4. ENVIRONMENTAL IMPACTS AND MITIGATION MEASURES
4.1 Introduction
Section 4 summarizes the findings from each of the 12 environmental issue areas included in the EIR. Within each issue area the following information is summarized: impacts identified for the proposed project, proposed mitigation measures, significant unavoidable impacts, and alternatives. Impacts are evaluated in each issue area using the following classification of the impacts:
Class I: Significant; cannot be mitigated to a level that is not significant
Class II: Significant; can be mitigated to a level that is not significant
Class III: Adverse, but not significant
Class IV: Beneficial impacts.
4.2 Air Quality
Impacts of the Proposed Project. The South Coast Air Quality Management District (SCAQMD) has developed emission thresholds for pollutants resulting from construction and operation of proposed projects, based on daily and quarterly emissions. Construction of the proposed pipeline and associated station modifications would generate significant amounts of emissions [primarily oxides of nitrogen (NOx), carbon monoxide (CO), and fine particulates (PM10)]. The Southern California Air Basin is currently in violation of air quality standards for ozone (O3) (which is created partly by oxides of nitrogen emissions), PM10, and CO. While SFPP has proposed several emission control measures, they were not specific enough that the emissions reductions could be calculated or adequately enforced. Therefore, the following impacts were identified as resulting from project construction and operation:
• Construction activities would create emissions from diesel- and gasoline-powered equipment, and would create dust. These emissions would result in exceedance of SCAQMD significance thresholds for NOx and PM10 (Class I for NOx and Class II for PM10)
• Emissions from operation of the pipeline (storage tanks, inspection and maintenance activities, power generation) would result in adverse, but not significant impacts (Class III)
• Based on the low probability of an actual spill, emissions resulting from a pipeline accident could be adverse (Class III) for a leak or spill, but not significant. The released hydrocarbons during a spill may contribute to ozone formation in the atmosphere. Based on the low probability of occurrence, this would be considered adverse (Class III), but less than significant.
Mitigation Measures. Nineteen mitigation measures are presented, including measures recommending revised scheduling of construction to eliminate concurrent station and pipeline construction, dust reduction techniques, and modification/adjustment of construction equipment to reduce NOx and other emissions.
Significant Unavoidable Impacts. While NOx emissions could be significantly reduced by implementation of the mitigation measures proposed, construction activities would still cause exceedances of the California one-hour NOx and the SCAQMD 3-month NOx thresholds.
Alternatives. Alternative segments would have the potential for more emissions than the proposed project if they required construction for a longer distance or a longer time period. Therefore, for the air quality issue area, alternative segment length generally controls evaluation of alternatives. However, in the case of the Bellflower Rail Alternative which is longer than the proposed route, the significantly greater speed of construction in the rail ROW as opposed to construction in urban streets would result in comparable emissions.
4.3 Biological Resources
Impacts of the Proposed Project. Because construction and operation of the proposed project would occur within an urbanized area, there are few locations where biological resources could be affected. The primary concern is the crossings of the three waterways: Compton Creek, Los Angeles River, and San Gabriel River. Several species of concern use the lower reaches of these rivers and the shores of the harbors for foraging or nesting (California least terns, brown pelicans, and western snowy plover). The following impacts on biological resources are identified:
• Open-cut crossing of Compton Creek or maintenance activities in Compton Creek could create sedimentation or erosion, affecting downstream resources (Class II)
• Construction in DeForest Park could damage eucalyptus trees, winter roosting habitat for raptors (Class III)
• A pipeline accident (spill or leak) resulting in products flowing into the Los Angeles or San Gabriel Rivers could result in death or injury to species living or feeding in downstream areas (Class I or II).
Mitigation Measures. Seven mitigation measures are proposed to reduce potential impacts to biological resources. Four measures would protect Compton Creek during construction or maintenance activities, one measure would protect raptors roosting in trees in DeForest Park, and one measure would strengthen SFPP’s Oil Spill Core Plan with respect to protection of aquatic and marine biological resources.
Significant Unavoidable Impacts. The potential for a large pipeline spill to contaminate the Los Angeles or San Gabriel Rivers, and possibly the harbor area, is considered to be a significant unavoidable impact. While the probability is very small that such a spill will occur, it is not possible to eliminate the possibility that it could occur, and a large spill could be damaging to coastal species and habitats.
