20230477 Ver 1_Application Attachments_20230120

Freshwater Mussel Survey Report
Proposed Carrier Bridge Pump Station Replacement in Asheville
Buncombe County, North Carolina
French Broad River Survey Reach I
Prepared for:
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2028 Riverside Dr, Woodfin, NC 28804
January 20, 2023

Prepared by:
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Durham, NC 27701

Table of Contents
1.0 Introduction.......................................................................................................................... 1
2.0 Waters Impacted..................................................................................................................
2
2.1. 303(d) Classification........................................................................................................
2
2.2. NPDES Discharges..........................................................................................................
2
3.0 Target Federally Protected Species Description..................................................................
3
3.1 Appalachian Elktoe (Alasmidonta raveneliana)..............................................................
3
3.1.1 Species Characteristics..............................................................................................
3
3.1.2 Habitat Requirements, Distribution, and Status........................................................
5
3.1.3 Current Baseline in the Upper French Broad River ..................................................
6
3.1.4 Threats to Species.....................................................................................................
7
3.1.5 Designated Critical Habitat.......................................................................................
9
4.0 Survey Efforts....................................................................................................................
10
4.1. Methodology..................................................................................................................
10
5.0 Results................................................................................................................................11
5.1. Conditions and Results: French Broad River Reach I ...................................................
11
5.2. Conditions and Results: French Broad River Reach 2...................................................
12
6.0 Discussion/Conclusions.....................................................................................................
12
7.0 Literature Cited..................................................................................................................
13
Appendix A Figures:
Figure 1: Project Vicinity & Survey Reach
Figure 2: NCNHP Element Occurrence
Figure 3: 303(d) Listed Streams and NPDES Discharges

1.0 INTRODUCTION
The Metropolitan Sewerage District of Buncombe County (MSDBC) is proposing to replace the
Carrier Bridge Pump Station and portions of the adjacent sanitary sewer system, in Asheville,
Buncombe County, North Carolina (Appendix A, Figure 1). The proposed project is located
along Amboy Road and Lyman Street, entirely within City of Asheville parks and greenway
property, including Carrier Park and French Broad River Park.
The project is also proposing to cross the French Broad River in two locations adjacent to the
Project Study Area (PSA), as depicted in Figure 1. The US Fish and Wildlife Service (USFWS)
Information for Planning and Consultation (IPaC) system lists the Federally Endangered
Appalachian Elktoe (Alasmidonta raveneliana) as an aquatic species that may be affected by
activities in this location. As part of the federal permitting process that requires an evaluation of
potential project -related impacts to federally protected species, Three Oaks was contracted by
MSDBC to conduct surveys targeting the Appalachian Elktoe.
Table 1 lists the nearest element occurrence (EO) in approximate river miles (RM) for targeted
species for the project crossings. Data is according to the NC Natural Heritage Program database
(NCNHP 2022), most recently updated in October 2022 (Appendix A, Figure 2).
Table 1— Element Occurrence
Distance
from
crossing
First
Last
EO
Figure
Species Name
EO ID
EO Waterbody
(RM)
Observed
Observed
Status*
Number
French
Appalachian
October
21150
Broad/Swannanoa
At crossing
1840
C
2
Elktoe
2019
River
*:C — NCNHP Current
At the time of listing, the only records of the Appalachian Elktoe from the French Broad River
Basin were from the Swannanoa River and French Broad River near Asheville (EO 21150). This
EO, which extended from the lower portion of the Swannanoa River into the French Broad River
upstream to the I-40 crossing was thought to have been extirpated. The species was re-
discovered within the Little River in the Upper French Broad River Basin in the mid- 1990's.
Since then, the known range of Appalachian Elktoe in the basin has expanded into the mainstem
of the French Broad River and now appears to be established at a low density over a broad area
(USFWS 2022). In 2017, records were found that extended the previously known extant range of
this species in the mainstem of the river 32 RM downstream, into the Asheville area. 2019
surveys near the Bent Creek confluence of the French Broad River subsequently expanded the
EO further downstream. NCNHP extended EO 21150 to include these recent records and
changed the EO from "historic" to "current" (NCNHP 2022).
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2.0 WATERS IMPACTED
This portion of the French Broad River is located in the Upper French Broad River subbasin
(Hydrologic Unit Code [HUC] # 06010105). From the PSA, the French Broad River flows north
through Asheville in Buncombe County and into Madison County. The river continues in a
generally northwest direction through Cocke County, Tennessee where it flows into Douglas
Lake. Below Douglas Lake, the French Broad River joins the Holston River in Knoxville to
form the Tennessee River.
2.1. 303(d) Classification
Within the PSA, the French Broad River is listed as impaired on the North Carolina Department
of Environmental Quality (NCDEQ) - Division of Water Resources 2022 303(d) list of impaired
streams; it is listed for Fecal Coliform (exceeding criteria) (NCDEQ 2022, Appendix A, Figure
3). The Swannanoa River flows into the French Broad at the edge of the PSA; it is listed as
impaired for Fecal Coliform (exceeding criteria).
