4.4.5

4.4.4.4 Impairment Evaluation
Impairment (as defined by NPS policy) to the aquatic wildlife of GSMNP and the AT would not occur under
the No-Action Alternative, Monetary Settlement Alternative, Laurel Branch Picnic Area, and ihe Partial-
Build Alternative to Bushnell. The Northern Share Corridar is not likely to impair the aquatic wildlife of
GSMNP ar the AT based on the information obtained to date. Due to the magnitude of this alternative, it is
likely that additional NEPA documentation would be required to address sit�specific impacts not currently
known, to determine detailed a�oidance, minimization, and mitigation measures as they relate to final
design, and to re-evaluate the impairment determination related to aquatic wildlife.
4.4.5 Vegetation Communities
4.4.5.1 Methodology for Assessing Impacts to Vegetation Communities
The following sections define the duration, context, and intensity for evaluating impacts to vegetation
communities and summarize the impacts of the alternatives. Impacts on ecosystems involve the evaluation
of component resources, as well as the spatial and temporal organization (patterns and process) of these
components with consideration for rare species and biological communities in ecosystems. For the purposes
of this analysis, communities were considered rare when the Global Rank was G1 or G2 or when the global
rank indicated an uncertainty (G2? or G3?) that included the potential for a G1 or G2 community. All other
community global ranks (G3, G4, G5, GD, GW) were considered as secure. It should, however, be noted
that under this ranking system that G3 communities are defined as vulnerable, but not imperiled. Table 3-9
lists the global rank for all of the vegetation communities within the project study corridors, and they are
depicted in Figure 3-6.
Vegetation community impact analysis utilizes the acreage expected to be lost or altered as a result of the
new location of a road or recreational facilities or disturbance during construction. ArcGIS software was
used to determine the approximate area of vegetation community, as mapped on the GSMNP final vegetation
thematic map (CRSM 2004), which would be directly impacted by the construction limits. The construction
limits include estimated cut-and-fill slopes for the proposed road designs and a construction access buffer.
Based on a review of the described communities in the ICEC-GSMNP, especially the rare vegetation
communities, it was noted that they primarily consist of unique assemblages of relatively common plant
species in a relatively uncommon microenviron�nent. In other words, the communities are rare due to abiotic
factors (topographic position, aspect, soil rype, hydrology and eXposure) or due to prior human activities and
not due to the rariry of any one or more plant species. Impacts to the community at one location should not
affect the ability of the community at another location to survive (regional impacts as defined below).
The potential for indirect impacts to bisected or exposed portions of a vegetation community (local impacts
as defined below) due to changes in abiotic factors are expected. These abiotic factors include potential
alteration of downstream hydrology, changes in environmental conditions associated with edge effects such
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-198
North Shore Road Final Environmental Impact Statement

as alteration of atmospheric moisture levels, increased wind and sunlight exposure, and changes in
temperature regimes. Other indirect impacts include the increased potential for human disturbance, such as
the creation of unplanned walking trails or the occasional Park maintenance need to remove a"hazard tree."
Indirect impacts are also expected from the increased potential of arson and spread of invasive exotic
species.
Fire is a natural process that is important in maintaining healthy, diverse ecosystems. From the 1930s until
1996, fire suppression was practiced with GSMNP. GSMNP currently manages fires by suppressing fires
that endanger human life or structures, and by utilizing prescribed burns to invigorate a species or ecosystem
that benefits froin fire (such as table mountain pine [Pinus pungens] and red-cockaded woodpecker) and/or
to reduce accumulation of fuel (dead wood/debris). While fires can be beneficial to adapted species or
vegetation communities, arson fires often occur in areas not normally subject to natural fire. Therefore,
arson fires can be harmful and endanger rare species ar vegetation communities. Increased access to this
section of the Park is likely to increase the incidence of arson fires (Forman and Hersperger 1996). (See
Section 4.2.5.2. ] 3 for more information on arson.)
Fire and fir�fighting activities also increase the potential for the spread of invasive exotic plant species,
which can also have adverse impacts. Invasive exotic species are non-indigenous species able to
aggressively proliferate and alter or displace indigenous biological communities. One such species, royal
princess tree (Paulownia tomentosa), is a major concern after a fire as it is known to quickly colonize
recently burned sites. The impacts caused by the invasive exotics include decrease in biodiversity,
disturbance to or elimination of habitat for rare and endangered species as well as for other native species,
and an alteration of the relationsbip between native animal and plant communities. The road will increase
the potential for the introduction and spread of invasive exotic species that could dramatically alter the
current natural communities present within the project study corridors. Tbese impacts are discussed in
Section 4.4.9.
Context
Context is defined as sit�specific, local, or regional. Sit�specific is the area within the construction
footprint of the road. Local is defined as the area within 2 mi (3.2 km) of the construction footprint or the
northern share of Fontana Lake (whichever is less). The 2-mi (3.2-km) radius was selected because it is the
general rule utilized within North Carolina when discussing a known population of threatened or endangered
species. Regional is the area bounded by the northern shore of Fontana Lake, the North Carolina/Tennessee
state line, Twentymile Ridge on the west, and Noland Creek on the east. This area was selected because the
mountain ridges and lake form a natural ecological boundary, and it is an area for which a suitable analysis
and discussion of possible impacts could be undertaken.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-199
North Shore Road Final Environmental Impact Statement

