20090969 Ver 5_Mitigation Plans_20090801

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DRAFT MITIGATION PLAN
PERRY CREEK 1 MITIGATION SITE
Developed Through
ENHANCEMENT AND PRESERVATION OF
WETLANDS AND STREAMS
ADJACENT TO PERRY CREEK
Wake County, North Carolina
PREPARED BY:
HAZEN HAZEN AND SAWYER
AND SAWYER
Environmental Engineers & Scientists 4011 WESTCHASE BOULEVARD
RALEIGH, NORTH CAROLINA 27607
AND
AXIOM ENVIRONMENTAL, INC.
20 ENTERPRISE STREET, SUITE 7
RALEIGH, NORTH CAROLINA 27607
Axiom Environmental, Inc.
AUGUST 2009
EXECUTIVE SUMMARY
The City of Raleigh proposes the establishment of the Perry Creek 1 stream and wetland
mitigation site along Perry Creek (hereafter the Mitigation Site) located approximately 2 miles
northeast of Rolesville in eastern Wake County, east of U.S. Highway 401 near the intersection
of U.S. Highway 401 and N.C. Highway 96. The Mitigation Site is anticipated to be one of
several included in an umbrella stream and wetland mitigation bank sponsored by the City of
Raleigh. The Mitigation Site is located within the Neuse River Basin in 14-digit USGS
Cataloging Unit 0302020 1 1 80020 of the South Atlantic/Gulf Region (NCDWQ Subbasin
Number 03-04-06).
The proposed Mitigation Site encompasses approximately 296 acres of land that includes
approximately 140.0 acres of forested and/or marsh wetlands. The Mitigation Site also
encompasses approximately 13,720 linear feet of stream associated with Perry Creek and
unnamed tributaries to Perry Creek. Land uses in the vicinity of these wetlands and streams
include pasture, agriculture, residential, and unmanaged forest. Protection of Mitigation Site
resources through conservation easements or restrictive covenants will promote the sustainability
and/or improvement of aquatic resources in the Perry Creek watershed, as well as downstream of
the Mitigation Site, which are under increasing pressure from development. Wetland and stream
functions currently provided include flood attenuation, slow release of water to maintain stream
baseflow, removal of watershed pathogens, a sink for particulate and soluble matter (including
nutrients), aquatic and riparian habitat, and landscape-scale wildlife travel corridors.
The primary goals of this stream and wetland mitigation project focus on promoting
sustainability and improvement of aquatic resources within the Perry Creek watershed.
Protection of existing aquatic resources (forested wetlands, emergent wetlands, and streams)
with a conservation easement and/or fee-simple purchase is likely to result in net gains in
hydrology, water quality, and habitat functions of Mitigation Site streams and wetlands. Primary
goals will be accomplished through the following measures:
• Protecting, on a watershed scale, streams in eastern Wake County from nonpoint sources
of pollution associated with urban services area expansion and development.
• Promoting water quality by protecting jurisdictional wetlands adjacent to Mitigation Site
streams and tributaries.
• Perpetually providing a diverse wooded vegetative buffer adjacent to Mitigation Site
streams and wetlands.
• Promoting floodwater attenuation by a) allowing bankfull stream flows to develop over
time and b) protecting vegetation on Mitigation Site floodplains to increase frictional
resistance on floodwaters crossing the Mitigation Site.
• Improving aquatic habitat by promoting stable stream banks, shading open waters, and
providing structure within the Mitigation Site.
• Providing a wildlife corridor and refuge in an area rapidly expanding with residential and
commercial development.
This Mitigation Site mitigation plan includes 1) preservation of approximately 13,720 linear feet
of streams, 2) enhancement of approximately 0.5 acre of jurisdictional wetlands, 3) preservation
Draft Perry Creek 1 Mitigation Plan August 18, 2009
of approximately 139.5 acres of jurisdictional wetlands, and 4) establishment of a permanent
conservation easement to encompass all mitigation activities, as well as a 50-foot wooded
riparian buffer adjacent to wetlands and ponds, and a 100-foot wooded riparian buffer adjacent to
streams.
Preservation and enhancement options outlined in this report are as follows:
Proposed Mitigation Proposed Credits
Proposed Mitigation
Activit
Y
Streams Wetlands

(linear feet) (acres)

Stream Credits Wetland Credits
Stream Preservation 13,720 2,744
Wetland Enhancement 0.5 0.25
Wetland Preservation 139.5 27.9
Totals 13,720 140.0 2,744 28.2
After completion, the Mitigation Site will offer 2,744 stream mitigation credits and 28.2
wetland mitigation credits. The proposed mitigation credits provided in the table above are
based on an onsite, cursory determination of Mitigation Site resources. Prior to generation of a
final mitigation plan, aquatic resources within the Mitigation Site will be delineated in the field
and accurately mapped for the generation of quantities. Detailed quantities of streams, wetlands,
and wooded buffers within the Mitigation Site will be provided in the final mitigation plan.
Three federally protected species are listed for Wake County (USFWS 2008): dwarf
wedgemussel (Alasmidonta heterodon), red-cockaded woodpecker (Picoides borealis), and
Michaux's sumac (Rhus michauxii). Each of these species is listed as Endangered. Additionally,
the bald eagle (Haliaeetus leucocephalus) is protected by the Bald and Golden Eagle Protection
Act, and 15 Federal Species of Concern (FSC) are listed for Wake County.
While unlikely to support habitat for red-cockaded woodpecker, the Mitigation Site may support
suitable habitat for dwarf wedgemussel within stream channels and Michaux's sumac in open
areas and along woodland edges. With a range of habitats, including pine forest, mixed
hardwood forest, marsh, and open areas, the Mitigation Site may provide suitable habitat for bald
eagle and any or all of the 15 FSC species on the USFWS 2008 list. One FSC mussel, green
floater (Lasmigona subviridis) was found in the Little River approximately 2 miles downstream
of the Mitigation Site during surveys performed in 2007 (The Catena Group 2008).