2.2. NPDES Discharges
There are multiple minor permitted National Pollutant Discharge Elimination System (NPDES)
dischargers near the PSA; Harrins Sand & Gravel (NCG520121) is located immediately adject to
the PSA. Two major permitted dischargers in the immediate vicinity of the study area are the
Asheville Steam Electric Power Plant (NC0000396) and the French Broad River Water
Reclamation Facility (NC0024911) (NCDEQ 2020; Table 2; Appendix A, Figure 3).
Table 2 —NPDES Discharges within vicinity
Permit
Receiving
Distance from
Number
Facility Name
Permitee
Stream
Class
PSA
Asheville Steam Electric
Duke Energy
French Broad
11.3 RM
NC0000396
Major
Power Plant
Progress LLC
River
(upstream)
French Broad River
MSD of Buncombe
French Broad
6.5 RM
NC0024911
Major
WRF
County
River
(downstream)
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3.0 TARGET FEDERALLY PROTECTED SPECIES DESCRIPTION
3.1 Appalachian Elktoe (Alasmidonta raveneliana)
Status: Endangered
Family: Unionidae
Listing: November 23, 1994
Critical Habitat: Designated, see Section 3.1.4
3. L I Species Characteristics
Isaac Lea (1834) described Appalachian Elktoe from the
French Broad River system in North Carolina. Its shell is thin,
but not fragile, oblong and somewhat kidney -shaped, with a
sharply rounded anterior margin and a broadly rounded
posterior margin. Parmalee and Bogan (1998) site a maximum
length of 3.1 inches (80 mm). However, recently observed
individuals from the Little River (French Broad River Basin) in
Transylvania County and West Fork Pigeon River (French
Broad River Basin) in Haywood County measured in excess of
3.9 inches (100 mm) in length (USFWS 2009). The
periostracum (outer shell) of the adult Appalachian Elktoe
varies in color from dark brown to yellowish -brown. Rays may be prominent in some
individuals, usually on the posterior slope, and nearly obscure in other specimens. The nacre
(inside shell surface) is a shiny bluish white, changing to salmon color in the beak cavity portion
of the shell. A detailed description of the shell characteristics is contained in Clarke (1981).
Ortmann (1921) provides descriptions of the soft anatomy.
The reproductive cycle of Appalachian Elktoe is similar to that of other native freshwater
mussels. Males release sperm into the water column and the sperm are then taken in by the
female through their siphons during feeding and respiration. The females retain the fertilized
eggs in their gills until the larvae (glochidia) fully develop. The mussel glochidia are released
into the water and within a few days they must attach to the appropriate species of fish, which
they parasitize for a short time while they develop into juvenile mussels. They then detach from
their fish host and sink to the stream bottom where they continue to develop, provided they land
in a suitable substrate with the correct water conditions (USFWS 2002). Appalachian Elktoe are
moderately long lived, with an estimated age of approximately 12 years (Pandolfi et al. 2022).
Many mussel species have specific fish hosts that must be present to complete their life cycle.
Based upon laboratory infestation experiments (Wafters 1994), Banded Sculpin (Cottus
carolinae) was identified as a potential fish host for Appalachian Elktoe; however, the ranges of
these two species rarely overlap. Keller documented transformation of Appalachian Elktoe
glochidia on Mottled Sculpin (Cottus bairdi) in 1999 (USFWS 2002), and ongoing research at
Tennessee Technical University (TTU) identified 10 fish species with encysted Appalachian
Elktoe glochidia from the Little Tennessee River in North Carolina (Jim Layzer and Kendall
Mole 2014, TTU personal communication; Table 3).
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Table 3 - Fish species collected from the Little Tennessee River (NC) that contained encysted Alasmidonta
raveneliana glochidia.
Common Name
Scientific Name
Banded Darter
Etheostoma zonale
Wounded Darter
Etheostoma vulneratum
Greenfin Darter
Etheostoma chlorobranchium
Tangerine Darter
Percina aurantiaca
Mottled Sculpin
Cottus bairdi
Black Redhorse
Moxostoma duquesnei
River Redhorse
Moxostoma carinatum
Sicklefin Redhorse
Moxostoma sp.
Northern Hog Sucker
Hypentelium nigricans
Warpaint Shiner
Luxilus coccogenis
Additionally, nine of the species shown in Table 4 were shown to successfully transform
Appalachian Elktoe glochidia in laboratory induced infestations (Jim Layzer and Kendall Mole
2014, TTU, personal communication). All species listed, with the exception of the Wounded
Darter and Rosyside Dace, are known to occur within the Upper French Broad River subbasin
(Rhode et al. 1994, Menhenick 1991). A 2011 study at NC State University found Mottled
Sculpin had the most success transforming juveniles, with Central Stoneroller, Gilt Darter,
Greenfin Darter, and River Chub also successfully transforming juveniles (USFWS 2017).
Table 4 - Fish species collected from the Tuckasegee River (NC) on April 21, 2004 and used for laboratory
induced infestations.
