We approve a route consisting of a hybrid of Route Option 1B and PG&E's Proposed Project in the southern segment and PG&E's Proposed Project in the northern segment modified to include Route Option 4B. The southern and northern segments will be connected using a new transition tower at Glenview Drive. The northern route may be modified, depending on the preference of the City of San Bruno, to implement Mitigation Measure T-9a if desired to avoid the Huntington Avenue grade separation project. The approved route will have no significant unmitigable (Class I) impacts and, thus, its choice does not require a Statement of Overriding Considerations.
A. Southern Segment
We conclude that a hybrid of Route Option 1B and PG&E's Proposed Project should be authorized for the southern segment of the Jefferson-Martin project.
The southernmost portions of the PUA and the Proposed Project would each cause significant, unavoidable, and permanent visual impacts. For the Proposed Project, the FEIR describes significant unmitigable (Class I) impacts at key viewpoints at Edgewood County Park, along southbound I-280, Lexington Avenue, Black Mountain Road, and north of the Carolands substation. While the PUA would eliminate those visual impacts, it would create its own set of significant unmitigable visual impacts, particularly along Cañada Road near Edgewood Road, at the I-280 crossing south of Carolands substation, and at one of the new transition structures needed to cross San Mateo Creek. Route Option 1B would have no or at most minimal visual impacts, depending on which crossing of Crystal Springs Dam is chosen.
PG&E's proposed overhead route, with its taller and bulkier towers and widened right of way, would cause permanent degradation of recreation at Edgewood County Park just north of the Jefferson substation. The PUA would enhance the recreational resource because it would allow existing transmission towers to be removed from the park. Route Option 1B would not be routed through and thus would maintain the existing baseline environmental conditions in the park.
Of the southern route options, Route Option 1B would have the least impact on biological resources. Because construction would be in existing roadways, habitat disturbance would be minimized. Both the southern portion of the Proposed Project and the PUA would have impacts on wetlands and habitats for protected species which would require careful mitigation. The Proposed Project would require extensive construction and increased permanent disruption in SFPUC watershed lands. The PUA would require two new overhead corridors and the underground section would require trenching through serpentine grassland. The MPUA, which would move the underground segment of the PUA to the west, would require development of a new right of way and trenching and disturbance through more areas of undisturbed serpentine grassland and sensitive habitat.
Due to underground construction and in particular its reliance on Trousdale Drive and El Camino Real, Route Option 1B would cause more intense construction-related impacts than would the other southern alternatives. These construction impacts would include increased noise, traffic delays, and some limits on access to residences and businesses.
The FEIR finds that Route Option 1B is preferable to the other southern routes with respect to geology factors. Both the Proposed Project and the PUA raise seismic concerns because of their high exposure to the main trace of the San Andreas fault near San Bruno Avenue. Route Option 1B would route the transmission line further to the east and would avoid the need for a transition station near the main trace. However, the Trousdale Drive portion of Route Option 1B would cross several traces of the Serra fault, which is classified as potentially active. Route Option 1B could encounter difficult excavation conditions related to existing underground utilities or artificial fill along Trousdale Drive and El Camino Real.
The FEIR did not consider EMF exposure in its determination of the environmentally superior alternative. In Section VI, we describe the magnetic field levels that would be created by the route options and the EMF mitigation measures we adopt. Residential EMF exposures would occur in the southernmost portion of PG&E's proposed above-ground route where the existing 60 kV line runs near residential neighborhoods. The PUA and the MPUA would mitigate these effects through selective re-routing or undergrounding in those areas. For Route Option 1B, EMF exposures would be most problematic north of Golf Course Road along Skyline Boulevard and along Trousdale Drive and El Camino Real.
The FEIR describes the possible creation of hybrid alternatives in the southern segment, with an intermediate transition station or tower allowing combinations of Route Option 1B and either the Proposed Project or the PUA. The overall environmental impact of each of the hybrid alternatives would encompass the impacts of the transition station or tower and the impacts of the route segments it connects.
One type of hybrid alternative would include the southernmost portion of either the Proposed Project or the PUA and would use Route Option 1B north of the intermediate transition station. We reject such hybrids because, among other concerns, they would cause significant unmitigable impacts in the watershed lands south of the intermediate transition station.
The other type of hybrid alternative would include the southernmost portion of Route Option 1B, which would reduce visual and biological impacts in that area. Its use of either the Proposed Project or the PUA would avoid effects on Trousdale Drive, El Camino Real, and (with the Golf Course Drive transition station) Skyline Boulevard. Such a hybrid alternative would reduce EMF exposure relative to Route Option 1B. However, use of the Proposed Project or the PUA route between the intermediate transition station and the San Bruno Avenue area would cause impacts to watershed lands.
