Ascent Environmental Checklist
City of Sunnyvale
De Guigne Drive Residential Project Environmental Review 4-69 d) Have sufficient water supplies available to serve the project from existing entitlements and resources, or are new or expanded entitlements needed? As described in Impacts 3.11.1.1 and 3.11.1.3 in the LUTE Draft EIR, cumulative development in Sunnyvale would result in a net additional water demand of 2,274 acre-feet per year. The LUTE WSA identified that there is adequate water supply available to meet buildout of the City in year 2035 under normal, single-dry, and multiple-dry years. This impact was identified as less than significant under project and cumulative conditions.
Total water demand for the proposed project is estimated to be 14,667,432 gallons per year, which is equivalent to approximately 45 acre-feet per year (FirstCarbon Solutions 2025a). The proposed project is consistent with LUTE land use designations and development intensities that were utilized in the LUTE WSA. As noted above, the City adopted a 2020 UWMP (City of Sunnyvale 2021b) that is not reflected in the LUTE WSA, but both documents conclude that there is adequate water supply for growth anticipated under the LUTE under normal and drought conditions.
Therefore, the 2020 UWMP does not substantially change the water supply impact analysis in the LUTE EIR. The project provides housing that is part of the growth anticipated under the LUTE and the 2020 UWMP. Thus, the proposed project would have no (1) peculiar impacts, (2) impacts not analyzed in the LUTE EIR, or (3) significant off - site impacts and cumulative impacts not discussed in the LUTE EIR, and (4) there is no substantial new information indicating that an impact would be more severe than discussed in the LUTE EIR. The findings of the certified LUTE EIR pertaining to water supplies remain valid and no further analysis is required. e) Result in a determination by the wastewater treatment provider that serves or may serve the project that it has adequate capacity to serve the project’s projected demand, in addition to the provider’s existing commitments? Impact 3.11.2 in the LUTE Draft EIR evaluated whether implementation of the LUTE would require the construction of new or expanded wastewater infrastructure and treatment facilities. The analysis identified that the City’s wastewater collection system has the capacity to convey sewage and industrial wastes generated when Sunnyvale is fully developed in accordance with the LUTE’s development potential (with an approximately 55.7 mgd collection capacity). The City’s Wastewater Collection System Master Plan and Capital Improvement Program identify the conveyance improvements projects including improvements to lift stations, pump stations 1 and 2, and pipeline improvements. Wastewater treatment capacity is addressed under item a) above. This impact was identified as less than significant under project and cumulative (Impact 3.11.2.3) conditions.
The project is consistent with LUTE land use designations and development intensities that were utilized in the LUTE EIR wastewater impact analysis. As described under item a) above, the existing WPCP has sufficient capacity to treat the net increase in peak wet weather wastewater flows generated by the proposed project. The approximately 0.0573 MGD net increase in wastewater flows attributable to the proposed project would represent 0.3 percent of the WPCP’s excess current capacity of approximately 17.5 MGD and 0.2 percent of the WPCP’s design capacity of 29.5 MGD. The project would have no (1) peculiar impacts, (2) impacts not analyzed in the LUTE EIR, or (3) significant off - site impacts and cumulative impacts not discussed in the LUTE EIR, and (4) there is no substantial new information indicating that an impact would be more severe than discussed in the LUTE EIR. The findings of the certified LUTE EIR pertaining to wastewater treatment capacity remain valid and no further analysis is required. f) Generate solid waste in excess of state or local standards, or in excess of the capacity of local infrastructure, or otherwise impair the attainment of solid waste reduction goals? As identified in Impacts 3.11.3.1 and 3.11.3.3 of the LUTE Draft EIR, Sunnyvale would generate approximately 54,020 tons annually of solid waste at buildout. The LUTE Draft EIR identified that there is available combined remaining capacity of 32.8 million tons at three local landfills. This includes the Waste Management -owned Guadalupe Landfill, which has 11,055,000 tons of remaining capacity. By 2035, approximately 412,979 pounds (206.49 tons) of solid waste would be generated per day in Sunnyvale (including the LUTE, Peery Park Specific Plan, and Lawrence Station Area Plan). This amount of waste represents approximately 12.6 percent of the permitted daily throughput of the Kirby Canyon Landfill or 5.9 percent of the throughput at the Monterey Peninsula Landfill. This impact was identified as less than significant under project and cumulative conditions.