Duration
Short-term impacts are those that would occur for less than 1 year, rypically as an episodic or temparary
event. Long-term effects occur as a result of construction activities at a specific location throughout the life
of construction (this is assumed to be between 1 year and 15 years), but the impact is more than that of a
temporary event. Permanent impacts are considered to be anything that persists throughout the construction
period.
Intensity
Intensity is the degree to which resources would be affected and is categorized as no/negligible, minor,
moderate, or major.
The intensity definitions far vegetation communities were based on consideration of a wide range of factors
including the type of communities impacted, their degree of rarity (based on the Global Ranking system
[Anderson et al. 1998; Grossman et al. 1998]), the size and shape of the direct impact under the construction
footprint, indirect modifications to the remaining bisected communities, the potential for increased arson
fires, and the potential introduction of invasive exotic species. There are 22 vegetation communities
identified in the project study corridors, three of which are considered rare. Direct impact sizes, from the
construction footprint of the various alternatives and options, range from approximately 10 ac (4 ha) to just
over 400 ac (162 ha). Roads and other facilities can modify the surrounding environment which will tend to
modify the vegetation community. For instance, roads may modify the depth of forest leaf litter up to 328 ft
(100 m) from tbe faciliry (Haskell 2000). Increased access, througb addition of a road or trail, is likely to
increase the incidence of arson fires (Forman and Hersperger 1996). Roads provide dispersal of invasive
exotic species through providing habitat by altering eXisting conditions, making invasion more likely by
stressing or removing native species, modification of light levels in potential invasion sites and allowing
easier movement by wild or human vectors (Parendas and Jones 2000; Trombulak and Frissel 2000).
Additionally, consideration was given to the size of disturbance events occurring in the forest, such as
landslides and fires. Landslides were considered to impact a small area, estimated a less than 5 acres (2 ha).
The average area burned in a fu-e in GSMNP is just under 100 ac (40.5 ha) (NPS 2003e).
The following intensity definitions apply to the various vegetation communities found within or adjacent to
the construction footprint of the proposed project. The construction footprint includes the proposed area of
pavement, the adjoining cut and fill slopes, and the surrounding construction access buffer. There is no
scientific literature available that provides a scale to define or rank the severity of impacts from a project.
Therefore, the following intensity definitions are based on best professional judgment of what is reasonable
considering the complex interactions of the factors noted above.
Additionally, rare communities are already in peril and therefore, have much lower impact thresholds than
secure communities. Because the size of the rare communities is generally smaller than the size of the secure
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-200
North Shore Road Final Environmental Impact Statement

communities, indirect impacts to the remaining bisected portions of a rare vegetation community would have
a proportionally greater effect on the rare community than the relative impacts on the secure communities.
Negligible
The project impacts are less than 1.0 ac (0.4 ha) for rare communities and less than 20.0 ac (8.1 ha) for
secure communities.
Minor
The project impacts are from 1.0 to 5.0 ac (0.4 to 2.0 ha) for rare communities and from 20.0 to 100.0 ac (8.1
to 40.5 ha) for secure communities.
Moderate
The project impacts are from 5.0 to 10.0 ac (2.0 to 4.1 ha) for rare communities and from 100.0 to 200.0 ac
(40.5 to 80.9 ha) far secure communities.
Major
The project impacts are greater than 10.0 ac (4.1 ha) for rare communities and greater than 200.0 ac (80.9 ha)
for secure communities.
4.4.5.2 Summary of Impacts
4.4.5.2.1 No-Action
The No-Action Alternative would have no impacts on vegetation communities in the project study corridors.
4.4.5.2.2 Monetary Settlement
The Monetary Settlement Alternative would not directly or indirectly impact vegetation communities within
GSMNP.
4.4.5.2.3 Laurel Branch Picnic Area
The Laurel Branch Picnic Area would directly impact 3.40 ac (1.38 ha) of Appalachian Montane Alluvial
Forest, a G2-ranked community. This impact to this rare com�nuniry was assessed to be minor, adverse, site-
specific, and permanent. Potential alteration of downstream hydrology, changes in environmental conditions
associated with edge effects such as alteration of atmospheric moisture levels, increased wind and sunlight
exposure, changes in temperature regimes, and the increased potential for human disturbance have the
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-201
North Shore Road Final Environmental Impact Statement

