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Re: TRAC calls for hsr return to Tejon route
Author: Spokker
Date: 02-11-2011 - 02:26
"Why was the route via Palmdale selected between the Central Valley and Los Angeles?
As part of the Statewide Program EIR/EIS document (certified November 2005), the Authority selected the alignment through the SR-58/Soledad Canyon Corridor (Antelope Valley) with an high-speed train station at Palmdale as the preferred option for crossing the Tehachapi Mountains between the Central Valley and Southern California. Although the longer Antelope Valley alignment would add about 10 minutes to express service travel times between northern and southern California and have less intercity ridership potential (trips between regions) than the I-5 alignment option, it would have fewer potential environmental impacts, it would be less subject to seismic activity and have considerably less tunneling and thereby have fewer constructability issues, and would increase connectivity and accessibility.
The most significant difference in regards to potential environmental impacts between the Antelope Valley option and I-5 alignments is in regards to major parklands. The Antelope Valley alignment would not go through major parks. In contrast, the I-5 options would potentially impact Fort Tejon Historic Park, Angeles and Los Padres National Forests, Hungry Valley State Vehicular Recreation Area, Pyramid Lake and other local parks. The Antelope Valley alignment would also have a lower overall potential for water-related impacts, less potential impacts to wetlands and non-wetland waters, and was forecast to have less impacts on urbanized land and farmland conversion than the I-5 options (because the I-5 options would result in more growth in the Central Valley).
The Antelope Valley alignment traverses less challenging terrain than the I-5 options, which would result considerably less tunneling overall (13 miles 21 km of tunneling for the Antelope Valley option versus 23 37 km miles for I-5 options), and considerably shorter tunnels (maximum length of 3.4 miles 5.5 km for the Antelope Valley option versus two tunnels greater than 5 miles 8 km for the I-5 options) which would result in fewer constructability issues. Although the Antelope Valley option is about 35 miles longer than the I-5 alignment options, it is estimated to be slightly less expensive to construct as a result of less tunneling through the Tehachapi Mountains. In addition, due to its more gentle gradient, geology, topology and other features, the SR-58/Soledad Canyon Corridor offers greater opportunities for using potential high-speed train alignment variations, particularly through the mountainous areas of the corridor, to avoid impacts to environmental resources. In contrast, the more challenging terrain of the I-5 Corridor greatly limits the ability to avoid sensitive resources and seismic constraints. The alignment optimization system (Quantm) that was utilized to identify and evaluate approximately 12 million alignment options for each mountain crossing could only find one practicable alignment option through the Tehachapi Mountains for the I-5 Corridor.
Additional seismic hazards relating to the I-5 alignment that further differentiate these options from the Antelope Valley alignment. Since the I-5 alignment options follow the San Gabriel fault for over 20 miles and cross through the area where the San Andreas and Garlock faults meet, they would have greater seismic hazard and constructability issues than the Antelope Valley option. The Authority concluded that there are additional seismic hazards and risks for the I-5 alignment options from paralleling the San Gabriel fault, and also from traversing the “triangle” where the San Andreas and Garlock faults meet.
The Antelope Valley option would provide direct service to the Palmdale/Lancaster area, which increases the connectivity and accessibility of the high-speed train network. The Antelope Valley is the fastest growing area in Los Angeles County and currently regional population forecasts estimate the Antelope Valley population could exceed 1 million by the year 2020. The high-speed train system would also provide connectivity to Palmdale Airport and Metrolink commuter rail service.
Public and agency support for the Antelope Valley option is strong in Los Angeles County because of the increased connectivity and accessibility it would provide for the Antelope Valley. Agencies which have indicated support for the Antelope Valley alignment include: the City of Los Angeles, the County of Los Angeles, Los Angeles County Metropolitan Transportation Authority (LAMTA), Los Angeles Department of Transportation, Southern California Association of Governments (SCAG), the City of Palmdale, City of Lancaster, County of Kern, Kern Council of Governments, and the City of Bakersfield."