Attachment 6
Environmental Checklist Ascent
City of Sunnyvale
4-70 De Guigne Drive Residential Project Environmental Review Using CalRecycle’s Estimated Solid Waste Generation Rates for office building types, the existing site structures (six, two-story buildings totaling approximately 381,000 sf) are estimated to generate approximately 417 tons of solid waste per year (CalRecycle 2026). Construction of the project is estimated to generate approximately 34,514 tons of demolition debris and the export of 10,000 cubic yards of material during grading activities. Once operational, the proposed project is estimated to generate approximately 271 tons of solid waste per year (approximately 146 annual tons less than existing operations) (FirstCarbon Solutions 2025a). The proposed project’s contribution to solid waste generation were factored in the LUTE EIR given that the project’s land use and intensities are consistent with the LUTE. Therefore, the project would have no (1) peculiar impacts, (2) impacts not analyzed in the LUTE EIR, or (3) significant off-site impacts and cumulative impacts not discussed in the LUTE EIR, and (4) there is no substantial new information indicating that an impact would be more severe than discussed in the LUTE EIR. The findings of the certified LUTE EIR pertaining to landfill capacity remain valid and no further analysis is required. g) Comply with federal, state, and local statutes and regulations related to solid waste? As discussed in Impact 3.11.3.2 of the LUTE Draft EIR, Sunnyvale had a waste diversion rate of 66 percent as of 2011, and under current methods for tracking progress with AB 939, the per capita disposal rates are less than the targets.
The City has developed its Zero Waste Strategic Plan (City of Sunnyvale 2013), intended to identify the new policies, programs, and infrastructure that will enable the City to reach its zero waste goals of 75 percent diversion by 2020 and 90 percent diversion by 2030. Additionally, the City has committed to the waste reduction programs, plans, and policies that would apply to new development. Construction of subsequent projects under the LUTE that would result in demolition or renovation of existing structures would generate solid waste, and the City requires the recycling and reuse of materials to reduce landfill disposal. Therefore, implementation of the L UTE would not conflict with a federal, state, or local statute or regulation related to solid waste disposal. This impact would be less than significant under project conditions and less than cumulatively considerable under cumulative conditions (Impact 3.11.3.3).
As discussed under item f), the proposed project would not generate solid waste in excess of what was evaluated in the LUTE EIR. In addition, the proposed project is required to comply with City solid waste reduction standards.
Therefore, with the application of uniformly applied development standards and policies, the project would have no (1) peculiar impacts, (2) impacts not analyzed in the LUTE EIR, or (3) significant off-site impacts and cumulative impacts not discussed in the LUTE EIR, and (4) there is no substantial new information indicating that an impact would be more severe than discussed in the LUTE EIR. The findings of the certified LUTE EIR pertaining to solid waste remain valid and no further analysis is required.
Mitigation Measures
No mitigation measures were identified for the certified LUTE EIR regarding utilities, nor are any additional mitigation measures required for the project.
Conclusion
No new circumstances or project changes have occurred nor has any new information been identified requiring new analysis or verification. Therefore, with the application of uniformly applied development standards and policies, the proposed project would have no (1) peculiar impacts, (2) impacts not analyzed in the LUTE EIR, or (3) significant off - site impacts and cumulative impacts not discussed in the LUTE EIR, and (4) there is no substantial new information indicating that an impact would be more severe than discussed in the LUTE EIR. The conclusions of the LUTE EIR pertaining to utilities and service systems remain valid and no further analysis is required.
Attachment 6
Ascent Environmental Checklist
City of Sunnyvale
De Guigne Drive Residential Project Environmental Review 4-71
4.20 WILDFIRE
Environmental Issue Area
Where Impact
Was Analyzed in
LUTE Draft and
Final EIR
Any
Peculiar
Impact?
Any Impact
Not
Analyzed as
Significant
Effect in
LUTE EIR?
Any
Significant
Off-Site or
Cumulative
Impact Not
Analyzed?
Any Adverse
Impact More
Severe Based
on Substantial
New
Information?
Do EIR Mitigation
Measures or Uniformly
Applied Development
Policies or Standards
Address/Resolve
Impacts?
20. Wildfire.
a) Substantially impair an adopted
emergency response plan or
emergency evacuation plan?
Draft EIR Setting
pp. 3.3-1 to 3.3-9
Impacts 3.3.5 and
3.3.6 No No No No NA, impacts would
remain less than
significant
b) Due to slope, prevailing winds, and
other factors, exacerbate wildfire risks,
and thereby expose project occupants
to, pollutant concentrations from a
wildfire or the uncontrolled spread of
a wildfire?