Alternatives. Impacts of the Santa Fe and Alondra Alternative route segments are similar to those of the proposed project because they have the same type of waterway crossings. Several segments (Cherry, Paramount, Artesia, and Shoemaker) involve no waterway crossings. The Bellflower Rail Alternative is preferred to the comparable segment of the proposed route because it would have a bored crossing of the San Gabriel River (less risk of rupture).
4.4 Cultural Resources
Impacts of the Proposed Project. The proposed pipeline would traverse urban areas that have been disturbed by construction of roads and structures for over 100 years. A records search and survey was performed for the entire area of the proposed route and alternative segments. One recorded archaeological site (CA-LAN-389, in the area west of Compton Creek, which is reported as having been destroyed) may be within the area affected by the proposed pipeline. There are also a few historic sites near the route (Long Beach Dairy, Dominguez Ranch Adobe, Carpenter Dairy, and the site of the first US Air Meet), but they are not expected to be affected by pipeline construction or operation. There is the possibility that during trenching for the pipeline, unexpected resources will be found. Potential impacts include the following:
• Construction of the proposed project would involve trenching in and near Compton Creek, which has the potential to disturb intact deposits from site LAN-389 (Class II)
• Previously unrecorded cultural resources could be discovered during trenching (Class II)
• Spill cleanup activity could impact archaeological resources (Class II).
Mitigation Measures. Four mitigation measures are proposed, recommending that an archaeologist monitor all trenching and excavation, that appropriate testing and data recovery be performed if resources are discovered, and that SFPP’s Oil Spill Core Plan be modified to address the potential for disturbance of cultural resources during spill cleanup.
Significant Unavoidable Impacts. No significant unavoidable impacts to cultural resources are identified.
Alternatives. There is no significant difference between the alternatives with respect to cultural resources because construction and operation is not expected to affect identified cultural sites.
4.5 Environmental Contamination
This section evaluates potential for the proposed and alternative routes to encounter existing contaminated materials in the environment. The potential for the proposed project to cause contamination (resulting from a pipeline leak or rupture) is addressed in the section on System Safety and Risk of Upset (see Section 4.11).
Impacts of the Proposed Project. The proposed pipeline traverses lands that have been used for industrial and commercial purposes, including oil production and refining, for many years. As a result, there are numerous contaminated sites recorded with the various State and Federal oversight agencies. The principal environmental impact involving these sites is the excavation and handling of contaminated soil, which can expose both construction workers and the public to contaminants. A detailed list of contaminated sites was prepared, and this list is ranked to identify sites with High, Medium, and Low potential for releasing contaminants during construction.
The proposed pipeline would also require construction within the Defense Fuels Supply Point (DFSP) Norwalk Station, which has been contaminated with jet fuels and gasoline as a result of storage tank and pipeline leakage. The contaminated groundwater below this site is deeper than the level of the pipeline trench that would be required; therefore, the existing contamination at this location may not be encountered.
The following impacts are identified:
• Construction through areas with known, existing contamination or areas where unexpected contamination is found, poses risks to construction workers and the nearby public (Class II).
• Contamination at the Norwalk Station, or at other station sites, could affect workers and the nearby public (Class II)
• Pipeline construction could interfere with abandoned or inactive oil wells (Class II).
Mitigation Measures. Six mitigation measures are suggested. Three measures require additional investigation of existing sites prior to construction, as well as preparation of a contingency plan defining actions required if unexpected contamination is encountered. The contingency plan would define specific requirements for protection of workers and the nearby public if certain contaminants were discovered. The fourth measure specifically requires sampling and investigating at the Norwalk Station prior to construction, and the fifth requires evaluation of the Watson, Industry, and Colton stations prior to construction. The last measure requires research on possible abandoned oil wells along the pipeline route.
Significant Unavoidable Impacts. No significant unavoidable impacts were identified for the environmental contamination issue area.
Alternatives. Specific sites are identified for each alternative route segment. While the impacts of any route are considered to be mitigable to a level that is not significant, only two of the seven alternative segments were found to be preferred to the comparable route segments: Cherry Alternative and Bellflower Rail Alternative.
