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HomeMy WebLinkAbout2016-06-28 City Council Agenda PacketMATERIALS RELATED TO AN ITEM ON THIS AGENDA SUBMITTED TO THE CITY COUNCIL AFTER DISTRIBUTION OF THE AGENDA PACKET ARE AVAILABLE FOR PUBLIC INSPECTION IN THE CITY CLERK’S OFFICE AT PALO ALTO CITY HALL, 250 HAMILTON AVE. DURING NORMAL BUSINESS HOURS. City Council REVISED June 28, 2016 Special Meeting Council Chambers 6:00 PM Agenda posted according to PAMC Section 2.04.070. Supporting materials are available in the Council Chambers on the Thursday 10 days preceding the meeting. PUBLIC COMMENT Members of the public may speak to agendized items; up to three minutes per speaker, to be determined by the presiding officer. If you wish to address the Council on any issue that is on this agenda, please complete a speaker request card located on the table at the entrance to the Council Chambers, and deliver it to the City Clerk prior to discussion of the item. You are not required to give your name on the speaker card in order to speak to the Council, but it is very helpful. TIME ESTIMATES Time estimates are provided as part of the Council's effort to manage its time at Council meetings. Listed times are estimates only and are subject to change at any time, including while the meeting is in progress. The Council reserves the right to use more or less time on any item, to change the order of items and/or to continue items to another meeting. Particular items may be heard before or after the time estimated on the agenda. This may occur in order to best manage the time at a meeting or to adapt to the participation of the public. To ensure participation in a particular item, we suggest arriving at the beginning of the meeting and remaining until the item is called. HEARINGS REQUIRED BY LAW Applicants and/or appellants may have up to ten minutes at the outset of the public discussion to make their remarks and up to three minutes for concluding remarks after other members of the public have spoken. Call to Order Agenda Changes, Additions and Deletions Oral Communications 6:00-6:15 PM Members of the public may speak to any item NOT on the agenda. Council reserves the right to limit the duration of Oral Communications period to 30 minutes. Action Items Include: Reports of Committees/Commissions, Ordinances and Resolutions, Public Hearings, Reports of Officials, Unfinished Business and Council Matters. 1.CONTINUED PUBLIC HEARING: to Hear Objections to the Levy of Proposed Assessments on the Palo Alto Downtown Business Improvement District; Adoption of a Resolution Confirming the Report of the Advisory Board and Levying Assessment for Fiscal Year 2017 on the Downtown Palo Alto Business Improvement District; and Possible Council Direction on Next Steps 1 MATERIALS RELATED TO AN ITEM ON THIS AGENDA SUBMITTED TO THE CITY COUNCIL AFTER DISTRIBUTION OF THE AGENDA PACKET ARE AVAILABLE FOR PUBLIC INSPECTION IN THE CITY CLERK’S OFFICE AT PALO ALTO CITY HALL, 250 HAMILTON AVE. DURING NORMAL BUSINESS HOURS. 2.Review of Recommendations From the Storm Drain Blue Ribbon Committee Regarding Future Storm Water Management Funding and Request for Council Direction on Whether to Proceed With a Proposition 218 Hearing and Property Owner Ballot-by-Mail to Approve Future Storm Water Management Rates (Continued From June 6, 2016) 6:15-7:15 PM 2A. PUBLIC HEARING: 567 Maybell Avenue [15PLN-00270]: Approval of Mitigated Negative Declaration and Tentative Tract Map with Lot Size Exceptions to Subdivide Four Parcels Totaling 2.47 Acres Into 16 Single-Family Lots, Ranging from 5,000 SF to 6,186 SF, and one Parcel for a Private Street. Environmental Assessment: Mitigated Negative Declaration. Zoning Districts: R-2 and RM-15 9 (CONTINUED FROM JUNE 20, 2016) 7:15-8:45 PM 3.CONTINUED PUBLIC HEARING: 1601 California Avenue [15PLN- 00500]: Request by The Board of Trustees of the Leland Stanford Junior University to Amend the Final Map for Tract Number 10281 Recorded January 2015 for the 1451-1601 California Avenue Development, Which Includes a Total of 180 Dwelling Units. Environmental Assessment: City of Palo Alto/Stanford Development Agreement and Lease Project Environmental Impact Report (State Clearinghouse No. 2003082103) Zoning District: Research Park and Alternative Standards Overlay Two (RP(AS2)) District (Continued From June 27, 2016) Adjournment AMERICANS WITH DISABILITY ACT (ADA) Persons with disabilities who require auxiliary aids or services in using City facilities, services or programs or who would like information on the City’s compliance with the Americans with Disabilities Act (ADA) of 1990, may contact (650) 329-2550 (Voice) 24 hours in advance. MEMO City of Palo Alto (ID # 6956) City Council Staff Report Report Type: Action Items Meeting Date: 6/20/2016 City of Palo Alto Page 1 Summary Title: 567 Maybell T-Map Title: PUBLIC HEARING: 567 Maybell Avenue [15PLN-00270]: Approval of Mitigated Negative Declaration and Tentative Tract Map with Lot Size Exceptions to Subdivide Four Parcels Totaling 2.47 Acres Into 16 Single-Family Lots, Ranging from 5,000 SF to 6,186 SF, and one Parcel for a Private Street. Environmental Assessment: Mitigated Negative Declaration. Zoning Districts: R-2 and RM-15. From: City Manager Lead Department: Planning and Community Environment Recommendation Staff recommends that the City Council: 1. Adopt the Mitigated Negative Declaration (Attachment F); and 2. Approve the Record of Land Use Action, including the Mitigation Monitoring and Reporting Program, for the Tentative Tract Map and related lot size exceptions based on findings and conditions of approval (Attachment B) Executive Summary The project applicant is proposing a subdivision tract map that would allow for the construction of 16 single-family residences on 2.47 acres at the northeast intersection of Maybell Avenue and Clemo Avenue. The project would result in the demolition of four single-family residences constructed between 1953 and 1968; the structures are not historic resources. Five new single- family residences are proposed with access to Maybell Avenue and 11 new single-family residences are proposed with access via a private street to Clemo Avenue. The project is subject to subdivision and architectural review applications. However, only the subdivision request is being processed at this time. The project was the subject of a public hearing before the Planning & Transportation Commission on May 25, 2016. Staff recommended inclusion of a pedestrian path from the interior lots to Maybell Avenue to encourage non-automotive movement to commercial areas, parks and schools. After hearing public testimony, the Commission determined that the pedestrian path was unnecessary and also determined that as designed, the project meets the City of Palo Alto Page 2 applicable zoning requirements, with exceptions requested for lot size and lot dimensions for certain lots. Background The applicant initially submitted applications for Architectural Review and Subdivision in support of a 23-unit residential development in June 2015. As a result of various comments on consistency with the City’s codes and policies and the applicant’s public outreach, the project was revised in December 2015 to only include 16 single-family dwelling units. As a result of this revision, the applicant proposes to move forward with the subdivision request first and then follow up with revised plans for the Architectural Review with the Architectural Review Board (ARB). The PTC reviewed the application request at their May 25, 2016. The staff report and packet is available at: https://www.cityofpaloalto.org/civicax/filebank/blobdload.aspx?BlobID=52513. Most of the discussion focused on a staff recommended pedestrian link between the interior lots to Maybell Avenue. Staff’s position was that it was an opportunity to include an amenity that would have the potential to reduce walking time and encourage non-vehicular movement. Of those members of the public that gave testimony there was overwhelming support for the project as proposed by the applicant and not the pedestrian connection to Maybell Avenue. The Commission recommended approval of the project without the pedestrian connection (4-0) citing that the connection was a good idea, however, it would not benefit a lot of people. Discussion The applicant requests approval of a Tentative Tract Map to create 16 single-family lots. The lots would range in size from 5,000 square feet to 6,186 square feet. The standard is 6,000 square feet and two of the lots would be smaller than the standard. In addition, the standard dimensions are 60’-0” wide by 100’-0” deep and various lots do not meet that standard. Attachment C provides a summary of the project’s compliance with the zoning standards. Lots one through five would have access on Maybell Avenue. Lots two and three would share a driveway and this is also the situation for Lots four and five, so that there would only be three curb cuts for five dwellings along Maybell Avenue. On the interior, a private street is proposed with a sidewalk on one side. This street provides the exclusive access for eleven lots to Clemo Avenue. The project proposes as part of the subdivision to construct a new sidewalk along Maybell Avenue where there is no sidewalk currently. Requested Entitlements, Findings and Purview: The following discretionary applications are being requested:  Subdivision (Tentative Map): The process for evaluating this type of application is set forth in Title 21 of the Palo Alto Municipal Code and Government Code Section 66474. Palo Alto Municipal Code Section 21.12.090 requires the Commission to first review whether the City of Palo Alto Page 3 proposed subdivision complies and is consistent with the Subdivision Map Act (in particular Government Code 66474), Title 21 of the Palo Alto Municipal Code, the Palo Alto Comprehensive Plan, and other applicable provisions of the Palo Alto Municipal Code and State law. The Commission’s recommendation is forwarded to the City Council for final approval.  Subdivision Map Exceptions: Pursuant to PAMC 21.32, a subdivider may apply for exceptions to any of the requirements and regulations set forth in this title. Such exceptions may be granted only by the City Council after recommendation by the PTC. Application for such exception shall be made by petition of the subdivider, stating fully the grounds of the application and the facts relied upon by the petitioner. Such petition shall be submitted with the tentative or preliminary parcel map for which the exception is requested and shall be reviewed and processed concurrent with said map. The findings and conditions associated with these two discretionary actions are contained in the Draft Record of Land Use Action (Attachment B) and key issues are discussed further below. Neighborhood Character The 2.47 acre site is relatively flat; a portion of the property is zoned R-2 (0.81 acres) and includes four single-family dwellings that front Maybell Avenue; and the other portion of the property is zoned RM-15 (1.65 acres) and is vacant (former orchard) that fronts Clemo Avenue. The property is bounded by two to three-story multi-family dwellings to the north; an eight- story residential tower to the east; Briones Park to the south, and single-family residences to the west. Within the vicinity is Juana Briones Elementary School, Terman Middle School, Gunn High School, the City’s Fire Station #5 and other single-family neighborhoods. Clemo Avenue has no vehicular access to Maybell Avenue, however, pedestrian and bicycle access is allowed. Zoning Compliance1 The subdivision application follows the zoning regulations set forth in the R-2 and RM-15 zone districts, which allow a maximum of two units per 7,500 square feet (R-2) and 15 dwelling units per acre (RM-15). These zoning districts permit single-family dwellings. The proposal for 16 units equates to 6.5 dwelling units per acre and therefore less than the allowed maximum density for the site. The subdivision and project comply with the applicable zoning development standards. According to the City’s Housing Element, a realistic yield of dwellings on the site is 27 units. Traffic and Circulation A Traffic Impact Analysis (TIA) was completed for the project and incorporated as part of the Initial Study/Mitigated Negative Declaration (Attachment F). The TIA analyzed a 23-unit project 1 The Palo Alto Zoning Code is available online: http://www.amlegal.com/codes/client/palo-alto_ca City of Palo Alto Page 4 (the initial project) and a 16-unit project (the current project). In addition, based on initial concerns regarding existing traffic conditions in the vicinity, two site access alternatives are analyzed for each project scenario. Under the 16-unit project, only the Arastradero and Clemo intersection was studied because it is the closest intersection to the project. The trip distribution would remain the same as with the 23-unit proposal, and the amount of trips from the project site would be reduced. The 16-unit project is expected to generate 114 net daily trips, including 9 net trips during the a.m. peak hour and 12 net trips during the p.m. peak hours. Six of those trips would be using the Arastradero and Clemo intersection in the morning peak hour. Under existing conditions (without the project), all study intersections operate at a Level of Service (LOS) D or better in the a.m. and p.m. peak hours, which are acceptable under the City’s thresholds. When including the project, because of the low amount of trips, all study intersections still remain acceptable. There are three schools within the vicinity of the project site. Maybell Avenue, Clemo Avenue and Arastradero Road are considered safe routes to school (Attachment G). Community Comments and Corridor Improvements Throughout the outreach period, community members expressed general traffic safety concerns about traffic on Maybell Avenue and Arastradero Road. There are two roadway projects which will be implemented independent of this project: The Maybell Avenue Bicycle Boulevard (Attachment H) and the Charleston Arastradero Corridor Project. Both projects are approved, funded for construction, and are currently entering final design. The Charleston- Arastradero project proposes widened sidewalks and corner “bulb outs” at Arastradero and Clemo. The Maybell Avenue Bicycle Boulevard project employs a range of traffic calming measures to reduce vehicle speeds. At Maybell Avenue and Amaranta Avenue, the plans propose a “raised intersection” with masonry pavers to reduce vehicle speeds while adding a decorative element to the street. Affordable housing The project is subject to the regulations within PAMC 18.14 (Below Market Rate Housing Program). Based on the project, 2.4 affordable housing units are required to be included in the project, unless determined to be infeasible, and then an in-lieu fee could be paid by the developer to meet the requirements. A condition has been added to the Record of Land Use Action requiring the developer to enter into a Regulatory Agreement prior to recordation of the final map. This agreement will set forth the applicant’s BMR obligations. Palo Alto Subdivision Code Compliance Chapter 21 includes standards for reviewing tentative maps. Because the project includes deviations from the zoning standards for lot size and dimensions, the applicant