4.3.1

42.9.1.6 Cumulative Impacts
As mentioned above, poaching, vandalism at the tunnel and other illegal activities have occurred and
continue to occur in the Park. As tourisin increases and residential populations in the study area surrounding
GSMNP continue to grow, these activities would be likely to continue and potentially increase. The limited
impacts to public health and safery from the proposed alternatives would have a sligbt cumulative effect on
public health and safety in the study area when added to the effects of past, present and reasonably
foreseeable actions in the area.
4.3 Impacts to the Physical Environment
4.3.1 Topography, Geology, and Soils
4.3.1.1 Methodology for Assessing Impacts to Topography, Geology, and Soils
The following paragraphs summarize the impact topics, thresbolds and durations as defined far topography,
geology, and soils. A more detailed report is included in Appendix I.
To develop the impact thresholds related to the topography, geology, and soils, the following topics were
reviewed for each alternative cor►-idor.
■ Topographic relief
■ Engineering aspects
■ Site layout
■ Natural drainage patterns
■ Views and vistas
■ Uniqueness and historical significance
■ Environmental aspects
■ Rock and soil types and mineral assemblages
■ Similar projects occurring under the same geologic conditions
Type
In regards to geology, topography, and soil resources, any disturbance of the existing geology, topography,
and soils as a result of the proposed project is considered to be an adverse impact.
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 — 4-100
North Shore Road Final Environmental Impact Statement

Duration
To assign durations of impact, the following parameters were considered far each alternative corridar: area
of disturbance, volume of disturbance, revegetation process, erosion characteristics, and construction
intervals. The durations are short-term and long-term and have been defined as follows.
Short-term impacts include areas that would not be impacted for longer than 2 years past completion of
construction and r�vegetation. This involves smaller areas of minimal disturbance where re-vegetation is
relatively simple and quickly achieved.
Long-term impacts include areas that would be impacted for greater than 2 years past completion of
construction and r�vegetation. These areas would have substantial cuts or fills, considerable topographic
relief, and modifications that involve complete clearing on steep slopes.
Intensity
To help quantify potential impacts, a set of thresholds were defined so that a relative comparison could be
made within the study corridors. The impact thresholds were: no/negligible, minor, moderate, and major.
They are defined below.
No/Negligible
Disturbances of geologic features, soils, and topographic features are slightly detectable in localized areas.
These disturbances occur only in areas where rock and soil have no acid potential. The disturbances result in
no changes to natural drainage patterns.
Minor
Disturbances of geologic features, soils and topographic features are detectable including the removal and
relocation of relatively small volumes of rock and soil cover. The disturbance of AP rock and acidic soil
would be avoided within the corridor. Localized areas of cut and fill would require slightly detectable slope
modifications. Subtle changes to topographic features would occur without detectable changes occurring to
the natural drainage patterns. No slope hazards would be created by excavation.
Moderate
Disturbances of and modifications to the geologic features, soils, and topographic features are readily
apparent. Large areas are disturbed by excavation across multiple ]ocations. The disturbance of AP rock and
acidic soil is unavoidable, and modifications would require localized, engineered cut and fill areas capable of
encapsulating rock and soil that have acid potential. Regional areas would require slope modifications
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 — 4-101
North Shore Road Final Environmental Impact Statement

including man-made reinforcement measures. Large, localized changes to topographic features would occur,
requiring slight modifications to natural drainage patterns.
Major
Disturbance of and modifications to geologic features, soils, and topographic features are readily apparent
and change the character of these features over large areas. Large areas of cut and fill would be required, and
excavation of AP rock and acidic soil is unavoidable. Large quantities of AP rock and acidic soil would
require treatment or transport offsite. If used onsite as fill, large encapsulation cells would be necessary for
proper disposal. Disturbances will require extensive slope stabiliry modifications, and large areas of fill
would be necessary to maintain road alignment. Natural drainage patterns would be disturbed and modified.