4.6 Geology and Soils
Impacts of the Proposed Project. Southern California is a seismically active area with the potential for the proposed project to be affected by several geologic hazards. The most significant hazards to the pipeline are fault rupture, strong ground shaking, and liquefaction. The pipeline crosses the Newport-Inglewood fault zone at its western end. This is an active fault with potential for significant ground movement. In addition, corrosive soils could erode the pipeline over time, increasing the potential for a leak. The following specific impacts are identified:
• Potential rupture of the pipeline in the Newport-Inglewood fault zone (Class I)
• Liquefaction, lateral spreading, and differential settlement could cause pipeline rupture (Class II)
• Corrosive soils could damage the pipe, increasing the potential for leaks or ruptures (Class II).
Mitigation Measures. Three mitigation measures are proposed. The first requires a detailed fault investigation for the Newport-Inglewood fault crossing to identify the type of fault movement anticipated, so the pipeline design at the fault can be improved. The second measure requires geotechnical studies to further define areas of potential liquefaction; this will allow development of specific design measures for the pipeline in those areas. The third measure calls for installation of a cathodic protection system to eliminate the potential for corrosive soils to erode the pipe.
Significant Unavoidable Impacts. While pipeline design measures, as required in mitigation, can increase the ability of the pipeline to withstand fault movement, they cannot eliminate the potential for the Newport-Inglewood Fault to cause pipeline rupture. Therefore, this fault crossing is considered to be a significant unavoidable impact.
Alternatives. The Newport-Inglewood Fault and corrosive soils would affect the proposed and alternative segments equally. However, because there are areas of moderate to high liquefaction potential between Carson and Norwalk, 2 segments have differences evident. The Paramount Alternative segment is preferred over the comparable portion of the proposed route, and the proposed route segment is preferred over the Cherry Alternative segment.
4.7 Hydrology and Water Resources
Impacts of the Proposed Project. The potential impacts of the proposed project on both surface water and ground water resources are evaluated. Maintenance of groundwater quality in the project area is important because several communities along the pipeline route obtain their municipal water from wells in the vicinity of the proposed pipeline. Surface water can be affected only at or near any of the three waterway crossings. Potential impacts of the project on water resources include the following:
• Contamination of Compton Creek during open cut construction from sediment loading or accidental equipment spills/leaks (Class II)
• Contamination of groundwater from a pipeline leak or rupture could result in potential contamination of water wells; contamination of surface water could result from pipeline leak or rupture (Class I)
• Potential for scour in Compton Creek to expose buried pipeline and cause a leak or rupture (assuming that the crossing is trenched) (Class II).
Mitigation Measures. Six mitigation measures are suggested, including protection for Compton Creek during open-cut construction, review of the pipeline location with respect to water wells, protection of the pipeline at the open-cut Compton Creek crossing (either by appropriate burial depth, using a thicker-walled pipe, or by boring the crossing), and expansion of the Oil Spill Core Plan to better address spills into the Los Angeles or San Gabriel Rivers.
Significant Unavoidable Impacts. Contamination of groundwater from a pipeline leak or rupture could result in potential contamination of water wells. Also, contamination of surface water could result from pipeline leak or rupture if the leak was located in a place where products could flow directly or through storm drains into a waterway. While the probability of a such a leak or rupture is small, the risk cannot be eliminated. Therefore, these impacts remain as significant and unavoidable.
Alternatives. The same surface waterways are affected by all alternative segments. There is some difference between alternative segments in the proximity of the proposed and alternative segments to water wells.
4.8 Land Use and Recreation
Impacts of the Proposed Project. Construction of the proposed project would affect residential land uses, schools, and other adjacent land uses, by temporary disruptions of public services such as water, gas, and electricity, as well as disruption of access and parking and disturbance at some parks. Also, residents and other adjacent landowners would be subjected to short-term increased noise, dust, and odor levels due to truck traffic, equipment operation, and trenching activities. Construction within the Norwalk Station would have the potential to disturb adjacent residences to the south of the facility. In addition, a pipeline accident could result in significant impacts to adjacent land uses. Specific impacts include the following:
• Short-term disruption or inconvenience to residents and other sensitive land uses adjacent to the pipeline ROW during construction (Class II, Class III)
• Short-term disturbance to recreational users during pipeline construction (Class III).
• Pipeline accidents (spills, leaks, fire, explosion) could contaminate land or water or cause injuries or death (Class I).
• Cumulative impacts of pipeline construction with other construction projects could affect land uses on adjacent lands (Class III).
