INITIAL STUDY
ENVIRONMENTAL CHECKLIST

 

1.

Project Title:

PG&E Monta Vista/Wolfe/Stelling Looping Project (Application Number A. 98-10-026)

2.

Lead Agency Name and Address:

California Public Utilities Commission
505 Van Ness Avenue, Fourth Floor
San Francisco, CA 94102-3298

3.

Contact Person and Phone Number:

Stephen Rutledge, Regulatory Analyst
Energy Division (415) 703-1637

4.

Project Location:

Monta Vista substation is located in Santa Clara County within the City of Cupertino; Santa Clara Valley Water District property is located on the north side of I-280 adjacent to Stevens Creek and the southern end of Homestead Court within the City of Cupertino (Figure 1).

5.

Project Sponsorís Name and Address:

Pacific Gas and Electric Company
P.O. Box 7442
San Francisco, CA 94120

Attn: Steven Appleton (415) 973-8272

6.

General Plan
Designation:

Monta Vista Site: Public/Quasi Public

SCVWD Site: Public/Quasi Public

7.

Zoning:

Monta Vista Site: Public Building (BA)

SCVWD Site: Public Facility

8.

Description of Project:

 

Purpose and Need

Pacific Gas and Electric Company (PG&E) is requesting a permit to construct the Monta Vista/Wolfe/Stelling Looping project. The proposed project is needed in order to meet the increase in electrical demand in the DeAnza electrical service area, which includes the cities of Cupertino, Mountain View, Los Altos, and Sunnyvale. The project would balance and distribute power more efficiently, ensure reliable service, and reduce the potential for circuit overloads and potential service disruptions by creating a new Circuit #3 between the Wolfe, Stelling and Monta Vista substations.

The Ames substation in Mountain View and the Monta Vista substation in Cupertino are connected by Circuits #1 and #2 of the Monta Vista-Ames 115 kV power line (see Figure 1). Circuit #1 supplies power to the Whisman and Mountain View substations, and Circuit #2 supplies power to the Wolfe and Stelling substations. Both Circuits #1 and #2 receive power from both the Ames and Monta Vista substations.

The cities of Mountain View and Cupertino have recently experienced dramatic economic growth along with an increased demand of approximately 8 megawatts (MW) per year and a predicted growth of an average of 10 MW per year for the next three years. The proposed project would balance the electrical transmission system between the Mountain View, Whisman, Wolfe and Stelling substations by reducing the number of substations served by existing Circuits #1 and #2.

According to PG&E, the proposed project will need to be on-line by the summer of 1999 in order to prevent thermal emergency overloads on Circuits #1 and #2 and to prevent potential service interruptions for PG&E customers in the service area (PG&E, 1998).

Project Description

Location

The DeAnza electrical service area includes the Cities of Cupertino, Mountain View, Los Altos, and Sunnyvale. The northwestern DeAnza electrical service area is served by the Monta Vista-Ames 115kV power line (Circuits #1 and #2), which run parallel to each other and are approximately seven miles long.

The Monta Vista substation and the Santa Clara Valley Water District (SCVWD) property are located in the City of Cupertino, with portions of the project also located in unincorporated Santa Clara County.

The reconductoring of approximately three miles of the existing Wolfe Loop-Ames/Wolfe Loop-Monta Visa (WLA/MLMV) power line between the SCVWD property and the Stelling and Wolfe substations would be located in the City of Cupertino (see Figure 2).

Proposed Components and Construction

The proposed project consists of disconnecting the Whisman substation from Circuit #1 and connecting it to Circuit #2, and disconnecting the Wolfe and Stelling substations from Circuit #2. The Wolfe and Stelling substations would then be connected to the Mountain View substation by the new Circuit #3.

In order to separate these substations and create Circuit #3, approximately one mile of combined new overhead and underground double-circuit 115 kV line would be constructed between the Monta Vista substation and the SCVWD property. In addition, the existing three-mile WLA/WLMV line between the SCVWD property and the Wolfe and Stelling substations would be reconductored in order to create Circuit #3.

The proposed project would include the following components:

· Overhead Line Construction

· Transition Structures

· Underground Line Construction

· Horizontal Dry Boring

· Reconductoring

 

Overall Construction Management

For construction at the SCVWD property and Monta Vista site, all construction equipment, vehicles, personnel, and staging areas would be accommodated within the site, or off-site storage would be made available at the PG&E Cupertino Service Area. Except for the underground line construction, all project components would be constructed concurrently.