Additionally, the potential creation of a large, open body of water in the near vicinity (the
proposed Little River Reservoir) may induce bald eagle to utilize portions of the Mitigation Site
for nesting.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY ............................................................................................................. i
1.0 INTRODUCTION ................................................................................................................ ..1
2.0 OBJECTIVES ....................................................................................................................... ..1
3.0 SITE SELECTION ............................................................................................................... ..2
4.0 SITE PROTECTION INSTRUMENT ................................................................................. ..3
5.0 BASELINE INFORMATION .............................................................................................. ..3
5.1 Physiography, Topography, and Land Use ................................................................. ..3
5.2 Jurisdictional Streams and Wetlands ........................................................................... ..4
5.3 Water Quality .............................................................................................................. ..5
5.4 Vegetation .................................................................................................................... ..6
5.5 Soils and Land Form .................................................................................................... ..6
5.6 Federally Protected Species ......................................................................................... ..7
6.0 DETERMINATION OF CREDITS ...................................................................................... ..8
6.1 Credit Determination ................................................................................................... ..8
6.2 Proposed Credit Release Schedule .............................................................................. ..9
7.0 MITIGATION WORK PLAN .............................................................................................. 10
7.1 Stream Preservation ..................................................................................................... 10
7.2 Wetland Enhancement and Preservation ..................................................................... 10
8.0 MAINTENANCE PLAN ...................................................................................................... 11
9.0 PERFORMANCE STANDARDS ........................................................................................ 11
10.0 MONITORING REQUIREMENTS ..................................................................................... 11
11.0 LONG-TERM MANAGEMENT PLAN .............................................................................. 11
12.0 ADAPTIVE MANAGEMENT PLAN ................................................................................. 12
13.0 FINANCIAL ASSURANCES .............................................................................................. 12
14.0 CORPORATE EXPERIENCE ............................................................................................. 12
15.0 REFERENCES ..................................................................................................................... 14
Appendix A. Figures
LIST OF FIGURES
Figure 1. Project Location
Figure 2. Hydrologic Unit Map
Figure 3. Site Topography and Drainage Area
Figure 4. Existing Conditions
Figure 5. NRCS Soils
Figure 6. Mitigation Potential
LIST OF TABLES
Table 1. Existing Stream Characteristics ........................................................................................5
Table 2. Perry Creek 1 Mitigation Site Soils ..................................................................................7
Table 3. FSC Species Listed for Wake County ..............................................................................8
Table 4. Proposed Mitigation Quantities vs. Mitigation Credits ....................................................9
Table 5. Proposed Credit Release Schedule ...................................................................................9
Draft Perry Creek I Mitigation Plan August 18, 2009
DRAFT MITIGATION PLAN
PERRY CREEK 1 MITIGATION SITE
ENHANCEMENT AND PRESERVATION OF
WETLANDS AND STREAMS
ADJACENT TO PERRY CREEK
Wake County, North Carolina
1.0 INTRODUCTION
The City of Raleigh proposes the establishment of a stream and wetland mitigation site at the
Perry Creek 1 Mitigation Site (hereafter the Mitigation Site; the Mitigation Site has been labeled
as Perry Creek 1 to identify it as including properties on Perry Creek which are east of U.S.
Highway 401), located approximately 2 miles northeast of Rolesville in eastern Wake County,
east of U.S. Highway 401 near the intersection of U.S. Highway 401 and N.C. Highway 96
(Figure 1, Appendix A). The Mitigation Site is anticipated to be one of several included in an
umbrella stream and wetland mitigation bank (Bank) sponsored by the City of Raleigh
(Sponsor). The Mitigation Site is located within eight-digit United States Geological Survey
(USGS) Hydrologic Unit Code (HUC) 03020201. The Bank is expected to offset unavoidable
impacts associated with Sponsor projects, such as the proposed construction of the Little River
Reservoir, located just downstream of the Mitigation Site (Figure 1, Appendix A).
This document serves as the Draft Mitigation Plan for the Mitigation Site, which encompasses
approximately 296 acres of land. Supporting figures are located in Appendix A. The Mitigation
Site generally consists of the area within 50 feet of all jurisdictional ponds and wetland areas and
within 100 feet of all jurisdictional streams, and is primarily characterized by mature to disturbed
hardwood forest stands and freshwater marshes within floodplains and adjacent side slopes
associated with Perry Creek. Within the Mitigation Site, approximately 13,720 linear feet of
stream and approximately 140.0 acres of jurisdictional wetlands are proposed for mitigation.
Directions to the Mitigation Site:
? From the City of Raleigh travel north on U.S. Highway 401
? Travel - 14 miles on U.S. Highway 401 to the intersection with Pulley Town Road
? The Site is located east of U.S. Highway 401 from Pulley Town Road to NC Highway 96
? Point on road at the intersection of U.S. Highway 401 with Perry Creek
Latitude: 35.93804° N, Longitude: 78.42978° W
2.0 OBJECTIVES
Currently, the areas included in the proposed Mitigation Site are characterized by hardwood
forest, marsh, and agricultural land. However, the Mitigation Site is located in an area of
increasing development pressure. Although the Mitigation Site is located in an area protected by
state water supply classification and riparian buffer rules, development adjacent to streams may
encroach upon floodplains or adjacent side slopes. If the proposed stream and wetland
mitigation does not occur, erosion and nutrient inputs into the proposed reservoir may be
exacerbated, and anthropogenic hydrological modification may reduce wetland area.