Not addressed,
criterion was not
part of CEQA
Appendix G when
Final EIR was
certified
NA NA NA NA NA, no impact would
occur
c) Require the installation or
maintenance of associated
infrastructure (such as roads, fuel
breaks, emergency water sources,
power lines, or other utilities) that may
exacerbate fire risk or that may result
in temporary or ongoing impacts to
the environment?
Not addressed,
criterion was not
part of CEQA
Appendix G when
Final EIR was
certified
NA NA NA NA NA, no impact would
occur.
e) Expose people or structures to
significant risks, including downslope
or downstream flooding or landslides,
as a result of runoff, post-fire slope
instability, or drainage changes?
Draft EIR Setting:
p. 3.3-15
No impact
No No No No NA, no impact would
occur.
4.20.1 Discussion
In the LUTE Draft EIR, wildfire was analyzed in Section 3.3, “Hazards and Human Health.” As described on page 3.3-15 of the LUTE Draft EIR, No Fire Hazard Severity Zones, state responsibility areas, Very High Fire Hazard Severity Zones, or local responsibility areas are located in or adjacent to Sunnyvale. Given that the C ity is urbanized and not adjacent to large areas of open space or agricultural lands that are subject to wildland fire hazards, no impacts associated with exposure to wildland fire would occur.
a) Substantially impair an adopted emergency response plan or emergency evacuation plan?
Refer to Section 4.9, Hazards and Hazardous Materials, item g).
Attachment 6
Environmental Checklist Ascent
City of Sunnyvale
4-72 De Guigne Drive Residential Project Environmental Review b) Due to slope, prevailing winds, and other factors, exacerbate wildfire risks, and thereby expose project occupants to, pollutant concentrations from a wildfire or the uncontrolled spread of a wildfire?
As described on page 3.3-15 of the LUTE Draft EIR, no Fire Hazard Severity Zones, state responsibility areas, Very High Fire Hazard Severity Zones, or local responsibility areas are located in or adjacent to Sunnyvale. Given that the City is urbanized and not adjacent to large areas of open space or agricultural lands that are subject to wildland fire hazards, no impacts associated with exposure to wildland fire would occur.
The project site is surrounded by urbanized uses and would not be subject to wildland fire risks. No changes to the risks from wildfires have occurred since approval of the LUTE. Therefore, no impact would occur. c) Require the installation or maintenance of associated infrastructure (such as roads, fuel breaks, emergency water sources, power lines, or other utilities) that may exacerbate fire risk or that may result in temporary or ongoing impacts to the environment?
Refer to item b) above. In addition, as described in item a) in Section 4.15, Public Services, the proposed project would be required to meet all City requirements regarding fire protection and public safety, including fire access. The project does not propose any infrastructure that would exacerbate fire risk, such as overhead power lines. Therefore, no impact would occur.
d) Expose people or structures to significant risks, including downslope or downstream flooding or landslides, as a result of runoff, post-fire slope instability, or drainage changes?
Refer to Section 4.9, Hazards and Hazardous Materials, item h).
Mitigation Measures
No significant wildfire impacts were identified in the LUTE EIR, and no additional mitigation measures are required for this project.
Conclusion
With the application of uniformly applied development standards and policies, the project would have no (1) peculiar impacts, (2) significant off-site impacts and cumulative impacts not discussed in the LUTE EIR, and (3) there is no substantial new information indicating that an impact would be more severe than discussed in the LUTE EIR .
Therefore, the conclusions of the LUTE EIR related to impacts from wildfire remain valid and the project would not require additional CEQA analysis.
Attachment 6
Ascent Environmental Checklist
City of Sunnyvale
De Guigne Drive Residential Project Environmental Review 4-73
4.21 MANDATORY FINDINGS OF SIGNIFICANCE
Environmental Issue Area
Where Impact
Was Analyzed in
LUTE Draft and
Final EIR
Any
Peculiar
Impact?
Any Impact
Not Analyzed
as Significant
Effect in LUTE
EIR?
Any
Significant
Off-Site or
Cumulative
Impact Not
Analyzed?
Any Adverse
Impact More
Severe Based on
Substantial New
Information?
Do EIR Mitigation
Measures or Uniformly
Applied Development
Policies or Standards
Address/Resolve
Impacts?
21. Mandatory Findings of Significance.
a) Does the project have the potential
to degrade the quality of the
environment, substantially reduce
the habitat of a fish or wildlife
species, cause a fish or wildlife
population to drop below self-
sustaining levels, threaten to
eliminate a plant or animal
community, substantially reduce the
number or restrict the range of an
endangered, rare, or threatened
species, or eliminate important
examples of the major periods of
California history or prehistory?