Mitigation Measures. Eight mitigation measures are proposed. Three measures define notification procedures for affected property owners and residents, and establish a public liaison during construction. Other measures requires construction scheduling to avoid peak use periods at adjacent parks and schools. One measure recommends that there be more detail added to the Oil Spill Core Plan to protect sensitive land uses along the pipeline route. Two measures are proposed to minimize cumulative impacts of pipeline construction that could result from construction of multiple projects in close proximity to each other.
Significant Unavoidable Impacts. The primary land use and recreation concern with the operation of the Proposed Project is the long-term safety risk to existing or planned uses in the vicinity of the pipeline. The potential for rupture of the pipeline near populated areas is a significant, unavoidable impact.
Alternatives. Impacts for the alternative route segments would be similar to those described for the Proposed Project, except that different sets of land uses would be affected.
• The Santa Fe Alternative is preferred because it would avoid construction impacts adjacent to the Del Amo Mobile Estates, the Dominguez Adobe, and Dominguez Seminaries, as well as to the agricultural land adjacent to Compton Creek.
• The Cherry Alternative route would avoid impacts to the commercial uses on South Street between Cherry and Paramount which have been subjected to long-term construction impacts from the new rail overcrossings; however, more residences would be affected so the proposed segment is preferred.
• The Paramount Alternative is preferred over Artesia Boulevard because it would affect substantially fewer residential units.
• The Alondra Alternative route is preferred because it would avoid residential areas as well as potential contamination risks to the water supply reservoir and well located on Studebaker Road.
• The Bellflower Rail Alternative would affect fewer residences than the proposed route segment.
• The Artesia Alternative route avoids land use impacts on Studebaker Road and 166th Street, thus eliminating potential impacts to the water supply reservoir on Studebaker and the residential zone on 166th Street.
• The Shoemaker Alternative would have short-term construction impacts extended over a longer distance, but construction and operation at the Norwalk Station (within the Defense Fuel Support Point Norwalk site) would be avoided, thus eliminating construction disturbances to residences that are very close to the proposed ROW and eliminating the introduction of another possible source of leaks or spills in an area that is undergoing a major clean-up operation.
The No Project Alternative would not result in any new construction, so no construction-related land use impacts would occur. However, product would continue to be shipped via truck through southern California and increased demand would result in more truck trips. Spills from truck accidents would have the potential to cause significant unavoidable impacts on adjacent land uses (Class I). This long-term risk cannot be mitigated to level of non-significance, as many homes and populated facilities would be subjected to the risks of an accident.
4.9 Noise
Impacts of the Proposed Project. Two impact were identified related to noise from pipeline and station construction:
• Short-term noise from pipeline and station construction could affect sensitive noise receptors adjacent to construction areas (Class II).
• Construction within the Norwalk Station could produce disturbing noise to the residents of the housing units adjacent to the station (Class II).
Construction noise can be controlled or reduced through a variety of techniques as described under Mitigation Measures below. No noise impacts are noted for operation of the proposed pipeline.
Mitigation Measures. Impacts of project construction can be reduced through implementation of 4 mitigation measures, including: limitation of construction hours (particularly adjacent to schools); provision of 72-hour notice prior to start of construction to adjacent businesses and landowners; establishing a toll-free telephone hotline for noise complaints; and maintenance of mufflers on construction equipment. An additional measure would require use of soundwalls during construction within the Norwalk Station.
Significant Unavoidable Impacts. No significant unavoidable noise impacts would result from the proposed project.
Alternatives. Evaluation of noise impacts is based on impacts to sensitive and residential receptors, as in land use. The following alternatives are preferred to the proposed route segments: Santa Fe Alternative, Paramount Alternative, Alondra Alternative, Bellflower Rail Alternative, Artesia Alternative, and Shoemaker Alternative.