Sediment from development is deleterious to benthic macroinvertebrate habitat and can be
expected to reduce fisheries populations in the existing and downstream reaches. In addition,
Draft Perry Creek 1 Mitigation Plan August 18, 2009
proposed mitigation activities will protect wildlife and fish habitat, shade/cool surface waters
(thereby increasing dissolved oxygen levels), filter nutrients, reduce sedimentation, reduce
downstream flooding, and increase bed morphology (habitat) through maintenance of
perpendicular flow vectors.
The primary goals of this stream and wetland mitigation project focus on promoting
sustainability and improvement of aquatic resources within the Perry Creek watershed.
Protection of existing aquatic resources (forested wetlands, emergent wetlands, and streams)
with a conservation easement and/or fee-simple purchase is likely to result in net gains in
hydrology, water quality, and habitat functions of Mitigation Site streams and wetlands. Primary
goals will be accomplished through the following measures:
• Protecting, on a watershed scale, streams in eastern Wake County from nonpoint sources
of pollution associated with urban service area expansion and development.
• Promoting water quality by protecting jurisdictional ponds and wetlands adjacent to
Mitigation Site streams and tributaries.
• Perpetually providing a diverse wooded vegetative buffer adjacent to Mitigation Site
streams, ponds, and wetlands.
• Promoting floodwater attenuation by a) allowing bankfull stream flows to develop over
time and b) protecting vegetation on Mitigation Site floodplains to increase frictional
resistance on floodwaters crossing the Mitigation Site.
• Improving aquatic habitat by promoting stable stream banks, shading open waters, and
providing structure within the Mitigation Site.
• Providing a wildlife corridor and refuge in an area rapidly expanding with residential and
commercial development.
These goals will be achieved by:
• Providing approximately 2,744 stream mitigation credits
(preserving approximately 10,740 linear feet of perennial stream channel and preserving
approximately 2,980 linear feet of intermittent stream channel).
• Providing approximately 28.2 wetland mitigation credits
(enhancing approximately 0.5 acre of jurisdictional wetland and preserving
approximately 139.5 acres of jurisdictional wetland).
• Protecting the Mitigation Site in perpetuity with appropriate legal mechanisms (either
conservation easement or fee-simple purchase).
3.0 SITE SELECTION
Primary considerations for Mitigation Site selection include in-kind mitigation and the potential
for protection/improvement of water quality within a portion of North Carolina under
developmental pressure. More specifically, considerations include desired aquatic resource
functions, hydrologic conditions, soil characteristics, aquatic habitat diversity, habitat
connectivity, compatibility with adjacent land uses, reasonably foreseeable effects the mitigation
project will have on ecologically important aquatic and terrestrial resources, and potential
development trends and land use changes.
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The Mitigation Site is located upstream of the proposed reservoir. The Mitigation Site supports
similar aquatic resources (bottomland hardwood forest, riverine swamp forest, and non-tidal
freshwater marsh) to aquatic systems in this portion of the state. According to the Neuse River
Basinwide Water Quality Plan (NCDWQ 2008), due to the presence of rare species in the Little
River, this watershed should be targeted for land acquisition to protect the riparian area beyond
the 50-foot required buffer. The proposed mitigation will result in perpetual protection of
wetlands and streams in the Little River watershed. The Mitigation Site is located in a
developing region of the state; therefore, protection of streams and wetlands is expected to result
in immediate water quality benefits in the vicinity of the impact reach.
4.0 SITE PROTECTION INSTRUMENT
The Sponsor intends to purchase a conservation easement or land in fee-simple for portions of 22
parcels totaling approximately 296 acres. The owners of these parcels have indicated a
willingness to have the properties considered for this purpose, but no arrangements have been
finalized. Upon approval of the prospectus for the Sponsor's proposed Bank, the Sponsor will
delineate jurisdictional boundaries, complete a Mitigation Banking Instrument (MBI), and
proceed toward acquiring a conservation easement or land in fee simple for portions of the
subject parcels. The Mitigation Site information presented in this Mitigation Plan is based on the
optimum Mitigation Site to maximize mitigation credits, and may be adjusted prior to
completion of the MBI. The Sponsor will remain the owner of the land or conservation
easement or will transfer the land or conservation easement to a land-management entity
approved by the Interagency Review Team (IRT).
5.0 BASELINE INFORMATION
Mitigation Site aquatic resources are similar to those found within this portion of the state.
Ridges and side slopes support a mixture of hardwood forests, agriculture, pasture, and scattered
residences. Floodplains adjacent to streams support forested wetlands, emergent wetlands, and
some open water. And, in some cases, streams dissipate into beaver impoundments. Forested
wetlands include headwater forest (when characterized by seasonal saturation to intermittent
inundation and associated with a less than second-order stream), bottomland hardwood forest
(when characterized by intermittent to seasonal inundation and associated with a second-order or
larger stream), and riverine swamp forest (when characterized by seasonal to semi-permanent
inundation). With increasing length of time of surface inundation, forested wetlands grade to
non-tidal freshwater marsh. Some marsh areas occur adjacent to small areas of open water. This
wetland complex provides hydrology functions such as runoff and flow-velocity reduction,
energy dissipation, maintenance of stream baseflow, and groundwater recharge and discharge.
Water quality functions include sediment retention, toxicant and nutrient reduction and
transformation, and bacterial and viral reduction of watershed runoff. Habitat functions include
a complexity of physical structures, dispersion of open waters within vegetated wetlands, a
reduction of habitat fragmentation, and travel corridors.