requests to apply for exceptions pursuant to PAMC 21.32. The applicant included justifications for the City of Palo Alto Page 5 exceptions provided for in Attachment E. Generally, the lots are 6,000 square feet in size and the dimensions are roughly equivalent to the requirements (plus or minus several feet). The proposal includes a substantial amount of lots that are 6,000 square feet. Two of the lots with reduced dimensions are at the end of the private roadway “hammer-head” and are not visible from the public road or park. From the public view along Clemo Avenue or Maybell Avenue, the lots would substantially conform to the surrounding single-family neighborhoods. Based on the zoning, the site could have more density than the project proposes. The applicant proposes the large lot single-family development in part to address resident concerns about a more dense development on this property. Policy Implications The site includes two Comprehensive Plan land use designations and is not subject to any area plan or specific guidelines. The proposed Tentative Map is consistent with the Comprehensive Plan, in that the site is designated as “Single-Family Residential” and “Multi-family Residential,” land use categories that support residential uses. Single-family residential uses are also consistent with the site’s RM-15 and R-2 zoning districts, which do not require minimum densities. The proposed 6.5 dwelling units per acre is well within the prescribed maximum densities. Consistency with other Comprehensive Plan policies is addressed in Attachment B. The site is included in the 2015-2023 Housing Element inventory of housing sites, which indicates a maximum yield of 27. While the project would provide fewer units than the number specified in the Housing Element, the Element’s inventory contained a buffer in excess of the city’s State allocation to account for projects such as this. Public Outreach In addition to public noticing requirements, the project was the subject of two stakeholder meetings (October 22, 2015 and November 4, 2015) conducted by the City and one community meeting (April 14, 2016) conducted by the applicant. In summary, the commenters at the stakeholder meeting objected to high density on the site and had concerns over the traffic that may be attributed to such a project. At the most recent community meeting, it was noted that generally there was no opposition to the 16-unit density and it was acknowledged that the heavy traffic perceived during the mornings is an existing condition. There was some concern about how the trips would leave the site and be distributed throughout the road network. Environmental Review The subject project has been assessed in accordance with the authority and criteria contained in the California Environmental Quality Act (CEQA), the State CEQA Guidelines, and the environmental regulations of the City. Specifically, the project requires adoption of a Mitigated City of Palo Alto Page 6 Negative Declaration (Attachment F) and a Mitigation Monitoring and Reporting Program (included in Attachment B). The Mitigated Negative Declaration was circulated between May 6, 2016 and May 26, 2016 and indicated the potential for significant impacts to biological resources. The site contains a number of existing mature trees and these may be habitat for nesting birds protected under the Migratory Bird Treaty Act. Incorporation of Mitigation Measure BIO-1 would reduce this impact to less than significant. Attachments:  Attachment A: Location Map (PDF)  Attachment B: RLUA with Findings and Conditions (DOCX)  Attachment C: Zoning Compliance (DOCX)  Attachment D: Correspondence (DOCX)  Attachment E: Applicant's Project Description (PDF)  Attachment F: Draft Initial Study and Mitigated Negative Declaration (PDF)  Attachment G: Final Briones Walk and Roll Map 2015-12-17 (PDF)  Attachment H: Maybell Avenue Bike Boulevard Concept Approved (PDF)  Attachment I: Project Plans (PDF) 4151 41474143 4139 4133 4146 628 622 612 4150 4154 4158 619 4169 590 41344136 4138 41444140 4150 638 571 545 4133 4171 4173 4175 4 2 0 5 578 5 7 4 5 7 0 581 579 4 2 0 1 575 5 7 9 5 8 7 4 2 1 5 4 2 2 1 4 2 5 7 7 4 2 0 6 4 2 0 8 4 2 1 2 4 2 1 6 607 4 2 0 2 609 580 600 595 4155 578 576 570 4137 4143 4151 4155 4163 4148 4152 4158 566 564 574 587 575 550 556 562 559 557 564 568 567 566 572 557 560 554 4170 4174 54 538 9 4175 4185 565 567 610 609 AMARA NT A AVENU E NUE MAYB ELL AV E NUE GEO R G ABEL AVENUE MAYBELL AVENUE MAYBELL A VENUE CL EMO AV ENU E AR AS T RAD ER O ROA D IRVEN C AL TA MES A AVE N U STRADERO ROAD S U Z A N N K E L L Y W A Y AR ANTA C OU RT This map is a product of the City of Palo Alto GIS Legend Major Institution/Special Facility Multi-Family Res Public Park Single Family Res Project Site - Lot Lines 0'150' 56 7 - 5 9 5 M a y b e l l A v e n u e Pr o j e c t S i t e Ar e a M a p Pr o p o s e d S i n g l e - F a m i l y De v e l o p m e n t CITY O F PALO A L TO I N C O R P O R ATE D C ALIFOR N IA P a l o A l t oT h e C i t y o f A P RIL 16 1894 This document is a graphic representation only of best available sources. The City of Palo Alto assumes no responsibility for any errors. ©1989 to 2016 City of Palo Alto twong, 2013-05-15 13:57:50 (\\cc-maps\gis$\gis\admin\Personal\twong.mdb) Attachment A 5 ATTACHMENT B ACTION NO. 2016-XX DRAFT RECORD OF THE COUNCIL OF THE CITY OF PALO ALTO LAND USE ACTION FOR 567 MAYBELL AVENUE: PRELIMINARY TENTATIVE MAP 15PLN-000270 (YURONG HAN, APPLICANT) At its meeting on June 20, 2016, the City Council of the City of Palo Alto approved the Preliminary Tentative Map for the development of a 16-lot subdivision project with exceptions, making the following findings, determinations and declarations: SECTION 1. Background. The City Council of the City of Palo Alto (“City Council”) finds, determines, and declares as follows: A. On June 15, 2015, Yurong Han on behalf of Golden Gate Homes, LLC applied for a Preliminary Tentative Map with exceptions for the development of a 23-lot subdivision project and subsequently on December 22, 2015 amended its project for the development of a 16-lot subdivision project (“The Project”). B. The project site is comprised of two lots (APN No. 137- 25-108 & -109) of approximately 2.46 acres. The site contains four residential structures. Single-family residential land uses are located adjacent to the lot to the west; multi-family land uses are to the north and east; and a public park is located to the south. C. Following staff review, the Planning and Transportation Commission reviewed the project and recommended approval on May 25, 2016 subject to conditions of approval. SECTION 2. Environmental Review. The City as the lead agency for the Project has determined that the project is subject to environmental review under provisions of the California Environmental Quality Act (CEQA) under Guideline section 15070, Decision to Prepare a Mitigated Negative Declaration. An environmental impact assessment was prepared for the project and it has been determined that there is the potential to have a significant impact on Biological Resources if the project is implemented. However, with incorporation of a mitigation measure, the project would have a less than significant impact on the environment. The Mitigated Negative Declaration was made available for public review beginning May 6, 2016 through May 26, 2016. The Environmental Impact Assessment and Mitigated Negative Declaration are contained as Attachment F. The City Council hereby approves the Mitigated Negative Declaration and incorporates the Mitigation and Monitoring Report attached as Exhibit A into this Record of Land Use. SECTION 3. Preliminary Tentative Map Findings. A legislative body of a city shall deny approval of a Parcel Map, if it makes any of the following findings (California Government Code Section 66474): 1. That the proposed map is not consistent with applicable general and specific plans as specified in Section 65451: 6 The site is consistent with the Comprehensive Plan as described below. 2. That the design or improvement of the proposed subdivision is not consistent with applicable general and specific plans: The Project is consistent with the following Comprehensive Plan policies: Policy L-1: Continue current City policy limiting future urban development to currently developed lands within the urban service area. The Project site is located within the urban growth boundary and the Project is consistent with this policy by continuing the reuse of land within this area; and Policy L-5: Maintain the scale and character of the City. Avoid land uses that are overwhelming and unacceptable due to their size and scale. The Project would allow construction of 16 single- family residential structures, which is a permitted use within the R- 2/RM-15 districts and which is compatible with other R-1 properties in the neighborhood; and Policy L-12: Preserve the character of residential neighborhoods by encouraging new or remodeled structures to be compatible with the neighborhood and adjacent structures. The Project would permit the subsequent construction of 16 single-family residential units, which would be subject to the R-1 site development regulations as the adjacent R-1 sites in the neighborhood. 3. That the site is not physically suitable for the type of development: The Project site is comprised of two large relatively flat lots in a residential neighborhood that would be subdivided into 16 lots for the purposes of single-family development. Each lot would mostly meet the minimum lot size and dimension requirements for R-1 zoned properties. Conditional exceptions are requested for those deviations and those findings are discussed in a later section. The character of the project site is consistent with the neighboring R-1 development. 4. That the site is not physically suitable for the proposed density of development: The project would create 16 lots that mostly meets the minimum lot size and dimensions of the site development regulations for properties using the R-1 Single family Residence development standards. Conditional exceptions are requested. However, the character of the development is consistent with the neighboring R-1 developments. 5. That the design of the subdivision or the proposed improvements are likely to cause substantial environmental damage or substantially and avoidably injure fish or wildlife or their habitat: The Project will not cause environmental damage or injure fish, wildlife, or their habitat, in that while a portion of the property is vacant, it is not adjacent to sensitive habitat areas and mitigation will be incorporated to ensure any potential nesting birds are not harmed. 6. That the design of the subdivision or type of improvements is likely to cause serious public health problems: The Project will not cause serious public health problems, as the environmental concerns have been reviewed in the Mitigated Negative Declaration that was prepared for the subdivision project. 7 7. That the design of the subdivision or the type of improvements will conflict with easements, acquired by the public at large, for access through or use of, property within the proposed subdivision. In this connection, the governing body may approve a map if it finds that alternate easements, for access or for use, will be provided, and that these will be substantially equivalent to ones previously acquired by the public. This subsection shall apply only to easements of record or to easements established by judgment of a court of competent jurisdiction and no authority is hereby granted to a legislative body to determine that the public at large has acquired easements for access through or use of property within the proposed subdivision. There are no easements on the subject property and no off site easement will be affected by the proposed project. SECTION 4. Exception Findings The project proposes exceptions to the zoning standards for lot size, lot width and lot depth for the following and depicted on Tentative Map Golden Gate Homes:  Lot Size (less than 6,000 square feet): Lots 14 and 15;  Lot Width (less than 60 feet): Lot 8 and Lots 10 – 14; and  Lot Depth (less than 100 feet): Lots 1 -7 and Lots 14 – 16. 1. There are special circumstances or conditions affecting the property. There are special circumstances in that the underlying R-2 and RM-15 zoning allows for a higher density project and the proposal is to voluntarily develop in accordance with R-1 standards in an effort to serve the community in which the project is located. The applicant proposes a project that is consistent in character with its surroundings. 2. The exception is necessary for the preservation and enjoyment of a substantial property right of the petitioner. The City of Palo Alto interprets this finding to describe the existence of a hardship in relation to other neighboring properties. The original intent of the applicant was to develop the property to be consistent with the R-2 and RM-15 zoning, which would have included at least 23 dwelling units. It was evident through the process that a compromised plan was needed to reduce opposition and receive support from the community. The proposed project at 16 dwelling units (current project) is below the full potential of the site by ten units and by developing the site with R-1 development standards it is in character with the surrounding R-1 properties. 3. The granting of the exception will not be detrimental to the public welfare or injurious to other property in the territory in which the property is situated. 8 The division of these parcels into 16 separate parcels will not have adverse impacts to other properties in the vicinity. The Mayell fronting properties meet the width, however, do not meet the depth, so from Maybell, the character is similar to those across the street. The smaller lots are on the interior at the end of the private street and not visible from Clemo Avenue. Therefore, the visual impacts will not be significant. The additional dwelling units will add a small amount of traffic and as determined by the project’s Traffic Impact Analysis no intersections in the vicinity will fall below acceptable thresholds for level of service. 4. The granting of the exception will not violate the requirements, goals, policies, or spirit of the law. The granting of the exception is consistent with the goals and policies of the Comprehensive plan as well as the spirit of the law. The subdivision of these parcels only serves to add further consistency to the existing lot pattern thus preserving the character of the neighborhood. The interior lot is zoned RM-15, however, it is not likely that the site will yield multi-family densities given the neighborhood opposition. The subdivision would allow the creation of 16 lots that are more consistent with Palo Alto Municipal Code (“PAMC”) Section 18.12.040. SECTION 5. Preliminary Tentative Map Approval Granted. Preliminary Tentative Map approval is granted by the City Council under PAMC Sections 21.12 and 21.20 and the California Government Code Section 66474, subject to the conditions of approval in Section 7 of this Record. SECTION 6. Tentative Map Approval. The Final Map submitted for review and approval by the City Council shall be in substantial conformance with the Preliminary Tentative Map prepared by BKF Engineers “Tentative Map Golden Gate Homes”, consisting of eleven (11) pages, dated March 3, 2016 except as modified to incorporate the conditions of approval in Section 7. A copy of this plan is on file in the Department of Planning and Community Environment, Current Planning Division. Within two years of the approval date of the Preliminary Tentative Map, the subdivider shall cause the subdivision or any part thereof to be surveyed, and a Tentative Map, as specified in Chapter 21.08, to be prepared in conformance with the Preliminary Tentative Map as conditionally approved, and in compliance with the provisions of the Subdivision Map Act and PAMC Section 21.16 and submitted to the City Engineer (PAMC Section 21.16.010[a]). 