potential to indirectly impact vegetation species distributions and thus alter the vegetation community type.
The indirect impacts to the remaining ]ocal portions of the rare vegetation communities were assessed to be
minor, adverse and permanent. Additionally, 5.54 ac (2.24 ha) of secure vegetation communities would be
directly impacted. The direct and indirect impacts to the secure communities from this alternative would be
negligible, adverse, sit�specific, and permanent.
4.4.5.2.4 Partial-Build Alternative to Bushnell (Primitive and Principal Park Roads)
Partial-Build Alternative to Bushnell (Primitive Park Road)
The baseline Partial-Build Alternative to Bushnell (Primitive Park Road) would directly impact 18.34 ac
(7.34 ha) of Appalachian Montane Alluvial Forest, a G2-ranlced community. This impact to this rare
community was assessed to be major, adverse, sit�specific, and permanent. The potential type of indirect
impact is the same as noted above. The indirect impacts to the remaining local portions of the rare
vegetation communities were assessed to be major, adverse, and permanent. Additionally, 80.76 ac
(32.70 ha) of secure vegetation communities would be directly impacted. The direct and indirect impacts to
the secure communities from this alternative would be minor, adverse, site-specific, and permanent.
Southern Option at Forney Creek Embayment (Primitive Park Road)
The Southern Option at Forney Creek Embayment would reduce the direct impacts to Appalachian Montane
Alluvial Forest Communiry by S.S l ac (2.23 ha) and to secure communities by 4.30 ac (1.74 ha) compared to
the baseline Partial-Build Alternative to Bushnell (Primitive Park Road). There would be an associated
proportional decrease in the potential indirect impacts.
Partial-Build Alternative to Bushnell (Principal Park Road)
The baseline Partial-Build Alternative to Bushnell (Principal Park Road) would directly impact 19.90 ac
(8.06 ha) of rare vegetation communities and 7l .53 ac (28.96 ha) of secure vegetation communities. The
assessed impact thresholds would be the same as for the Primitive Park Road
Southern Option at Forney Creek Embayment (Principal Park Road)
The Southern Option at Forney Creek Embayment would reduce the direct impacts to rare vegetation
communities by 7.29 ac (2.95 ha), and to secure communities by 8.00 ac (3.24 ha) compared to the baseline
Partial-Build Alternative to Bushnell (Principal Park Road). There would be an associated proportional
decrease in the potential indirect impacts.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-202
North Shore Road Final Environmental Impact Statement

4.4.5.2.5 Northern Shore Corridor (Primitive and Principal Park Roads)
Northern Shore Corridor (Primitive Park Road)
The baseline Northem Shore Corridar (Primitive Park Road) would directly impact 38.8 ac (15.8 ha) of rare
vegetation communities. This impact to these rare communities was assessed to be major, adverse, sit�
specific, and permanent. The indirect impacts to the remaining local portions of the rare vegetation
communities were assessed to be major, adverse, and permanent. Additionally, 358.95 ac (145.32 ha) of
secure vegetation communities would be directly impacted. The direct and indirect impacts to the secure
communities from this alternative would be major, adverse, site-specific, and permanent. Part of the secure
vegetation communities within the footprint of baseline Northern Share Corridor is approximately 0.99 ac
(0.40 ha) of area mapped as "rocic outcrop." This area is located near the western terminus of the project
study corridors. From a review of aerial photography and field observations, it appears tbat this "rock
outcrop" area is associated with the human-disturbed area under the powerline rights-of-way west of Fontana
Dam. No impacts to a known rare rock outcrop community are anticipated; however, additional field
investigations would be conducted prior to completion of the final design.
Southern Option at Forney Creek Embayment (Primitive Park Road)
The Southern Option at Forney Creek Embayment would reduce the direct impacts, from the baseline
Northern Shore Corridor (Primitive Park Road), to rare vegetation communities by 5.51 ac (2.23 ha), and to
secure communities by 4.30 ac (1.74 ha). There would be an associated proportional decrease in the indirect
impacts.
Southern Option at Hazel and Eagle Creek Embayments (Primitive Park Road)
The Southern Option at Hazel and Eagle Creek Embayments would reduce the direct impacts to rare
vegetation communities by 19.49 ac (7.89 ha) and to secure communities by 10.18 ac (4.12 ha) compared to
the baseline Northern Shore Corridor (Primitive Park Road). There would be an associated proportional
decrease in the indirect impacts to both community categories.
Southern Option Crossing Fontana Darn (Primitive Park Road)
For the Southern Option Crossing Fontana Dam, there would be no change from the baseline Northern Shore
Corridor (Primitive Park Road) impacis for rare vegetation communities and a reduction to secure
communities of 18.86 ac (7.64 ha). There would be an associated proportional decrease in the indirect
impacts to the secure vegetation communities.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-203
North Shore Road Final Environmental Impact Statement