5.1 PHYSIOGRAPHY, TOPOGRAPHY, AND LAND USE
The Mitigation Site is located in the Northern Outer Piedmont ecoregion of North Carolina
within USGS HUC 03020201 (North Carolina Division of Water Quality [NCDWQ] Subbasin
Number 03-04-06) of the Neuse River Basin. Regional physiography is characterized by
dissected irregular plains and some low rounded hills and ridges; low- to moderate-gradient
streams with mostly cobble, gravel, and sandy substrates are typical (Griffith et al. 2002). Onsite
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elevations range from a high of 420 feet National Geodetic Vertical Datum (NGVD) on slopes to
a low of approximately 310 feet NGVD at the lowest point of the Mitigation Site (USGS
Rolesville, North Carolina 7.5-minute topographic quadrangle). Topography within the
Mitigation Site is depicted on Figure 3 (Appendix A).
The Mitigation Site provides water quality functions to an approximately 6.0-square mile
watershed at the outfall of Perry Creek from the Mitigation Site (Figure 3, Appendix A). The
watershed is characterized by sparse residential development, agricultural land, forested land,
and fragmented forested areas. Impervious surfaces account for less than 5 percent of the
upstream watershed land surface.
Surrounding area land use is primarily agricultural, with some low-density residential housing
and intermittent high-density development. Onsite land use is characterized by hardwood forest
and agricultural land (hay fields and row crop production) (Figure 4, Appendix A). Riparian
zones and wetland areas are primarily composed of mature to disturbed hardwood forest grading
to marsh wetlands in areas impacted by beaver. Hardwood forest is characterized by sycamore
(Platanus occidentalis), willow oak (Quercus phellos), hickories (Carya spp.), red maple (Acer
rubrum), sweetgum (Liquidambar styraciua), tulip poplar (Liriodendron tulipifera), river birch
(Betula nigra), eastern red cedar (Juniperus virginiana), loblolly bay (Gordonia lasianthus),
green ash (Fraxinus pennsylvanica), loblolly pine (Pinus taeda), white oak (Quercus alba),
American holly (Ilex opaca), black willow (Salix nigra), Chinese privet (Ligustrum sinense),
multiflora rose (Rosa multiflora), Japanese honeysuckle (Lonicera japonica), muscadine (Vitis
rotundifolia), and giant cane (Arundinaria gigantea). Marshes are dominated by emergent
vegetation such as rushes (Juncus spp.), sedges (Carex spp.), and polygonums (Polygonum spp.)
with lesser amounts of shrubs and trees.
5.2 JURISDICTIONAL STREAMS AND WETLANDS
The main hydrologic features of the Mitigation Site include Perry Creek, unnamed tributaries to
Perry Creek, and associated floodplains and ponds. Mitigation Site streams consist of the fourth
order Perry Creek, and first-order intermittent to second- and third-order perennial tributaries to
Perry Creek. Perennial streams within the Mitigation Site may be generally characterized as
riverine and upper perennial with unconsolidated bottoms consisting of sand and gravel
(R3UB1/2). Intermittent streams within the Mitigation Site may generally be characterized as
riverine and intermittent with streambeds consisting of sand and mud (R4SB4/5). Streams are
surrounded by a mixture of mature riparian vegetation and marsh, and remain relatively stable
despite expanding developmental pressures. The Mitigation Site encompasses approximately
13,720 linear feet of stream channel (Table 1 and Figure 4, Appendix A).
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Table 1. Existing Stream Characteristics

Stream Reach Approximate

Stream Length

(linear feet)
USGS

Stream Order
USGS Stream

Classification
In-Field Stream

Classification
Perry Creek 990 fourth perennial perennial
UT I 170/1490 first intermittent intermittent/perennial
UT2 310 not shown not shown perennial
UT3 540 second perennial perennial
UT4 1400/90 first intermittent perennial
UT5 510 first perennial intermittent
UT6 540/1,090 first intermittent intermittent/perennial
UT7 2,870 second intermittent/perennial perennial
UT8 615 first intermittent perennial
UT9 172 first intermittent intermittent
UT10 350/325 not shown not shown intermittent/perennial
UT11 155 first intermittent intermittent
UT 12 895/1110 first intermittent/perennial intermittent/perennial
UT 13 100 first intermittent intermittent
Total 13,720
Jurisdictional wetlands are defined by the presence of three criteria: hydrophytic vegetation,
hydric soils, and evidence of wetland hydrology during the growing season (Environmental
Laboratory 1987). Portions of the Mitigation Site supporting jurisdictional wetlands are
characterized by temporarily to seasonally inundated, palustrine, forested wetlands (bottomland
hardwood forest and headwater forest); seasonally to semi-permanently inundated, forested
wetlands (riverine swamp forest); and semi-permanently flooded, palustrine, emergent wetlands
(non-tidal freshwater marsh). Wetlands are underlain by hydric soils that are grey to bluish-gray
(gley) in color and are striated with lenses of coarse materials deposited in a fluvial environment.
Vegetative communities are composed of various strata, including canopy, relatively open
understory, and herbaceous groundcover. Groundwater springs and surface runoff contribute
hydrology to these areas, although the dominant hydrological influence is overbank flooding and
impounding due to beaver activity.
According to the Cowardin classification (Cowardin et al. 1979), jurisdictional wetlands located
within the Mitigation Site along the margins of open water may be generally characterized as
palustrine, forested, broad-leaved deciduous systems that are saturated, temporarily flooded, or
seasonally flooded (PFOIA/B/C). Jurisdictional wetlands located along Perry Creek often show
signs of beaver activity and may be generally classified as palustrine, forested, broad-leaved
deciduous systems that are semi-permanently to permanently flooded (PFO 1 F/Hb). The
Mitigation Site encompasses approximately 140.0 acres of wetlands. The approximate locations
of jurisdictional wetland areas within the Mitigation Site are depicted on Figure 4 (Appendix A).