Common Name
Scientific Name
Number
Gilt Darter
Percina evides
6
Banded Darter
Etheostoma zonale
8
Wounded Darter*
Etheostoma vulneratum
17
Greenfin Darter*
Etheostoma chlorobranchium
32
Greenside Darter*
Etheostoma blennioides
3
Olive Darter
Percina squamata
1
Mottled Sculpin*
Cottus bairdi
19
Rock Bass
Ambloplites rupestris
1
River Chub*
Nocomis micropogon
20
Northern Hogsucker*
Hypentelium nigricans
3
Central Stoneroller*
Campostoma anomalum
6
Longnose Dace*
Rhinichthys cataractae
9
Rosyside Dace*
Clinostomus funduloides
1
Mirror Shiner
Notropis spectrunculus
3
Tennessee Shiner
Notropis leuciodus
2
Total
15
131
* Species that successfully transformed Alasmidonta raveneliana glochidia.
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Based on over two years of ongoing monitoring of Appalachian Elktoe population in the Little
Tennessee River by the NC Wildlife Resource Commission (NCWRC), it is apparent that
Appalachian Elktoe is a bradytictic (long-term) breeder, with the females retaining glochidia in
their gills from late August to mid -June (USFWS 2009). Glochidia are released in mid -June,
attaching to either the gills or fins of a suitable fish host species and encysting within 2-36 hours.
Transformation time for Appalachian Elktoe occurs within 18 to 22 days at a mean temperature
of 18' C (Layzer and Mole 2014, TTU, pers. comm). Encystment time for freshwater mussels is
reduced at higher temperatures (Zale and Neves 1982). McMahon and Bogan (2001) and
Pennak (1989) should be consulted for a general overview of freshwater mussel reproductive
biology.
3.1.2 Habitat Requirements, Distribution, and Status
The Appalachian Elktoe is known only from the mountain streams and rivers of western North
Carolina and eastern Tennessee. It is found in gravelly substrates often mixed with cobble and
boulders, in cracks of bedrock, and in relatively silt -free, coarse sandy substrates (USFWS
1996).
At the time of listing, two known populations of the Appalachian Elktoe existed in North
Carolina: the Nolichucky River and its tributaries and the Little Tennessee River and its
tributaries. Historically, the species had also been recorded from Tulula Creek (Tennessee River
drainage), the main stem of the French Broad River, and the Swannanoa River (French Broad
River system) (Clarke 1981), but it was reported to have been eliminated from these streams
(USFWS 1994, USFWS 1996). In fact, Ortmann (1918) reported that the mussel fauna in the
French Broad River had been eliminated by pollution coming from lumber production in the
Davidson River. Since listing, the Appalachian Elktoe has been found in additional areas. These
occurrences include a rediscovery in the French Broad River Basin (Pigeon River, Little River,
Mills River, and French Broad River). Since 2004, the known range of Appalachian Elktoe in
the main stem of the French Broad River has expanded and now appears to be established at low
density over a broad area (USFWS 2022). USFWS (2022) further notes that overall, most of the
surviving Appalachian Elktoe populations are comprised of scattered occurrences, restricted to
pockets or short reaches of suitable habitat.
Current distribution and status are detailed in the 2022 5-Year species status review (USFWS
2022) which outlines twelve populations/subpopulations in the larger Upper Tennessee River
and French Broad River Basins. Each is defined by river kilometers (RKM) occupied length,
relative density (high, medium, low), relative threat level (high, medium, low) with notes on
trends. These are summarized as follows:
Upper Tennessee River Basin
1. Burningtown Creek — 5 RKM, High Density, Low Threat Level. Discovered in 2019
and considered stable/potentially increasing.
2. Little Tennessee River — 40 RKM, Low Density, Medium Threat Level. Unstable
population following 2005 collapse.
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3. Tuckasegee River — 49 RKM, Medium Density, Medium Threat Level. Extant but
possibly decreasing.
4. Cheoah River — 15 RKM, Low Density, Low Threat Level. Small hatchery
augmented population in protected watershed.
French Broad River Basin
5. French Broad River — 102 RKM, Low Density, Medium Threat Level. Potentially
stable expanding population distributed over large area.
6. Little River — 4 RKM, High Density, Medium Threat Level. Possibly most dense
population with high recruitment.
7. Mills River — 9 RKM, Low Density, Medium Threat Level. Extant in very low
density.
8. Pigeon River— 23 RKM, Medium Density, Medium Threat Level. Land use impacts
in watershed, but stable and reproducing.
9. Nolichucky River — 21 RKM, Low Density, High Threat Level. Extant but
decreasing due to land use pressures and potentially high temperature.
10. North Toe River — 42 RKM, Low Density, High Threat Level. Extant but decreasing
due to land use pressures and potentially high temperature.
11. South Toe River— 33 RKM, High Density, Low Threat Level. Stable and one of best
subpopulations increasing in density in upper reaches.
12. Cane River— 40 RKM, Low Density, High Threat Level. Extant but depressed after
chemical spill impacts.
