The project team followed a standard development process to move through the individual tasks within the study. Project team members relied on project development/technical judgment and recommendations from EWG members to define extents of the study area and geographic boundaries for individual control points. The team identified conceptual corridors between Savannah and Knoxville and screened them against fatal flaws to eliminate unreasonable and infeasible options. Corridors passing the screening advanced for additional Phase I study. The following subsections describe the iterative process employed to complete these tasks.
The project team worked with the EWG to develop a study area, to describe the geographic region containing the study corridors that would be large enough to facilitate an examination of traffic flows, and to identify an area of influence for focused public outreach.
The study area was defined to follow existing Interstate routes along the boundary of a General Study Area (shown in Figure 1). On the east, the General Study Area runs northeast on I-95 from Savannah to I-26; northwest on I-26 through Columbia and Asheville to I-40; then west on US 25 to I-40 into Knoxville. On the west, the General Study area runs northwest on I-16 from Savannah to I-75 in Macon to Atlanta and north on I-75 to Knoxville. Following the eastern boundary of the General Study Area, 420 miles of existing Interstate connect Savannah and Knoxville. Following the western boundary of the General Study Area, 460 miles of existing Interstate connect Savannah and Knoxville.
Major cities within the General Study Area include: Savannah, GA; Augusta, GA; Atlanta, GA; Columbia, SC; Greenville, SC; Asheville, NC; Chattanooga, TN; and Knoxville, TN. The I-20 and I-85 pass through the General Study Area, traveling from Atlanta east and north to Columbia and Greenville, respectively. The Savannah River Parkway forms a recently constructed four lane highway link between Savannah and Augusta in the southern portion of the study area.
Control Points represent "wickets" through which corridors must pass. Control Points were defined in Savannah, Augusta, Knoxville, and I-85 at Lavonia.
Within the General Study Area, the control points serve as "wickets" through which potential corridors must pass. The alignments of the corridors can vary significantly between control points, but all corridors must pass through each.
The SAFETEA-LU specified that the 3rd Infantry Division Highway corridor should link Savannah, Augusta, and Knoxville. Control points are to be near these cities, plus may include other points, if warranted. They are defined as the end of a section of highway improvement, near the cities cited in the statute, that shows independent utility (for example, a location where there is a substantial change in traffic volumes).
While the legislation requires that potential corridors connect the three cities identified, the Task Order for this study included a fourth control point at Lavonia, Georgia. The intent of this control point was to facilitate the development of corridors between the cities noted in the legislation while allowing consideration of corridors which would avoid the Great Smoky Mountains (GRSM) National Park.
The development of control points was based on various considerations: stakeholder preferences, the location of economic development activities and major traffic generators, the location of military bases, logical points in accordance with logical termini definition, and others. The location of the four control points is presented in the following subsections; additional information about the development of these points is provided in the Control Points Technical Memo.
Included in the original legislation, the Savannah Control Point addresses access to the third largest and fastest growing seaport on the eastern seaboard (Port of Savannah) and other resources in the Savannah area, such as tourist attractions, manufacturing sites, and military installations. The Savannah Control Point was defined as a connection along I-516 between the US 80/17 interchange and the SR 25 Connector (West Bay Street) interchange to better serve the key economic resources of Fort Stewart and the Port of Savannah.
The control point at Augusta is also included in the statutory language establishing the corridor concept. Augusta lies between Columbia, SC and Atlanta, GA along I-20. The I-520 is a ring road around Augusta and provides a bypass of the city center. Fort Gordon lies just west of the city and is a major contributor to the regional economy. The proposed Augusta Control Point was defined as crossing I-520 around Augusta or I-20 from the western edge of Augusta to a point just to the west of Fort Gordon.
Augusta is also the eastern terminus for the 14th Amendment Corridor (southern option) which is being studied concurrent with the 3rd Infantry Division Highway corridor. The 14th Amendment Corridor heads west from Augusta toward Macon, GA.
The Lavonia Control Point is identified in the FHWA Task Order for the study. Lavonia itself is not an economic driver in the region; rather, it represents a break point from which potential corridors could be developed while considering the GRSM National Park. In other words, this control point would facilitate consideration of potential corridors that would avoid the park or use existing routes to traverse it, where possible. The Lavonia Control Point was defined as following I-85 from west of the Greenville Bypass to the US 441 interchange.