5.3 WATER QUALITY
The Mitigation Site is located within the Neuse River Basin in 14-digit USGS Cataloging Unit
03020201180020 of the South Atlantic/Gulf Region (NCDWQ Subbasin Number 03-04-06)
(Figure 2, Appendix A). Perry Creek has been assigned Stream Index Number 27-57-2 and a
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Best Usage Classification of WS-II, HQW, NSW (NCDWQ 2009). Streams with a designation
of WS-II are protected as water supplies which are generally in predominantly undeveloped
watersheds. Local programs to control nonpoint sources and stormwater discharges of pollution
are required. These waters are suitable for all Class C uses including aquatic life propagation
and survival, fishing, wildlife, secondary recreation, and agriculture. Secondary recreation
includes wading, boating, and other uses not involving human body contact with waters on an
organized or frequent basis. The supplemental classification HQW (High Quality Waters)
includes waters rated as excellent based on biological and physical/chemical characteristics; all
water supply watersheds classified as WS-1 or WS-II receive this supplemental classification.
The designation NSW (Nutrient Sensitive Waters) includes streams with water quality problems
associated with excessive plant growth resulting from nutrient enrichment.
NCDWQ has assembled a list of impaired waterbodies according to the Clean Water Act Section
303(d) and 40 CFR 130.7, which is a comprehensive public accounting of all impaired
waterbodies. An impaired waterbody is one that does not meet water quality standards,
including designated uses, numeric and narrative criteria, and anti-degradation requirements
defined in 40 CFR 131. Perry Creek within and adjacent to the Mitigation Site is not listed on
the NCDWQ Final 2006 303(d) list (NCDWQ 2007).
5.4 VEGETATION
The Mitigation Site is characterized primarily by mature to disturbed hardwood forest,
agricultural land, and open-water ponds. Agricultural land is dispersed along the margins of
riparian zones. Hardwood forest dominates the Mitigation Site and is primarily characterized by
mesic, floodplain species adjacent to stream channels, such as tulip tree (Liriodendron
tulipifera), sweetgum (Liquidambar styrac flua), American sycamore (Platanus occidentalis),
eastern red cedar (Juniperus virginiana), red maple (Acer rubrum), green ash (Fraxinus
pennsylvanica), and various oak species (Quercus spp.). Marsh areas associated with beaver
impoundments support emergent herbs such as cat-tails (Typha spp.) and wool grass (Scirpus
cyperinus), and scattered shrubs such as black willow (Salix nigra) and tag alder (Alnus
serrulata).
5.5 SOILS AND LAND FORM
Based on county soil survey mapping (NRCS 2008), the Mitigation Site contains five soil series:
Augusta fine sandy loam (Aerie Endoaquults), Colfax sandy loam (Aquic Fragiudults),
Wehadkee silt loam (Fluvaquentic Endoaquepts), Wehadkee and Bibb soils (Fluvaquentic
Endoaquepts and Typic Fluvaquents), and Worsham sandy loam (Typic Endoaquults). Soils that
occur within the Mitigation Site are depicted on Figure 5 (Appendix A) and described in Table 2.
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Table 2. Perrv Creek I Mitigation Site Soils
Map
Unit Hydric
Symbol Ma Unit Name Status Description
Au Augusta fine sandy loam Non-hydric, This series consists of somewhat poorly drained,
may contain moderately-high to highly permeable soils on stream
hydric terraces that are occasionally flooded. Slopes are
inclusions generally between 0 and 2 percent. Depth to the seasonal
high water table is between 12 and 24 inches below the
soil surface. Bedrock occurs at a depth of more than 80
inches.
Cn Colfax sandy loam Non-hydric, This series consists of somewhat poorly drained, very low
may contain permeability soils on depressions of footslopes. Slopes
h
i are generally between 0 and 3 percent. Depth to the

us
ons
incllusio
seasonal high water table is between 6 and 18 inches
below the soil surface. Bedrock occurs at a depth of more
than 60 inches.
Wn Wehadkee silt loam Hydric This series consists of poorly drained, moderately-high to
highly permeable soils on floodplain depressions that are
frequently flooded. Slopes are generally between 0 and 2
percent. Depth to the seasonal high water table is between
0 and 12 inches. Bedrock occurs at a depth of more than
80 inches.
Wo Wehadkee and Bibb soils Hydric This series is composed of generally even areas of
Wehadkee and Bibb soils that consist of poorly drained,
moderately-high to highly permeable soils in depressions
on floodplains that are frequently flooded. Slopes are
generally between 0 and 2 percent. Depth to the seasonal
high water table is between 0 and 12 inches. Bedrock
occurs at a de th of more than 80 inches.
Wy Worsham sandy loam Hydric This series consists of poorly drained soils in depressions
which have very low to moderately-low permeability.
Slopes are generally between 0 and 3 percent. Depth to
the seasonal high water table is between 0 and 12 inches.
Bedrock occurs at a depth of more than 80 inches.
5.6 FEDERALLY PROTECTED SPECIES
Species with the classification of Endangered (E), Threatened (T), or officially Proposed (P) for
such listing are protected under the Endangered Species Act of 1973 (ESA), as amended (16
U.S.C 1531 et seq.). Three species are federally listed for Wake County by the United States
Fish and Wildlife Service (USFWS) (USFWS 2008): dwarf wedgemussel (Alasmidonta
heterodon), red-cockaded woodpecker (Picoides borealis), and Michaux's sumac (Rhus
michauxii). Each of these species is listed as Endangered. Additionally, the bald eagle
(Haliaeetus leucocephalus) is protected by the Bald and Golden Eagle Protection Act.