Use of heavy equipment along the roadways for installation of new poles, for pulling wire or for trenching operations, may require the temporary closure of single lanes of traffic. PG&E would coordinate the dates and times for construction closures of traffic lanes with the City of Cupertino, and to the extent feasible, lane closures would occur during off-peak traffic periods.

Overhead Line Construction. The new overhead portion of Circuit #3 would be constructed in part at the upper portion of the Monta Vista substation on two separate circuits and take-off structures (see Figure 3). The two new lines would be 115kV each and would be located on four new self-supporting tubular steel poles approximately 40 to 75 feet in height (see Figure 4). They would then be connected to a new riser pole structure on the lower Monta Vista substation property (see Figure 5).

Boring the foundation holes for the new poles, which would range from four to six feet in diameter, to depths of eight to 15 feet would require the use of a heavy-duty, truck mounted auger. Before concrete is added to each hole, reinforcing bars and anchor bolts would be set in place. Each hole may take four to six weeks to cure before the poles are erected.

Each of the new poles would be assembled on the ground at the site then raised into position and set on their foundations. After installation of the tubular steel poles and conductors, all equipment would be tested and the line would be energized. This portion of the overhead line construction would require a crew of six to ten workers approximately six to eight weeks to complete.

Transition Structures. A 75-foot riser pole would be used to connect the two overhead 115kV lines from the upper Monta Vista substation to the new underground power line at the lower Monta Vista substation (see Figure 6).

The SCVWD property has two existing 55-foot dead-end lattice structures. Each of these lattice structures would be used to mount 29-foot platforms containing termination equipment. The new underground line would terminate at the SCVWD property below the lattice structures and connect to newly installed termination equipment (see Figure 7).

This portion of the overhead line construction would require a crew of 10 to 12 workers, and would take approximately two weeks to complete.

Underground Line Construction. This portion of the project would require 10 to 20 workers and six months to complete. Approximately one mile of underground line would be placed in trenches along:

  • The lower portion of Monta Vista substation on PG&E property;
  • East on Salem Avenue to Foothill Boulevard;
  • North on Foothill Boulevard to Starling Drive;
  • East on Starling Drive to Baxter Avenue;
  • North on Baxter Avenue to Creston Drive;
  • East on Creston Drive to Groveland Drive; and,
  • North on Groveland Drive to the SCVWD property.

Underground line construction is comprised of trenching and excavation, equipment installation, and backfilling and paving.

Trenching and excavation would take place in a 20 foot-wide work area along the routes described above. Trenching spoils would be trucked to an approved Class III disposal site. Trench construction includes digging to a depth of six to ten feet, 36-inches wide, and approximately 600 feet in length. Equipment used for this phase of underground construction would include a concrete saw, pavement breaker, jack hammer, a front end loader, a flatbed with a hoist, and a crane with outriggers.

When the excavation and trenching portion of the project is completed the nine 6-inch polyvinyl chloride (PVC) conduits, the conduit pipes, and concrete duct banks would then be installed. The concrete duct banks would be located at a minimum depth of 24 inches below grade and include number 5 rebar in six locations when under existing roadways.

After the equipment is installed, including duck banks, splice vaults, and riser structures, the cable will be installed. Cable would be pulled between the riser structures or the 12 splice vaults then rough cut, joined together mechanically with connectors, and sealed with a waterproof covering. Upon completion of the cable installation, the trench would be backfilled and the road surface would restored in compliance with locally issued permits.

Horizontal Dry Boring. There are two sites that require the use of horizontal dry boring: underneath I-280 and the Union Pacific Railroad tracks at the SCVWD property, and at Heney Creek. This segment of the project would require approximately four to six workers and six weeks to complete both sites. At the SCVWD property the horizontal dry boring would be located approximately six feet below the Union Pacific Railroad and 15 feet below I-280. A bore pit on the SCVWD property would be excavated, and an angle bore would be drilled to a receiving pit at Groveland Drive.

The horizontal dry boring at Heney Creek would be located approximately 10 feet below the surface of the creekbed and would originate 50 feet west of Heney Creek and extend 50 feet to the east side.