Knoxville, TN is the northernmost control point identified in the originating legislation. Knoxville can be accessed from the west (via I-75), from the south (via I-140), or from the east (via I-40). Therefore, the Knoxville Control Point is identified as a connection to an existing limited access highway at Knoxville.
Figure 2 identifies each of the four control points within the General Study Area, along with other key transportation facilities in the area such as Interstates, Corridor K, and the 14th Amendment Corridor.
At the second meeting of the EWG in December 2010, the project team presented a set of illustrative corridors to facilitate discussion among EWG members on the range of study alignment corridors. The EWG members also identified potential issues for consideration in the corridor evaluation process.
The EWG members offered a number of comments regarding sensitive resources that should be considered during the corridor development process. Corridors should avoid protected environmental resources: National Forest lands, federally designated Wilderness Areas, National Parks, National Wildlife Refuges, and critical endangered species habitats. Geologic concerns such as pyritic rock and mountain ranges, major river crossings, and the Savannah River Site nuclear reservation should be avoided. The EWG suggested that a special cross-section should be developed for segments in sensitive areas, similar to the I-70 tunnel sections near Denver or the elevated viaducts along the Blue Ridge Parkway. Also, all potential corridors should be developed before any are eliminated, for example, a link that provides access to Atlanta.
Corridors were developed for a high level comparison between conceptual alternatives and do not represent a recommended alignment.
Based on the known constraints and input from the EWG, five study corridors were developed by a team of design professionals to follow existing roadways where possible, to avoid major resources (e.g., National Wildlife Refuges, National Forests, and State and National Parks) and major waterways to the extent possible, and to incorporate EWG input while connecting the metropolitan areas identified in the statutory language. These corridors are shown in Figure 3.
Following is a brief description of the five study corridors:
|Corridor A West||Farthest west option, running along I-16 west out of Savannah, passing west of Augusta, passing east of Athens and Gainesville, and following the western boundary of the National Forests to I-75 at Cleveland|
|Corridor A East||Follows Corridor A in the south, running along I-16 west out of Savannah, passing west of Augusta, passing east of Athens and Gainesville, then crosses through the National Forests north of Dahlonega to I-75 near Sweetwater|
|Corridor B||Follows the Savannah River Parkway from Savannah, running west of the Georgia/South Carolina State line, and following existing roadways through the National Forests and along the western boundary of the Great Smoky Mountains National Park to Knoxville; also includes a bypass option for
SR 21 north of Savannah
|Corridor C||Follows the Savannah River Parkway from Savannah, following new and existing alignments through South Carolina from Augusta to west of Greenville, and crosses through the National Forests and the Great Smoky Mountains National Park on existing alignments|
|Corridor D||Follows existing alignments from Savannah to Columbia, following I-26 and US 25 north and west to Knoxville|
It should be noted that corridors describe approximate, conceptual locations, shown with an initial width of 1 mile. This reduced level of detail was used to facilitate a planning-level comparison between potential alternatives and development of preliminary planning-level cost estimates; these concepts do not represent an actual alignment nor is there a recommendation to advance these corridors unless policy-makers determine that additional project development activities should be undertaken.
In addition to the five primary corridors, a series of small connectors was also identified to form potential links between corridors. These connectors allow transitions from one corridor to another; for example, Segment AB forms a link between the southern portion of Corridor A and the northern portion of Corridor B.
For comparison, the distance between downtown Savannah (I-16/I-516 interchange) to downtown Knoxville (I-40/I-275 interchange) is 420 miles along the eastern boundary of the study area, following I-95 to I-26 to US 25 to I-40. Along the western boundary, the route is 460 miles long, following I-16 to I-75. The distance between these points is 435 miles along Corridor A, 365 miles along Corridor B, 370 miles along Corridor C, or 385 miles along Corridor D. All distances in this report are measured along the centerline of the corridor and do not account for horizontal/vertical curves that would occur along an actual roadway alignment.
