SVP Homestead Substation Rebuild Project
COMMENTS AND COMMENT RESPONSES
February 2023 1 MND/Initial Study
COMMENTS AND COMMENT RESPONSES
This document presents responses to the comments received during the public review period for the Mitigated Negative Declaration. SVP received three public comments from the various State agencies, tribes, and the public that were notified of the intent to adopt the Mitigated Negative Declaration.
Table 1 lists the persons and agencies that submitted comments on the Proposed MND. The individual comments are numbered, and responses immediately follow the comments. No revisions were made to the MND and supporting Initial Study based on the comments.
Table 1. Comments Received on the Proposed Mitigated Negative Declaration Commenter Date of Comment Comment Set
Santa Clara Valley Water District 12/28/2022 A1
Kinson Tam 12/07/2022 B1
Kinson Tam 12/15/2023 B2
Comment Set A1 – Santa Clara Valley Water District
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Responses to Comment Set A1 – Santa Clara Valley Water District A1-1 The commenter for SCVWD notes that project construction should be consistent with Valley Water guidelines and standards for land use near streams. The commenter notes various types of elements to consider, such as setbacks, enhancement for trails, and flood protection.
SVP is aware of the SCVWD guidelines and standards. The substation rebuild would occur within the existing fenced property and, while near Saratoga Creek, is at low risk of flooding.
No part of the project would extend into SCVWD-managed land adjacent to the creek, which is an unpaved access road outside of the north fence line of the project. The creek -side area is fenced and not available for public access. The substation project is set back from the existing creek top of bank. The proposed concrete bloc k wall around the substation would prevent direct runoff to the creek. Site drainage would be to an existing storm sewer. During final design, it would be determined if on-site detention of stormwater is needed.
A1-2 The commenter notes that development is subject to stormwater quality requirements, and the project should meet all State standards.
A Stormwater Pollution Prevention Plan (SWPPP) would be implemented during construction to ensure that sediment or silt-laden water does not migrate offsite and enter the creek. The final project would include paving of the existing compact rock surface o f the property, reducing the potential for erosion of soil/silt that otherwise might enter the stormwater system and Saratoga Creek. The project would meet all standards applicable to stormwater management during construction and subsequent operation.
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Comment Set B1 – Kinson Tam (12/7)
Responses to Comment Set B1 – Kinson Tam (12/7)
Mr. Kinson Tam owns/manages the Homestead Road Apartments, the rear of which faces the south side of the Homestead Substation site. He communicated with SVP during the IS/MND comment period, requesting a meeting and providing two written comments. Comment B1 is a December 7, 2022, email requesting a meeting and providing two comments.
B1-1 The commenter asks what is the setback from the property line of the concrete block wall proposed to surround the substation site?
Per the City of Santa Clara Planning Department, no setback is required for a fence or wall around the site. Typically, SVP constructs walls around its facilities at or near the property line. The question of setbacks also is addressed in responses B2-2, B2-3, B2-7 and B2-8 below.
B1-2 The commenter requests dimension for the proposed layout, including dimensions and elevations.
See response B2-7.
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Comment Set B2 – Kinson Tam (12/15)
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Responses to Comment Set B2 – Kinson Tam (12/12)
Comment B2 provides detailed comments provided by Mr. Tam on December 15, 2022, subsequent to meeting with SVP. He thinks the proposed substation upgrade will have a negative impact on his tenants and his property value.
B2-1 The commenter believes polychlorinated biphenyls (PCB) may be present in the soil at the substation and would be disturbed during and after excavation, causing them to become air- borne. The commenter thinks the potential presence of PCB contamination at the substation must be explored and documented during the design stage, and before construction.
PCBs were widely used in the past, including in the electric industry. In the past, PCB oil was commonly used in transformers. Transformers on site today have less than 5 parts per million (ppm) of PCB content in the cooling oil, which is the industry des ignation for a non -PCB content. A typical action undertaken by SVP during project design is to take soil samples and test for various hazardous materials. This will inform SVP as to what precautions and special handling, if any, might be required for soils that are to be disturbed during construction. This will ensure that PCB contamination or other hazardous contamination is identified, if present, and properly handled so as to not become mobilized and migrate offsite. Any contaminated soil would be handled and disposed of in accordance with federal and state regulations.
B2-2 The commenter thinks the IS/MND fails to present the visual impact of the height of new structures on the surrounding community and should include information on the height of structures and a plan view for consideration by the community. The commente r thinks that perspective views from four directions should be included along with photo mock-ups.
Views of the substation from publicly accessible areas are limited. The substation is an interior property surrounded by residential, commercial, and park land uses. It does not front on a public street. See IS/MND Figure 4.1 Homestead Substation Location . A plan view of the substation expansion is provided in IS/MND Figure 4.3 Homestead Substation Rebuild Layout.
