STATE OF CALIFORNIA
PETE WILSON, GovernorPUBLIC UTILITIES COMMISSION
505 VAN NESS AVENUE
SAN FRANCISCO, CA 94102-3298
DRAFT MITIGATED NEGATIVE DECLARATION
PACIFIC GAS AND ELECTRIC COMPANY’S
APPLICATION NO. A.97-10-037
CORONA SUBSTATION
PROJECT DESCRIPTION
In compliance with the California Public Utilities Commission (CPUC) General Order No. 131-D, Pacific Gas & Electric Company (PG&E) has applied for a Permit to Construct (PTC) the Corona Substation, a 115 kV - 12 kV substation, and associated power tap line, in Petaluma, Sonoma County, California. PG&E proposes the project to meet the load growth expected to occur in Petaluma and to ensure that PG&E can provide an adequate and reliable supply of electric power in the future. Currently, PG&E supplies electric power by load transfers from the Petaluma A, Petaluma C, Lakeville, and Cotati Substations; PG&E projects that its ability to accommodate the expected growth in the northern portion of Petaluma by load transfers will be exhausted by the summer of 1998.
The proposed substation would be a remote-controlled, two transformer bank, compact design facility on a 0.55 acre site. The substation would operate without on-site personnel, but would require maintenance inspections, generally expected to occur several times a month.
The proposed Corona Substation would be located within the existing PG&E Petaluma Service Center at 210 Corona Road. The Service Center occupies 3.87 acres, and the proposed substation would occupy an existing flat and paved area near the center of the Service Center. Current activities of the Service Center would continue without change. The project would not require additional staff at the Service Center.
The substation would include 115 kV - 12 kV transformer banks, breakers, switches and related electrical equipment, two tubular steel clearance poles to support the tap line, lighting, a pond, and an eight-foot-high chain link fence. The first 115 kV - 12 kV transformer bank would be installed in 1998, and the second installed about the year 2002.
The connector loop power line would tap into the 115 kV Lakeville-Santa Rosa power line at North McDowell Boulevard and carry current to and from the substation. The 115 kV power tap line would run along the north side of Corona Road on a double circuit tubular steel pole, 60-feet in height for a total distance of 630 feet, to an 75-foot-high tubular steel pole at the northeast corner of the intersection of Corona Road and North McDowell Boulevard. The three-way, 75 foot tubular steel pole would be constructed adjacent to the existing wood pole that supports both the Lakeville-Santa Rosa 115 kV power line and a distribution circuit. This wood pole would remain in place. The proposed loop configuration from the Lakeville-Santa Rosa power line to the substation would allow power to reach the substation from either of two different sources in the event of a failure of the Lakeville-Santa Rosa power line north or south of the interconnection point with the tap line.
At build out, the project would feed up to eight 12 kV underground distribution lines. Two distribution lines would be constructed first, with others added as electricity demand grows. The distribution lines would cross and then run along the north side of Corona Road to both the east and the west, and also would run along the southern edge of Corona Road to the east. Three existing wood pole distribution lines on the north side of Corona Road would be removed, as would two existing wood service poles on the south side of Corona Road east of the Service Center. An existing wooden pole on the north side of Corona Road (northwest of the Service Center) and adjacent to the Highway 101 overpass would be modified, increased in height to serve as a transition between existing overhead and proposed underground distribution lines. To accommodate the proposed loop tap line, an existing wood-pole-supported distribution line would be undergrounded.
PG&E proposes a conceptual landscaping plan,with plantings both on-site and off-site. On-site landscaping includes evergreen and large canopy trees within the Service Center and small flowering trees, shrubs, and ground cover at the entrance at Corona Road and in newly designed employee and customer parking areas.
Along Corona Road, PG&E proposes landscaping that includes redwood trees and riparian species trees and ground cover along the north side of Corona Road from the Service Center entrance drive to the Highway 101 overpass and east to North McDowell Road. The trees would be less than 15 feet in height in the eastern section to clear the proposed overhead 115 kV power line. PG&E proposes to plant riparian tree species and native grasses and to convert the existing drainage ditch to an urban creek to carry runoff from Corona Road. Redwood trees with an understory of native grass would be planted along the southern side of Corona Road from the entrance drive to the Highway 101 right-of-way. PG&E proposes to dedicate the completed creek improvements and Corona Road landscaping to the City.