Draft EIR
Sections 3.9,
Biological
Resources, and
3.10, Cultural
Resources
No No No No Yes, but impact
remains significant and
unavoidable
b) Does the project have impacts that
are individually limited, but
cumulatively considerable?
(“Cumulatively considerable” means
that the incremental effects of a
project are considerable when
viewed in connection with the
effects of past projects, the effects
of other current projects, and the
effects of probable future projects.)
Draft EIR
Sections 3.1
through 3.13
and Sections 4.1
through 4.4
No No No No Yes, but impact
remains significant and
unavoidable
c) Does the project have
environmental effects which will
cause substantial adverse effects on
human beings, either directly or
indirectly?
Draft EIR
Sections 3.3,
Hazards and
Human Health,
3.5, Air Quality,
and 3.6, Noise
No No No No Yes, but impact
remains significant and
unavoidable
4.21.1 Conclusion
The project site is developed and would not degrade the quality of the environment for biological resources nor eliminate examples of California history or prehistory as discussed in Sections 4 .4 and 4.5. While the LUTE EIR identified significant cumulative impacts, the project’s contribution to air quality, biological resources, cultural resources, aesthetic, noise, and transportation impacts (and other resource impacts) would not be cumulatively considerable as analyzed throughout this checklist. Impacts to human beings are associated with air quality, hazards and hazardous materials, geology and soils, noise, traffic safety, and wildfires. Through the implementation of applicable mitigation measures and the application of uniformly applied development standards and policies for air quality and noise, the project would not result in a substantial adverse effect on human beings.
Since the LUTE Final EIR was certified, regulatory changes have occurred, as noted in the above checklist. However, these regulatory changes would not affect the analysis or conclusions in the LUTE EIR. Regarding the above-listed Attachment 6
Environmental Checklist Ascent
City of Sunnyvale
4-74 De Guigne Drive Residential Project Environmental Review mandatory findings of significance, with the implementation of applicable mitigation measures and the application of uniformly applied development standards and policies, the proposed project would have no (1) peculiar impacts, (2) impacts not analyzed in the LUTE EIR, or (3) significant off-site impacts and cumulative impacts not discussed in the LUTE EIR, and (4) there is no substantial new information indicating that an impact would be more severe than discussed in the LUTE EIR.
All applicable mitigation measures in the LUTE EIR would continue to be implemented with the proposed project.
Therefore, no new significant impacts would occur with implementation of the proposed project.
Attachment 6
City of Sunnyvale
De Guigne Drive Residential Project Environmental Review 1 5 LIST OF PREPARERS
Ascent
Pat Angell ............................................................................................................................................................................. Principal-in-Charge Kirsten Burrowes ...................................................................................................................................................................... Project Manager Nicole Greenfield ........................................................................................................................................... Senior Environmental Planner Nicole Wang .................................................................................................................................................................. Environmental Planner Lizzy Celentano ...................................................................................................................................................................... Cultural Specialist Julia Wilson ................................................................................................... Senior Air Quality, Greenhouse Gases, Energy Specialist Matt Brehmer ............................................................................................................. Air Quality, Greenhouse Gases, Energy Specialist Dimitri Antoniou ........................................................................................................................................................... Senior Noise Specialist Kenneth Nguyen ........................................................................................................................................................................ Noise Specialist Gayiety Lane ....................................................................................................................................................................... Publishing Specialist Riley Smith ........................................................................................................................................................................... Publishing Specialist Brian Perry .............................................................................................................................................................................. Graphics Specialist Attachment 6
List of Preparers Ascent
City of Sunnyvale
5-2 De Guigne Drive Residential Project Environmental Review This page is intentionally left blank.
Attachment 6
City of Sunnyvale
De Guigne Drive Residential Project Environmental Review 6-1 6 REFERENCES
AEI Consultants. 2024a (March). Phase I Environmental Site Assessment for 490, 510 De Guigne Drive; 920, 935, 940, 945, 960 Stewart Drive. Prepared for Hines. Prepared by AEI Consultants, Walnut Creek, CA. ———. 2024 b (August). Phase I Environmental Site Assessment for 920-950 De Guigne Drive. Prepared for Hines.
Prepared by AEI Consultants, Walnut Creek, CA.