Final design will determine exact locations and dimensions. The image below in Figure B2 -A for SVP’s Walsh Substation illustrates the appearance of a concrete masonry unit (CMU) block wall with electrical equipment beyond. Switch gear and control enclosures and transformers are screened by the wall. The exact configuration and positioning of steel structures at the Homestead site will be determined in final design.
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Figure B2-A: Walsh Substation view of concrete block wall with substation beyond.
The photo below (Figure B2-B) shows the existing substation as viewed from the north, with the Homestead Road Apartments in the background. This existing substation transformer and ancillary equipment shown in the figure would be replaced by three transf ormers with new ancillary equipment. These would be somewhat similar in appearance to the existing unit.
Two units would be located to the west (right in the photo) of the existing unit. The third new unit would replace the current unit at its current lo cation. The wood poles to the right in the background and other poles on the south side of the site would be removed and replaced by poles on the north side, farther from the apartments and near where the photo was taken.
Overall, the new site configuratio n would be as shown in IS/MND Figure 4.3. The vegetation in the background of Figure B2 -B (between the substation and the apartments) would be replaced by the concrete block wall, which would screen lower elements of the substation from view. Other views of the existing substation from different angles show similar conditions: a largely barren site with the existing enclosure and steel within the site.
Figure B2-B: View of existing substation looking south toward Homestead Road Apartments.
Views of the site from public locations are limited, the proposed wall would visually screen most of the site equipment and structures from view, and the site is already “industrial” in nature; therefore, visual impacts would be less than significant. Howe ver, SVP will enter into discussions with the apartment building management regarding the possibility of planting vegetation between the wall and the apartment parking area. Any vegetation would need to be of a type that would not damage the wall directly or by its roots.
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B2-3 The commenter believes that the proposed wall will have a profound visual impact and that trees should be used to enhance the aesthetics of the area and the proposed wall.
See Response B2-2. SVP now typically installs concrete block walls around its substation facil- ities for security/safety and to partially screen views of equipment from offsite. At the prop- erty line between the Homestead Substation and the adjacent apartment complex is a chain link fence with vegetation growing intermittently along the fence line. Some vegetation is within SVP’s property, and some is on private property. SVP plans to replace th e fence with a nominal 13 -foot-high wall and to remove the ve getation within the substation property.
Vegetation on the apartment property, situated between apartment parking and the fence, would remain. To the extent that it overhangs or interferes with the wall or substation, it may be trimmed in consultation with the apartment complex management. A large oak has grown on the existing chain link fence near the driveway gate. The tree appears to be on both sub- station and apartment property. SVP will consult with an arborist to determine if the tree can be salvaged and if the wall in this area needs to be set back or modified to accommodate the tree.
Figure B2 -C is a view looking northwest toward the substation from the apartment’s rear parking area, showing a portion of the fence line with the substation beyond. The tall wooden pole in this view would be removed as part of the project. The chain lin k fence would be replaced with a 13 -foot-high wall. The tall vegetation in this view is on SVP property and would be removed. The shorter vegetation is on private property.
Figure B2-C: View northwest from apartment complex’s rear parking area adjacent to substation site looking northwest, near end of driveway from Homestead Road.
Figure B2-D looking west shows the area between the apartment buildings and the substation property. The tall wood poles in this view would be removed as part of the project. Residents with windows on the second story would have views over the wall.
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Figure B2-D: View looking west at apartment complex’s rear parking area adjacent to substation site.
Final site plans and layout have not been developed for the Homestead Rebuild project.
IS/MND Figure 4.3 Homestead Substation Rebuild Layout (reproduced below) shows the anticipated layout and location of equipment. The existing substation structures are located at approximately the site of what would be the eastern -most of the new transformers. The location of the gate shown in Figure B2 -C above is indicated at the lower right of the drawing. The apartment property extends approximately one -third of the distance along the substation property to the left of the gate
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The wall would provide a uniform visual form screening much of the substation’s equipment from views at ground level. A few second story apartments have existing views of the substation, as shown in Figure B2 -D above, a situation that would remain.
The removal of the existing wood poles would improve the view. Structural steel framing that would support the transformers, and lines to them, would be visible above the wall.
The new steel structures would be similar in nature to the existing substation visua l effect.
B2-4 The commenter notes that the IS/MND identifies the driveway adjacent to the apartment complex as a secondary entrance to the substation site and thinks this is not acceptable.