7 SECTION 7. Conditions of Approval. Department of Planning and Community Environment Planning Division 1. The applicant shall confirm the location all existing features of the site, including protected and non-protected trees, wells, structures, utilities, and easements to the satisfaction of Public Works, the Planning Division, and any other agency that would have an interest in those features. 2. The owner or designee prior to issuance of any building permit shall pay the applicable Development Impact fees. 3. Below Market Rate (BMR) Housing Requirement: The project is subject to the regulations within PAMC 18.14 (Below Market Rate Housing Program). Based on the project, 2.4 affordable housing units are required to be included in the project. Two of the units must be provided on-site unless the applicant demonstrates the on-site construction is infeasible. The fractional increment shall be paid through in lieu fees at the rate specified in the Municipal Fee Scheduled in affect at the time the fees are paid. Prior to final map recordation, the applicant shall enter into a Regulatory Agreement with the City setting forth their obligation to comply with this condition and PAMC Chapter 18.14. 4. The owner or designee prior to building permit issuance shall submit for review and approval a construction traffic plan and construction phasing plan for development to the City. 5. Applicant or a common-interest development organization is responsible for maintaining on-site utilities, street lighting, paths, roadways, and drainage features to the extent required by the city’s Public Works and Utilities Departments throughout the life of the project. Prior to building permit final, the applicant shall obtain city approval of CC&R’s or other documentation acceptable to the city describing, at minimum the structure of the common interest development organization maintenance responsibilities for the on-site utility mains and services. 6. The development impact fees for this project are estimated to be $1,067,232, California Government Code Section 66020 provides that a project applicant who desires to protest the fees, dedications, reservations, or other exactions imposed on a development project must initiate the protest at the time the development project is approved or conditionally approved or within ninety (90) days after the date that fees, dedications, reservations or exactions are imposed on the Project. Additionally, procedural requirements for protesting these development fees, dedications, reservations and exactions are set forth in Government Code Section 66020. IF YOU FAIL TO INITIATE A PROTEST WITHIN THE 90-DAY PERIOD OR FOLLOW THE PROTEST PROCEDURES DESCRIBED IN GOVERNMENT CODE SECTION 66020, YOU WILL BE BARRED FROM CHALLENGING THE VALIDITY OR REASONABLENESS OF THE FEES, DEDICATIONS, RESERVATIONS, AND EXACTIONS. If these requirements constitute fees, taxes, assessments, dedications, reservations, 8 or other exactions as specified in Government Code Sections 66020(a) or 66021, this is to provide notification that, as of the date of this notice, the 90-day period has begun in which you may protest these requirements. 7. The applicant is hereby notified, as required by Government Code § 66020, that the approved plans, these conditions of approval, and the adopted City fee schedule set forth in Program H3.1.2 of the City of Palo Alto Comprehensive Plan constitute written notice of the description of the dedications, reservations, amount of fees and other exactions related to the project. As of the date of project approval, the 90 day period has begun in which the applicant may protest any dedications, reservations, fees or other exactions imposed by the City. Failure to file a protest in compliance with all of the requirements of Government Code § 66020 will result in a legal bar to challenging the dedications, reservations, fees or other exactions. 8. To the extent permitted by law, the Applicant shall indemnify and hold harmless the City, its City Council, its officers, employees and agents (the “indemnified parties”) from and against any claim, action, or proceeding brought by a third party against the indemnified parties and the applicant to attack, set aside or void, any permit or approval authorized hereby for the Project, including (without limitation) reimbursing the City for its actual attorneys’ fees and costs incurred in defense of the litigation. The City may, in its sole discretion and at Applicant’s expense, elect to defend any such action with attorneys of its own choice. Building Division 9. The existing buildings within the project area shall be demolished prior to recording the map. A separate permit shall be required for the removal of the building. 10. New addresses will be assigned to each lot with the subdivision, following recordation of the subdivision map. The applicant shall file and “Address request Form” and pay the required fee, to the Palo Alto Development Center. Public Works Engineering Department PRIOR TO FINAL MAP APPROVAL 11. Subdivider shall prepare and submit documents per PAMC 21.16.020 along with the Parcel Map. 12. Subdivider shall provide closure calculations and cost estimate for the off-site improvements described above. 13. Subdivider shall revise the Map to include the 10-foot wide street dedication area Public Access Easement along Maybell Avenue. 14. A Subdivision Improvement Agreement is required to secure compliance with condition of approval and security of improvements onsite and offsite per PAMC Section 21.16.220. 15. The Final Map shall include CITY ENGINEER STATEMENT, CITY SURVEYOR STATEMENT, 9 BENEFICIARY STATEMENT, DIRECTOR OF PLANNING AND COMMUNITY ENVIRONMENT STATEMENT and CITY CLERK. 16. The Subdivider shall provide the offer of dedication for the 10-foot strip of land designed for the purpose and use of a public street along Maybell Avenue. 17. City Surveyor and cost recovery. The City of Palo Alto does not currently have a City Surveyor we have retained the services of Siegfried Engineering to review and provide approval on behalf of the City. Siegfried will be reviewing, signing and stamping the Final Map associated with your project. In effort to employ the services of Siegfried Engineering, and as part of the City’s cost recovery measures, the subdivider or designee is required to provide payment to cover the cost of Siegfried Engineering’s review. The Final Map will be forwarded to Siegfried for an initial preliminary review of the documents. Siegfried will then provide a review cost amount based on the complexity of the project and the information shown on the document. We will share this information with the Subdivider once the City receives it and ask that the Subdivider return a copy acknowledging the amount. Subdivider may then provide a check for this amount as payment for the review cost. The City must receive payment prior to beginning the final review process. 18. Provide electronic copies of the documents provided. PRIOR TO FINAL MAP RECORDATION 19. Submit wet signed and stamped mylar copy of the Final Map to the Public Works for signature. Map shall be signed by Owner, Notary and Surveyor prior to formal submittal. 20. Signed Subdivision Improvement Agreement and Security Bonds as described per PAMC 21.16.230. PRIOR TO ISSUANCE OF A BUILDING PERMIT OR GRADING AND EXCAVATION PERMIT 21. Final Map shall be recorded with County Recorder. UTILITIES ELECTRICAL ENGINEERING 22. Applicant shall grant easement to all electric equipment including transformers, switches, electric pull boxes and vaults, electric conduit. 23. All equipment shall be pad mounted, NO underground equipment is allowed. 24. All the weather head shall follow CPAU standard (lower than 18') 25. Applicant shall install, owned and maintain the streetlight system on the private street. These street lights shall be fed through a meter pedestal. 10 Utilities Water Gas Wastewater Department 26. The applicant shall submit a request to disconnect all utility services and/or meters to the existing building including a signed affidavit of vacancy. Utilities will be disconnected or removed within 10 working days after receipt of request. The demolition permit will be issued by the Building Inspection Division after all utility services and/or meters have been disconnected and removed. 27. The applicant shall submit a completed water-gas wastewater service connection application-load sheets for City of Palo Alto Utilities. The applicant must provide all the information requested for utility service demands. 28. The applicant shall be responsible for installing and upgrading the existing services a necessary to handle anticipated peak loads. This responsibility includes all cost associated with design and construction for the installation/upgrade of the utility services. 29. Each parcel shall have its own water service, gas service and sewer lateral connection shown on the plans. 30. All utility installations shall be in accordance with the City of Palo Alto utility standards for water, gas, & wastewater. SECTION 8. Term of Approval. 1. Preliminary Tentative Map. All conditions of approval of the Preliminary Tentative Map shall be fulfilled prior to approval of a Parcel Map (PAMC Section 21.16.010[c]). Unless a Tentative Map is filed, and all conditions of approval are fulfilled within a two- year period from the date of Preliminary Tentative Map approval, or such extension as may be granted, the Preliminary Tentative Map shall expire and all proceedings shall terminate. PASSED: AYES: NOES: ABSENT: ABSTENTIONS: ATTEST: APPROVED: City Clerk Director of Planning and Community Environment APPROVED AS TO FORM: Senior Asst. City Attorney PLANS AND DRAWINGS REFERENCED: Those plans prepared by BKF Engineers titled “Tentative Map, Golden Gate Homes”, consisting of eleven page, dated March 3, 2016. Exhibit A Mitigation monitoring and Reporting Program The Initial Study-Mitigated Negative Declaration identifies the mitigation measures that will be implemented to reduce the impacts associated with the 567 Maybell Avenue Residential Project. The California Environmental Quality Act (CEQA) requires a public agency to adopt a monitoring and reporting program for assessing and ensuring compliance with any required mitigation measures applied to proposed development. As stated in section 21081.6(a)(1) of the Public Resources Code: ... the public agency shall adopt a reporting or monitoring program for the changes made to the project or conditions of project approval, adopted in order to mitigate or avoid significant effects on the environment. Section 21081.6 also provides general guidelines for implementing mitigation monitoring programs and indicates that specific reporting and/or monitoring requirements, to be enforced during project implementation, shall be defined as part of adopting a mitigated negative declaration. The mitigation monitoring table lists those mitigation measures that may be included as conditions of approval for the project. To ensure that the mitigation measures are properly implemented, a monitoring program has been devised which identifies the timing and responsibility for monitoring each measure. The project applicant will have the responsibility for implementing the measures, and the various City of Palo Alto departments will have the primary responsibility for monitoring and reporting the implementation of the mitigation measures. 3 567 Maybell Avenue Residential Project Initial Study-Mitigated Negative Declaration Mitigation Monitoring and Reporting Plan Mitigation Measure Action Required When Monitoring to Occur Implementation Responsibility Monitoring Responsibility BIOLOGICAL RESOURCES BIO-1 Nesting Bird Protection. To avoid disturbance of nesting and special- status birds, activities related to the project, including, but not limited to, vegetation removal, ground disturbance, and construction and demolition shall occur outside of the bird breeding season (typically February through August in the project region). If construction must begin within the breeding season, then a pre- construction nesting bird survey shall be conducted no more than 3 days prior to initiation of ground disturbance and vegetation removal activities. The nesting bird pre-construction survey shall be conducted within the Project Boundary, including a 300-foot buffer (500-foot for raptors), on foot, and within inaccessible areas (i.e., private lands) afar using binoculars to the extent practical. The survey shall be conducted by a biologist familiar with the identification of avian species known to occur in the area. If nests are found, an avoidance buffer (which is dependent upon the species, the proposed work activity, and existing disturbances associated with land uses outside of the site) shall be determined and demarcated by the biologist with bright orange construction fencing, flagging, construction lathe, or other means to mark the boundary. All construction personnel shall be notified as to the existence of the buffer zone and to avoid entering the buffer zone during the nesting season. No ground disturbing activities shall occur within this buffer until the avian biologist has confirmed that breeding/nesting is completed and the young have fledged the nest. Encroachment into the buffer shall occur only at the discretion of the qualified biologist. If construction work is planned during nesting season, verification of completed surveys will be required. Verification that prescribed mitigation measures are taken including adhering to time delays (due to nesting or breeding season) if species are observed. At least once before work commences . Periodically during initial ground disturbance and/or vegetation removal. Applicant City of Palo Alto 4 ATTACHMENT C ZONING COMPARISON TABLE 567 Maybell Avenue / File No. 15PLN-00270 Table 1: COMPARISON WITH CHAPTER 18.12 (R-1 DISTRICT) per TITLE 18.13.040 (c) Regulation Required Existing Proposed1 Minimum/Maximu m Site Area, Width and Depth 6,000-9,999 sf area, 60 foot width, 100 foot depth 2.46 acres Min 6,000 sf except Lot 14: 5,000 sf Lot 15: 5,682 sf Width varies - Lots 8 and 10 – 13 are less than 60 ft. Depth varies - Lots 1-7 and 14-16 are less than 100 ft. Minimum/Contextu al Front Yard (2) 20 feet or the average setback (18.12.040(e)) 20 feet NA Rear Yard 20 feet 236 feet NA Interior Side Yard 6 feet 6 feet NA Street Side Yard 16 feet 16 feet Special Setback None NA NA Max. Building Height 30 feet or 33 feet for a roof pitch of 12;12 or greater Single-story NA Side Yard Daylight Plane 10 feet at interior side lot line then 45 degree angle NA NA Rear Yard Daylight Plane 16 feet at rear setback line then 60 degree angle NA NA Max. Site Coverage 