A corridor to/through Atlanta was not included in the list of options to be considered, since Interstate and arterial links within the metropolitan area already experience congestion and substantial delays. The Atlanta Regional Commission's 2007 Regional Transportation Plan identified the majority of regional roadways in DeKalb, Cobb, Gwinnett, and northern Fulton Counties as congested based on travel times during peak periods. Previous proposals to create a new bypass north and east of Atlanta met with substantial local opposition and were dismissed from further development. In addition, the Task Order for the study identifies a control point at Lavonia, east of Atlanta, as an intermediate destination along the proposed corridor. For these reasons, corridors within the Atlanta metropolitan area were not explored.
Readily available data from a variety of online sources was assembled to provide an overview of major environmental attributes within the study area.
Geospatial data from State and Federal databases was assembled to identify large tracts of protected lands: National Forests, National Parks and Recreational Areas, state parks, federally designated Wilderness Areas, water bodies, military installations, nature preserves, and more. These areas are shown in Figures 4 and 5. Protected Federal lands are concentrated in the northern portion of the General Study Area, north of the Lavonia Control Point.
Although these areas do not represent all of the constraints to highway development in the study area, they do represent the largest protected features. At the scale shown, each corridor is 1 mile wide. Smaller features – individual buildings, wetlands, cemeteries, etc. – are not visible at this scale and can generally be avoided by shifting an alignment within the wider corridor. Therefore, a large number of these types of smaller features are not presented for this level of analysis.
Federally designated Wilderness Areas are "lands designated for preservation and protection in their natural condition … which generally appear to have been affected primarily by the forces of nature, with the imprint of man's work substantially unnoticeable."1 These areas are stringently protected for recreational, scenic, scientific, educational, conservation, and historic uses and can only be removed from the National Wilderness Preservation System by a congressional designation. Use of motorized equipment or mechanical transport is prohibited within these areas. Numerous Wilderness areas exist within the General Study Area:
10 miles northwest of the Georgia/North Carolina/Tennessee State lines
Two National Parks fall within the General Study Area. A large number of State and local parks also exist within the area. Public recreation lands – including public parks, historic sites, recreational areas, and wildlife/waterfowl reserves – are stringently protected from transportation uses by Section 4(f) of the 1966Department of Transportation Act(Public Law 89-670). The law mandates that Section 4(f) properties may be converted to a transportation use only if there is no prudent and feasible alternative and the project includes all possible planning to minimize harm to the resource.
National Forest lands cover around 5,000 square miles of the General Study Area. A limited number of Interstates, highways and local roads pass through the forest lands, but some areas have been designated as roadless conservation areas based on a 2001 FEIS.2 The following National Forests exist within the General Study Area.
National Wildlife Refuges (NWR) are managed lands set aside for conservation of fish, wildlife, and plants, managed by the U.S. Fish and Wildlife Service. In addition to federally designated NWRs, States and local communities have established conservation areas serving similar purposes, overseen by a range of government agencies and private organizations. These lands are also protected under Section 4(f) laws. Federal NWRs in the General Study Area include the following sites:
As shown in Figures 4 and 5, a number of protected lands exist within or adjacent to Corridors A, B, C, and D, particularly north of the Lavonia Control Point. Table 1 summarizes the number of parks, National Forests, and nature preserves that lie within or adjacent to the mile-wide corridors.
|Corridor||Parks Impacts||Distance in National Forests||Wilderness & Wildlife Zones|
|Savannah to Augusta|
|A||Adjacent to 1 SP||None||None|
|B||Adjacent to 1 SP||None||None|
|C||Adjacent to 1 SP||None||None|
|D||None||None||3 miles in NWR|
|Augusta to Lavonia|
|A||Adjacent to 1 SP and 1 Recreational Area||None||3.5 miles in WMA|
|B||None||None||3.5 miles in WMA|
|C||Adjacent to 1 SP||18 miles||Adjacent to 1 WMA|
|D||None||None||Adjacent to NHA|
|Lavonia to Knoxville|
|A West||None||1.5 miles||2 WMA within corridor and 2 WMA adjacent|
|A East||None||53 miles||2 WMA within corridor|
|B||3 parks adjacent, including GRSM||79 miles||Gamelands and 1 NHA within corridor; 6 NHA adjacent|
|C||20 miles through GRSM||29 miles||Black bear sanctuary and 7 NHA within corridor, plus 7 NHA adjacent|
|D||Adjacent to 1 SP||41 miles||Black bear sanctuary and 3 NHA within corridor, plus 2 NHA adjacent|
Key to abbreviations:
NHA = NC Natural Heritage Program natural heritage area;
WMA = wildlife management area
SP = State Park
GRSM = Great Smoky Mountains National Park
Table 2 lists major water features and other key resources within or adjacent to the four corridors. The density of large natural resources north of the Lavonia Control Point is higher than the density of resources in areas further south.