4.3.1.2 Summary of Impacts
Impacts for each alternative and the southem options, where applicable, are summarized below and in the
impact matrix summary in Appendix I. The impacts on the Park's natural resources from disturbing AP rock
and acidic soils are addressed in Impacts to the Natural Environment, Section 4.4. All exca�ated materials
were assumed to require treatment to neutralize AP rock.
Some of the study area's underlying rocks are known to contain "black shales" or monazite deposits.
Monazite contains varying levels of variety elements, such as thorium and uranium, which are radioactive.
Such rocks have been termed NORMs — Naturally Occurring Radioactive Materials (Kohn 2005). The need
for geotechnical testing related to NORMs would be considered if an alternative involving construction is
implemented.
C�c�i�.��C.�_T�iL7i1
The No-Action Alternative is not expected to cause adverse impacts to topography, geology, or soils.
4.3.1.2.2 Monetary Settlement
The Monetary Settlement Alternative is not expected to cause adverse impacts to topography, geology, or
soils.
4.3.1.2.3 Laurel Branch Picnic Area
Functional designs for the Laurel Branch Picnic Area Alternative include a 0.766-mi-long (1.2 km) paved,
two-way entrance/exit road. This alternative would involve excavation of approximately 24,700 cubic yards
(yd3) (18,900 cubic meters [m3]) and embankment of approximately 25,300 yd3 (19,300 m3) of rock and soil
with the potential to produce acid. Excavated rock and soil would be used in the embankment. Surplus
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 — 4-102
North Shore Road Final Environmental Impact Statement

excavated material is not anticipated for this alternative. All disturbed rock and soil would require testing for
acid potential and may require major mitigation and monitoring efforts such as encapsulation, removal, and
pr� and post-construction monitaring. New rock cut slopes may be exposed. While excavated material can
be encapsulated to abate acid drainage, no treatrnent has been discovered for effectively abating the oxidation
process on rock cut slopes bearing significant amounts of sulfide minerals. Strategies that enhance the
alkalinity of the water in the bedrock of the cut slope or divert water from the material can reduce the risk of
generating acid drainage. Soils within this corridor are members of the Soco series and classify as very
strongly acidic with thicknesses averaging 30 inches (76.2 cm). The acidic nature of these soils indicates
that rocks within this corridor would produce acid. The rocks underlying this corridar are mapped as the
Copperhill Formation, which includes feldspathic metasandstone with interbedding of inetaconglomerate,
graphitic and sulfidic mica schist, and nodular calo-silicate granofels. Adverse impacts to topographic
features and natural drainage patterns would be major due to a topographic relief of approximately 70 ft(76
cm) within the footprint. It is possible that unstable slope conditions will be encountered during excavation
or embankment construction, which could require non-intrusive engineering methods for slope stabilization.
Erosion control measures would be required throughout construction and re-vegetation. Based on the impact
threshold definitions, this alternative would have major, adverse, long-term impacts to both geology and
soils, and the topographic features would face major, adverse, and short-term impacts.
4.3.1.2.4 Partial-Build Alternative to Bushnell (Primitive and Principal Park Roads)
The Primitive Park Road to and development at Bushnell would involve excavation of approximately
693,900 yd3 (530,600 m3) and embankment of approximately 356,500 yd3 (272,500 m3) of rock and soil. A
surplus of approximately 337,400 yd3 (258,100 m3) of excavated rock and soil requiring removal and
potential treatment off-site is projected. The Principal Park Road to and development at Bushnell would
involve excavation of approximately 945,100 yd3 (722,600 m3) and embankment of approximately 662,800
yd3 (506,700 m3) of rock and soil. A surplus of approximately 282,300 yd3 (215,900 m3) of excavated rock
and soil requiring removal and potential treatment off-site is projected. Again, it is likely that this material
would produce acid drainage if disturbed and that new rock cut slopes bearing sulfide materials would be
exposed. The soils are Junaluska series and classify as very strongly to strongly acidic, and the rocks are of
the Copperhill Formation as described for the previous alternative. The topographic relief across this
alternative is approximately 300 ft (91.4 m), and the area to be disturbed by excavation and embankment
construction averages 95 ac (38.4 ha) for either road design. It is possible that unstable slope conditions will
be encountered during excavation or embankment construction, which could require non-intrusive
engineering methods for slope stabilization. Based on the impact threshold definitions, this alternative would
have major, adverse, long-term impacts to topography, geology, and soils.