3.1.3 Current Baseline in the Upper French Broad River
Appalachian Elktoe is established at a low density in the mainstem French Broad River
represented as multiple EOs. At the time of listing in 1993, the only records of the Appalachian
Elktoe from the French Broad River Basin were from the Swannanoa River and French Broad
River near Asheville (EO ID 21150), which is the type locality for the species. This EO, which
extended from the lower portion of the Swannanoa River into the French Broad River upstream
to the I-40 crossing, was thought to have been extirpated. The species was re -discovered within
the French Broad River Basin in the mid- 1990's, first in the Little River (EO 019162)', followed
by the Mills River (EO ID 7990) in the early 2000's. Since then, the known range of
Appalachian Elktoe in the French Broad River Basin has expanded into the mainstem of the
French Broad River, as records available ftom the NCWRC's database indicate that Appalachian
Elktoe were first "rediscovered" in 2005 from the French Broad River main stem at the Crab
Creek Road crossing, just downstream of the Little River confluence in Transylvania County.
Subsequent surveys have documented a known range expansion both upstream and downstream
of this area. In 2017, records were found by Three Oaks Engineering that extended the
previously known extant range of this species in the mainstem of the river 32 RM (51 RKM)
' H. Porter observed Appalachian Elktoe at an unspecified location in the Little River in 1953 and reported this
observation in a 1980 letter to WRC. It was "re -discovered" at multiple locations in the Little River in the late
1990's and has been consistently observed in the river since.
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downstream, into the Asheville area. NCNHP extended EO ID 21150 to include these recent
records and changed the EO from "historic" to "current" (NCNHP 2022). Although the species
is currently represented as three separate EO's within the French Broad River Basin (IDs 21150,
019162, and 7990) recent survey data supports that there are no gaps in occupancy of the
Appalachian Elktoe between the EOs. The total occupied habitat is approximately 64 RM (102
RKM) in the mainstem French Broad from the confluence with Hominy Creek near Asheville to
the confluence with the East Fork French Broad near Rosman (USFWS 2022).
Since the rediscovery in 2005, the known range of the Appalachian Elktoe has expanded
considerably; it is now known to occupy a substantial portion of the Upper French Broad River
between the municipalities of Rosman and Asheville, NC. The rediscovery in the main stem of
the French Broad River was close to the confluence with the Little River, where it was already
known to occur. Given the proximity to the Little River and the upstream and downstream
direction of subsequent "discoveries" in the river, the scientific consensus is that these recent
records of the Appalachian Elktoe in the French Broad represent a range expansion from the
Little River, rather than the species having been previously overlooked (USFWS 2022). Reasons
for potential population expansion in the Upper French Broad River Basin may include improved
water quality, stabilization of suitable habitat providing for mussel colonization, and increased
abundance of host fish.
3.1.4 Threats to Species
The decline of Appalachian Elktoe throughout its historic range has been attributed to a variety
of factors, including sedimentation, point and non -point source pollution, habitat modification
(impoundments, channelization, etc.), disease, predation, and the synergistic effects of combined
threats (USFWS 2022).
The majority of remaining populations are isolated from one another by impoundments or
degradation and natural gene flow is not possible and or potentially limited, often resulting in
poor demographic and genetic health (USFWS 2022). Since most Appalachian Elktoe
populations are restricted to scattered areas of suitable habitat, they are vulnerable to extirpation
from catastrophic events (USFWS 2022). Catastrophic events may consist of natural events such
as flooding or drought, as well as human influenced events such as toxic spills associated with
highways, railroads, or industrial -municipal complexes. USFWS (2022) states that most of the
surviving populations of the Appalachian Elktoe continue to face substantial threats associated
with development activities, agriculture operations, wastewater discharges, stormwater runoff,
and nonpoint source.
Siltation resulting from improper erosion control of various types of land usage, including
agriculture, forestry, and development, has been recognized as a major contributing factor to
degradation of mussel populations (USFWS 1996). Siltation has been documented to be
extremely detrimental to mussel populations by degrading substrate and water quality, increasing
potential exposure to other pollutants, and direct smothering of mussels (Ellis 1936, Marking and
Bills 1979). Sediment accumulations of less than 1 inch have been shown to cause high mortality
in most mussel species (Ellis 1936). In Massachusetts, a bridge construction project decimated a
population of the endangered Dwarf Wedgemussel (Alasmidonta heterodon) because of
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accelerated sedimentation and erosion (Smith 1981). The abrasive action of sediment on mussel
shells has been shown to cause erosion of the outer shell, which allows acids to reach and
corrode underlying layers (Harman 1974).
The impact of impoundments on freshwater mussels has been well -documented (USFWS 1992,
Neves 1993). Construction of dams transforms lotic habitats into lentic habitats, which results in
changes with aquatic community composition. These changes associated with inundation
adversely affect both adult and juvenile mussels as well as fish community structure, which
could eliminate possible fish hosts for glochidia (Fuller 1974). In addition, the construction of
dams often results in fragmentation of mussel populations by effectively blocking upstream
expansion and recruitment of mussel and fish species. Along with modification of habitat, dams
can indirectly impact freshwater mussel species by posing as a barrier to fish migration. The
construction of the Petitcodiac River Causeway in Canada in 1968, resulted in the extirpation of
the Dwarf Wedgemussel because the causeway restricted the migration of the diadromous Inner
Bay of Fundy stock of Atlantic Salmon (Salmo salar), which served as the fish host for the
Dwarf Wedgemussel in this region (Locke et al. 2003).