|Savannah to Augusta|
|A||No major features identified|
|B||No major features identified|
|D||Does not intersect Augusta Control Point|
|Augusta to Lavonia|
|A||Clarks Hill Lake|
|B||Clarks Hill Lake|
|C||Clarks Hill Lake|
|D||Does not intersect Lavonia Control Point|
|Lavonia to Knoxville|
|A West||Lake Zwerner dam, Carters Lake, Hiwassee River, Tennessee River|
|A East||Hiwassee River, Blue Ridge Lake, Tennessee River, Appalachian Trail|
|B||Little Tennessee River, Tallulah Falls Lake, Appalachian Trail, Fort Foudon Lake, Tellico Lake, Chilhowee Lake, Calderwood Lake, Santeetlah Lake, Cheoah River|
|C||Eastern Band of Cherokee Indians Reservation, Douglass Lake, French Broad River, Appalachian Trail|
|D||Appalachian Trail, French Broad River, Douglass Lake|
Aggressive mountainous terrain, particularly in the northern portion of the General Study Area, is another major constraint to development. Corridors B and C face the highest elevations with peaks up to 5,020 and 6,170 feet above sea level, respectively. Corridor A West faces the fewest terrain challenges with a maximum elevation of 2,510 feet.
Portions of Corridors A (East and West Options) and B pass through areas in northern Georgia that are designated as Protected Mountains by the GA Department of Natural Resources.
According to data from the U.S. Geological Survey, karst fissures exist in both the southeastern and northwestern portions of the General Study Area. Karst features form when a landscape underlain by soluble bedrock (such as limestone or dolomite) erodes below the ground surface, forming underground cavities, sinkholes, ridges, caves, or similar features. These features form a direct link to groundwater supplies; erosion or spills from construction projects are more likely to infiltrate groundwater flows in karst areas and are less likely to be neutralized through natural processes. This poses a risk to water quality, aquatic species, wildlife, and human drinking water supplies. Special design measures to minimize and channel runoff are required for construction projects in karst areas.
Karst features are common in the northeastern and southeastern portions of the study area. Areas south and east of Jeffersonville, GA; Millen, GA; Barnwell, SC; and Orangeburg, SC are likely to contain features less than 1,000 feet in length. Bands of karst features greater than 1,000 feet in length run northeast-to-southwest on either side of I-75 from Calhoun, GA; Chattanooga, TN; Cleveland, TN; and Knoxville, TN to Newport, TN along I-40. Pockets of large karst features also exist throughout north Georgia near Jasper, around Ellijay, from Blue Ridge to Murphy to Bryson City, in Gainesville, and near Toccoa.
Landslides are also a concern in the study area. The majority of the area north of Atlanta and Columbia is moderately to highly susceptible to landslides. The highest incidence areas are along the North Carolina/Tennessee border as far east as Asheville, and dipping down into Georgia almost to Atlanta.
Acid-bearing rock is another geological issue which may be found within the northern portion of the General Study Area. Pyrite is a crystalline mineral found in some areas of the Appalachian Mountains. Exposing the mineral to moisture and oxygen can lead to the formation of Acid Rock Drainage (ARD). The ARD occurs naturally as part of the rock weathering process and represents a threat to the sustainability of rivers, streams and other freshwater systems; however, it can be exacerbated by highway construction activities. The potential for soil erosion and subsequent ARD due to disturbance is greatest in areas with rugged topography that require extensive cut/fill sections during construction. There are numerous options for addressing ARD. The most common practices include containment and neutralization at the point of disturbance or offsite. The impacts of acid-bearing rock have been seen on a variety of projects, including the North Shore Road highway project within the GRSM. Construction of the highway was suspended in the 1970s in part due to the environmental damage caused by the acidic rock encountered.