It is anticipated that the primary construction access to the substation site will be via an existing driveway from Kiely Boulevard on the east side of the site, which is not near the apartment complex. Primary operations access would be via the driveway from Homestead Road, located between the apartment complex and the adjacent City fire station. This driveway is currently used by apartment residents and visitors, vendors, the fire department, and SVP. SVP plans to use the Kiley Blvd driveway for construc tion access; however, circumstances may occasionally dictate use of the secondary access route from Homestead Road during construction. Use of the secondary access is permitted and such use does not constitute an undue hardship or environmental impact. The existing driveway has some cracking and small potholes. It is anticipated that the driveway will be rebuilt or resurfaced by SVP to accommodate any new or replacement distribution substructures, any drainage changes, and any potential damage from SVP construction activities.
B2-5 The commenter notes that IS/MND page 5.13-4 indicates equipment noise by individual type of equipment. He inquires regard total noise is all equipment is used at the same time.
The rear of the apartment complex is 50 feet from the substation property line with only a few second story windows facing the substation site. Most construction would occur at a greater distance than 50 feet, i.e., within the substation property. The proposed 13-foot-high concrete block wall would be installed around the substation. The sequence of construction is determined by the construction contractor. Concrete masonry unit (CMU) walls are typically installed early in the project schedule, but this varies with the project. The timing of the con- struction of the wall is as yet unknown. Noise from multiple sources is not additive. The decibel scale used in describing noise levels is logarithmic and results in only slight increases in perceived noise when multiple noise sources are combined. Construction wo uld occur within the times allowed under the City’s noise ordinance. Not all equipment listed would be used at the same time, nor would they be used for extended periods. Actual pieces of equip- ment used would vary depending on the construction stage, e.g., site grading/preparation; equipment/structure delivery; equipment/structure installation; etc. As noted in the IS/MND, the maximum intermittent noise levels from a construction work spread would typically range from 84 to 90 dBA at 50 feet. (This does not consider the attenuating effect of the wall.) After construction, ambient noise levels would not exceed local requirements and would be similar to current noise levels.
B2-6 The commenter suggests that ground vibration during construction may cause damage and that the project should bear the responsibility for monitoring damage and providing reim - bursement.
Groundborne vibration attenuates quickly with distance, and the effects would be temporary and localized. Annoyance from vibration may occur when the vibration exceeds the threshold SVP Homestead Substation Rebuild Project
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of perception. However, the threshold of perception occurs at a much lower level of ground displacement than the level that would be likely to lead to structural damage. Most construction-related vibration would not be capable of causing structural damage, with the exception of impact activities such as pile driving. No pile driving would occur with the project.
The peak particle velocity (PPV) is defined as the maximum instantaneous peak displacement of a vibration signal in inches per second (in/sec). The PPV is most frequently used to describe vibration impacts to buildings. As an example of the potential effect, a vibratory roller may cause approximately 0.21 in/sec PPV at a distance of 25 feet from the source. Adjusting for propagation over additional distance, the level at a receiver 50 feet away would be less than
0.1 in/sec PPV. Vibration at this level would not exceed the criterion of 0.12 in/sec that indicates a potential for damage to the most susceptible types of buildings, based on impact assessment procedures established by the Federal Transit Administration (in Section 7.2 of FTA, 2018).1
As noted on page 5 -82 of the IS/MND, “The impact from construction‐related groundborne vibration would be short‐term and confined to only the immediate area around activities (within about 25 feet). Except of wall construction and paving, most work within the substa- tion site would be more than 25 feet from residences.” The apartment complex is 50 feet from the substation fence line, with the intervening space mostly paved for parking and a driveway. Construction-related vibration at the apartment complex would not occur at levels that could cause any structural damage. Accordingly, the analysis concludes any adverse effects from groundborne vibration would not lead to a potentially significant impact, and the vibration levels caused by the project would not be excessive.
B2-7 The commenter thinks that a site plan, elevation, set back and landscaping/screening draw - ings are needed for review of negative impacts.
See Responses B2 -2, B2 -3, and B2 -8. Final engineering will determine final positioning of project elements and their heights.
B2-8 The commenter notes that the 13-foot wall is higher than the apartment’s balconies and win- dows and asks what is the wall’s setback from the property line. He thinks that landscaping is required and, absent a landscaping drawing, the magnitude of negative impact is hard to determine.
See Responses B2-2 and B2-3, which address the wall and setback relative to the apartment complex. The proposed wall would be at the property line. At ground level, the rear of the apartment complex provides parking along the existing SVP substation fence and in carports beneath the apartment building’s second story (see Figures B2-C and B2-D above). There are only a few windows overlooking the substation, and no balconies. Therefore, few apartments would have views of the wall or substation. The wall would replace an existing chain-link fence and intermittent vegetation (see Response B2-3).