Sewage treatment effluent has been documented to significantly affect the diversity and
abundance of mussel fauna (Goudreau et al. 1988). Goudreau et al. (1988) found that recovery of
mussel populations might not occur for up to 2 mi (3.2 km) below points of chlorinated sewage
effluent. Most of the water bodies where Appalachian Elktoe still exist have relatively few point
source discharges within the watershed and are rated as having `good' to `excellent' water
quality (NCDWQ 2012, USFWS 1996).
The introduction of exotic species such as the Asian Clam (Corbicula fluminea) and Zebra
Mussel (Dreissena polymorpha) has also been shown to pose significant threats to native
freshwater mussels. The Asian Clam is now established in most of the major river systems in the
United States (Fuller and Powell 1973). Concern has been raised over competitive interactions
for space, food, and oxygen between this species and native mussels, possibly at the juvenile
stages (Neves and Widlak 1987; Alderman 1997). When Appalachian Elktoe was listed, it was
speculated that due to its restricted distribution, it "may not be able to withstand vigorous
competition" (USFWS 1996).
The Zebra Mussel, native to the Black, Caspian and Aral Seas, is an exotic freshwater mussel
that was introduced into the Great Lakes in the 1980s. Since its introduction, this species has
rapidly expanded its range into the surrounding river basins, including those of the South
Atlantic slope (O'Neill and MacNeill 1991). This species competes for food resources and space
with native mussels and is expected to contribute to the extinction of at least 20 freshwater
mussel species if it becomes established throughout most of the eastern United States (USFWS
1996). The Zebra Mussel is not currently known from any river supporting Appalachian Elktoe
populations.
Another exotic species that has the potential to adversely impact aquatic species, including
Appalachian Elktoe, is Japanese Knotweed (Reynoutria japonica). The plant is an invasive
species that can reproduce from its seed or from its long, stout rhizomes. It can tolerate a variety
of conditions such as full shade, high temperatures, high salinity, and drought. It can be spread
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by wind, water, and soil movement to an area where it quickly forms dense thickets that excludes
native vegetation and greatly alters the natural ecosystem. This species has become established in
riparian habitats throughout western North Carolina. The species' root system does not prevent
erosion as well as many native riparian plant species, therefore riparian zones colonized by
Japanese knotweed may be susceptible to erosion during flood events.
3.1.5 Designated Critical Habitat
The Appalachian Elktoe is listed as a Federally Endangered Species under the Endangered
Species Act (ESA) with Critical Habitat Designation. Critical Habitat for listed species consists
of:
1. The specific areas within the geographical area occupied by the species at the time it is
listed in which are found those physical or biological features (constituent elements) that
are:
a. essential to the conservation of the species, and
b. which may require special management considerations or protection
2. Specific areas outside the geographical area occupied by the species at the time it is listed
in accordance with the provisions of Section 4 of the Act, upon a determination by the
Secretary that such areas are "essential for the conservation of the species."
Critical Habitat for Appalachian Elktoe has been designated in 144.3 total RM (232.2 km) in six
distinct units. Those units are as follows:
1. Encompasses approximately 24 mi (38.5 km) of the main stem of the Little Tennessee
River from the Lake Emory Dam in Franklin, Macon County, NC, downstream to the
backwaters of Fontana Reservoir in Swain County, NC.
2. Encompasses approximately 26 mi (41.6 km) of the main stem of the Tuckasegee River,
from NC State Route 1002 bridge in Cullowhee, Jackson County, NC, downstream to the
NC 19 bridge north of Bryson City, Swain County, NC.
3. Encompasses approximately 9.1 mi (14.6 km) of the main stem of the Cheoah River from
the Santeelah Dam downstream to its confluence with the Little Tennessee River, in
Graham County, NC.
4. Encompasses approximately 4.7 mi (7.5 km) of the main stem of the Little River (French
Broad River Basin) from the Cascade Lake Power Plant, downstream to its confluence
with the French Broad River in Transylvania County, NC.
5. Encompasses approximately 11.1 mi (17.8 km) of the main stem of the West Fork Pigeon
River (French Broad River Basin) from the confluence with the Little East Fork Pigeon
River downstream to the confluence with the East Fork Pigeon River, and the main stem
of the Pigeon River from the confluence of the East Fork Pigeon River and West Fork
Pigeon River downstream to the NC 215 crossing, south of Canton, Haywood County,
NC.
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6. Encompasses approximately 3.7 mi (5.9 km) of the main stem of the North Toe River,
Yancey and Mitchell counties, NC, from the confluence with Big Crabtree Creek,
downstream to the confluence of the South Toe River; approximately 14.1 mi (22.6 km)
of the main stem of the South Toe River, Yancey County, NC, from the NC State Route
1152 crossing, downstream to its confluence with the North Toe River; approximately
21.6 mi (34.6 km) of the main stem of the Toe River, Yancey and Mitchell counties, NC,
from the confluence of the North Toe River and South Toe River, downstream to the
confluence of the Cane River; approximately 16.5 mi (26.4 km) of the main stem of the
Cane River, Yancey County, NC, from the NC State Route 1381 crossing, downstream to
its confluence with the Toe River; and approximately 13.5 mi (21.6 km) of the main stem
of the Nolichucky River from the confluence of the Toe River and the Cane River in
Yancey County and Mitchell County, NC downstream to the US 23/19W crossing,
southwest of Erwin, Unicoi County, TN (USFWS 2002).