The FEIR finds that most of the hybrid alternatives using Route Option 1B south of the intermediate transition station would have no significant unmitigable environmental impacts. The FEIR concludes that Route Option 1B for the entire southern segment is environmentally superior to such hybrid configurations because it would be underground and would not incur the visual impacts and disturbance to native habitat of the hybrid alternatives along the above-ground portions of their routes. The FEIR did not consider concerns regarding EMF exposure in making its determination regarding the environmentally superior route.
We find that the hybrid alternative using Route Option 1B north of the Jefferson substation, a transition tower replacing tower 11/70 west of Trousdale Drive, and PG&E's proposed overhead route north of the transition tower provides the best balance among the competing considerations. The portion of Route Option 1B south of the new transition tower will minimize visual and biological impacts in that portion of the route and will avoid impacts on Edgewood Park and the Pulgas Ridge Natural Preserve. The use of PG&E's proposed aboveground route north of the new transition tower will avoid Route Option 1B's effects on residences and businesses along Trousdale Drive and El Camino Real as well as seismic concerns in that area.
We reject use of a Golf Course Drive transition station because of adverse biological and visual impacts associated with both overhead options between that location and Trousdale Drive. The Proposed Project in this segment would have unmitigable (Class I) visual impacts and would traverse sensitive serpentine grasslands. The PUA would require a new right of way west of I-280, with substantial construction and access disturbance to this portion of the SFPUC watershed.
The chosen hybrid route eliminates most EMF concerns regarding the 230 kV line in the southern segment. Along the aboveground portion of the route, the new 230 kV line will be collocated on rebuilt towers with one of the two existing 60 kV lines, and the second 60 kV circuit will be eliminated. This portion of the line is routed away from populated areas so that EMF exposures are and will remain minimal.
The only place that the 230 kV line will pass near residential homes in the underground portion of the southern segment is the portion of Route Option 1B along Skyline Boulevard just south of Trousdale Drive. With the adopted EMF management plan, it appears that magnetic field levels from the 230 kV underground line should not exceed 2.5 mG during medium loading conditions in any residence along this portion of the route.31 While these levels may not entirely allay public concerns about EMF exposure, we believe that the chosen hybrid route provides a reasonable balance of EMF concerns and other considerations.
The FEIR identified six options for crossing Crystal Springs Dam that would avoid creation of significant unmitigable impacts, including a revised overhead crossing, a "top of the dam" option, a submarine cable option, a "face of the dam" option, and temporary overhead and top of the dam crossings that would be used until the cable could be incorporated into a new bridge planned by the County of San Mateo. The first three options were included in the FEIR's environmentally superior alternative. The Town of Hillsborough has requested that the permanent overhead crossing not be allowed due to its visual and biological impacts and its proximity to residences. In accordance with Pub. Util. Code § 1002, Hillsborough's request is granted. PG&E is authorized to determine which of the remaining five options to utilize, in order to allow the most timely and effective option in light of planned bridge and dam construction projects. We expect that PG&E's determination of which option to implement will take into account the preferences of the SFPUC, the County of San Mateo, and the USFWS.
We authorize a transition tower at Glenview Drive for the transition between the hybrid southern route and the underground northern route. We agree with the FEIR's conclusion that, of the four transition options presented in the FEIR, the Glenview Drive transition tower is preferable because it avoids an underground crossing of the San Andreas Fault, is less visible than other alternatives, and avoids land use conflicts. It would have no significant unmitigable impacts.
In summary, the authorized hybrid alternative is expected to have no significant unmitigable (Class I) environmental impacts. Biological and other potential adverse impacts that could arise due to this hybrid can be mitigated satisfactorily with the mitigation measures we adopt in Section VIII.B and the EMF management plan we adopt in Section VI.C. While this hybrid route is expected to cost approximately $19 million more than PG&E's cost estimates for the southern segment of the original Proposed Project, as described in Section XI, this additional cost is reasonable in light of the benefits of the adopted route.
We are not in a position to assess the validity of the assertion by the NPS that it would have discretionary authority to review and approve any Jefferson-Martin configuration that requires expansion of PG&E's existing right of way through the SFPUC watershed. We note, however, that the NPS has suggested that it is willing to consider the hybrid route that we authorize.
B. Northern Segment
For the northern segment of the Jefferson-Martin project, the FEIR provides environmental analysis that allows a choice between the Proposed Project's underground segment and the Collocation Alternative. The FEIR finds that both routes, with certain modifications, are environmentally superior and that neither route would have significant unmitigable (Class I) impacts. We approve PG&E's Proposed Project in the northern segment modified to include Route Option 4B. The route may be modified, depending on the preference of the City of San Bruno, to implement Mitigation Measure T-9a if desired to avoid the Huntington Avenue grade separation project.