Southern Option at Forney C�eek Embayment
While there is a decrease in the amount of soil disturbed with the southern option to the Partial-Build
Alternative to Bushnell, these changes do not alter the overall geologic impact of this alternative.
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 — 4-103
North Shore Road Final Environmental Impact Statement

4.3.1.2.5 Northern Shore Corridor (Primitive and Principal Park Roads)
Construction of the Primitive Park Road would involve excavation of approximately 1,714,300 yd3
(],310,700 m3) and embankment of approximately 1,299,500 yd3 (993,600 m3) of rock and soil. A surplus of
approximately 414,800 yd3 (317,100 m3) of excavated rock and soil requiring removal and potential
treatment off-site is projected. The baseline Northern Shore Corridor (Principal Park Road) would involve
excavation of approximately 2,906,600 yd3 (2,222,300 m3) and embankment of approximately 2,512,600 yd3
(],921,000 m3) of rock and soil. A surplus of approximately 394,000 yd3 (30],300 m3) of excavated rock and
soil requiring removal and potential treatment off-site is projected. While problematic rock formations are
located throughout the study area, this corridor would involve construction west of the confluence of Hazel
Creek and Fontana Lake, where the underlying rocks are believed to have the highest potential for acid
production and are likely to contain higher concentrations of inetallic minerals than the surrounding rocks.
Again, it is likely that this material would produce acid drainage if disturbed and that new rock cut slopes
bearing sulfide materials and metallic minerals would be exposed. The soils are Junaluska series and classify
as very strongly to strongly acidic, and the rocks are of the Copperhill Formation previously described. The
topographic relief across this alternative is approximately 300 ft(91.4 m), and the area of disturbance
averages 395 ac (159.9 ha), depending upon the road rype. It is possible that unstable slope conditions will
be encountered during excavation or embankment construction, which could require non-intrusive
engineering methods for slope stabilization. Based on the impact threshold definitions, this alternative would
have major, adverse, long-term impacts to topography, geology, and soils.
Southern Options at Forney Creek Embayment, Hazel and Eagle Creek Embayments, and CNOSSing Fontana
Dam (Primitive and Principal Park Roads)
While there is a decrease in the amount of soil disturbed with the southern options of the Northern Shore
Corridor, these changes do not alter the overall geologic impact of this alternative.
4.3.1.2.6 Construction Impacts
Each alternative corridor involves complex mountainous terrain with complicated geologic structures. This
combination would necessitate geological, geotechnical, and engineering expertise throughout all phases of
the project, including design and construction. The potential impact with primary concern is the disturbance
of AP rock and acidic soils. If disturbed, this material can only be dealt with in two ways. Tl�is material
could be blended with neutralizing agents and reused as common fill in einbankments. If this is not an
option, the material must be disposed of in an appropriate off-site area. Should a partial-build or build
alternative be implemented, additional testing would be conducted prior to construction to determine the
extent of AP rock. (Note: Geotechnical drilling may cause impacts to other resources within the Park.) A
more detailed report regarding the potential far construction impacts related to topography, geology and soils
is included as Appendix I.
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 — 4-104
North Shore Road Final Environmental Impact Statement

For road construction, mountainous topography requires the greatest extent of earthwork. Additionally, a
warm and humid environment greatly increases the oxidation rate of sulfide minerals. Therefore, rock and
soil with acid potential must be dealt with immediately upon excavation. To avoid, minimize or mitigate
adverse impacts to plants, wildlife, and water quality when exca�ating AP material, special design and
construction practices are required.