The "re -discovery" of the Appalachian Elktoe in the mainstem of the French Broad occurred
after Critical Habitat was designated, as such, there are no Critical Habitat Units that encompass
the French Broad River. The PSA does not drain into any Critical Habitat Unit. The closest
Critical Habitat Unit (4) is located in the Little River, which flows into the French Broad River
approximately 37 RM upriver from the PSA.
4.0 SURVEY EFFORTS
Surveys were conducted by Three Oaks Engineering personnel Tim Savidge (Permit # 22-
ES0034), Tom Dickinson (Permit # 22-ES00343), Wade Biltoft and Zach Biltoft, Matt Haney of
NCDOT, and Jay Mays of the USFWS on September 22, 2022. Water levels were clear and
close to median levels for the time of year, running at 1140 cfs and 1.67 feet at the USGS
Asheville Gage # 03451500.
4.1. Methodology
Mussel surveys were conducted from approximately 1,312 feet (400 meters) downstream to
approximately 328 feet (100 meters) upstream of the respective crossings for a distance of
approximately 1,640 feet (500 meters) in each reach (Figure 1). Areas of appropriate habitat
were searched, concentrating on the stable habitats preferred by the target species. The survey
team spread out across the creek into survey lanes. Visual surveys were conducted using mask
and snorkel and weight belts to access deeper habitats. All freshwater bivalves were recorded
and returned to the substrate. Timed survey efforts provided Catch Per Unit Effort (CPUE) data
for each species. Relative abundance for freshwater snails and freshwater clam species were
estimated using the following criteria:
Carrier Bridge Pump Station Mussel Report January 2023
Job# 21-644 Page 10

➢ (VA) Very abundant > 30 per square meter
➢ (A) Abundant 16-30 per square meter
➢ (C) Common 6-15 per square meter
➢ (U) Uncommon 3-5 per square meter
➢ (R) Rare 1-2 per square meter
➢ (P-) Ancillary adjective "Patchy" indicates an uneven distribution of the species within the
sampled site.
5.0 RESULTS
The conditions observed and results for the two project crossing locations are detailed by reach
as follows.
5.1. Conditions and Results: French Broad River Reach 1
The survey reach occurs adjacent to Carrier Park. Surveys concentrated on areas considered to
provide the best habitat attributes for Appalachian Elktoe, however, all in -reach habitat types
were surveyed. Each surveyor stayed in a loosely defined survey lane of variable width. Surveys
proceeded in an upstream direction following the upstream transitions between microhabitats.
The river was approximately 50 to 65 meters wide with relatively stable banks up to five meters
high. Water depth ranged from up to 1.5 meters deep however, most was under one meter.
Water levels were normal with high clarity. The majority of the reach consisted of run with
areas of slackwater occurring along riverbanks and behind woody debris, which was common.
The substrate consisted of mixed cobble, gravel, and sand with scattered bedrock and boulders.
Stable rocky substrates were often covered in riverweed (Podostemum sp.) and accumulations of
silt and sand were present in depositional areas, especially along riverbanks and behind woody
debris.
A total of 9.5 person hours of survey time were spent in the reach during which no mussels were
located. The only mollusk species found (Table 5) were the Asian Clam (abundant), the Pointed
Campeloma (rare), and Sprite Elimia (patchy common).
Table 5. Mussel Survey Results: French Broad River Reach 1
Scientific Name
Common Name
# live
Abundance/
CPUE
Freshwater Mussels
CPUE
one
Freshwater Snails and Clams
Relative
Abundance
Cam eloma decisum
Pointed Cam eloma
R
Corbicula uminea
Asian Clam
A
Elimia proxima
Sprite Elimia
P-C
Carrier Bridge Pump Station Mussel Report January 2023
Job# 21-644 Page 11

5.2. Conditions and Results: French Broad River Reach 2
The survey reach occurs adjacent to the French Broad River Park. The river was approximately
50 to 70 meters wide with banks up to three meters high that have been stabilized with rip rap in
some areas. Water depth ranged up to 1.5 meters deep and water levels were normal with high
clarity.
General habitat conditions consisted of a relatively high gradient riffle/run sequence. The
substrate was well sorted and consisted of cobble, gravel, and sand with scattered bedrock and
boulders. Areas of accumulated sand and silt were present along riverbanks.
A total of 12.5 person hours of survey time was spent in the reach, during which a single Eastern
Elliptio (Elliptio complanata), a mussel species native to Atlantic Slope river basins, that has
been introduced to the French Broad River Basin, was found. Other mollusk species observed
were the Asian Clam (very abundant) and Sprite Elimia (common).