35% with an additional 5% for covered patio/ overhangs (20,839 sf + 5%) 35% (36,354 sf) max potential Max. Total Floor Area Ratio 45% for first 5,000 sf lot size and 30% for lot size in excess of 5,000 sf (18,612.3 sf) 45% (46,848 sf) max potential Max. House Size 6,000 sf NA Residential Density One unit, except as provided in 18.12.070 Four NA 1. The project is a subdivision and does not include architectural detail for evaluation. Table 2: CONFORMANCE WITH SECTION 18.12.060 for Single-Family Type Required Existing Proposed1 Vehicle Parking 2 spaces per unit, of which one must be covered 8 spaces NA 1. Project is a subdivision and does not include detailed architectural plan for evaluation. Petitioning City of Palo Alto Planning Commission and 6 others SUPPORT REASONABLE DEVELOPMENT PLAN ON MAYBELL/CLEMO IN PALO ALTO (Measure D Follow-Up) Elaine D Palo Alto, CA Change.org ATTACHMENT D WE SUPPORT A REASONABLE DEVELOPMENT PLAN FOR THE MAYBELL/CLEMO PROPERTY IN PALO ALTO. In November 2013, our neighborhood sent a clear signal about reasonable development on the Maybell/Clemo property by defeating Measure D. The passage of Measure D would have given a developer permission to build a 60 high-density apartment complex in addition to 15 single-family homes for a total of 75 housing units at 567-595 Maybell Avenue (later reduced to 12 homes for 72 total housing units). Maybell is a city-designed "Bicycle Boulevard" with higher protections and a school district-supported "Safe Route to School" - but neighbors here daily witness "near-miss" accidents as hundreds of children and teenagers on bikes share space on Maybell, a narrow road with high volumes of automobile and commercial traffic as people rush to get to school and work in the mornings. The residents of Palo Alto were gravely concerned about irresponsible high- density development in a small neighborhood that already encompasses several schools and after-school care programs: Juana Briones Elementary, Juana Briones Orthopedically Handicapped Center, Barron Park Elementary, Terman Middle School, Gunn High School, Barron Park Child-Care Center, Juana Briones Kids Club, in addition to two preschools and a K-8 private school. After countless hours of hearings and meetings, the City did not listen to community concerns, compelling a city-wide referendum vote - the result of which was a resounding NO on the proposed high-density development in 2013. Now it's time for the community to take action again. The current owner and developer of the property, Golden Gate Homes (GGH), originally proposed building 30 homes on the property. However, after working collaboratively with neighborhood residents through community outreach and meetings, GGH has ultimately decided to reduce housing density to 16 single family homes. This is a significant accommodation, and represents close to an 80% density reduction from 72 housing units if Measure D had passed to a REASONABLE & RESPONSIBLE 16 homes for a school-dense area filled with families. GGH has also proposed plans to ensure that each home complies with R-1 parking code requirements with driveways for additional parking, in order to curb any overflow parking on adjacent streets, retention of existing heritage Oak trees on Clemo, R- 1 lot sizes, and an installation of a sidewalk on the Maybell property line to improve pedestrian safety. I SUPPORT GGH'S 16-HOME CIRCULATION PLAN FOR THE MAYBELL/CLEMO PROPERTY (567-595 Maybell Avenue) WHICH EASES TRAFFIC AND SAFETY CONCERNS FOR OUR SCHOOL-AND-FAMILY-POPULATED NEIGHBORHOOD. I DO NOT SUPPORT A CHANGE IN CIRCULATION WHICH WOULD RESULT IN HIGHER-DENSITY HOUSING AND CONSEQUENT NEGATIVE TRAFFIC AND SAFETY IMPACTS. *This petition is NOT an endorsement or representation of the quality of GGH's developments, ONLY for the proposed lower- density plan which GGH created in collaboration and cooperation with neighboring residents. **There will be a Community Meeting on Thursday, April 14 at 6:30pm at Gunn High School Library to discuss the Maybell-Clemo project among neighborhood residents, the developer, and the City of Palo Alto. You can also show your SUPPORT by attending this meeting. Page 1 of 4 Golden Gate Homes LLC 2225 East Bayshore Rd, Suite 200 Palo Alto 94303 Tel: (650) 735-2777 Email: info@goldengatehomes.us Original: January 19, 2016 Updated: February 2, 2016 Updated: March 4, 2016 City of Palo Alto Planning Manager & Staff Department of Planning and Community Environment 250 Hamilton Street, 5th Floor Palo Alto, CA 94303 Tel: (650) 329-2441 Re: 567-595 Maybell Avenue, Palo Alto File# 15PLN-00248 To: Planning Staff and Planning & Transportation Commission: Relative to the Tentative Map submitted to the City on December 22, 2015 by Golden Gate Homes, we provide this letter to formally request Conditional Exceptions per Palo Alto Municipal Code Chapter 21.32. As you know, the Municipal Code allows for exceptions where the approval of such exceptions would secure substantially the objectives of the regulations and protect the general welfare of the community. With the community in support of the Tentative Map as submitted, to create project that substantially complies with the R-1 single family zoning regulations, Golden Gate Homes believes that the findings can be made to support and approve the requested conditional exceptions. Since acquiring the property in April 2014, Golden Gate Homes (GGH) has in good faith undertaken and performed the following: Comprehensively studied all aspects of land use, zoning, neighborhood and circulation alternatives for the site. Participated in or hosted numerous meetings with City Staff and the neighborhood constituencies to further an in-depth understanding of site characteristics and the community. Attachement E Page 2 of 4  Submitted a Preliminary Architectural Review Board (ARB) Application in September 2014 for 30 total dwelling units, consisting of 5 detached single-family units, 9 detached single-family units on small lots and 16 attached duet units. The 5 detached single-family units generally followed R-1 guidelines while the majority of the site used Village Residential guidelines in the RM-15 zone. The site plan offered access points from both Maybell Avenue and Clemo Avenue. Given lack of neighborhood support, the application was subsequently withdrawn in January 2015.  After spending additional time and resources working to reduce the density and respond to neighborhood comments, in June 2015 GGH submitted Applications for Major ARB and Major Subdivision (Tentative Map) for 23 total dwelling units (7 fewer than the first application), consisting of 5 detached single-family units and 18 detached single-family units on small lots. The 5 detached single-family units generally followed R-1 guidelines while the majority of the site used Village Residential guidelines in the RM-15 zone. The site plan offered a vehicular access point from Clemo Avenue and a pedestrian and bicycle easement onto Maybell Avenue. Despite generally complying with the underlying zoning for the site, the neighborhood feedback was that this proposal was still too dense.  Golden Gate Homes again seriously considered the neighborhood comments and worked to reduce the density, this time well below the allowable density. In December 2015 GGH submitted an updated Tentative Map Application to the City seeking to subdivide 16 lots for detached single-family units that substantially follow R-1 design guidelines. This plan includes 7 fewer units than the June 2015 plan and 14 fewer than the original proposal. The updated plan provides a single access point for 11 units from Clemo Avenue with no pedestrian or bicycle easement directly onto Maybell Avenue. Palo Altans for Sensible Zoning (neighborhood group) submitted a letter on January 7, 2016 indicating support for this plan. The current zoning of R-2 along Maybell and RM-15 on the interior of the site along Clemo Avenue allow a more dense project with smaller lots, but the current proposal seeks to generally follow the R-1 standards. There are two (2) Conditional Exceptions related to R- 1 standards that GGH respectfully requests City Staff, Planning & Transportation Commission and City Council approve: 1. Lot Dimensions. The proposed site complies with R-1 and R-2 standards with a minimum of 6,000 square foot lots; however, the lot dimensions are not a minimum of 60 feet by 100 feet for both zoning classifications. GGH requests that the dimensions as proposed in the Tentative Map be allowed. The dimensions of these lots will not be detrimental to the public welfare. In fact, by creating a project with R-1 sized lots, even ones whose dimensions do not exactly comply with R-1 standards, the community will be benefitted as this is a project the community supports with the look and feel of a single-family development. All other aspects of R-1 will be adhered to, most importantly appropriate setbacks. Page 3 of 4 2. Lot Size. Two of the proposed lots are not the minimum R-1 or R-2 standard size of 6,000 square feet. Lot 14 (which is in the RM-15 zoned property), as identified on the Tentative Map, is 5,000 square feet. Lot 15 is 5,682 square feet. GGH requests these lots be allowed as it does not change the goal of creating a less dense R-1 project on a site where the zoning allows greater density. Sub-6,000 square foot lots of this type exist throughout Palo Alto, and contextually in the corridor between Arastradero and Maybell Avenue where the site is located. These lots would also adhere to required setbacks as all others. By granting the requested Exceptions, it is GGH's opinion that, per code 21.32:  “Approval will secure substantially the objectives of the regulations or requirements to which the exceptions are requested”. In subdividing the site into 16 lots, the exceptions will secure a proposed plan that follows substantially the R-1 regulations, i.e. setbacks, building heights, parking, open space, site coverage, etc. The dimensions of the lots will not undermine the objective of the R-1 regulations, nor will the approval of two lots at a smaller lot size.  “Shall protect the public health, safety, convenience, and the general welfare and shall be consistent with and implement the policies and objectives of the comprehensive plan”. Please reference the letter of support from Palo Altans for Sensible Zoning (PASZ) regarding general welfare and commentary. Regarding the comprehensive plan, there are guidelines provided for maintaining scale and character of the City (Policy L-5) and promoting compatibility (Policy L-6) where the neighborhood is predominantly R-1 in character. GGH believes that these small exceptions protect the public and achieve the objective of creating a single family development on this site. Specifically, GGH believes that the City can make those findings identified in Municipal Code Section 21.32.020 and PAMC 21.12.050(j) as follows: 1. There are special circumstances or conditions affecting the property. This site is unique as it possesses a political condition where an approved (and far more dense, 75 unit) site plan by a previous owner was defeated through a public referendum. There are special circumstances in that the underlying R-2 and RM-15 zoning allows for a higher density project and the proposal is to voluntarily develop in accordance with R-1 standards in an effort to serve the community in which the project is located. Additionally, with the current support of the neighborhood, GGH believes the City can make the finding that there are special circumstances or conditions affecting the property that support granting the exceptions. 2. The exception is necessary for the preservation and enjoyment of a substantial property right of the petitioner. GGH acquired this property with the full intent to develop for residential uses as zoning would allow (R-2 and RM-15). A considerable amount of time and expense has been taken to arrive at a compromised site plan that GGH, the City and the neighborhood can all agree to move forward. This compromised plan is substantially reduced from allowable Page 4 of 4 development density under the zoning. Approval of the exception would preserve the property right of GGH to develop this property. 3. The granting of the exception will not be detrimental to the public welfare or injurious to other property in the territory in which the property is situated. Again, referencing the letter of support from a key public and neighborhood constituency, PASZ. 4. The granting of the exception will not violate the requirements, goals, policies, or spirit of the law. Aside from lot dimensions and two slightly smaller lot sizes, all other aspects of the code shall be followed related to R-1 standards and substantially are represented in the Tentative Map. The goal and the spirit of an R- 1 project will be captured with this proposal. We appreciate City’s prompt review and consideration of the requested Conditional Exceptions to the Tentative Map. We respectfully request that City Staff:  Schedule the application for Planning & Transportation Committee (PTC) calendar.  Subject to and subsequent of PTC, schedule to City Council calendar. This project has been in process for a long time and much of that time has been spent working with the various stakeholders to create a winning project. As it now appears this project has broad support, GGH hopes that the City can favorably expedite review of this project. We look forward to continuing to work with the Planning Staff on the review of this application. Please contact us with any questions or further information we may furnish. Best Regards, Yurong Han Manager, Golden Gate Homes LLC Attachment F  Initial Study and Mitigated Negative Declaration  This document is available for viewing online at:   http://www.cityofpaloalto.org/news/displaynews.asp?NewsID=3186&Target=319 Hard copies of IS/MND is available at City Hall, 5th Floor, Planning and Community Environment  Department.   