B2-9 The commenter believes that lighting near the gate at the end of the driveway adjacent to the apartment complex needs to be lower than 4 feet. The commenter believes SVP owns the property with a Kiely Blvd commercial building at the east side of subst ation and there is no
1 FTA (Federal Transit Administration). 2018. Transit Noise and Vibration Impact Assessment Manual (Report 0123). September. [Online]: https://www.transit.dot.gov/sites/fta.dot.gov/files/docs/research -innovation/118131/transit-noise-and-vibration- impact-assessment-manual-fta-report-no-0123_0.pdf.
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need for a tall light post at the gate. He also thinks lights must be below eye level, with motion sensors, less than 40 watts, and pointing away from the apartment building.
SVP owns the driveway from Kiely Blvd to the substation that will be the primary access route to the site during construction. There is a use agreement between the commercial property owner and the City regarding the parking area and driveway, which is loc ated between the commercial buildings and the nearby creek. SVP does not own the property with the commercial building. The commercial building currently has night lighting on the rear of the building that illuminates a part of the substation site as well as the rear of the building. The existing substation has an overhead light on a light pole adjacent to the substation equipment.
The public park north of the substation site has extensive night lighting. The parking area at the rear of the apartment building also has night lighting. Overall, the substation and vicinity, being in a highly urbanized area, has extensive lighting for safety.
As part of the substation rebuild, SVP proposes to install photo -cell controlled LED security lighting on the interior the perimeter wall, at gates, and on certain steel structures. Fixtures would be downward focused to minimize light spillage offsite. At each gate, a 2-head fixture is proposed to be installed, with one head illumining the area around the exterior of the gate.
SVP is presently evaluating its substation perimeter security lighting methods. LED lighting is different from the existing lighting at Homestead Substation. In the past, SVP has done a lighting simulation for new substation with CMU walls at the perimeter and found that there was very little light spillage outside the walls. SVP may make further adjustments based on changes in lighting technology. SVP will consult with the apartment owner regarding lighting fixtures at the south gate to the site.
B2-10 The commenter thinks that the site plan must preserve existing vegetation and add landscap- ing to shield new structures.
The site currently supports limited vegetation along the south fence line and in the northwest corner of the site. This vegetation would be removed to accommodate project construction and ensure that vegetation does not interfere with the substation’s safe operation. If the City determines there is a need to replace any removed vegetation it would be at locations elsewhere in the City and would be coordinated with the City arborist. Most of the substation components would be less than 13 feet high and sh ielded from view by the proposed wall.
Existing tall wooden poles and their conductors near the apartment complex would be removed and replaced by poles and conductors on the north side of the site, farther from the apartments. Steel structures supporting conductors and other electrical equipment requiring ground clearance would be higher that the wall. (See illustration B2-A in Response B2-2). The substation would not be visible from nearby public locations except on its north side, were the substation abuts Saratoga Creek and is separated from the park by the creek and exten- sive vegetation located outside of the substation site. The proposed wall will adequately screen the substation from external views. As noted in Responses B2 -2 and B2 -3, SVP will work with the apartment owners to determine if appropriate vegetation can be ins talled or retained to further reduce the visibility of the project.
B2-11 The commenter reserves the right to add to his list of comments.
This comment is noted; however, the formal comment period has passed. However, the City anticipates conducting outreach with adjacent property owners during the design phase to explore potential issues and concerns with the intention of reaching mutually a greeable understandings.
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B2-12 The commenter notes that some transmission lines passing out of the substation property are near the apartment building and believes this is a fire hazard and the lines should be moved farther away.
The line in question is a 12 kV distribution line and is not part of the Homestead Substation Rebuild. Whether to move the line is a separate matter between SVP and the apartment owners and is not part of the proposed project. SVP and the apartment owners may separately discuss changing the routing of the line.
B2-13 The commenter request that the City put in a new driveway after construction and thinks that the existing driveway has been damaged by expansion of the adjacent fire station and by ingress and egress at the substation.
SVP intends to use the Kiely Blvd driveway as its primary access but may use the Homestead Road access driveway on an as needed basis. Past construction activity at the fire station on Homestead Road is unrelated to the current proposed substation project . SVP periodically accesses the substation site using the Homestead driveway, which is a permitted right. It is assumed that the most frequent use of the driveway is by residents and delivery and service trucks and vehicles/vans coming to the apartment complex. The proportion of wear and tear on the driveway attributable to various users is unknown. There is reportedly some cracking of the driveway surface near the gate to the substation. As noted in Response B2 -4, it is anticipated that the driveway will b e rebuilt or resurfaced by SVP to accommodate any new or replacement distribution substructures, any drainage changes, and any potential damage from SVP construction activities.