As part of the Statewide Program EIR/EIS document (certified November 2005), the Authority selected the alignment through the SR-58/Soledad Canyon Corridor (Antelope Valley) with an high-speed train station at Palmdale as the preferred option for crossing the Tehachapi Mountains between the Central Valley and Southern California. Although the longer Antelope Valley alignment would add about 10 minutes to express service travel times between northern and southern California and have less intercity ridership potential (trips between regions) than the I-5 alignment option, it would have fewer potential environmental impacts, it would be less subject to seismic activity and have considerably less tunneling and thereby have fewer constructability issues, and would increase connectivity and accessibility.
The most significant difference in regards to potential environmental impacts between the Antelope Valley option and I-5 alignments is in regards to major parklands. The Antelope Valley alignment would not go through major parks. In contrast, the I-5 options would potentially impact Fort Tejon Historic Park, Angeles and Los Padres National Forests, Hungry Valley State Vehicular Recreation Area, Pyramid Lake and other local parks. The Antelope Valley alignment would also have a lower overall potential for water-related impacts, less potential impacts to wetlands and non-wetland waters, and was forecast to have less impacts on urbanized land and farmland conversion than the I-5 options (because the I-5 options would result in more growth in the Central Valley).
The Antelope Valley alignment traverses less challenging terrain than the I-5 options, which would result considerably less tunneling overall (13 miles 21 km of tunneling for the Antelope Valley option versus 23 37 km miles for I-5 options), and considerably shorter tunnels (maximum length of 3.4 miles 5.5 km for the Antelope Valley option versus two tunnels greater than 5 miles 8 km for the I-5 options) which would result in fewer constructability issues. Although the Antelope Valley option is about 35 miles longer than the I-5 alignment options, it is estimated to be slightly less expensive to construct as a result of less tunneling through the Tehachapi Mountains. In addition, due to its more gentle gradient, geology, topology and other features, the SR-58/Soledad Canyon Corridor offers greater opportunities for using potential high-speed train alignment variations, particularly through the mountainous areas of the corridor, to avoid impacts to environmental resources. In contrast, the more challenging terrain of the I-5 Corridor greatly limits the ability to avoid sensitive resources and seismic constraints. The alignment optimization system (Quantm) that was utilized to identify and evaluate approximately 12 million alignment options for each mountain crossing could only find one practicable alignment option through the Tehachapi Mountains for the I-5 Corridor.
Additional seismic hazards relating to the I-5 alignment that further differentiate these options from the Antelope Valley alignment. Since the I-5 alignment options follow the San Gabriel fault for over 20 miles and cross through the area where the San Andreas and Garlock faults meet, they would have greater seismic hazard and constructability issues than the Antelope Valley option. The Authority concluded that there are additional seismic hazards and risks for the I-5 alignment options from paralleling the San Gabriel fault, and also from traversing the “triangle” where the San Andreas and Garlock faults meet.
The Antelope Valley option would provide direct service to the Palmdale/Lancaster area, which increases the connectivity and accessibility of the high-speed train network. The Antelope Valley is the fastest growing area in Los Angeles County and currently regional population forecasts estimate the Antelope Valley population could exceed 1 million by the year 2020. The high-speed train system would also provide connectivity to Palmdale Airport and Metrolink commuter rail service.
Public and agency support for the Antelope Valley option is strong in Los Angeles County because of the increased connectivity and accessibility it would provide for the Antelope Valley. Agencies which have indicated support for the Antelope Valley alignment include: the City of Los Angeles, the County of Los Angeles, Los Angeles County Metropolitan Transportation Authority (LAMTA), Los Angeles Department of Transportation, Southern California Association of Governments (SCAG), the City of Palmdale, City of Lancaster, County of Kern, Kern Council of Governments, and the City of Bakersfield."