Even with route options and mitigation measures designed to lessen its impacts, the Collocation Alternative would create greater impacts than the Proposed Project in several significant respects because of its construction through contaminated areas. The Collocation Alternative would have a high likelihood of encountering contaminated soils and groundwater during construction through and near three leaking underground tanks, two brownfield sites, and a capped landfill. By contrast, only one known contaminated site is likely to affect construction of the northern segment of the Proposed Project. Because construction would occur nearer to the San Francisco Bay, the Collocation Alternative would increase the likelihood of water quality effects on the Bay, compared to the Proposed Project.
The Proposed Project and the Collocation Alternative raise different seismic issues. The majority of the Collocation Alternative route would be in areas with either a very high or a high liquefaction potential along the Bay, whereas the Proposed Project runs further west near the San Andreas fault. We reject alternative configurations of the Proposed Project that would require the line to travel along or cross an active trace of the San Andreas fault. In Section IV.C, we describe that the Jefferson-Martin line diversifies the path and source of power brought into San Francisco. Some of the benefit of that diversification would be lost if this portion of the line were collocated in the existing San Mateo-Martin corridor, particularly since the line would share liquefaction risks with the existing 230 kV underground line through that same area.
The Collocation Alternative raises concerns, although perhaps not insurmountable, regarding commercial and emergency access to hotels and other businesses along the route. As a benefit, the Collocation Alternative would avoid construction-related impacts to residential areas, schools, and transportation corridors that will be affected by the Proposed Project. The northern segment of the Proposed Project will be routed adjacent to about 120 residences, several apartment buildings, and several schools. The Collocation Alternative would affect very few residences and no schools and, thus, would engender less EMF concern.
The FEIR notes that the Collocation Alternative would require work near pre-historic resources east of San Bruno Mountain, whereas the Proposed Project will require excavation into native undisturbed soils and potentially fossil-bearing rock during construction. The Collocation Alternative would avoid crossing San Bruno Mountain in Guadalupe Canyon Parkway. The Proposed Project will require construction work in the Hillside Boulevard bikeway and work near other recreational facilities, especially in San Bruno Mountain State and County Park.
On balance, we find that risks associated with construction through contaminated areas and along the Bay, along with the loss of diversification arising from collocating the line with the existing underground 230 kV line, militate against our choosing the Collocation Alternative. While the Proposed Project will require careful mitigation to ensure that its construction and other impacts are less than significant and to reduce EMF concerns, we find that it is better than the Collocation Alternative for the northern segment of the Jefferson-Martin project. We turn now to certain details regarding its route and mitigation measures.
In Section VII.A, we determine that a transition tower should be constructed at Glenview Drive to connect the overhead portion of the route to the northern segment. We find that, after transiting underground and exiting the Glenview Drive transition site, the line should travel north in Glenview Drive to San Bruno Avenue. San Bruno's request that the line use Skyline Boulevard rather than Glenview Drive to reach San Bruno Avenue is unacceptable because the line would travel along and cross an active trace of the San Andreas fault.
Consistent with the FEIR's assessment, we authorize the use of San Bruno Avenue for the project from Glenview Drive to Huntington Avenue. Seismic considerations are the primary factor in our choice of San Bruno Avenue rather than either Sneath Lane or Westborough Boulevard. While there are existing underground utilities, it appears that addition of the new 230 kV line will be feasible within San Bruno Avenue.
In the Proposed Project, the 230 kV line would turn north from San Bruno Avenue onto Huntington Avenue to the BART right of way. The FEIR describes that from San Bruno Avenue, two options are available depending on local jurisdiction preference as to whether the grade separation project at San Bruno Avenue and Huntington Avenue should be avoided or engineered as defined in Mitigation Measure T-9a. We authorize PG&E to determine, depending on the preference of the City of San Bruno and subject to Section XIV in G.O. 131-D, whether to construct the line to the intersection of San Bruno Avenue and Huntington Avenue or route the line north on El Camino Real and then east on Sneath Lane consistent with Mitigation Measure T-9a.
As detailed in Section VI.B, several buildings along the BART right of way would be very close to the transmission line and, without mitigation, would receive quite high EMF exposure. In Section VI.C, we require that PG&E undertake strategic line placement and other EMF mitigation measures to reduce EMF exposure along the BART right of way.
We agree with the FEIR that Route Option 4B is preferable to Route Option 4A. Route Option 4B will avoid construction impacts to residences along Hoffman and Orange Streets. Because Hillside Boulevard and East Market Street are wider than Hoffman and Orange, construction impacts will be less and EMF levels in residences along the way will be less. While some buildings at Pollicita Middle School and Colma Elementary School are close to East Market Street, others are set further back. The adopted EMF mitigation measures will reduce EMF levels to some extent through deeper trenches and strategic placement within the right of way.
31 With elimination of one of the two 60 kV circuits north of tower 11/70, it is not clear whether or the extent to which PG&E would de-energize or dismantle that 60 kV circuit between the Trousdale Drive transition tower and the Jefferson substation. If there are reduced power flows on the 60 kV line, this would reduce EMF levels along this line as well.