4.10 Socioeconomics, Public Services, and Utilities
Impacts of the Proposed Project. Project construction and operation could result in short-term degradation of air quality, noise, traffic, and disruption or displacement impacts on businesses along the ROW. In addition, the temporary closure of traffic lanes during construction, or lane closures due to a pipeline accident during pipeline operation and subsequent impedance of traffic on several major thoroughfares would result in a potentially significant impact on patrol and response capabilities. Socioeconomics, public services, and utilities impacts would include the following:
• Construction could have a short-term beneficial impact (Class IV) by generating employment in businesses that supply materials and services to the construction activity
• Dust generation, increased emissions from heavy equipment, and noise during construction has the potential to disrupt businesses along project route (Class II)
• Lane closures and heavy equipment traffic could impede access to businesses along the project route
• Sales tax revenues during construction, property taxes on the pipeline, and ongoing franchise revenues during project operation could have beneficial impact (Class IV) on the affected jurisdictions along the pipeline ROW
• Proposed project use of water for dust suppression and hydrotesting could have an impact on water capacity (Class III)
• Spill and clean-up activities could impact businesses along the pipeline route (Class II)
• The potential consequences of a co-location accident that disrupts utility services could be significant (Class I)
• In the event of multiple ruptures of the proposed pipeline or multiple accident in the vicinity of the proposed pipeline, there would be a significant (Class I) impact on public services.
Property Values. An analysis of the potential impact of a pipeline accident on property values was conducted. Because property values can be affected by a number of variables (lot size, home size, condition of the home, market conditions, proximity to busy streets, availability of financing, etc.), it is difficult to attribute a difference in value to just one factor (i.e., proximity to contamination). Recent sale prices of hundreds of homes in the vicinity of the Norwalk Station were compared to similar homes in nearby comparable neighborhoods to see if the contaminated soil and groundwater directly affected house prices. The data does not indicate that the contamination from the Norwalk Station has had a negative impact on property values of homes adjacent to the Station. However, other factors, such as time required to sell a house, were not analyzed.
Mitigation Measures. Five mitigation measures are proposed, including the development of a Business Impact Mitigation Plan, compensation to businesses, and direct cost recovery in the event of disruption or displacement due to construction or operation accidents. To help reduce the impacts of co-locational accidents, one of the mitigation measures requires SFPP to set priorities for disaster repair efforts on utility lines and transportation networks. In addition, there is a measure that requires the use of reclaimed water, where available, for dust suppression and hydrotesting to reduce impacts on water capacity.
Significant Unavoidable Impacts. Despite the small likelihood of a spill, the cumulative socioeconomic, public services, and utilities impacts of a spill from the proposed project and the potential for co-located ruptures of other oil, gas, chemical, and/or other product pipelines would be significant and unavoidable.
Alternatives. In general, impacts for the alternative route segments would be similar to those described for the Proposed Project. However, since the Bellflower Rail Alternative segment would eliminate 2.4 miles of construction on Artesia Boulevard which has a number of major businesses and the pipeline would be located within a 100-foot wide railroad ROW, there would be significantly less impacts on socioeconomics, public services, and utilities than the Proposed Project.
4.11 System Safety and Risk of Upset
Impacts of the Proposed Project. Construction and operation of the proposed Carson to Norwalk Pipeline could result in threats to the safety of construction workers and to the residents and businesses along the pipeline route. Construction hazards are considered to be adverse, but not significant, and can be reduced with implementation of proper workplace safety measures. Operational hazards are potentially very serious. They include the following:
• Pipeline leak
• Pipeline rupture
• Fires or explosions resulting from leak or rupture.
The probability of each event occurring is very small. Based on probability estimates, 1 leak would be expected to occur every 60 years of project operation, and a rupture would be expected to occur once every 100 years. A fire or explosion could result from ignition of hydrocarbon vapors at either a leak or rupture, possibly causing injury to nearby people.
Despite the predicted small likelihood that these events could occur, each of these impacts is considered to be significant. While SFPP has proposed several pipeline safety measures, and there are many more mitigation measures suggested in this EIR, it is not possible to ensure that a pipeline accident will not occur, so the impact is considered to be unmitigable (Class I).
Mitigation Measures. In addition to the safety and design measures that SFPP has incorporated into its proposed pipeline, 24 additional mitigation measures are suggested:
• 5 measures address construction safety and protection of existing utilities.
• 9 mitigation measures are suggested to improve SFPP’s proposed leak detection system.
• 5 measures would enhance SFPP’s spill response plan and emergency response notification
• 2 measures are proposed to reduce fire hazards
• 2 general measures would ensure the overall safety of the project.
Significant Unavoidable Impacts. While pipeline accidents (leak, rupture, or fire/explosion) are expected to occur on an infrequent basis, they are still considered to be significant and unavoidable impacts of the project.