Along the both sides of Corona Road, at the north side of the Service Center, PG&E proposes to remove five to seven existing redwoods and several eucalyptus trees, to eliminate the hazards associated with tall trees under the proposed 115 kV power line, and to replace removed trees with lower-growing trees.
PG&E proposes to construct a six-foot wood fence, plant screening vegetation and install an irrigation system between the Service Center and the Youngstown Mobile Home Park, along the southern and western boundaries of the Service Center.
Construction of the substation project would take about four months. Site development would include removal of paving, regrading and resurfacing of the site, trenching for the underground distribution feeders and construction of ditches, and construction of foundations and the substation fence. Trees under the 115 kV power line alignment would also be removed. Approximately 550 cubic yards of soil and gravel/crushed rock would be imported to create the raised transformer pad and cover the substation equipment yard area. A service road would be constructed. Mechanical equipment for the substation would be installed, including installation of the first transformer bank, bus structure, and switchgear. Tubular steel single poles would be installed with replacement of wood poles with tubular steel poles. The existing overhead distribution lines would be put underground at this time. The pond would be constructed. The final steps would include testing and energizing of the substation, construction clean-up, and installation of landscaping and irrigation systems. At this point, the substation would be operational.
All construction equipment, vehicles, personnel and staging areas would be accommodated within the fenced portion of the proposed substation site. Access to the substation would be from the existing easement across the neighboring mobile home park property.
Electrical service interruptions to customers in the area not expected by PG&E during the construction of the substation and 115 kV connector loop line. Brief interruptions (for up to four hours) for as many as about 10 customers will occur for replacement of the pole-supported distribution line with an underground distribution line. Those customers will receive advance notification (48 hours) of the interruption in service.
Future activities would include the construction of additional underground distribution lines, as needed, and the future addition of the second transformer bank.
Further details on proposed construction methods and the proposed facilities are included in the Initial Study prepared for the project and in PG&E’s application and PEA.
The CPUC’s process for granting a permit to Construct requires compliance with the requirements of the California Environmental Quality Act (CEQA). An Initial Study was prepared for this project, specifically to examine to the construction of each component of the Corona Substation project at its proposed location. A CEQA Initial Study does not study project alternatives; however, under the General Order 131-D process, the CPUC considers alternatives to the project in determining whether or not to issue the Permit to Construct.
ENVIRONMENTAL DETERMINATION
An Initial Study was prepared to assess the potential effects on the environment, and the respective significance of those effects, from the proposed Corona Substation project. Based on that Initial Study, the proposed Corona Substation project would have less than significant environmental effects or no impact in the areas of:
|
|
|
|
|
|
|
|
|
|
|
Based on the Initial Study, the proposed Corona Substation project would have potentially significant environmental effects in the areas of:
|
|
|
|
|
Each of the identified potential impacts can be mitigated to avoid the impact or to reduce it to a less than significant level by mitigation measures. PG&E has agreed to comply with these measures and incorporate them as part of the project actions. These mitigation measures and monitoring requirements are as follows:
MITIGATION MEASURES AND MITIGATION MONITORING REQUIREMENTS
Water
Impact
Mitigation Measure: The following mitigation measure would reduce the potential impact of surface water discharge to a less-than-significant level.
Measure IV.c.1. If construction is scheduled during the rainy season, PG&E shall employ best construction management practices to prevent discharges of silt and other substances from construction into storm drains. PG&E shall develop and implement a plan to control excavated soils and runoff, specifying practices such as the use of detention basins, straw bales, silt fences or other deterrents, and site clean-up procedures and practices to minimize contact of construction materials with stormwater.
Monitoring Action: The CPUC mitigation monitor shall review and approve the control plan submitted by PG&E.
If rain occurs during construction, the CPUC mitigation monitor shall visit the site to confirm the effectiveness of mitigation measures.
PG&E shall provide the CPUC mitigation monitor with documentation of compliance actions in regular progress reports.