4.3.1.2.7 Cumulative Impacts
Several past actions have occurred within the study area that affected topographic, geologic, and soil
resources in addition to the effects of the presently proposed action. Past actions that have affected these
resources date back to the mining and the timber industries during the early 1900s and include the
construction of Fontana Dam and the partial construction of Lake View Road (up to the tunnel). The timber
and mining industries of the early 1900s resulted in a loss of topsoil and removed geologic resources. The
mining industry also exposed AP rock to the elements, causing other resources within the Park to be affected
by acid drainage. The creation and expansion of the GSMNP preserved large natural areas, allowing
vegetation to r�establish in many areas, stabilizing topsoil and minimizing exposure of AP rock. The
flooding of land as a result of construction of Fontana Dam in the early 1940s permanently altered the
topography and soils in the area. The construction of Lake View Road required blasting and exposed AP
rock to the elements, affecting other resources with acid drainage. The proposed partial-build and build
alternatives would require large quantities of excavation resulting in majar impacts to geology, topography
and soils as discussed above and resulting in the potential for acid drainage. Additional information on the
effects of exposing AP rock to the elements is discussed in Water Quality, Section 4.4.3.
Other projects, such as completed sections of Foothills Parkway and Cherohala Skyway, have changed
specific topography and removed/altered soils in the study area vicinity. Future projects, such as the
completion of Foothills Parkway, have the potential to further these impacts. The addition of soils and rock
to the existing landscape can result in indirect impacts such as the spread of invasive exotics. Offsite
materials used for fill material often harbor seeds of invasive exotics and other non-native pests. These
impacts are discussed in Invasive Exotics, Section 4.4.9.
4.3.1.3 Avoidance and Minimization Techniques
The best technique for avoiding and minimizing deleterious rock would involve designing road grades and
alignments based on the rock's AP potential. Totally avoiding AP rock and acidic soil would not be
practical, however. To minimize the disturbance of this material, a"plan-in-hand" method may be the best
approach for road alignment. Designing with the plan-in-hand method involves characterizing the rock and
soil along the road alignment far in advance of any earthwork far road construction. However, getting the
equipment necessary for preliminary drilling into the sampling locations would involve earthwork to create
an access road. An analysis of the impacts of preliminary drilling would need to be conducted before
beginning such activities. The plan-in-hand method involves preliminary drilling and sampling and visual
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 — 4-105
North Shore Road Final Environmental Impact Statement

classification of the material supplemented by laboratory testing. Early characterization is beneficial when
adjustments in road alignments are necessary to minimize disturbance of AP rock.
In the event that slope stability probleins arise during excavation or embanlar►ent construction, special non-
intrusive engineering methods for slope stabilization could be required. This includes, but is not limited to,
the use of inechanically stabilized earth (MSE) walls. MSE walls can also be used when shifting an
alignment to a�oid excavating AP rock.
4.3.1.4 Mitigation and Monitoring Techniques
If an alternative involved road construction were executed, an approved work plan and material handling
plan would be in place prior to any disturbance or excavation. Standard guidelines for handling deleterious
material are included in the FHWA's 1990 publication, Guidelines For Handling Excavated Acid-Producing
Materials. This publication offers detailed guidelines for the preliminary investigations, the design phase,
and the construction phase for projects that involve the excavation of deleterious rock and associated acidic
soil.
The three most restrictive characteristics regarding this project are:
■ the inability of the local rocks and soils to buffer or neutralize acid,
■ the distance to a rock quarry that contains sufficient quantities of acid-neutralizing rocks, and
■ the volumes of cut and fill necessary for construction in the mountainous terrain.