Alternatives. While there are varying numbers of residences and other sensitive receptors along the proposed and alternative segments, each alternative segment has approximately the same likelihood of an accident occurring as does the proposed pipeline route. Therefore, there is considered to be no significant difference between the proposed route and alternative segments for the safety issue area.
The No Project Alternative would also have potentially significant safety impacts. The increase in trucking, which has much higher accident rates than pipelines, would result in much more frequent accidents than the proposed pipeline or alternative route segments. Therefore, the proposed pipeline is preferred over the No Project Alternative in the safety issue area.
4.12 Traffic and Transportation
Impacts of the Proposed Project. Construction within city streets would result in short-term disruption to traffic and transit services. The following impacts were identified:
• Pipeline construction would block traffic lanes, causing traffic congestion and a potential increase in traffic accidents (Class II)
• Pipeline construction would restrict access to residences and businesses along the ROW (Class II)
• Pipeline construction could disrupt pedestrian/bicycle traffic or cause increased accidents (Class II)
• Emergency response vehicles could be blocked or impeded by pipeline construction activities (Class II)
• Construction worker parking and traffic congestion could result from convergence at staging areas and construction equipment traffic (Class II)
• Parking of construction equipment on public roadways could limit available parking (Class III)
• Construction activities and vehicles could damage road surfaces (Class II)
• Construction could affect public transit operations (Class II) or rail operations (Class III).
The potential impact of a pipeline accident are also considered to be significant (Class I). In the event of a pipeline rupture or leak, significant impacts on rail operations, highway traffic, pedestrian circulation, and transit activity could result as partial or complete closures of transportation facilities may be required.
Mitigation Measures. Sixteen mitigation measures are proposed to reduce or minimize potential impacts on traffic and transportation. These measures require development of Traffic Control Plans, minimizing lane closures and access restrictions, construction at night to reduce traffic impacts where residences are not affected, coordination with businesses and emergency service providers, provision of alternative bicycle and pedestrian routes, review of staging areas, and use of shuttle buses to transport workers. In addition, measures require replacement of parking spaces, repair of damaged road surfaces, coordination with rail and transit operators, and coordination with local agencies to minimize cumulative traffic impacts.
Significant Unavoidable Impacts. The disruption to traffic resulting from a pipeline accident is considered to be a significant and unavoidable impact.
Alternatives. The Santa Fe, Paramount, and Bellflower Rail Alternative Segments are preferred to proposed route segments with respect to traffic impacts. Construction along Alondra Boulevard (for the Alondra Alternative segment) would impact high traffic volumes adjacent to Cerritos College; a mitigation measure is proposed to require scheduling of construction to avoid major traffic periods, but the Alondra Alternative is still not preferred in comparison to the proposed route.
4.13 Visual Resources
Impacts of the Proposed Project. Construction impacts on visual resources would result from the presence of equipment, materials and work force along the ROW, constituting a visual intrusion to motorists driving on adjacent streets, by residents and businesses, and by pedestrians in the project area. Although there are a large number of potential viewers within the project area, the visual impact of project construction is not anticipated to be significant because construction would occur primarily within urban streets. Light and glare emanating from sites where night time construction would occur, has the potential to impair the vision of motorists and pedestrians and could disturb the normal night time activities of residences.
Operation of the proposed pipeline is not expected to have a significant effect on visual resources within the study area. Upon completion of pipeline construction, the pipeline would not be visible to viewers since it is located subsurface to streets, or it is bored under and trenched through river channels. Potential impacts of the project on aesthetics include the following:
• Construction activities and equipment would result in visual intrusion to viewers along the ROW (Class III)
• The intrusion of night time construction light source would present a potential significant impact (Class II) on motorists, residents, and pedestrians along the ROW.
Mitigation Measures. Project construction impacts on visual resources can be minimized through the application of two mitigation measures, including: confinement of construction activities and materials storage to within the pipeline ROW and above-ground facility sites; and directing night construction lights away from the visual field of motorists and pedestrians along the ROW. In addition, night construction shall be prohibited within 500 yards of residences and sensitive receptors.
Significant Unavoidable Impacts. No significant unavoidable visual impacts have been identified for the proposed project.
Alternatives. Because construction in all alternative segments would occur in urban streets, visual impacts for alternative segments are similar to those for the proposed route.