Table 6. Mussel Survey Results: French Broad River Reach 2
Scientific Name
Common Name
# live
Abundance/
CPUE
Freshwater Mussels
CPUE
lli do com lanata Eastern Elli do 1
0.08/hr
Freshwater Snails and Clams
Relative
Abundance
Corbicula uminea
sian Clam
VA
Elimia proxima
ISprite Elimia
C
6.0 DISCUSSION/CONCLUSIONS
The Appalachian Elktoe was not found during these efforts, but recent surveys have documented
the species in the mainstem French Broad upstream, approximately 2.4 RM upstream of the
PSA. Based on habitat conditions and the difficulty detecting species that are present in low
numbers, it is probable the Appalachian Elktoe is present in the PSA. A recommended
biological conclusion on potential impacts from the project to this species is provided below.
The USFWS is the regulating authority for Section 7 Biological Conclusions and as such, it is
recommended that they be consulted regarding their concurrence with the finding of this
document. The federal action agency, or its nonfederal designee must render a biological
conclusion for the species.
Biological Conclusion Appalachian Elktoe: May Affect, Likely To Adversely Affect
Given the presumed presence of Appalachian Elktoe within the project area, it is anticipated all
potential Adverse, Beneficial, and Cumulative effects to the species resulting from the
construction of the project will need to be evaluated and disclosed as part of Section 7
Consultation process of the Endangered Species Act.
Carrier Bridge Pump Station Mussel Report January 2023
Job# 21-644 Page 12

7.0 LITERATURE CITED
Alderman, J.M. 1997. Monitoring the Swift Creek freshwater mussel community. Pages 98-107 in
K.S. Cummings, A.C. Buchanan, C.A. Mayer, and T.J. Naimo, eds. 1997. Conservation and
Management of Freshwater Mussels II: Initiatives for the future. Proceedings of a UMRCC
symposium, 16-18 October 1995, St. Louis, Missouri. Upper Mississippi River Conservation
Committee, Rock Island Illinois. 293 pp.
Clarke, A.H. 1981. The tribe Alasmidontini (Unionidae: Anodontinae), Part I: Pegias, Alasmidonta,
and Arcidens. Smithsonian Contributions to Zoology, (326), 101 pp.
Ellis, M.M. 1936. Erosion silt as a factor in aquatic environments. Ecology. 17:29-42.
Fuller, S.H. 1974. Clams and mussels (Molluska: Bivalva). Pp 215-273 in J.W. Hart and S.H. Fuller,
eds. Pollution Ecology of Freshwater Invertebrates. Academic Press, New York City, NY.
Fuller, S.L.H. and C.E. Powell. 1973. Range extensions of Corbicula manilensis (Philippi) in the
Atlantic drainage of the United States. Natilus. 87(2):59.
Goudreau, S.E., R.J. Neves, and R.J. Sheehan. 1988. Effects of sewage treatment effluents on
mollusks and fish of the Clinch River in Tazewell County, Virginia. Final Rep., U.S. Fish
and Wildl. Serv. 128 pp.
Harman, W.N. 1974. The effects of reservoir construction and channelization on the mollusks of the
upper Delaware watershed. Bull. Am. Malac. Union 1973:12-14.
Layzer, J., and K. Mole. 2014. Tennessee Technical University. Personal Communication regarding
target species.
Locke, A., Hanson, J.M., Klassen, G.J., Richardson. S.M., and Aube, C.I.2003. The Damming of the
Petitcodiac River: Species, populations, and habitats lost. Northeastern Naturalist: 10 (No. 1),
pp. 39-54.
Lea, I. 1834. Observations on the naiads and descriptions of new species of that and other families.
Transactions of the American Philosophical Society 5: 23-119, plates 1-19.
Marking, L.L., and Bills, T.D. 1979. Acute effects of silt and sand sedimentation on freshwater
mussels. Pp. 204-211 in J.L. Rasmussen, ed. Proc. of the UMRCC symposium on the Upper
Mississippi River bivalve mollusks. UMRCC. Rock Island IL. 270 pp.
McMahon, R.F. and Bogan, A.E. 2001. Mollusca: Bivalva. Pp. 331-429. In: J.H. Thorpe and A.P.
Covich. Ecology and Classification of North American freshwater invertebrates. 2nd edition.
Academic Press.
NCDWQ. 2012. Little Tennessee River Basinwide Water Quality Plan. N.C. Department of
Environment and Natural Resources, Division of Water Quality, Raleigh, NC.
Carrier Bridge Pump Station Mussel Report January 2023
Job# 21-644 Page 13

North Carolina Department of Water Quality (NCDEQ). 2020. DWR Permits Map. https://data-
ncdenr.opendata.arcgis.com/apps/ncdenr::permits-map/explore. Accessed January 18, 2023.
North Carolina Department of Environmental Quality (NCDEQ) - Division of Water Resources.
2022. 2022 Final North Carolina 303(d) List. https:Hdeq.nc.gov/about/divisions/water-
resources/water-planning/modeling-assessment/water-quality-data-assessment/inte ram
report -files. Accessed January 18, 2023.
North Carolina Natural Heritage Program. 2022. Biotics Database. Division of Land and Water
Stewardship. Department of Natural and Cultural Resources, Raleigh, North Carolina.