In addition to the bald eagle and E, T, and P species, the USFWS list includes a category of
species designated as "Federal Species of Concern" (FSC). A species with this designation is
one that may or may not be listed in the future (formerly C2 candidate species or species under
consideration for listing for which there is insufficient information to support listing). The FSC
designation provides no federal protection under the ESA for the species listed. The 15 FSC
species listed on the current USFWS list are presented in Table 3.
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Table 3. FSC Species Listed for Wake Countv
Common Name Scientific name
American eel Anguilla rostrata
Bachman's sparrow Aimophila aestivalis
Carolina darter Etheostoma collis lepidinion
Carolina madtom Noturus furiosus
Pinewoods shiner Lythrurus matutinus
Roanoke bass Ambloplites cavifrons
Southeastern myotis Myotis austroriparius
Southern hognose snake Heterodon simus
Atlantic pigtoe Fusconaia masoni
Diana fritillary (butterfly) Speyeria diana
Green floater Lasmigona subviridis
Yellow lance Elliptio lanceolata
Bog spicebush Lindera subcoriacea
Grassleaf arrowhead Sagittaria weatherbiana
Sweet pinesap Monotropsis odorata
Virginia least trillium Trillium pusillum var. virginianum
While unlikely to support habitat for red-cockaded woodpecker, the Mitigation Site may support
suitable habitat for dwarf wedgemussel within stream channels, and Michaux's sumac in open
areas and along woodland edges. With a range of habitats, including pine forest, mixed
hardwood forest, marsh, and open areas, the Mitigation Site may provide suitable habitat for bald
eagle and any or all of the 15 FSC species on the USFWS 2008 list. One FSC mussel, green
floater (Lasmigona subviridis) was found in the Little River approximately 2 miles downstream
of the Mitigation Site during surveys performed in 2007 (The Catena Group 2008).
Additionally, the potential creation of a large, open body of water in the near vicinity (the
proposed Little River Reservoir) may induce bald eagle to utilize portions of the Mitigation Site
for nesting.
6.0 DETERMINATION OF CREDITS
6.1 CREDIT DETERMINATION
The Mitigation Site encompasses Perry Creek, unnamed tributaries to Perry Creek, and
associated jurisdictional wetlands, floodplains, and ponds. Mitigation Site mitigation options
outlined in this report are as follows.
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Table 4. Proposed Mitigation Quantities vs. Mitigation Credits
Proposed Mitigation Proposed Credits
Proposed Mitigation
Activity
Streams

(linear feet)
Wetlands

(acres)

Stream Credits

Wetland Credits
Stream Preservation 13,720 2,744
Wetland Enhancement 0.5 0.25
Wetland Preservation 139.5 27.9
Totals 13,720 140.0 2,744 28.2
After completion, the Mitigation Site will offer 2,744 stream mitigation credits and 28.2
wetland mitigation credits. The proposed mitigation credits provided in the table above are
based on an onsite, cursory determination of Mitigation Site resources. Prior to generation of a
final mitigation plan, aquatic resources within the Mitigation Site will be delineated in the field
and accurately mapped for the generation of quantities. Detailed quantities of streams, wetlands,
and wooded buffers within the Mitigation Site will be provided in the final mitigation plan.
6.2 PROPOSED CREDIT RELEASE SCHEDULE
A credit release scenario is proposed that complies with interagency guidelines. Under this
scenario, the credit release schedule is based upon satisfactory completion of project milestones.
Project milestones and percent of credit released include the following:
Table 5. Proposed Credit Release Schedule
Percent of
Task Completion Verification Credit
Release
Preconstruction 1. Execution of MBI by the Sponsor, USACE, and other agencies eligible 15
for membership in the Interagency Review Team who choose to execute
the agreement
2. Approval of the final mitigation plan
3. Delivery of financial assurances
4. Recordation of the preservation mechanism, as well as the title opinion
covering the property that is acceptable to the USACE
Construction Completion of all initial physical and biological improvements made 15
pursuant to the mitigation plan
l st Year Monitoring Monitoring Report* 10
2"d Year Monitoring Monitoring Report* 10
3rd Year Monitoring Monitoring Report* 10
4th Year Monitoring Monitorinb Report* 10
5th Year Monitoring Monitoring Report* 15
Bankfull Events Occurrence of two Bankfull Events** 15
Total 100
* Provided that the channel is stable and all other success criteria are met.
** The release of 15 percent is contingent upon at least two bankfull event occurrences, in separate years, provided that the
channel is stable and all other success criteria are met. In the event that less than two bankfull events occur during the
monitoring period, the release of the remaining credit shall be at the discretion of the Interagency Review Team.
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Since the majority of the Mitigation Site is primarily composed of preservation-based mitigation
alternatives, an alternative credit release schedule may be suitable. Preservation is not expected
to require annual monitoring of stream, wetland, or vegetative parameters; therefore, the majority
of credit may be released after the execution of the MBI and approval of this Mitigation Plan.
7.0 MITIGATION WORK PLAN
The primary goals of this mitigation plan include 1) protecting a watershed from nonpoint
sources of pollution associated with urban services area expansion and development; 2)
promoting water quality by protecting jurisdictional wetlands adjacent to Mitigation Site streams
and tributaries; 3) perpetually providing a diverse woody vegetative buffer adjacent to Mitigation
Site streams, ponds, and wetlands; 4) promoting floodwater attenuation by protecting vegetation
on Mitigation Site floodplains to increase frictional resistance on floodwaters crossing the
Mitigation Site; 5) improving aquatic habitat by promoting stable stream banks, shading open
waters, and providing structure within the Mitigation Site; and 6) establishing fee-simple
ownership or a permanent conservation easement which will encompass all mitigation activities.