Reconductoring. Reconductoring would occur between the Wolfe and Stelling substations along the WLA/WLMV 115kV line. Temporary crossing structures would be installed over roads, railroads, and other power lines in order to avoid accidental contact with energized lines.

Operation and Maintenance

The Monta Vista substation and the SCVWD facility would operate without on-site personnel, but would require annual inspection by PG&E personnel. The overhead segments of the project would be inspected for corrosion, equipment misalignment, loose fittings, or other mechanical problems. The same vaults used during underground line construction would be used for routine inspection of the power line and to perform maintenance and repairs.

Construction Schedule

The Monta Vista/Wolfe/Stelling Looping Project is proposed to be constructed between February and July of 1999.

9.

Surrounding Land Uses and Setting:

The project area contains a mix of low-rise residential and commercial development, several freeways and expressways, and relatively dense urban landscaping.

To the northwest of the Monta Vista substation is a 212-acre parcel owned by the Roman Catholic Diocese of San Jose. To the southwest of the Monta Vista substation, mineral resources extraction in the form of open-pit mining is currently conducted in the Kaiser Cement Plant quarry, and the Stevens Creek quarry. Immediately adjacent to the Monta Vista site are horse-boarding facilities and single and multi-family residential subdivisions.

The Foothill Plaza Shopping Center is located 600 feet to the north of the SCVWD property at Foothill Boulevard and Homestead Road. Commercial facilities (typically strip-malls) can be found along Stevens Creek Boulevard and Homestead Road. The project area is densely developed and urban in character.

10.

Other public agencies whose approval is required: (e.g., permits, financing approval, or participation agreement)

Pursuant to State Law, the California Public Utilities Commission (CPUC) is the permitting authority for the project.

An existing overhead easement on SCVWD property would be amended prior to construction to accommodate the project. In addition, PG&E would need to obtain a construction permit for activities on the SCVWD property.

Activity for all underground work within the road franchise would require encroachment permits from the City of Cupertino and Santa Clara County.

Under PG&Eís Master Agreement with the Union Pacific Railroad Corporation, PG&E would prepare an application for new easements for electric utility crossings.

Work such as dry boring and duct bank construction under I-280, and reconductoring over I-280 will require a California Department of Transportation encroachment permit.

ENVIRONMENTAL FACTORS POTENTIALLY AFFECTED

The environmental factors checked below would be potentially affected by this project, involving at least one impact that is a "Potentially Significant Impact" as indicated by the checklist on the following pages.

 

Land Use and Planning

 

Transportation/Circulation

 

Public Services

 

Population and Housing

X

Biological Resources

 

Utilities and Service Systems

 

Geological Problems

 

Energy and Mineral Resources

 

Aesthetics

X

Water

 

Hazards

 

Cultural Resources

 

Air Quality

 

Noise

 

Recreation

   

Mandatory Findings of Significance

 

DETERMINATION

On the basis of this initial evaluation:

I find that the proposed project COULD NOT have a significant effect on the

 

environment, and a NEGATIVE DECLARATION will be prepared.

 

I find that although the proposed project could have a significant effect on the environment, there will not be a significant effect in this case because the mitigation measures described on an attached sheet have been added to the project. A

 

NEGATIVE DECLARATION will be prepared.

X

I find that the proposed project MAY have a significant effect on the environment,

 

and an ENVIRONMENTAL IMPACT REPORT is required.

 

I find that the proposed project MAY have a significant effect(s) on the environment, but at least one effect 1) has been adequately analyzed in an earlier document pursuant to applicable legal standards, and 2) has been addressed by mitigation measures based on the earlier analysis as described on attached sheets, if the effect is a "potentially significant impact" or "potentially significant unless mitigated." An ENVIRONMENTAL IMPACT REPORT is required, but it must analyze only the

 

effects that remain to be addressed.

 

I find that although the proposed project could have a significant effect on the environment, there WILL NOT be a significant effect in this case because all potentially significant effects (a) have been analyzed adequately in an earlier EIR pursuant to applicable standards and (b) have been avoided or mitigated pursuant to that earlier EIR, including revisions or mitigation measures that are imposed upon the proposed project.

 
   

 

Natalie Walsh, Program Manager
Analysis Branch
Energy Division
California Public Utilities Commission

 

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