Northern Shore Corridor (Principal Park Road)
The baseline Nortbern Shore Corridor (Principal Park Road) would directly impact 36.4 ac (14.7 ha) of rare
vegetation communities and 351.30 ac (142.23 ha) of secure vegetation communities. The assessed impact
thresholds would be the same as noted for the baseline Northern Shore Corridor Primitive Park Road Part of
the secure vegetation communities within the footprint of baseline Northern Shore Corridor is approximately
1.33 ac (0.54 ha) of area that is mapped as a"rock outcrop." This area is located in the western terminus of
the project study corridors. From a review of aerial photography and field observations, it appears that this
"rock outcrop" area is associated with the human-disturbed area under the powerline rights-of-way west of
Fontana Dam. No impacts to a known rare rock outcrop community are anticipated; however, additional
field investigations would be conducted prior to completion of the final design.
Southern Option at Forney Creek Embayment (Principal Park Road)
The Southern Option at Forney Creek Embayment would reduce the direct impacts, from the baseline
Northern Shore Corridor (Principal Park Road), to rare vegetation communities by 7.29 ac (2.95 ha) and to
secure communities by 8.00 ac (3.24 ha). There would be an associated proportional decrease in the indirect
impacts.
Southern Option at Hazel and Eagle Creek Embayments (Principal Park Road)
The Southern Option at Hazel and Eagle Creek Embayments would reduce the direct impacts to rare
vegetation communities by 18.47 ac (7.48 ha) and to secure communities by 19.02 ac (7.70 ha) compared to
the baseline Northern Shore Corridor (Principal Park Road). There would be an associated proportional
decrease in the indirect impacts to both community categaries.
Southern Option Crossing Fontana Dam (Principal Park Road)
For the Southern Option Crossing Fontana Dam, there would be no change from the baseline Northern Shore
Corridor (Principal Park Road) impacts for rare vegetation communities and a reduction to secure
communities of 18.80 ac (7.61 ha). There would be an associated proportional decrease in the potential
indirect impacts to the secure vegetation communities.
4.4.5.2.6 Cumulative Impacts
Other actions in the study area were reviewed to determine potential cumulative impacts. Some of the
projects listed in Section 4. ].2 have affected or have the potential to affect vegetation communities, including
Appalachian Montane Alluvial Farest, in the study area. In the past, the study area's historically forested
landscapes have been divided by roads and reduced by commercial and residential development. The
Appalachian Montane Alluvial Forest Community is rypically found along medium to large sized rivers.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-204
North Shore Road Final Environmental Impact Statement