Primary activities include stream and wetland enhancement and preservation. The mitigation
concept as outlined in Figure 6 (Appendix A) is expected to achieve the following:
• Preserve approximately 13,720 linear feet of stream channel
• Enhance approximately 0.5 acre of jurisdictional wetland
• Preserve approximately 139.5 acres of jurisdictional wetland
• Establish an approximately 296-acre area permanently protected by either fee-simple
ownership or conservation easement
7.1 STREAM PRESERVATION
Stream preservation is being proposed on approximately 10,740 linear feet of perennial stream
and approximately 2,980 linear feet of intermittent stream (Figure 6, Appendix A). Based on
preliminary analysis and field investigations, Mitigation Site streams are relatively stable due to
a lack of human-induced impact and a well-developed riparian buffer.
Preservation areas will be protected in perpetuity through the establishment of a conservation
easement or fee-simple purchase, including a 100-foot wooded buffer adjacent to each stream
bank. Preservation of the existing stream resources will remove a threat to or prevent the decline
of functions such as maintenance of baseflow, floodflow attenuation in adjacent floodplains,
energy dissipation during flood events, and in-stream and streamside habitat.
7.2 WETLAND ENHANCEMENT AND PRESERVATION
Wetland enhancement is being proposed on approximately 0.5 acre, and wetland preservation is
being proposed on approximately 139.5 acres within floodplains adjacent to Mitigation Site
stream reaches (Figure 6, Appendix A). Based on preliminary analysis and field investigations,
wetlands occur as two general types: forested wetlands and marsh wetlands dominated by
emergent vegetation. Forested wetlands, targeted for preservation, are characterized by mature
forest vegetation and undisturbed hydric soils, and are subject to jurisdictional wetland
hydrology. Emergent marsh wetlands, targeted for enhancement, are characterized by a
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prevalence of emergent herbs due to continual maintenance within agricultural fields, causing a
loss of mature trees.
Mitigation areas will be protected in perpetuity through the establishment of a conservation
easement or fee-simple purchase, including a minimum 50-foot forested buffer adjacent to
jurisdictional wetland margins. Preservation and enhancement of existing wetland resources will
remove a threat to or prevent the decline of functions, such as surface and sub-surface storage
and retention; will maintain the system's ability to remove pathogens, soluble chemicals
(including nutrients), and particulates from the water column; and will provide physical structure
for habitat and landscape patch structure for wildlife.
8.0 MAINTENANCE PLAN
The wetland enhancement portion of the Mitigation Site will be monitored annually for five
years or until success criteria are met. Monitoring is discussed in more detail in Section 10.0
(Monitoring Requirements), and will entail visual inspections, photographic documentation, and
vegetation survival counts within wetland enhancement areas.
9.0 PERFORMANCE STANDARDS
Mitigation Site preservation areas will be deemed successful if photo documentation and post
project walkthroughs of the Mitigation Site indicate an undisturbed riparian community, healthy
jurisdictional wetland community, and functioning stream channels. The project enhancement
areas will be deemed successful if photo documentation, vegetation counts for survival, and
visual assessments indicate functional uplift. Once the project has been deemed successful by
the IRT, Mitigation Site wetland and stream functions will be protected from anthropogenic
disturbance through fee-simple ownership or restrictive land uses outlined in conservation
easements.
10.0 MONITORING REQUIREMENTS
Based on interagency guidance outlined in the Stream Mitigation Guidelines (USACE et al.
2003), preservation-based monitoring is primarily administrative; therefore, a 5-year monitoring
plan is not required for preservation areas within the Mitigation Site. However, reference photos
will be taken within preservation areas and provided to document the status of aquatic resources,
including streams, wetlands, and riparian zones. Photos will adequately document the Mitigation
Site preservation areas, and will include a detailed description of the locations at which the
photos were taken.
Monitoring efforts within the wetland enhancement areas of the Mitigation Site are expected to
occur annually for five years or until success criteria, as determined by the IRT, are met.
Reference photos will be taken in enhancement areas of the Mitigation Site, and planted
vegetation counts will be conducted annually within the enhancement wetland areas to ensure
adequate plant survival.
11.0 LONG-TERM MANAGEMENT PLAN
The Mitigation Site is proposed to be protected and managed under fee-simple ownership or
restrictive covenants outlined in perpetual conservation easements. Conservation easements will
be written to prohibit incompatible uses that might jeopardize the objectives of the Mitigation
Site. Easements may be maintained by the Sponsor, or by a land management entity approved
by the IRT. The holder of the easements will be responsible for long-term management.
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12.0 ADAPTIVE MANAGEMENT PLAN
Planting is required for the enhancement components of this project; therefore, any changes in
the mitigation plan that may occur due to unanticipated construction constraints will be adapted
accordingly to meet performance standards. The Mitigation Site will be visited at least annually
for a check of the status of aquatic resources. Likely challenges are limited, but may include a
loss of vegetation structure due to natural or man-made causes, a growing presence of invasive
species, or some type of contaminated spill upstream of the Mitigation Site. In the event that
unforeseen changes occur that affect the management or performance standards of the Mitigation
Site, the holder of the easements will work with the IRT to determine appropriate measures to
rectify deficiencies in the Mitigation Site in order to provide targeted aquatic functions.
13.0 FINANCIAL ASSURANCES
The Mitigation Site is anticipated to be part of an umbrella mitigation bank, which will have its
own distinct cost center number within the City's budgeting and financial tracking system.
Therefore, all accounting for revenues, contract encumbrances, fund transfers, and expenses will
be performed and reported independent from all other capital budget or operating budget
accounting. A distinct revenue account will be used to account for only stream/wetland
mitigation-dedicated revenues and fund transfers. The Sponsor shall provide the IRT with an
annual estimate of the cost of work required by this agreement, and a statement of funds
available to perform that work, after each annual budget of the Sponsor is adopted.