Suggested Routes Briones Elementary School WALKAND ROLLTO SCHOOL Drive Safely Wear your helmet and buckle it every time. It’s the law. To best protect your brain, your helmet must fi t properly: snug and level on your head, just above your eyebrows. Be predictable. Obey ALL stop signs and traffi c signals. Never ride the wrong way. The best way to avoid bike crashes as well as traffi c tickets is to follow the same rules of the road as apply to car drivers. Be alert. Watch out for drivers turning left or right, or cars coming out of driveways. Avoid car doors opening in front of you by riding out of the door zone. Yield to pedestrians. Be alert. Look for cars coming from all directions before entering the street - including behind you. Cross at corners and crosswalks. This is where drivers expect pedestrians. Don’t assume drivers see you. Make eye contact before crossing intersections. City of Palo Alto Safe Routes to School www.cityofpaloalto.org/saferoutes saferoutes@cityofpaloalto.org 650.329.2156 Bike Safely Walk or Skate Safely BIKE LANE check all directions Slow down and use extra caution in school zones and along commute routes! Signal your turns and yield to pedestrians. Help reduce traffi c congestion near Briones and neighboring schools by carpooling with a neighbor and avoiding the last minute rush whenever possible. Obey adult crossing guards and “No Right Turn on Red” signs posted at designated school intersections. This allows students to cross safely without cars turning through crosswalks. Don’t make U-turns and other unsafe maneuvers that put other road users at risk. When dropping off or picking up your student, follow school guidelines and always ensure that he/she exits or enters the car from the curb side. Never double park, block access ramps or stop where prohibited. Avoid texting, phone calls and other distractions when driving. We welcome volunteers to help with Safe Routes to School events and programs at this school! Contact your PTA or email saferoutes@cityofpaloalto.org. New Street Marking! Cyclists should ride down the center of this “sharrow” symbol to stay outside the “door zone” on streets without bike lanes. Sharrows also remind drivers to watch for cyclists. Parents: Help your student learn how to share the road safely with other users. Children who regularly practice safe walking and biking skills are more likely to make safer choices as teenagers. Obey adult crossing guards. They are there to help everyone cross congested intersections safely. Attachment G 7 (2) 6 (2) 17 (6) 19 (6) 7 (2) 9 (3) 8 (3) 17 (6) I Or m e Los R o b l e s A v e n u e Enc i n a G r a n d e Cle m o Ge o r g i a A v e n u e L o s P a l o s A v e n u e Wi l k i e W a y Pa r k B o u l e v a r d Cha r l e s t o n Roa d Edl e e A v e n u e A m a r a n t a Do n a l d Dri v e Co u l o m b e May b e l l A v e n u e Ara s t r a d e r o Roa d Jam e s R d Ca m p a n a Bak e r Geo r g i a Po m o n a A v e n u e Ricke y s Lane Deod a r Stree t F o o t h i l l E x p r e s s w a y B o l P a r k P a t h El C a m i n o R e a l Al m a S t r e e t Los Altos-Pal o A l t o Bike Path Mi r a n d a A v e n u e Arroy o Cour t Par a d i s e W a y La D o n n a W. M e a d o w D r i v e 1 /2 M i l e 1/4 Mile Briones Elementary School Terman Middle School Gunn High School Barron Park Elementary School Monroe Park Monroe Park Robles Park Briones Park Terman Park 01/41/8 Miles BrionesElementary School WALK AND ROLL TO SCHOOL SUGGESTED ROUTES Pedestrian-Only Access Pedestrian and Bicycle Access Bicycle Parking Multi-use Path & Attendance Area Traffic Signal Parks and Open Space Est. Walking Time (Biking Time) XX (X) Marked Crosswalk Crossing Guard Location Suggested Route (Walking and Biking) School All-Way Stop& Suggested Route (Walking Only)Pedestrian Beacon Vehicle BarrierI The Palo Alto Safe Routes to School Partnership encourages parents and students to use this map to explore options for commuting between home and school. Parents are responsible for choosing the most appropriate option based on their knowledge of conditions on the diff erent routes and the experience level of their student. For more Safe Routes to School information, please visit: www.cityofpaloalto.org/saferoutes Briones Elementary School Briones Elementary School Am a r a n t a A v e n u e Geo r g i a Ave n u e Or m e S t r e e t May b e l l A v e n u e Co u l o m b e Dri v e Inset See Inset Attachment H Attachment I  Architectural Drawings  Hard copies of the architectural drawings were provided to the Council and are available for  viewing at City Hall, 5th Floor, Planning and Community Environment Department.  The plans may also be viewed at the following website:   Architectural Concept Plans: http://www.cityofpaloalto.org/civicax/filebank/blobdload.aspx?BlobID=51792 Tentative Map Plans: http://www.cityofpaloalto.org/civicax/filebank/blobdload.aspx?BlobID=51764 City of Palo Alto (ID # 6929) City Council Staff Report Report Type: Action Items Meeting Date: 6/28/2016 City of Palo Alto Page 1 Summary Title: 1451-1601 California Ave - Stanford/Mayfield Housing Subdivision Amendment Title: CONTINUED PUBLIC HEARING: 1601 California Avenue [15PLN-00500]: Request by The Board of Trustees of the Leland Stanford Junior University to Amend the Final Map for Tract Number 10281 Recorded January 2015 for the 1451-1601 California Avenue Development, Which Includes a Total of 180 Dwelling Units. Environmental Assessment: City of Palo Alto/Stanford Development Agreement and Lease Project Environmental Impact Report (State Clearinghouse No. 2003082103) Zoning District: Research Park and Alternative Standards Overlay Two (RP(AS2)) District (Continued From June 27, 2016) From: City Manager Lead Department: Planning and Community Environment Recommendation: Staff recommends that Council adopt the Record of Land Use Action regarding the Amendment to the Final Map for Tract No. 10281 (Attachment A). Executive Summary: On June 23, 2014, the City Council approved a Tentative Map to subdivide three existing parcels (16.96 acres) into 83 parcels to accommodate the proposed development of 180 dwelling units located at 1451-1601 California Avenue, as envisioned in the 2005 Mayfield Development Agreement. Subsequently, the Final Map was recorded in January 2015 (Tract No. 10281). During demolition of the site, characterization sampling (soil, soil gas and groundwater) conducted pursuant to the Mayfield Development Agreement Mitigation Monitoring and Reporting Plan (MMRP) revealed an area of isolated elevated trichloroethylene (TCE) concentrations in the form of soil gas under the former footprint of 1601 California Avenue building, where a former plating solution sump is believed to have been a source contributing to this release. This area was not accessible for TCE testing until after the building was demolished. City of Palo Alto Page 2 The isolated TCE in soil gas remains between 14’-6” and 25’-0” below ground surface and has not migrated 50 feet beyond this localized area. Also within this isolated area, TCE was found in one perched groundwater sample at a concentration that would not contribute to vapor intrusion; concentrations in groundwater have not migrated from the property. As required by the MMRP, the applicant reported the test results to California Department of Toxic Substances Control (DTSC). Among other measures, the applicant proposed to DTSC that seven homes originally planned to be located on or near the elevated TCE readings be moved at least 50 feet away from the isolated area thereby eliminating any potential risk of vapor intrusion to future occupants. The isolated area would be used for open space and streets. DTSC agrees that there will not be a risk to future site users with the proposed redevelopment design (Attachment B). In order to relocate the seven affected houses, applicant proposes to redistribute 29 residences at the southern end of the site and create a jog in the new Amherst Street to accommodate the all 180 homes. The total square footage of lots has been reduced, which also lowers the size of the proposed homes on these parcels; however, there is now a proposed increase in common open space. The applicant requests an amendment to the Final Map (Tract No. 10281) to accommodate this redesign. This amendment affects only the southern portion of the (formerly 1601 California Avenue) project site; it does not affect the former 1451 and 1501 California Avenue sites. Background: In 2005, the City of Palo Alto and Stanford University entered into the Mayfield Development Agreement (MDA). Under the MDA terms, Stanford University was to lease to the City of Palo Alto the six acre Mayfield site, located at the corner of Page Mill Road and El Camino Real, for $1 per year for 51 years. Stanford was to construct soccer fields on the Mayfield site at its expense and turn the fields over to the City upon completion, which was done in 2006. In turn, the MDA provided Stanford with vested rights to build 250 housing units on two sites in the Stanford Research Park, where R&D/office buildings exist today. Given the City’s historic jobs/housing imbalance, the MDA recognized that the additional housing would be a mutual benefit to Stanford and the City. The MDA also granted Stanford the right to relocate 300,000 square feet (sf) of R&D/office floor area elsewhere within the Stanford Research Park. (This amount of floor area is less than the amount of non-residential floor area to be demolished at the two designated housing sites.) The California Avenue Site (1451-1601 California Avenue) would accommodate 180 dwelling units. The site received approval for the Tentative Map on June 23, 2014 and the Final Map was recorded in January 2015. An Environmental Impact Report (EIR) certified in 2005 covers the Development Agreement and subsequent projects that implement the agreement. When the EIR was prepared and the Development Agreement was entered into, the existence of contaminants at the project site City of Palo Alto Page 3 was known, and TCE was identified as a hazardous chemical that was typically used at the Stanford Research Park. In accordance with the MMRP, a full investigation could not be completed until the 1601 California Avenue buildings were demolished and testing could be conducted under the building footprints. Stanford was required to prepare a ‘work plan’ for corrective action and controls, and a risk assessment to identify acceptable clean up goals for the intended use of the California Avenue Site, and submitted this work plan to the DTSC for review and approval (Attachment D). As a result, the DTSC issued a ‘no further action’ status for the site (Attachment B). The specific area referred to is the open space area from which residences were moved to create the revised plan. The measures that will be reviewed and approved by DTSC are long-term management measures restricting or prohibiting activities such as building any structures in this area which would be enclosed (such as a community restroom, for example), drilling water wells, or disrupting vapor barriers in utility trenches in this area. Discussion: To implement the revisions necessary for the project, a limited revision to the recorded Final Map is required. Section 21.16.280 of the Palo Alto Municipal Code (PAMC) authorizes map amendments. After a final map or parcel map is filed in the Office of the County Recorder, the recorded map may be modified by a certificate of correction or an amending map if: i. there are changes in circumstances which make any or all of the conditions of such a map no longer appropriate or necessary, ii. that the modifications do not impose any additional burden on the present fee owner of the property, iii. the modifications do not alter any right, title, or interest in the real property reflected on the recorded map, and iv. the map as modified conforms to the provisions of the Subdivision Map Act and Chapter 21.16 of this title. The decision to approve or deny a modification shall be made by the City Council for final maps. The hearing shall be confined to consideration of and action on the proposed modification. The applicant’s request meets the four requirements of PAMC Section 21.16.280. First, there are changes in circumstances (elevated TCE readings under seven home sites) that make certain final map conditions (the locations of those homes) no longer appropriate or necessary. Second, the modifications were proposed by Stanford and thus do not impose any additional burden on the fee owner of the property. Third, the modifications do not alter any right, title, or interest in the real property reflected on the recorded map as Stanford has not sold or leased any of the affected lots. Fourth, the map as modified conforms to the provisions of the Subdivision Map Act and PAMC Chapter 21.16. Figure 1: City of Palo Alto Page 4 Previously Approved Layout Figure 2: Proposed Revised Layout City of Palo Alto Page 5 Summary of Key Issues: While the City does not have regulatory authority over the TCE, the previously approved Mitigation Monitoring and Reporting Plan (MMRP) for the project (Attachment F) requires the City to monitor Stanford’s preparation of a Work Plan and Corrective Action Plan as well as the DTSC’s approval of such plan. A Supplement Investigation and Risk Assessment (SIRA) report was prepared by Haley Aldrich to comply with the mitigation (Attachment D). The locations and depths of TCE soil vapor which could cause potential significant health risk via indoor air vapor intrusion are also given in the narrative Section of 6.2.1 (Future Residents) of the SIRA. It was from these readings at these depths at these locations that Stanford decided to move the homes rather than install mitigations at these houses left in place. This decision required the amendment to the Final Map. Along with “future residents”, the SIRA evaluated impacts to “future commercial/industrial workers” and “future users of recreation areas”. Figure 17 of the SIRA shows through the location of the former building and future development (house footprints, streets and recreation areas), the location of the site boring samples, the sample readings and depths. Other figures show the types of soils, the location of the soil types in relation to the boring samples. Concentrations of VOCs are lower near the surface, and exposure to VOCs in soil vapor via City of Palo Alto Page 6 inhalation of outdoor air is not expected to occur or pose an unacceptable health risk under the conditions evaluated. This is based on the results of shallow soil vapor samples collected within the recreational area. In the unlikely event that low concentrations of VOCs reach outdoor air, they would be destroyed by sunlight and or naturally diluted and dispersed by wind. The proposed location of the recreational area is not expected to pose a risk to the use of the area. The Site Management Plan will have a restriction on building any future enclosed structure in this localized area without adequate mitigation against vapor intrusion approved by DTSC. DTSC’s remaining role is to ensure that any approved mitigation measures in place be protective and maintained. Stanford is currently discussing with DTSC the option of a Site Management Plan in lieu of its standard Land Use Covenant to establish post-development mitigation management measures (if warranted). Either option would involve managing any soil activities greater than 10 feet below grade, requirements for human health protective measures within future building designs, notification requirements to DTSC, etc. Any of DTSC final requirements would be binding on Stanford and the community’s association. Policy Implications: The proposed revisions are consistent with the adopted Development Agreement. Environmental Review: The project implements the mitigations contained within the Mitigation Monitoring Reporting Program (MMRP) established by the Final EIR for the Mayfield Development Agreement (2005). The preparation of the work plan and subsequent review and conclusion by DTSC requires no further environmental evaluation for the project. The proposed final map amendment would not result in a substantial increase in the severity of the environmental impacts identified in the Mayfield Development Agreement EIR. During construction, impacts would be the same as under the approved final map. All Mayfield Development Agreement EIR mitigation measures would continue to apply. No additional protected trees would be removed or relocated. Once the project is complete, impacts would be the same, or slightly less than, the less-than- significant impacts identified with the approved final map. The reason for this is that although the amended map still provides for a total of 180 dwelling units at the project (as required under the Mayfield Development Agreement), as noted previously, some units will be reduced in square footage and bedroom count, as the house redistribution will be accomplished in part by switching some of the larger house plans to some of the smaller plans, and, in some cases, combining these smaller plans into duplexes. As a result, the project’s total occupancy and, therefore, its total vehicle trips, will likely be reduced compared to buildout under the January 2015 final map. Attachments: City of Palo Alto Page 7  Attachment A: Record of Land Use Action (DOCX)  Attachment B: DTSC Supplemental Investigation and Risk Assessment Report Concurrence (PDF)  Attachment C: Correspondence (PDF)  Attachment D: Supplemental Investigation Risk Assessment (DOCX)  Attachment E: Applicant Letter (PDF)  Attachment F: Upper California MMRP (PDF)  Attachment G: Project Plans (DOCX) 1451-1601 California Avenue Page 1 of 3 Attachment A APPROVAL NO.