October 2022 version.
Neves, R.J. 1993. A state of the Unionids address. Pp. 1-10 in K.S. Cummings, A.C. Buchanan, and
L.M. Kooch, eds. Proc. of the UMRCC symposium on the Conservation and Management of
Freshwater Mussels. UMRCC. Rock Island IL.189 pp.
Neves, R.J., and Widlak, J.C. 1987. Habitat ecology of juvenile freshwater mussels (Bivalvia:
Unionidae) in a headwater stream in Virginia. Amer. Malacol. Bull. 1(5):1-7.
O'Neill, C.R., Jr., and MacNeill, D.B. 1991. The Zebra Mussel (Dreissena polymorpha): an
unwelcome North American invader. Sea Grant, Coastal Resources Fact Sheet. New York
Sea Grant Extension. 12 pp.
Ortmann, A. E. 1918. The nayades (freshwater mussels) of the Upper Tennessee drainage. With
notes on synonymy and distribution. Proceedings of the American Philosophical Society
57:521-626.
Ortmann, A.E. 1921. The anatomy of certain mussels from the Upper Tennessee. The Nautilus
34(3):81-91.
Pandolfi, G. S., J. W. Mays, M. M. Gangloff. 2022 Riparian Land -Use and In -Stream Habitat Predict
the Distribution of a Critically Endangered Freshwater Mussel. Hydrobiologia 849:1763-
1776.
Parmalee, P.W. and Bogan, A.E. 1998. Freshwater Mussels of Tennessee. University of Tennessee
Press, Knoxville, TN.
Pennak, R.W. 1989. Fresh -water invertebrates of the United States, Protozoa to Mollusca Third
Edition, John Wiley & Sons, Inc. New York, 628 pp.
Smith, D. 1981. Selected freshwater invertebrates proposed for special concern status in
Massachusetts (Mollusca, Annelida, Arthropoda). MA Dept. of Env. Qual. Engineering, Div.
of Water Pollution Control. 26 pp.\
U.S. Fish and Wildlife Service (USFWS). 1992. Special report on the status of freshwater mussels.
U.S. Fish and Wildlife Service (USFWS). 1994. Endangered and Threatened Wildlife and Plants;
Appalachian Elktoe Determined to Be an Endangered Species. CFR, Vol. 59, No. 225.
Carrier Bridge Pump Station Mussel Report January 2023
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U.S. Fish and Wildlife Service (USFWS). 1996. Appalachian Elktoe (Alasmidonta raveneliana)
Recovery Plan. Atlanta, Georgia, 30 pp
U.S. Fish and Wildlife Service (USFWS). 2002. Endangered and Threatened Wildlife and Plants:
Designation of Critical Habitat for the Appalachian Elktoe. CFR, Vol. 67, No. 188.
U.S. Fish and Wildlife Service (USFWS). 2009. Appalachian Elktoe (Alasmidonta raveneliana) 5-
Year Review: Summary and Evaluation. Asheville, NC.
U.S. Fish and Wildlife Service (USFWS). 2017. Appalachian Elktoe (Alasmidonta raveneliana) 5-
Year Review. Asheville, North Carolina, 23 pp.
U.S. Fish and Wildlife Service (USFWS). 2022. Appalachian Elktoe (Alasmidonta raveneliana)
5-Year Review. Asheville, North Carolina, 18 pp.
Watters, G.T. 1994. An annotated bibliography of the reproduction and propagation of the Unionidae
(Primarily of North America). Ohio Biological Survey Miscellaneous Contributions (1): 158.
Zale, A.V. and Neves, R.J. 1982. Reproductive biology of four freshwater mussel species (Molluscs:
Unionidae) in Virginia. Freshwater Invertebrate Biology. 1: 17-28.
Carrier Bridge Pump Station Mussel Report January 2023
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Appendix A:
Figures
Carrier Bridge Pump Station Mussel Report January 2023
Job# 21-644 Page 16

Prepared For:
��Qo��i �� oE1NER.q�F�s
a
w
�E
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Carrier Bridge Pump
Station Replacement
and
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Freshwater
Mussel Survey
Vicinity Map
Buncombe County
North Carolina
Date:
January 2023
Scale: 0 200 400 Ft
I i I
Job No.:
21-644
Drawn By:
Checked By:
KEMS
JSM
Figure

Project Study
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a
Proposed
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Station Replacement
and
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Sewer Line Crossings
Freshwater
Mussel Survey
NCNHP
Element
Occurrences
Buncombe County
North Carolina
Date:
January 2023
Scale:
0 2,000 4,000 Feet
I i I
Job No.:
21-644
Drawn By:
Checked By:
KEMS
JSM
Figure

Project Study
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41
lkll
Proposed
Carrier Bridge Pump
Station Replacement
and
French Broad River
Sewer Line Crossings
Freshwater
Mussel Survey
303(d) Listed
Streams and
NPDES Discharges
Buncombe County
North Carolina
Date:
January 2023
Scale: 0 0.5 1 Miles
I i I
Job No.:
21-644
Drawn By:
Checked By:
KEMS
JSM
Figure