Table 3 presents a summary of likely geotechnical concerns for each corridor, divided into sections by control point.
|Corridor||Terrain||GA Protected Mountains||Karst Potential||Landslide Potential|
|Savannah to Augusta|
|Augusta to Lavonia|
|Lavonia to Knoxville|
Environmental justice regulations and Executive Orders protect minority and low-income populations from experiencing disproportionate adverse impacts on Federal projects. This distribution of minority and low-income community groups will have to be considered in-depth during future project development stages if any corridors are selected for implementation. Much of the study area population is considered low-income based on Federal poverty standards; the highest concentrations are south of I-20. The majority of rural counties are identified as economically distressed according to the U.S. Bureau of Economic Analysis and the U.S. Bureau of Labor Statistics. In the southern portion of the study area, a number of counties demonstrate above average minority population concentrations; concentrations are lower (less than 10%) for most counties in the study area north of I-85.
The Eastern Band of Cherokee Indians, located in western North Carolina, represent a sovereign nation and major economic generator/tourist attraction within the study area. Extensive coordination will be required if any corridors near this area are selected for additional project development activities.
Corridors were screened against fatal flaws to identify significant obstacles that make corridors infeasible or unreasonable for further study. Impacts within a National Park, extreme mountainous terrain, or avoiding control points represent fatal flaws.
Initially four corridors were developed between Savannah and Lavonia and five corridors were developed between Lavonia and Knoxville, with an EWG recommendation that no more than one corridor should pass through the GRSM National Park. These corridors were screened against "fatal flaws" to identify significant obstacles to implementation that effectively make a corridor infeasible or unreasonable for further study. The density of natural resources, the vast area protected by State or Federal designations, and aggressive terrain features throughout the northern portion of the study area create numerous challenges to highway development. A number of regional residents and organizations have been outspoken about their desire to protect natural and cultural resources by limiting development. Stakeholder input is discussed further in Section 7.
A variety of perspectives suggest that a western corridor provides the "least objectionable option" for the northern portion of the General Study Area (between Lavonia and Knoxville). The term "least objectionable" was recommended by the EWG as the best descriptor for the corridor selected to advance for cost estimating.
From a planning-level environmental constraints perspective, Corridor A West impacts the fewest protected lands. This corridor avoids the GRSM National Park, unlike Corridors B or C. Because of the park's wilderness areas, rich biodiversity, and protected status, transportation improvements within the park are strictly limited. According to 36 CFR 5.6, commercial traffic is prohibited within the park. A 2010 Environmental Assessment (EA) documents that a proposal to add turn lanes to a popular picnic area along Newfound Gap Road was rejected because of the extent of impacts on character-defining features along the roadway.3 Work on the proposed North Shore Road was suspended decades ago due to environmental impacts; the 2007 EIS supported a monetary settlement rather than completing the planned construction project because it would result in fewer impacts.4 Corridor C would also impact the Blue Ridge Parkway National Park; it follows the length of the existing alignment for 45 miles between SR 215 and US 441. No other alternatives would impact this park.
Impacts within the National Forests were considered alongside park impacts during the analysis of sensitive resources, described in Section 3.5. While impacts to National Forests represent a critical concern, they were not identified as a fatal flaw. Regulations governing forest management permit a number of uses that are exempt from stringent Section 4(f) protections, including guidelines for developing transportation facilities. Impacts should be avoided or minimized, but corridors were not eliminated solely for impacting National Forest lands. Corridor A West has the fewest impacts within the National Forests, with 1.5 miles passing through the Forest near the southwestern boundary by Chatsworth, GA. This compares to at least 40 miles through the National Forests for other corridors. Other corridors result in fewer impacts to State parks, State wilderness/wildlife zones, areas within Georgia designated as Protected Mountains, or waterways; however, Corridor A West provides the fewest National Forest impacts.
From a constructability perspective, mountainous terrain in the northern portions of the General Study Area provides another reason to favor a western corridor between Lavonia and Knoxville. Extremely aggressive terrain challenges are a second fatal flaw considered because of the associated cost and constructability concerns. Corridor A West has the fewest terrain challenges in the northern section, followed by Corridor A East with the next fewest. Corridors B, C, and D pass through more aggressive terrain in the southern Appalachian Mountains. Corridor A also passes through fewer areas highly susceptible to landslides when compared to Corridors B, C, and D.