______ RECORD OF THE COUNCIL OF THE CITY OF PALO ALTO LAND USE ACTION FOR 1451-1601 CALIFORNIA AVENUE: REVISED FINAL MAP APPLICATION [FILE NO. 15PLN-00500] On June 27, 2016, the City Council approved the Revised Final Map application to subdivide 16.97 acres into 68 lots for single-family use, two (2) condominium lots for 112 multi-family units, and 15 private street/common area lots for a total of 85 parcels, making the following findings, determination and declaration: SECTION 1. BACKGROUND. The City Council of the City of Palo Alto (“City Council”) finds, determines, and declares as follows: A. On April 4, 2016, the Department of Toxic Substances Control of the State of California determined that based on the Revised Supplemental Investigation and Risk Assessment Report (SIRA) dated March 18, 2016 for the 1601 S. California site that sufficient site characterization has been performed to define the nature and extent of contamination present at the site and agrees that there would be no significant risk to future site residents, based on the future redevelopment plans presented in the SIRA which illustrates the location of future residences outside of the localized on-site VOC soil vapor plume. B. On December 16, 2015, Chris Wuthmann of the Board of Trustees of the Leland Stanford Jr. University applied for a Final Map Revision for Tract Map 10281 for portions of the former 1451-1601 California Avenue site. Characterization sampling (soil, soil gas and groundwater) conducted pursuant to the Mayfield Development Agreement Mitigation Monitoring and Reporting Plan (MMRP) revealed an area of isolated elevated TCE concentrations in the form of soil gas under the former footprint of 1601 California Avenue building, where a sump is believed to have been a source contributing to this release. This area was not accessible for TCE testing until after the building was demolished. The isolated TCE in soil gas remains at depth and has not migrated 50 feet beyond this localized area; Also within this isolated area, TCE was found in one perched groundwater sample at a concentration that would not contribute to vapor intrusion; concentrations in groundwater have not migrated from the property. As required by the MMRP, Stanford reported the test results to DTSC. Among other measures, Stanford proposed to DTSC that seven homes originally planned to be located on or near the elevated TCE readings be moved at least 50 feet away from the isolated area thereby eliminating any potential risk of vapor intrusion to future occupants. The isolated area would be used for open space and streets. This design redistributes 29 residences at the former 1601 California Avenue so that the required 180 homes are still provided; creates a jog in the new Amherst Street to accommodate the redistributed homes; reduces the 1451-1601 California Avenue Page 2 of 3 total square footage of home sites and homes in the affected area; and increases common area open space. C. On June 23, 2014, the City Council upheld the Director’s approval of the Architectural Review application (13PLN-00433) and approved the Tentative Map application (11PLN-00203), to construct 68 single family homes and 112 multi-family homes and subdivide three existing parcels totaling 16.97 acres into 68 lots for single family use, two (2) condominium lots for 112 multi-family units, and 13 private street/common area lots for a total of 83 parcels. SECTION 2. ENVIRONMENTAL REVIEW. In conformance with the California Environmental Quality Act (CEQA), an Environmental Impact Report was certified by the City Council for the Mayfield Development Agreement in 2005. The City of Palo Alto/Stanford Development Agreement and Lease Project Environmental Impact Report (EIR) (State Clearinghouse No. 2003082103) concluded that the proposed project(s) would not have a significant effect on the environment with mitigation as proposed except there would be significant and unavoidable Noise impacts, due to the use of heavy equipment during construction. The certified, Final EIR is available for review on the City’s web site at: http://www.cityofpaloalto.org/gov/topics/projects/landuse/mayfield.asp. In March 2014, Staff prepared an Environmental Confirmation Memo and determined there are no substantive changes to the previously approved project or circumstances under which the project is being undertaken and no new information, therefore the EIR provides the necessary environmental clearance for this subject project. All mitigation measures as stated in the approved Mitigation Monitoring and Reporting Program (MMRP) have been incorporated into the conditions of approval for the associated Architectural Review project (13PLN-00433). SECTION 3. FINAL MAP REVISION FINDINGS In addition to the amendments authorized by Government Code Section 66469, after a final map or parcel map is filed in the office of the county recorder, the recorded map may be modified by a certificate of correction or an amending map if: 1. There are changes in circumstances which make any or all of the conditions of such a map no longer appropriate or necessary. There are changes in circumstances (elevated TCE readings under seven home sites) that make certain final map conditions (the locations of those homes) no longer appropriate or necessary. 2. That the modifications do not impose any additional burden on the present fee owner of the property. The modifications do not impose any additional burden on Stanford, which is the fee owner of the property. 3. The modifications do not alter any right, title, or interest in the real property reflected on the recorded map. The modifications do not alter any right, title, or 1451-1601 California Avenue Page 3 of 3 interest in the real property reflected on the recorded map. 4. The map as modified conforms to the provisions of the Subdivision Map Act and Chapter 21.16 of the Palo Alto Municipal Code. The map as modified conforms to the provision of the Subdivision Map Act and the PAMC. PASSED: AYES: NOES: ABSENT: ABSTENTIONS: ATTEST: APPROVED: City Clerk Director of Planning and Community Environment APPROVED AS TO FORM: Senior Assistant City Attorney Department of Toxic Substances Control Matthew Rodriquez Secretary for Environmental Protection April 4, 2016 Ms. Annette Walton Stanford Real Estate Office 3160 Porter Drive, Suite 200 Palo Alto, California 94304 Dear Ms. Walton: Barbara A Lee, Director 700 Heinz Avenue Berkeley, California 94710-2721 Edmund G. Brown Jr. Governor The Department of Toxic Substances Control (DTSC) has reviewed the Revised Supplemental Investigation and Risk Assessment Report (SIRA) dated March 18, 2016 for the 1601 S. California site (Site) in Palo Alto, California. The SIRA documents the supplemental investigation activities performed to further evaluate the presence of volatile organic compounds (VOCs) at the Site, as previously discovered during historical sampling, The SIRA also presents evaluation using the comprehensive data collected from the Site to determine if chemicals present would pose a significant risk to future Site receptors, in particular residents of the planned faculty housing development. DTSC concurs with the conclusions presented in the SIRA. DTSC agrees that sufficient Site characterization has been performed to define the nature and extent of contamination present at the Site, and agrees that there would be no significant risk to future Site residents, based on the future redevelopment plans presented in the SIRA which illustrates the location of future residences outside of the localized on-Site VOC soil vapor plume. DTSC hereby approves the SIRA. As detailed in the SIRA, elevated VOCs in soil vapor were detected at the Site in one area (specifically in the vicinity of a former plating solution sump and operational areas of the former manufacturing facilities) that could potentially pose a significant risk to human health in a residential scenario. DTSC must review and approve the measures by which this specific area will be addressed to ensure that future Site users will not be exposed to such health risks prior to certifying that all necessary actions have been taken at the Site. @ Oil Attachment B Ms. Annette Walton April 4, 2016 Page 2 If you have any questions, please contact Jovanne Villamater at Jovanne.Villamater@dtsc.ca.gov, or via telephone at (510) 540-3876. Sincerely, Mark E. Piros, P.E., Unit Chief Brownfields and Environmental Restoration Program -Berkeley Office cc: Mr. Christopher Wuthmann (email to: cwuthman@stanford.edu) Mr. James Keene (email to: James.Keene@cityofpaloalto.org) Ms. Cara Silver (email to: Cara.Silver@cityofpaloalto.org) Ms. Molly Stump (email to: molly.stump@cityofpaloalto.org) Ms. Hillary Gitelman (email to: Hillarv.Gitelman@cityofpaloalto.org) Ms. Jodie Gerhardt (email to: jodie.gerhardt@cityofpaloalto.org) Ms. Susan Gallardo (email to: SGallardo@haleyaldrich.com) Attachment C S Matthew Rodriquez Secretary for Environmental Protection March 18,2016 Mr. Richard Stolee President, CTRA Board rstolee@qmail.com Mr. Lenny Siegel Executive Director, Center for Public Environmental Oversight lsiegel@cpeo.orq Dear Mr. Stolee and Mr. Siegel: The Department of Toxic Substances Control (DTSC) thanks you and the other attendees for participating in the meeting held on January 6,2016 regarding the 1601 S. California site (Site) in Palo Alto, California. We appreciate everyone taking time out of their schedules to attend. Enclosed are the responses to the questions and comments posed to DTSC regarding the Site. The College Terrace Residents'Association (CTRA) submitted to DTSC a letter dated January 26,2016 (CTRA Letter), which requested that DTSC answer Site- specific questions, specifically regarding the presence of trichloroethylene in various environmental media at the Site. Along with the CTRA Letter, the submittal email also included comments from Mr. Lenny Siegel, the Executive Director of the Center for Public Environmental Oversight (CPEO), dated January 25,2016 (CPEO Comments). ln collaboration with Haley and Aldrich, !nc. and Stanford University Office of Real Estate, DTSC presents the enclosed responses to both the CTRA Letter and CPEO Comments, with the hope to provide answers as well as to provide additional insight. Edmund G. Brown Jr. Governor 9-t:kt : Department of Toxic Substances Control Barbara A. Lee, Director 700 Heinz Avenue Berkeley, California 947 10-2721 @ Printed cn Rccycled Faoer Mr. Richard Stolee and Mr. Lenny Siegel March 18,2016 Page 2 !f you have any questions, please contact me via email at Jovanne.Villamater@dtsc.ca.sov, or via telephone at (51 0) 540-3876. Sincerely, Jovanne Villamater Project Manager Brownfields and Environmental Restoration Program - Berkeley Office Enclosure cc: Via electronic email to: Mr. Christopher Wuthmann cwuthman@stanford.ed u M. Jean McCown imccown@stanford.edu Ms. Hillary Gitelman H i I larv. G itel man@citvofpaloalto.orq Ms. Jodie Gerhardt iod ie. qerha rdt@citvofpaloa lto. o rq Mr. Fred Balin fbalin@qmail.com Mr. Roland Vogl RVool@law.stanford.ed u Ms. Molly Stump mol lv. stu mp@citvofpa loalto.orq Ms. Cara Silver Cara. S i lver@citvofpaloalto.orq M. Margit Aramburu Maro ith i nd @comcast. net Mr. Brent Barker brentqbarker@omail.com Mr. Richard Stolee and Mr. Lenny Siegel March 18,2016 Page 3 Ms. Lucy Wicks lwicks@stanford.edu Ms. Annette Walton nettie@stanford.edu Mr. James Keene James. Keene@citvofpa loalto.orq Ms. Susan Gallardo SGa I lardo@ ha levald rich. com Ms. Kimi Klein Kimi. Klein@dtsc.ca.sov Mr. John Karachewski John. Karachewski@dtsc.ca.qov Ms. Veronica Lopez-Villasenor Veron ica. Lopez-Vi I lasenor@dtsc.ca.qov Ms. Sue Dremann Staff Writer, Palo Alto Weekly sd reman n@ paweeklv. co m RESPONSE TO CENTER FOR PUBLIC ENVIRONMENTAL OVERSIGHT      March 18, 2016    SUBJECT: Response to Center for Public Environmental Oversight (CPEO) Comments      This document provides responses to questions raised by the Center for Public Environmental Oversight  (CPEO) in its January 25, 2016, letter to the College Terrace Residents’ Association (CTRA) regarding the  presence of trichloroethene (TCE) in subsurface soils at the University Terrace development located at  1451, 1501, and 1601 S. California Avenue in Palo Alto, California. The CPEO letter was transmitted to  the Department of Toxic Substances Control (DTSC) by CTRA on January 26, 2015. The responses and  information provided herein were prepared by the DTSC; Stanford University, Office of Real Estate  (Stanford), the property owner and developer; and its technical consultant, Haley & Aldrich, Inc. As  subsurface chemical impacts primarily were detected at the 1601 S. California Avenue parcel and it is  the focus of the current Preliminary Endangerment Assessment, this parcel is referred to by its address  or as the “Site”. References to the other parcels that comprise the University Terrace development are  referred to by their address.     Our specific responses to the five questions (and sub‐questions) provided by CPEO are below. CPEO’s   “top‐level” questions are underlined.    1. THE DECEMBER 2015 RISK ASSESSMENT UNDERSTATES THE RISK FROM TCE VAPOR INTRUSION.      The human health risk assessment (HHRA) included in the Supplemental Investigation and Risk  Assessment (SIRA) Report1 was completed in accordance with guidelines provided by the U.S.  Environmental Protection Agency (USEPA) and California Environmental Protection Agency (Cal‐EPA).  Following this guidance, the risk assessment was performed with both the cancer and non‐cancer target  indoor air concentrations.     CPEO states that the screening level for the concentration of TCE in soil vapor that was utilized in the  Site evaluation is problematic because the default DTSC screening level is higher than that currently  recommended by the USEPA. The default screening levels were used to provide an initial understanding  of the data. The results for every soil vapor sample collected at the 1501 and 1601 S. California Avenue  parcels were individually evaluated in the site‐specific assessment, regardless of whether the result  exceeds the default screening level. If a default screening level is exceeded, it does not indicate that a  health risk exists, but rather that additional evaluation is warranted, such as additional sampling or risk  characterization. With respect to the detections of TCE at the 1501 and 1601 S. California Avenue  properties, a thorough Site characterization program and Site‐specific risk assessment were performed.     