Responsibility: PG&E shall verify compliance actions and reporting by on-site work crews and supervisors.
Timing: The CPUC review and approval of the control plan must precede the start of grading or foundation borings.
Control measures shall be in place on-site before rain occurs.
PG&E shall submit regular progress reports to the CPUC mitigation monitor.
Air Quality
Impact: Construction activities have the potential to generate airborne dust and particulates.
Mitigation Measure: The following mitigation measure would reduce the potential impact of dust and particulate generation to a less-than-significant level:
Measure V.a-1: PG&E shall require its construction contractors or its crews to implement a dust abatement program during construction activities. The dust abatement program should include the following (as adapted from BAAQMD):
· Sweep daily (with water sweepers) Corona Road, the paved access road to the substation site, and paved parking and staging areas at the substation site. Sweep each paved street area used to drill foundation holes and pour foundations for power line towers.
Monitoring Action: PG&E shall monitor activities at the site and document compliance with this measure daily.
The CPUC mitigation monitor shall visit site during construction and observe compliance actions.
PG&E shall provide the CPUC mitigation monitor with documentation of compliance actions in regular progress reports.
Responsibility: PG&E shall verify compliance actions and reporting by on-site work crews and supervisors.
Timing: PG&E shall keep daily records and shall submit copies to the CPUC mitigation monitor in regular progress reports.
Transportation/Circulation
The following mitigation measures would reduce the potential impact to a less than significant level:
Mitigation Measure VI.c-1: PG&E shall notify Fire Station officials and the City of Petaluma at least one week prior to project construction of any planned lane closures and days and times when access to the fire station may be impaired; this would allow the Fire Department to plan for potential delays, move trucks out of the fire station temporarily for better access, or undertake other measures.
Monitoring Action: PG&E shall notify the Fire Department and the City of Petaluma in a timely manner.
PG&E shall provide the CPUC mitigation monitor with documentation of compliance actions in regular progress reports.
Responsibility: PG&E shall verify compliance actions and reporting by on-site supervisors.
Timing: PG&E shall send a notice at least one week prior to any planned lane closure that would impair access to the fire station.
Noise
Impact: Construction activities have the potential to generate noise that affect nearby residents.
Mitigation Measure: The following mitigation measures would reduce the potential noise impacts to a less-than-significant level:
Mitigation Measure X.a-1: To reduce the construction noise effects, PG&E shall ensure that noisy construction activities at the substation site and near residences along the power line route shall be limited to the least noise-sensitive times of day and week as required by the City of Petaluma Noise Ordinance.
Mitigation Measure X.a-2: To reduce the construction noise effects, PG&E shall ensure that all construction equipment used on the substation site and for power line construction shall be adequately muffled and maintained.
Mitigation Measure X.a-3: To reduce the construction noise effects, PG&E shall ensure that all stationary construction equipment (i.e., compressors and generators) shall be located as far as practicable from the eastern and southerly property line.
Monitoring Action: PG&E shall monitor activities at the site and document compliance with measures X.a-1 and X.a-3.
PG&E shall obtain certifications or shall verify that construction equipment is adequately muffled and regularly maintained.
The CPUC mitigation monitor shall visit the site during construction and observe compliance with measure X.a-3.
PG&E shall provide the CPUC mitigation monitor with documentation of compliance actions in regular progress reports.
Responsibility: PG&E shall verify compliance actions and reporting by on-site work crews and supervisors.
Timing: Before on-site work begins, PG&E shall provide the CPUC mitigation monitor with verification that construction equipment is adequately muffled and regularly maintained.
PG&E shall keep daily records of each day’s work hours for construction activities and shall keep weekly records of the locations of noisy equipment.
PG&E shall provide copies of the compliance documentation in regular progress reports to the CPUC mitigation monitor.
FINDINGS
Based on the analysis in the Initial Study and the Mitigation Measures identified in the initial study and listed above for inclusion into the project, the CPUC finds that the Corona Substation project will not have a significant effect on the environment.
_________________________________
Natalie Walsh, Program Manager
Analysis Branch
Energy Division
California Public Utilities Commission