The creation of Fontana Dam significantly reduced this community type in the study area. In addition,
development on the wide, flat floodplains where this Appalachian Montane Alluvial Forest occurs has
further reduced this community type.
Approximately 30 ac (12 ha) of Appalachian Montane Alluvial Forest were excluded fram the Park in the
Ravensford Land Exchange (NPS 2003d). The implementation of the Elkmont Historic District plan would
also impact the Appalachian Montane Alluvial Farest (NPS 2006a). Future projects including NCDOT STIP
projects and future sections of Foothills Parkway, would result in loss of vegetation communities in the study
area viciniry. Private development, although greatly limited in the study area due to the amount of publicly-
owned land, would also affect vegetation. When combined with the partial-build alternatives or the build
alternative, these projects would result a cumulative loss of vegetation communities in the study area.
4.4.5.3 Options to Address Potential Impacts
NPS would employ a sequence of avoiding adverse impacts to vegetative communities to the extent
practicable, minimizing impacts that could not be avoided, and compensating for remaining unavoidable
adverse impacts via restoration of degraded communities. The construction footprint for any of the partial-
build or build alternatives would result in direct impacts to vegetation communities. Indirect impacts would
also likely take place. Avoidance and minimization techniques, along with enhancement measures, are
available and may reduce total acreage of impacts to vegetation communities. However, the successful
implementation and application of these techniques is uncertain. Impacts would still occur to vegetation
communities as the result of a partial-build or build alternative.
The following techniques focus on avoiding and minimizing impacts to rare vegetation communities.
However, these techniques could be applied to vegetation communities generally within any portions of the
partial-build or build alternatives.
Avoidance Techniques
Selection of the No-Action ar Monetary Settlement alternatives would avoid impacts to vegetation
communities within GSMNP from this project.
The two rare vegetation communities potentially directly impacted by the partial-build and build alternatives
are Southern Appalachian Red Oak Cove Forest and Appalachian Montane Alluvial Forest. The potential
impacis to Southern Appalachian Red Oak Cove Forest consist of relatively small areas, generally under
2.0 ac (0.8 ha). In areas mapped as Southern Appalachian Red Oak Cove Forest, the construction footprint
could potentially be realigned to avoid all impacts to this community. However, realignment may cause
additional impacts to other resources, including other rare vegetation communities. The potential benefits of
avoidance far one resource will need to be weighed against the potential to impact other resources on a case-
by-case basis.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-205
North Shore Road Final Environmental Impact Statement

Over 90 percent of the potential impacts to rare vegetation communities are to Appalachian Montane
Alluvial Forest. The Appalachian Montane Alluvial Forest is found in narrow bands in floodplains parallel
to many streams in the project study corridors and often spans the width of the project study corridors.
Therefore, in many cases, the build footprint cannot be realigned within the corridors to avoid all impacts to
Appalachian Montane Alluvial Forest.
Shifting the alignment outside of the existing project study corridors
would not avoid all impacts to this community. Stream bottams
containing Appalachian Montane Alluvial Forest are found throughout the
project study area. Most study area streams run in a north-south
alignment, while the alignment of the proposed roadway is generally east-
west. Therefare, it would be impossible to avoid all impacts to
Appalachian Montane Alluvial Forest. Bridging structures over the
smaller streams would not avoid direct or indirect impacts to this forest
communiry, since a mature farest cannot exist underneath a bridge and the
potential for alteration to abiotic factors would still exist.
Minimization Technigues
Appalachian Montane Oak-
Hickory Forests are common
within the study corridors.
Impacts to Appalachian Montane Alluvial Forest would be minimized by selection of either or both of the
two southern options at the three embayments.
Where no alternatives that avoid adverse impacts on rare vegetation communities are found to be practicable,
steps must be employed to minimize adverse impacts. Implementation of these steps would occur through
design modifications and implementation of BMPs to limit and control impacts during and after project
construction.
Realignment of the proposed roadway, in some cases, would minimize the impacts to Appalachian Montane
Alluvial Forest. For instance, the proposed alignments along Gray Wolf Creek and Shehan Branch occur
through long, narrow zones of Appalachian Montane Alluvial Forest. Shifting the alignments upslope away
from the creek bottoms in these areas would create large reductions in the impacts to this vegetation
community.
Additionally, there is a generally accepted technique to minimize impacts to stream channels that would also
minimize impacts to a vegetation community paralleling a stream channel. It is commonly understood in
roadway design that crossing a stream at a 90-degree angle (perpendicular to the flow), plus ar minus 15
degrees, has the smallest direct impact on the channel. Extending this perpendicular-crossing technique out
to the edges of the Appalachian Montane Alluvial Forest would minimize the direct and indirect impacts to
this community.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-206
North Shore Road Final Environmental Impact Statement