———. 2024 c (November). Limited Phase II Subsurface Investigation Report for 510 De Guigne Drive & 920, 930, 935, 945, and 950 Steward Drive. Prepared for TC III SPP North, LLC. Prepared by AEI Consultants, Walnut Creek, CA.
———. 2025a (August). Additional Soil Vapor Investigation Report for 510 De Guigne Drive. Prepared for TC III SPP North, LLC. Prepared by AEI Consultants, Walnut Creek, CA. ———. 2025b (December). Soil Management Plan. Prepared for TC III SPP North, LLC. Prepared by AEI Consultants, Walnut Creek, CA.
Atlas Tree Service, Inc. 2025 (January). Pre-Development Assessment Arborist Report.
Basin Research Associates, Inc. 2025 (April). Archaeological Due Diligence Literature Review for Redevelopment of 510 De Guigne Drive and Adjoining Project Parcels, City of Sunnyvale Santa Clara County (APN 205 -22-022 and APN 205-22-023). Prepared by Basin Research Associates, Inc., San Leandro, CA.
California Air Resources Board. 2023. California ambient air quality standards attainment maps. Available:
https://ww2.arb.ca.gov/resources/documents/maps-state-and-federal-area-designations. Accessed:
September 12, 2025.
California Historical Resources Information System. 2024 (December). NWIC File No.: 24-0892.
CalRecycle. 2026. Estimated Solid Waste Generation Rates. Available:
https://www2.calrecycle.ca.gov/wastecharacterization/general/rates. Accessed January 27, 2026.
CARB. See California Air Resources Board.
CBG. 2025 (April). Sewer Impact Analysis – 510 & 920 De Guigne Drive. Prepared for City of Sunnyvale. Prepared by CBG, San Ramon, CA.
City of Sunnyvale. 2013 (February). Zero Waste Strategic Plan: A Quantifiable Approach. Available:
https://www.sunnyvale.ca.gov/home/showpublisheddocument/2984/637822783379870000. Accessed September 10, 2025.
———. 2021a (October). Transportation Analysis Guidelines for Vehicle Miles Traveled and Local Transportation Analysis. Available:
https://www.sunnyvale.ca.gov/home/showpublisheddocument/3020/637822794490970000. Accessed August 26, 2025.
———. 2021b (June). 2020 Urban Water Management Plan. Prepared by HydroScience Engineers, Inc. Retrieved from:
https://www.sunnyvale.ca.gov/homes-streets-and-property/water-and-sewer/water. Accessed August 27, 2025.
———. n.d. Water Pollution Control Plant Master Plan. Retrieved from: https://www.sunnyvalecleanwater.com/water- pollution-control-master-plan. Accessed August 26, 2025.
EPA. See US Environmental Protection Agency.
FirstCarbon Solutions. 2025a (September). Air Quality, Greenhouse Gas Emissions, and Energy Technical Analysis for the 20-Acre Sunnyvale Project, City of Sunnyvale, California. Prepared for TC III SPP North. LLC. Prepared by FirstCarbon Solutions.
Attachment 6
References Ascent
City of Sunnyvale
6-2 De Guigne Drive Residential Project Environmental Review FirstCarbon Solutions. 2025b (September). Noise Impact Analysis Report. Prepared for TC III SPP North. LLC. Prepared by FirstCarbon Solutions.
Governor’s Office of Planning and Research. 2018 (December). Technical Advisory on Evaluating Transportation Impacts in CEQA. Available: https://lci.ca.gov/ceqa/docs/20190122-743_Technical_Advisory.pdf. Accessed September 10, 2025.
Madrone Ecological Consulting. 2024 (April). Biological Resources Assessment for the Sunnyvale Park Place Project.
Rockridge Geotechnical. 2024. Geotechnical Investigation Proposed Residential Development Sunnyvale Park Place De Guigne and Steward Drives Sunnyvale, California. Prepared by Rockridge Geotechnical, Emeryville, CA.
Prepared for TC III SPP North, LLC.
SWRCB 2025. Geotracker Database. Sunnyvale Park Place. Accessed September 21, 2025. Available:
https://geotracker.waterboards.ca.gov/profile_report.asp?global_id=T10000023282. Accessed September 12, 2025.
SWRCB. See State Water Resources Control Board.
TDM Specialists, Inc. 2025 (April). Sunnyvale Park Place Transportation Demand Management Plan (Trip Reduction Implementation Plan). Prepared by TDM, Specialists, Inc. Prepared for Tidewater.
US Environmental Protection Agency. 2025. Greenbook. Available: https://www.epa.gov/green-book. Accessed:
September 12, 2025.
Attachment 6