14.0 CORPORATE EXPERIENCE
Mitigation proposed for the Mitigation Site will involve the establishment, maintenance, and
protection of aquatic resources existing within the proposed Mitigation Site in perpetuity. The
Mitigation Site is proposed for use toward City of Raleigh public projects. Mitigation credits
provided by the Mitigation Site will be used for capital projects performed under the supervision
or direction of the City's Public Utilities Department. If possible and practicable, the Mitigation
Site may also be available for use by other City departments. Mitigation Site credits will not be
offered as mitigation for any other projects without approval of the IRT.
The City will maintain contracts with experienced mitigation providers to construct and maintain
the mitigation sites, including Hazen and Sawyer, Axiom Environmental, Inc. (Axiom), and
EcoScience Corporation (EcoScience). Hazen and Sawyer is an engineering consulting firm that
is assisting the City of Raleigh and the U.S. Army Corps of Engineers with the preparation of an
Environmental Impact Statement (EIS) and preliminary engineering services for the proposed
Little River Reservoir. Since 1985, the Raleigh office of Hazen and Sawyer has completed over
30 Environmental Assessment (EA)/EISs for water and wastewater projects, including water
supply reservoirs.
Axiom is a Ralcigh-based environmental consulting firm that is assisting Hazen and Sawyer with
the generation of this draft mitigation plan. The Axiom staff is experienced with coordination
among North Carolina natural resources agencies over a wide range of environmental issues
ranging from jurisdictional area identification and delineations, jurisdictional area functional
assessments, protected species, mitigation site assessments, mitigation site conceptual and
detailed planning and construction oversight, mitigation site monitoring, determination of
mitigation success, and mitigation bank development. Axiom has conducted over 100
investigations of potential mitigation sites, and completed 54 mitigation feasibility
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studies/prospectuses during the past four years for private landowners, mitigation bankers, and
in-lieu fee programs throughout North Carolina. Axiom has also developed many detailed plans
for stream, wetland, and riparian buffer mitigation.
EcoScience is a Raleigh-based, wholly-owned subsidiary of PBS&J and is assisting Hazen and
Sawyer with the field investigation and evaluation of potential mitigation sites. The EcoScience
staff is experienced with coordination among North Carolina natural resources agencies over a
wide range of environmental issues ranging from jurisdictional area identification and
delineations, jurisdictional area functional assessments, protected species, mitigation site
assessments, mitigation site conceptual and detailed planning and construction oversight,
mitigation site monitoring, determination of mitigation success, and mitigation bank
development.
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15.0 REFERENCES
Cowardin, Lewis M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classifications of Wetlands
and Deepwater Habitats of the United States. U.S. Fish and Wildlife Service. U.S.
Government Printing Office, Washington D.C.
Environmental Laboratory. 1987. Corps of Engineers Wetlands Delineation Manual. Technical
Report Y-87-1. United States Army Engineer Waterways Experiment Station,
Vicksburg, Mississippi.
Griffith, G.E., J.M. Omernik, J.A. Comstock, M.P. Schafale, W.H. McNab, D.R. Lenat, T.F.
MacPherson, J.B. Glover, and V.B. Shelbourne. 2002. Ecoregions of North Carolina
and South Carolina. U.S. Geological Survey, Reston, Virginia.
Natural Resources Conservation Service (MRCS). 2008. Web Soil Survey (online). Available:
http://websoilsurvey.nres.usda.gov/ [April 6, 2009]. Soil Survey Staff, Natural Resources
Conservation Service, United States Department of Agriculture.
North Carolina Division of Water Quality (NCDWQ). 2007. Final North Carolina Water
Quality Assessment and Impaired Waters List (2006 Integrated 305(b) and 303(d)
Report) (online). Available:
http://h2o.enr.state.nc.us/tmdl/documents/303d_Report.pdf [April 7, 2009]. North
Carolina Department of Environment and Natural Resources, Raleigh, North Carolina.
North Carolina Division of Water Quality (NCDWQ). 2008. Basinwide Planning Program.
Draft Neuse River Basinwide Water Quality Plan -- June 2008. North Carolina
Department of Environment and Natural Resources. Raleigh, North Carolina.
North Carolina Division of Water Quality (NCDWQ). 2009. North Carolina Waterbodies
Listed by Subbasin (online). Available:
http://h2o.enr.state.nc.us/bims/reports/basinsandwaterbodies/03-04-06.pdf [April 7,
2009]. North Carolina Department of Environment and Natural Resources. Raleigh,
North Carolina.
The Catena Group. 2008. City of Raleigh Freshwater Mussel Surveys of the Little River: Wake
and Johnston Counties. Prepared for Arcadis.
United States Army Corps of Engineers, United States Environmental Protection Agency, North
Carolina Wildlife Resources Commission, North Carolina Division of Water Quality
(USACE et al.). 2003. Stream Mitigation Guidelines.
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United States Army Corps of Engineers, United States Environmental Protection Agency, United
States Fish and Wildlife Service, North Carolina Wildlife Resources Commission, North
Carolina Division of Water Quality, and North Carolina Division of Water Resources
(USACE et al.). 2008. Determining Appropriate Compensatory Mitigation Credit for
Dam Removal Project in North Carolina (Version 7.1).
United States Fish and Wildlife Service (USFWS). 2008. Threatened and Endangered Species
in North Carolina (online). Available: http://www.fws.gov/nc-es/es/countyfr.html. [February
12, 2009]. United States Fish and Wildlife Service, Raleigh, North Carolina.
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