Further reduction of the construction footprint in areas containing Appalachian Montane Alluvial Forest
could be accomplished through additional use of retaining walls or construction of a viaduct. This would
reduce direct impacts, although not necessarily indirect impacts. The cost of such additional structures,
especially viaducts, has not been calculated, but could be significant.
As an additional minimization technique, the construction drawings for the partial-build or build altemative
would note the location of sensitive resources, such as rare vegetation communities, adjoining the
construction area. The construction contract language and drawings would note that the storage of
equipment and stock-piling of materials are prohibited in these sensitive areas.
Mitigation Technigues
The most common mitigation technique is compensatory mitigation. Compensatory mitigation far
unavoidable impacts to rare vegetation communities would involve restoring farest vegetation to an area that
previously supported the rare community. Such areas include pastures, mowed meadows, and other non-
forested sites. Appalachian Montane Alluvial Forest communities could be restored to an area that has
existing soils and hydrology, but lacks appropriate vegetation. Often the vegetation is being mowed, grazed,
or otherwise maintained. Potentially, Appalachian Montane Alluvial Forest can be restored by removing this
maintenance factor and planting appropriate vegetation. However, there are limited areas where this
restaration could take place within the Park, and success is not guaranteed. Care would be taken to utilize
only appropriate native woody and herbaceous vegetation in appropriate ratios to approximate the
community type being restored. Vegetation (primarily herbs and small shrubs) or seeds could potentially be
salvaged from a construction location. Replanting of salvaged vegetation would tend to limit the
introduction of exotic plant species. Priariry for restoration would be given to appropriate non-forested sites
within GSMNP. The minimum ratio for restoration would be 1:1.
Mitigation of impacts, through restaration, is to be used as a last resort after avoidance and minimization
efforts have been exhausted. The forested vegetation communities within the project study area have taken
over 70 years to establish and any restoration of communities would not have the same ecological function
until the trees at the restoration site would mature. The process to mitigate for vegetation impacts is time
consuming, expensive, and complex. The success of restoration efforts is uncertain, and the functionality
may never fully reach that of the naturally occurring commlinity.
Enhancement Measures
Enhancement measures are additional forms of mitigation that may be used to reduce impacts that result
from project construction. Such actions may increase the ecosystem value of an already existing, but
degraded, vegetation community or may focus on other Park needs related to natural resources. Additional
funding for invasive Park-wide exotic species management, increased law enforcement, and public
awareness educational programs are examples of enhancement measures.
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-207
North Shore Road Final Environmental Impact Statement

4.4.5.4 Impairment Evaluation
Impairment (as defined by NPS policy) to the vegetation communities of GSMNP and the AT would not
occur under the No-Action Alternative, Monetary Settlement Alternative, Laurel Branch Picnic Area, and the
Partial-Build Alternative to Bushnell. The Northern Share Corridor is not likely to impair the vegetation
communities of GSMNP or the AT based on the information obtained to date. Due to the magnitude of this
alternative, it is likely that additional NEPA documentation would be required to address sit�specific
impacts not currently known, to determine detailed avoidance, minimization, and mitigation measures as
they relate to final design, and to re-evaluate the impairment determination related to vegetation
communities.
4.4.6 Terrestrial Wildlife
4.4.6.1 Methodology for Assessing Impacts
Due to the variety of wildlife likely to be found in the project study corridors and their corresponding variety
of home-range sizes, the quantity of wildlife habitat lost under the project footprint was used as a surrogate
for estimations of direct loss of wildlife for the assessment of impacts. All of the undeveloped areas within
the project study corridors are considered to be habitat for the range of terrestrial wildlife known to live in
GSMNP. Impacts were calculated based on the area of the construction footprints for each alternative.
Detailed methodology and discussion of impacts is listed in Appendix N.
Type
There are two types of impacts, beneficial or adverse. Beneficial impacts have a positive effect on terrestrial
wildlife resources, whereas adverse impacts have a negative effect.
Context
Context is defined as sit�specific, local, or regional. Sit�specific impacts would occur within the
construction footprint. Local impacts would occur within 2 mi (3.2 km) of the construction footprint or the
northern shore of Fontana Lake (whichever is less). Regional impacts would occur outside of the localized
impacts and in an area north of Fontana Lake, south of the North CarolinalTennessee state line, east of
Twentymile Ridge, and west of Noland Creek.
Duration
Short-term impacts are those that would occur for less than 1 year, typically as an episodic or temporary
event. Long-term effects occur as a result of construction activities at a specific location tbroughout the life
of construction (this is assumed to be between 1 year and 15 years), but the impact is more than that of a
Clarification of the term "baseline" for this project:
The Partial-Build Alternative to Bushnell and the Northern Shore Corridor include a baseline route, as well as options to that route.
Baseline routes and options are detailed in Section 2.5 and shown on Figure 2-8. Baseline routes have been compared to existing
conditions. Impact analyses for the options are shown as a difference from the associated baseline route.
Environmental Consequences — 4-208
North Shore Road Final Environmental Impact Statement