering Evaluation for Gideon Solar
(Array Fields and Substation) Castalia, North Carolina. Prepared for Birdseye Renewable Energy.
Land Management Group, Inc. 2018. Wetland and Stream Delineation Summary Report for Gideon Solar LLC, Taylors Gin
Road, Castalia, Nash County, North Carolina. Prepared for Gideon Solar, LLC.
Natural Resources Conservation Service (NRCS). 2012c Accessed March 24, 2021. Stormwater Runoff Control. Available to
download at https://www.nres.usda.gov/wps/portal/nres/detail/national/water/?cid=nres144p2_027171 Purdue.
North Carolina Invasive Plant Council (NC-IPC) 2023. NC Invasive Plants List. Available to download at https://nc-
i pc.weebly.com/uploads/6/8/4/6/6846349/invasive_plant_I ist_-_ranked_-_2023-11-16.pdf.
North Carolina Department of Transportation (NCDOT). 2022. NCDOT Stormwater Quality Field Manual. Available to
download at https://connect.ncdot.gov/resources/roadside/EnvironmentalOperationsDocuments/Stormwater%20
Control%201nspection%20and%20Maintenance%20Manual.pdf.
North Carolina Pollinator Conservation Alliance. 2022. North Carolina Solar Site Pollinator Habitat Planning and
Assessment Form, available for download at https://ncpollinatoralliance.org/wp-content/uploads/2022/06/NC-
Solar-Technical-Guidance-FINAL-May-2022.pdf.
North Carolina Pollinator Conservation Alliance. 2022. North Carolina Technical Guidance for Native Plantings on Solar
Sites, available for download at https://ncpollinatoralliance.org/wp-content/uploads/2022/06/NC-Solar-Technical-
Guidance-FINAL-May-2022.pdf.
Pilot Environmental, Inc. 2022. Wetland Delineation for Gideon Solar LLC, Taylors Gin Road, Castalia, Nash County, North
Carolina. Prepared for Gideon Solar.
Pilot Environmental. 2023. Phase I Environmental Site Assessment, Gideon Solar, Approximate 481-acre Tract, Taylors Gin
Road, Castalia, Nash County, NC. Prepared for Birdseye Renewable Energy, LLC and Gideon Solar, LLC, 1125 E.
Morehead St, Suite 202, Charlotte, NC 28204.
United States Department of Agriculture (USDA). 2018. Soil Survey Manual. Available for download at
https://www.nres.usda.gov/sites/default/files/2022-09/The-Soil-Survey-Manual.pdf.
Duke Energy Solar Solutions I Red Bud Vegetation&Soil Management Plan