Our response to CPEO’s comment 1 is presented in further detail below.                                                               1 Haley & Aldrich, Inc., 2015, Revised Supplemental Investigation and Risk Assessment Report, 1601 S. California  Avenue, Palo Alto, California, December 21.  Response to Center for Public Environmental Oversight  March 18, 2016     Page 2          After comparing Site sampling results to default screening levels, further evaluation of the vapor  intrusion pathway was performed by comparing concentrations of volatile organic compounds (VOCs)  measured in soil vapor to risk‐based screening levels (RBSLs) that are protective of human health. The  RBSLs were developed with Site‐ and depth‐specific attenuation factors that incorporate soil physical  properties measured at the Site and the specific sampling depth at each soil vapor probe location.     By design, the HHRA included a conservative evaluation of the vapor intrusion pathway. Levels of  conservativism in the evaluation include, but are not limited to, the following:     At locations that were sampled several times, the maximum concentration of VOCs measured in  soil vapor at each sample point were evaluated in the HHRA.   Future residents at the Site were assumed to occupy their homes 24 hours per day for 350 days  a year for 26 years.     Site‐specific risk‐based screening levels were developed using target indoor air concentrations published  by USEPA and DTSC to evaluate cancer risks and non‐cancer adverse health effects.     To support the soil vapor fate and transport evaluation, an analysis was included in the HHRA to  evaluate the sensitivity of the Johnson & Ettinger vapor intrusion model (J&E model) to physical soil  properties and the heterogeneity of soil conditions at the Site (Appendix G, Section 8.3.2.2 of the SIRA   Report). The results of the sensitivity analysis supported the conclusions of the risk assessment. In  addition, a review of the near surface geology at the Site was performed, which supported the modeling  performed in the HHRA.     2. STANFORD’S PLAN DOES NOT SUFFICIENTLY MITIGATE THE RISK OF VAPOR INTRUSION.     Stanford’s proposed mitigation measures are protective of future University Terrace residents and there  is no significant public health risk associated with this development. Mitigation measures, including but  not limited to sub‐slab vapor barriers, were incorporated into the development plan to provide an  additional level of protection that is not required by DTSC. To be conservative, these measures were not  included for risk calculations presented in the HHRA. Specifically, the following measures have been or  will be implemented:     Clean compacted (95% relative density) engineered fill material was placed on Site in the latter  half of 2015 to raise grade up to 15 feet above current grade. Note that this material primarily  was imported from the excavation to construct a subterranean structure at the adjacent  1501/1451 S. California Avenue parcels; soil at these parcels is documented as predominantly  fine grained clay and silt. The fill material was tested for the presence of VOCs and other  constituents prior to use.    Homes, buffered away from the TCE‐impacted areas, will be constructed with 10‐inch thick post‐ tension slabs that are more resistant to cracking. Impacted areas overlying greater TCE  Response to Center for Public Environmental Oversight  March 18, 2016     Page 3        concentrations in soil vapor will be designated for outdoor recreational space, which is  considered acceptable per USEPA guidance.2   Future residents will not be permitted to alter the foundation slab of future homes based on  codes, covenants, and restrictions (CC&Rs); Stanford will retain ownership of the land.   Slab penetrations (e.g., pipes) will be sealed and the foundations will be constructed with vapor  barriers designed to prevent indoor vapor intrusion.    Utility corridors will be constructed with vapor plugs.    Stanford engaged external peer review of its findings and approach. Dr. Paul Johnson, an internationally  renowned expert on vapor intrusion, has reviewed, evaluated and concurred with the Site conceptual  model and Stanford’s approach to address vapor intrusion. A copy of his letter stating his position is  attached.    Our response to CPEO’s comment 2 is presented in further detail below.    CPEO advocates the use of two specific mitigation measures, subslab depressurization and venting  systems, at sites where there is “simply a potential for vapor intrusion.” In contrast, USEPA or Cal‐EPA  recommend evaluating the potential for vapor intrusion by using multiple lines of evidence to develop a  Site Conceptual Model to support informed risk management decisions.2,3 USEPA recommends several  risk management options for developing sites with the potential for vapor intrusion, including  designating areas as recreational space or undeveloped landscape, and constructing buildings with  vapor mitigation technologies. Similarly, DTSC recommends several options relative to the ranges of  risks and hazards that were observed at the Site in the risk management framework included in the  2011 Vapor Intrusion Guidance3 and 2011 Vapor Intrusion Mitigation Advisory.4 In this case, additional  data collection and risk characterization were performed, and potential risks to future residents were  addressed with the reconfiguration of the development plan (i.e., impacted areas are designated for  recreational space).      As described in the SIRA Report, a thorough characterization program was implemented at the Site to  develop and test the Site Conceptual Model. At the 8.5‐acre 1601 S. California Avenue parcel, 130 soil  vapor samples were collected from 118 soil vapor probes installed at 51 locations in 2004 and from 2012  to 2015. To evaluate potential sources of VOCs to the subsurface, soil samples were collected at 16  locations beneath the former building slab and pavement and 11 samples of soil/residual sludge were  collected from subsurface pipes during building demolition in 2015. Soil samples also were collected  from 23 soil borings advanced to depths between 25 and 35 feet bgs where TCE‐impacted soil vapor was  observed (Section 4.2.4 of the SIRA Report). Finally, a detailed stratigraphic analysis of the                                                               2 USEPA, 2015, OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface  Vapor Sources to Indoor Air, Office of Solid Waste and Emergency Response, Publication 9200.2‐154, June.  3 DTSC, 2011, Guidance for the Evaluation and Mitigation of Subsurface Vapor Intrusion to Indoor Air (Vapor  Intrusion Guidance), Final, October.   4 DTSC, 2011, Vapor Intrusion Mitigation Advisory, Final, Revision 1, October.   Response to Center for Public Environmental Oversight  March 18, 2016     Page 4        unconsolidated fluvial (stream and floodplain deposits) sediments was performed using boring log data  to construct geologic cross sections.     The following Site Conceptual Model was developed based on the results of the supplemental  investigation activities and historical Site data, including the stratigraphic analysis:     The source of the TCE appears to have been a plating solution sump located in the former Phase  1 building, and potentially a chemical storage area to the southeast. TCE has migrated laterally  from these areas, but the affected area is constrained.    The migration of TCE follows the more permeable and discontinuous channels    Migration of TCE beyond these channels is limited by the denser, more clayey soil conditions  that predominantly characterize the Site, as shown by significantly lower detections of TCE  around the perimeter and in other areas of the Site.     Finally, a HHRA was conducted to evaluate potential human health risks with respect to future  residential development. Based on the results of this HHRA, there is no significant public health risk  associated with future residential development of the Site based on the layout of houses as presented in  the University Terrace development plan. As additional protective measures, several vapor intrusion  mitigation measures will be in place at the University Terrace development. These measures were not  included in the HHRA evaluation (that is, conditions at the Site were evaluated assuming the absence of  protective mitigation measures). Specifically, the measures listed above have been or will be  implemented.    CPEO further states that “Without spending a lot of time calculating attenuation factors and assessing  risk, Stanford should design mitigation into all the new housing, not just at 1601 S. California.” As stated  in its letter, this position is supported with CPEO’s experience with the “Middlefield‐Ellis‐Whisman  (MEW) Superfund Study Area in nearby Mountain View. At the Site, a detailed characterization program  was implemented to support a Site‐specific vapor intrusion evaluation. A comparison of the conditions  at the Site and the MEW Study Area is presented in the attached Table 1. In summary, the MEW Study  Area is not comparable because the geologic and hydrogeologic conditions differ from the 1601  California Avenue Site. At the MEW Study Area, there is continuous water‐bearing stratum at relatively  shallow depths, VOC impacts to groundwater (including TCE) are sourced from multiple industrial sites  and cover an area of approximately 2 miles long by 1.2 mile wide. In contrast, no continuous water‐ bearing zone has been identified in the upper 45 feet of the 1601 California Avenue Site and the VOC  source to soil vapor impacts is localized.     Finally, CPEO indicates that vapor barriers will be used at the Site as a “stand‐alone vapor remedy.”  However, remediation was performed at the Site to remove historic TCE sources. The source of TCE in  the subsurface, the former plating solution sump was excavated and removed on March 19, 2015,  and  all subsurface piping, including process, sewer, storm drain lines, subterranean structures and  foundation elements were removed in March and April 2015. Essentially, all potential historic sources of  TCE have been removed from the Site and there is no significant risk to public health associated with the  University Terrace development plan. Mitigation measures, including but not limited to sub‐slab vapor  barriers, were included in the development plan to provide an additional level of protection.   Response to Center for Public Environmental Oversight  March 18, 2016     Page 5        3. THE TECHNICAL DOCUMENTS FOR THE THREE DEVELOPMENT PARCELS DO NOT ADEQUATELY  EXPLAIN THE SOURCES, FATE, AND TRANSPORT OF TCE AT THE SITE.     As discussed above, a Site Conceptual Model that explains the potential sources of TCE in soil vapor,  distribution, conditions that result in its stability, and barriers to its migration was developed and tested  with a thorough Site characterization program. A discussion of the Site Conceptual Model is presented in  the Section 7.0 of the SIRA Report.    Our response to CPEO’s comment 3 is presented in further detail below.    CPEO indicates that the “identification of the TCE source is unconvincing.” However, there is ample  evidence that the primary source of TCE‐impacted soil vapor at the Site was the former plating sump:      TCE was detected in soil samples collected from borings advanced in 1990 and 1991 at the  former location as part of closure activities;    In 2015, TCE was detected in a residual sludge sample collected from a pipe exiting from the  former plating sump at a concentration of 2,200 micrograms per kilogram (µg/kg); and   The highest concentrations of TCE in soil were detected in samples collected from borings  advanced in the vicinity of the former plating sump (EX4‐04 and EX4‐06) at depths between 25  and 35 feet bgs. The maximum detected concentration of TCE was detected in the 35‐foot  sample from boring EX4‐06 at a concentration of 640 µg/kg, which is below the DTSC residential  screening level.    At soil vapor probes located within the footprint of the former chemical storage area (SG‐32, SG‐33, SG‐ 34, and SG‐35), TCE was detected at relatively high concentrations in soil vapor (ranging from 9,100 to  110,000 µg/m3, with the highest concentrations detected at SG‐34 at 15 feet bgs [100,000 µg/m3] and  SG‐35 at 25 feet bgs [110,000 µg/m3]). TCE was detected at low concentrations (4.3 to 16 µg/kg) in  shallow soil samples (5 feet bgs) collected at this area (SG‐32, SG‐34, and SG‐35). TCE may have  migrated via preferential pathways from the former plating sump to these areas. TCE is heavier than air  and water, and migrates downward in the soil column along preferential pathways.     In addition, soil samples were collected beneath the slab and pipes during the removal of the building  slab and associated subsurface utilities in March and April 2015. Specifically, soil or residual sludge  samples were collected where 1) soil or sludge was identified within a subsurface pipe, 2) total VOCs  were measured in soil with a portable photo‐ionization detector (PID), or 3) former operational features  (e.g., utility and process water lines) were previously identified. Sixteen soil samples were collected at  beneath the building slab and pavement and an additional 11 samples of soil/residual sludge were  collected directly from subsurface pipes during building demolition in 2015 to evaluate potential sources  of VOCs to the subsurface. TCE was detected at a concentration of 2,200 micrograms per kilogram  (µg/kg) in one sample (PVC‐PIPE) of residual sludge collected directly from a polyvinyl chloride (PVC)  pipe at the former plating sump, indicating the presence of TCE at the sump. TCE was not detected in  any other soil samples collected directly beneath the building slab or pavement, or any residual sludge  Response to Center for Public Environmental Oversight  March 18, 2016     Page 6        samples. Finally, it is important to note that no potential sources of VOCs to the subsurface were  identified at the 1451 and 1501 S. California Avenue parcels.     In summary, the distribution of TCE at and near these potential source areas is well‐defined.    4. GROUNDWATER, SOIL, AND SOIL GAS CONTAMINATED WITH TCE SHOULD BE REMEDIATED AT THE  SITE.     As stated above, remediation to remove all potential sources of TCE was performed at the Site. The  source of TCE in the subsurface, the former plating solution sump was excavated and removed on March  19, 2015. In addition, during building demolition activities all subsurface piping, including process,  sewer, and storm drain lines were removed, as well as all subterranean structures and foundation  elements.     Deep excavation at the Site is not warranted as soil analytical results did not indicate the presence of a  significant source of TCE in soil; rather, it is the soil vapor that is identified as the media of concern at  the Site. Based on the proposed site layout of the future redevelopment project, the results of the HHRA  in conjunction with the University Terrace development plan indicate no significant public health risk on  Site or to the surrounding community. Additionally, excavation is not practical due to 1) the  considerable depth at which excavation could be required (greater than 35 feet below the pre‐ development grade5) to remove vapor‐impacted soil, and 2) the negative impacts to the surrounding  neighborhood. These negative impacts include increased traffic, dust generation, noise, and a much  longer project schedule associated with this type of excavation.    