From an economic perspective, corridors that avoid mountainous terrain are again preferable. Mountainous terrain has a significant impact on cost, both for initial construction and continuing maintenance activities. Based on decades of experience and data from completed projects, TDOT estimates that projects constructed in heavily mountainous terrain cost 2 to 5 times more than roadways constructed in mountainous or rolling terrain, respectively. Corridors B, C, and D are likely to be even more costly because the alignments bisect the mountain ranges rather than following the ridge lines. In today's era of financial constraint, financial feasibility is a major concern that deserves consideration when developing transportation projects.
The statutory language establishing the vision for the 3rd Infantry Division Highway corridor specifies that the corridor must connect Savannah, Augusta, and Knoxville. Any corridor that does not provide increased mobility and connectivity to all three of these urban centers is considered fatally flawed. Corridor D does not efficiently serve Fort Gordon or improve connectivity to the Augusta area. It also avoids the Lavonia Control Point, defined in the FHWA Task Order for the study.
From a regional transportation perspective, Corridor D provides minimal differences compared to the existing I-95 to I-26 corridor. Corridor D is 35 miles shorter than the existing I-95 to I-26 corridor between Savannah and Knoxville, an 8 percent savings compared to the existing route. However, it still travels through congested sections of existing Interstate in Columbia and Asheville.
Routes which bypass congested urban areas provide travel time savings by avoiding peak period delays. Reliability is a potential issue for routes through areas prone to landslides; I-40 in particular has been closed for several months in recent years to clean up slides.
Corridor A West provides a slightly shorter travel distance between Savannah and Knoxville (435 miles) than the existing I-16 to I-75 corridor (460 miles) and also bypasses major congestion and bottlenecks in the Atlanta area.
North of Augusta, Corridor B passes through largely undeveloped, rural areas. From a regional transportation viewpoint, it would not provide improved connectivity to any urban centers between Augusta and Knoxville.
Corridors A, B, and C each would provide opportunities to link to the proposed Corridor K and proposed 14th Amendment Highway, for an improved east-west mobility option.
As summarized in Table 4, a variety of perspectives suggest that a western corridor provides the least objectionable option for the northern portion of the General Study Area (between Lavonia and Knoxville). Based on environmental constraints, constructability and engineering concerns, economic considerations, and regional transportation connections, Corridor A West from I-85 at Commerce, along the western boundary of the National Forests, to I-75 at Cleveland was advanced for additional study to develop cost estimates. Other northern corridors should be eliminated because they would lead to greater impacts within the National Forests, would fall within the established boundaries of GRSM National Park, would face high costs and constructability issues from other terrain/geotechnical obstacles, and/or would not provide access to the four areas identified as control points. Construction through mountainous terrain is estimated to cost up to five times more than construction in flat or rolling terrain.
|Corridor||GRSM Impacts||Terrain||Control Points||Fatally Flawed|
|C||Yes||Extremely Aggressive||Crosses 4||Yes|
For the southern portion of the General Study Area (between Savannah and Lavonia), Corridors A, B, or B Bypass along the Savannah River Parkway should also be advanced for additional study to develop cost estimates. Either corridor provides a comparable level of mobility and impacts which could provide a reasonable, feasible connection to a western corridor beyond Lavonia.
Additional technical analysis and public involvement activities would be required to support this screening if the corridor were advanced for additional project development activities, specifically as part of the Preliminary Engineering and Environmental Analysis phase described in Section 6.4.
1 1964 Wilderness Act, Section 2
2 Forest Service Roadless Area Conservation, Final Environmental Impact Statement. US Department of Agriculture, Forest Service. November 2000. Available on the USFS Web site www.fs.usda.gov/
3 Environmental Assessment, Great Smoky Mountains National Park. Project PRA-GRSM 1B19. U. S. Department of the Interior, National Park Service. July 2005. Available online at http://www.efl.fhwa.dot.gov/files/projects/environment/nfg_ea.pdf
4 Per NPS briefing statement online at http://www.nps.gov/grsm/learn/management/upload/North-Shore-Rd-3-15-10.pdf