Based on the mineralogy, geochemistry, and low concentration of alkalinities in the waters of the study area,
the rocks are believed to have an extremely low acid-buffering capaciry. AP rock and acidic soil excavated
for the project would be used fill far embankments would have to be treated with limestone and
encapsulated. Excess excavated AP rock and acidic soil would be hauled offsite and also would be treated
with limestone. Preliminary estimates show tbat the volumes of limestone required to construct encapsulated
embankments for the partial-build and build alternatives would vary from approximately 25,000 tons (22,680
tonnes [t]) for Laurel Branch Picnic Area to 544,000 tons (493,510 t) of liinestone far the Northern Shore
Corridor (Principal Park Road). The nearest limestone quarry is 85 mi (137 km) away in Maryville,
Tennessee. Gravel can be a vector for seeds of invasive exotic plants, thus bringing limestone into GSMNP
to construct the encapsulated embankments could increase the spread of invasive exotic plants in the area.
Quarry inspections and other Park protocol should be followed to reduce the introduction of weeds.
While excavated material can be encapsulated to abate acid drainage, no treatment has been discovered for
effectively abating the oXidation process on rock cut slopes bearing significant amounts of sulfide minerals.
Strategies that enhance the alkaliniry of the water in the bedrock of the cut slope or divert water from the
material can reduce the risk of generating acid drainage. At present the BMP for dealing with rock exposed
on cut slopes involves diverting the runoff above the cut around the excavation and constructing a slope as
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 — 4-106
North Shore Road Final Environmental Impact Statement

near vertical as the rock structure will allow. The diversion of drainage reduces the amount of percolation
into and through the rock, thus reducing the transport of acidiry and potentially toxic metals. Steepening of
slope angles reduces the surface area exposed to precipitation. Furtber measures include using a source of
alkalinity in the drainage system.
Strategies used on the Cherohala Skyway to minimize acid drainage from cut slopes and additional measures
that could be applied to cut slopes to minimize acid production include: excavating slopes as steep as the
structural conditions would allow to reduce the exposed area and the amount of runoff; diverting runoff
around the cut face using limestone rip rap or concrete-lined ditches to retard acid production within the
rocic; and seeding flatter slopes with native grasses as soon after exposure as possible. An additional
measure for consideration in mitigating acid drainage from cut slopes in AP rocks is diversion of runoff from
the cut face area into open limestone channels (Ziemkiewicz et a1.1977). The alkalinity of the limestone
reduces acidity-causing precipitation of inetals, but the turbulence of the flow prevents the reactive surface of
the limestone rip rap from being coated with secondary iron materials. Another treatment that could be
effective, but is costly, is the formation of a grout curtain above the cut slope to prevent groundwater from
percolating through the bedrock and flushing acid and metals into the slope drainage.
4.3.1.5 Impairment Evaluation
Impairment (as defined by NPS policy) to the topography, geology, and soils of GSMNP and the AT would
not occur under the No-Action Alternative, Monetary Settlement Alternative, Laurel Branch Picnic Area,
and the Partial-Build Altemative to Bushnell. The Northem Shore Corridor is not likely to impair the
topography, geology, and soils 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
topography, geology, and soils.
4.3.2 Floodplains and Floodways
While the No-Action and Monetary Settlement alternatives would not impact floodplains within GSMNP,
Laurel Branch Picnic Area, the Partial-Build Alternative to Bushnell, and tbe Northern Shore Corridor would
encroach on the 100-year floodplain at locations of major stream crossings (Figure 3-3). If an alternative
involving construction is implemented, encroachments could be minimized during mare detailed design.
In compliance with Executive Order 1] 988 and Director's Order #77-2, a Statement of Findings for
floodplains would be developed and released for public review if a partial-build or build alternative was
selected for implementation. A Statement of Findings explains why an alternative with floodplain impacts
was identified as the preferred alternative, and details such information as a description of the flood hazard
assumed by implementation of the proposed action, an analysis of the comparative flood risk among
alternatives, a summary of the effects on floodplain values associated with the proposed action, and an
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 — 4-107
North Shore Road Final Environmental Impact Statement