Active remediation technologies, such as soil vapor extraction (SVE), would not likely be effective at this  Site. SVE, a proven technology for remediating coarser‐grained soils, is not practical at this Site due to  the clayey nature of the subsurface lithology which inhibits air flow between soil particles. The lack of air  flow in the subsurface at the Site was demonstrated during Site investigation as no flow conditions6  were encountered during sample collection on at least one occasion at more than 25 percent of the soil  vapor sample probes (that is, a sample could not be obtained due to the lack of soil vapor flow).     A Site‐specific HHRA was conducted to evaluate potential human health risks with respect to future  residential development. Based on the results of this focused HHRA, there is no significant public health  risk associated with future residential development of the Site based on the layout of houses as  presented in the University Terrace development plan. In addition, no public health risk was identified  for the surrounding community. Therefore, there are no requirements for remediation.     Finally, regarding the process that DTSC is following for this Site, the DTSC has reviewed the  Supplemental Investigation and Risk Assessment (SIRA) report for the site, and has concluded that site  characterization is complete and the risk assessment appropriately considers site conditions relative to                                                               5 Note that the site elevation has been raised by up to 15 feet over much of the area where the higher TCE  concentrations in soil vapor were detected.  6 “No flow conditions” refers to the inability to maintain a minimum soil vapor sampling flow rate.   Response to Center for Public Environmental Oversight  March 18, 2016     Page 7        public safety and future site development. With respect to the recommended formal finding, a summary  document to conclude the Preliminary Endangerment Assessment that has been conducted for the Site  will be prepared and reviewed and approved by DTSC. The summary document will summarize the  findings and conclusions from Site characterization reports, and provide the basis for the proposed  action to address the area of the Site where soil vapor has been found to be significantly impacted with  TCE. Land use restrictions are contemplated as an element of the proposed action since the area  currently cannot be used for unrestricted land use. The specific land use restrictions that are proposed  for the area will be identified and defined in the summary document. There will be a public notice prior  to a land use covenant or other mechanism with land use restrictions being put in place, which will give  CPEO an opportunity to provide input.    5. SAMPLING SHOULD BE CONDUCTED TO ENSURE THAT RESIDENTS OF COLLEGE TERRACE ARE NOT  AFFECTED BY TCE CONTAMINATION FOR THIS SITE.      Data collected at the Site adequately characterizes the extent of migration of soil vapor impacted by  TCE. Thus, no additional sampling is necessary.    Based on the sampling and subsequent evaluation conducted for the University Terrace site, soil vapor  with TCE at concentrations exceeding DTSC residential screening levels is more than 200 feet east of  California Avenue and does not extend to California Avenue. A figure that shows soil vapor sampling  locations parallel to California Avenue and highlights those locations where risk levels are below the  DTSC default residential screening level for TCE is attached (Figure 1). This figure additionally illustrates  those locations where concentrations were above screening levels but lower than the de minimis  incremental risk level of one in one million (1 x 10‐6) excess cancer risk, based on the Site‐specific risk  assessment performed for the Site.    Additionally, as shown on Figure 1, soil vapor sampling was conducted across the 1601 S. California  Avenue site in each compass direction to evaluate the distribution of TCE in soil vapor. Soil vapor  samples that did not contain detectable concentrations of TCE also were collected to the west, north,  northeast, and east of data point AMEC‐1 on the 1501 S. California Avenue parcel (note that not all of  these soil vapor sample locations are included on the figures presented in the appendix to the CTRA  letter).     The College Terrace community is safe with respect to potential vapor intrusion to constituents detected  in soil vapor at University Terrace based on several lines of evidence:     The lithology (geologic units) of primarily fine‐grained units along California Avenue inhibits  migration of soil vapor. A cross‐section parallel to California Avenue with concentrations of TCE  measured in soil vapor is presented as Figure 2.   The investigation data consistently indicate the absence of TCE above screening levels outside of  the operational and nearby area on the 1601 S. California Avenue site.    The release of TCE into the subsurface occurred at least several decades ago and all of the  potential sources of TCE (e.g., plating solution sump) were removed during Site demolition. Ten  Response to Center for Public Environmental Oversight  March 18, 2016     Page 8        years of soil vapor data at shallow depths have consistently demonstrated that concentrations  of TCE are below residential screening levels – levels designed to be fully protective of human  health and the environment ‐ except at some locations within and near the former operational  area of the Site.       Attachments:    Table 1  Comparison of Site Conditions, MEW Superfund Study Area, Mountain View and 1601 S.     California Avenue, Palo Alto  Figure 1  Soil Vapor Sample Locations  Figure 2  Cross Section X to X’     Letter from Dr. Paul Johnson to Annette Walton of Stanford dated January 5, 2016        Table 1  Comparison of Site Conditions  MEW1 Superfund Study Area, Mountain View and 1601 S. California Avenue, Palo Alto  MEW Superfund Study Area  1601 S. California Avenue  Depositional Environment Distal edge of Santa Clara Valley Alluvial Plain and   Bay Margin.  Upland margin of the Santa Clara Valley Alluvial  Plain.  Generalized Lithology Gravel, sand, silty and clayey gravels and sands; silts  and clay.  Clay, clayey sand, and subordinate sand with gravel  and clay.  Depth to First Water‐Bearing  Zone  Approximately 10 to 30 feet bgs. Greater than 45 feet bgs, although some lenses of  perched groundwater have been observed at  shallower depths.  VOC Source(s) Regional ‐ multiple sources  14 individual sites (some with multiple addresses) contribute to the regional groundwater plumes.  Localized  single facility VOCs of Concern Multiple VOCs, including but not limited to TCE,  tetrachloroethylene (PCE), cis‐1,2‐ dichloroethene,   trans‐1,2‐dichloroethene, and vinyl chloride.  TCE  VOC Concentrations in  Groundwater  TCE – varies; over 10,000 µg/L in certain source areas. TCE – 45 µg/L (maximum)  Soil Vapor Plume(s) area Approximately 2 miles long and ½‐mile wide. Local impact limited to on‐site former operational  area approximately 38,600 square feet (< 1 acre)   VOC = volatile organic compounds  bgs = below ground surface  VI = vapor intrusion  µg/L = micrograms per liter  1 Middlefield‐ Ellis‐Whisman (MEW) Study Area is comprised of three National Priorities List (NPL) or Superfund Sites as well as several other facilities and portions  of the former Naval Air Station Moffett Field Superfund site. The MEW Superfun Area is overseen by the U.S. Environmental Protection Agency. Detailed  information regarding the MEW Study area can be found at http://yosemite.epa.gov/r9/sfund/r9sfdocw.nsf/ViewByEPAID/CAD982463812  @@A @@A @@A @@A @@A@@A@@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A@@A@@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A@@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A@@A @@A @@A @@A @@A @@A @@A@@A@@A @@A @@A@@A @@A @@A @@A @@A @@A @@A@@A @@A@@A @@A @@A @@A 1601 S. CALIFORNIA 1501 S. CALIFORNIA 1451 S. CALIFORNIA RESIDENTIAL AM H E R S T S T R E E T BO W D O I N S T R E E T DRAKE W A Y S CALIFORNIA AVE AM H E R S T S T BO W D O I N S T CO L U M B I A S T DAR T M O U T H S T SG-35 SG-34 SG-40SG-32 SG-33 SG-36 SG-30 AMEC-6 AMEC-13 SG-15SG-24SG-21 SG-26 SG-27 SG-29 AMEC-1 AMEC-8 SG-14 SG-38 SG-41 SG-23 SG-28 AMEC-10 SG-19 AMEC-7 SG-16 SG-17 SG-25 SV-8 SV-6 SV-7 SG-37 SG-18 SG-20 SV-1 SVA-2 SV-2 SV-3 SV-4 SV-5 SVA-14 SVA-12 SVA-15 SVA-10 SVA-9 SVA-7 SVA-6 SVA-4SVA-3 SVA-5 SG-39 SG-42 SG-31 SV-1 SV-10 AMEC-11 SV-9 SV-3 AMEC-12 SV-2 AMEC-2 AMEC-4 AMEC-9 SV-1 SV-3 SV-4 AMEC-3SV-11 SV-6 SV-7SV-8 SV-9 SV-10 SV-12 SV-4 SV-13 SV-7 SV-15 SV-5SV-6 SV-14 SV-8 SV-11 NOTES 1. THE 1451, 1501, AND 1601 S. CALIFORNIA AV ENUE PARCELSCOM PRISE THE UNIV ERSITY TERRACE PROJECT. 2. DEV ELOPM ENT PLAN SOURCE: W ILLIAM HEZ M ALHALCHARCHITECTS INC., REV ISED SITE PLAN, 9-23-2015. 3. µg/m 3 = M ICROGRAM S PER CUBIC M ETER 4. AERIAL IM AGERY SOURCE: ESRI 1451, 1501 AND 1601 S. CALIFORNIA AV ENUEPALO ALTO, CALIFORNIA SOIL V APOR SAM PLE LOCATIONS FIGURE 1SCALE: AS SHOW NFEBRUARY 2016 LEGEND @@A DENOTES TCE W AS NOT DETECTED IN ANY SAM PLES AT ACONCENTRATION EXCEEDING THE RESIDENTIALSCREENING LEV EL (480 µg/m 3) @@A DENOTES TCE W AS NOT DETECTED IN ANY SAM PLES AT ACONCENTRATION EXCEEDING AN ESTIM ATED LIFETIM EEXCESS CANCER RISK OF ONE-IN-A-M ILLION (1X10 -6 ) @@A DENOTES TCE W AS DETECTED IN AT LEAST ONE SAM PLE ATA CONCENTRATION EXCEEDING AN ESTIM ATED LIFETIM EEXCESS CANCER RISK OF ONE-IN-A-M ILLION (1X10 -6 ) PROPERTY BOUNDARY 0 100 200 SCALE IN FEET 110 100 90 80 70 60 50 40 30 20 10 110 100 90 80 70 60 50 40 30 20 10 EL E V A T I O N ( F E E T A B O V E M S L ) EL E V A T I O N ( F E E T A B O V E M S L ) x x’ 01020 0 50 100 VERTICAL SCALE SCALE IN FEET HORIZONTAL SCALE SV-1 SV-2 SG-20 SG-31 SG-18 SG-17 SV-8 SV-10 AMEC-11 AMEC-12 EB-8 EB-14 EB-3 SG-19 44 W 49 W 43 E 4 W 2 E 6 E 47 E 3 W 2 W 35 E 51 E 19 E 16 W 24 E SV-1 48 W SV-2 1 E SO I L C O N D I T I O N S N O T L O G G E D SO I L C O N D I T I O N S N O T L O G G E D SO I L C O N D I T I O N S N O T L O G G E D SO I L C O N D I T I O N S N O T L O G G E D GROUND SURFACE ELEVATION ALONG SECTION LINE (SEE NOTE 4)<8 <8 <8 <8 <8 <8 <8 <8 <8 <8 <8 <8 <100 <100<100 NF <8 <7.1 <8 29 13.8 11.4 23.2 NF NF NF NF NF SVA-4 0 <100 1451, 1501 AND 1601 S. CALIFORNIA AVENUE PALO ALTO, CALIFORNIA CROSS SECTION X TO X' FIGURE 4SCALE: AS SHOWN FEBRUARY 2015 22016 SV-10 2 W <100 GEOLOGIC EXPLANATION BOREHOLE SYMBOLS FILL SILTS AND CLAYS (FINE GRAINED UNITS) CLAYEY GRAVELS AND SANDS (COARSE GRAINED UNITS) BORING DESIGNATION OFFSET DISTANCE BETWEEN BORING AND CROSS SECTION LINE (FEET) STRATUM BOUNDARY NO FLOW CONDITIONS DURING SOIL VAPOR SAMPLING MAXIMUM DETECTED SOIL VAPOR CONCEN- TRATION OF TRICHLOROETHENE (TCE) IN MICROGRAMS PER CUBIC METER TCE NOT DETECTED IN SOIL VAPOR SAMPLE. CONCENTRATION INDICATED IS THE TEST DETECTION LIMIT SG-17 16 W NF 300 <8 NOTES: 1. REFER TO FIGURE 1- SITE VICINITY WITH DEVELOPMENT PLAN AND CROSS SECTIONS, FOR PLAN LOCATION, DESIG- NATION, AND ORIENTATION OF SUBSURFACE SECTIONS AND AS-DRILLED EXPLORATION LOCATIONS. 2. TEST BORING GROUND SURFACE ELEVATIONS WERE ESTIMATED AND SHOULD BE CONSIDERED APPROXIMATE. 3. SATURATED SOIL CONDITIONS WERE NOT ENCOUN- TERED IN ANY OF THE TEST BORINGS SHOWN ON THIS SECTION. 4. BORINGS SHOWN ABOVE AND BELOW THE GROUND SURFACE ELEVATION ARE PROJECTED ONTO THE SECTION. THE TOP OF BORING REPRESENTS THE GROUND SURFACE ELEVATION AT THE LOCATION WHERE THE BORING WAS DRILLED. CROSS SECTION LOCATION PLAN LIMITS OF 1601 S. CALIFORNIA PROPERTY LIMITS OF 1501 S. CALIFORNIA PROPERTY LIMITS OF 1451 S. CALIFORNIA PROPERTY January 5, 2016 Annette Walton Director - Environmental Management Real Estate Operations 3160 Porter Drive, Suite 200 Palo Alto, California 94304 Dear Annette – As requested, this letter briefly summarizes key points of my review and our discussions related to the health risk assessment and development plans at Stanford’s University Terrace Project, which involves the redevelopment of three former industrial-use properties to a neighborhood consisting of Stanford faculty housing and open park space. No further action letters were issued in 2013 by the California State Department of Toxic Substances Control (DTSC) for two of the properties (1451 and 1501 California Avenue, Palo Alto, CA). Based on environmental reports provided to DTSC, they concluded that neither site posed a significant threat to human health or the environment under residential land use. Thus, my involvement has been focused on the third property at 1601 California Avenue, for which supplemental investigation was conducted to thoroughly assess the potential for significant health risks from post-remediation TCE residuals at depth in the subsurface. That assessment is summarized in the Supplemental Investigation and Risk Assessment Report, 1601 S. California Avenue, Palo Alto, California, prepared by Haley & Aldrich, Inc. Key points from my review and our discussions include the following: Relative to the initial draft, conclusions in the final version of the Supplemental Investigation and Risk Assessment Report, 1601 S. California Avenue, Palo Alto, California were the same, but strengthened by the thorough evaluation of the site conceptual model conducted by Murray Einarson and the expanded range of site-specific inputs that were incorporated by Haley & Aldrich, Inc. in their calculations. These additions increased confidence in the conclusions stemming from vapor intrusion pathway analysis because the selection of defensible site-specific inputs and considering a range of possible scenarios is critical to generating confidence in the results. It was also critical, because subsurface geology is a key controlling factor for vapor migration at this site. There is confidence in the use of the site data for the risk analysis because the historical information, subsurface geology conceptual model, and chemical distribution appear to be self- consistent. The site plan for the University Terrace Project reflects the analysis and conclusions contained in the Supplemental Investigation and Risk Assessment Report, 1601 S. California Avenue, Palo Alto, California. Future residences are placed in areas with projected negligible risks and the relatively isolated area of possible concern is open park space in the plan. The risk assessment report concludes that the future residences will not be exposed to significant health risks under any building construction design and that pre-emptive building-specific mitigation measures are not needed (e.g., sub-slab depressurization systems). The sub-foundation vapor barrier liners being incorporated in the residential construction, therefore, are not necessary, but will add an additional level of protectiveness from vapor intrusion and potential comfort for the occupants. Development plans also address the potential for vapor intrusion via alternative pathways, as we discussed recent studies where vapor intrusion was observed in buildings off-set from subsurface vapor sources as a result of transport along utilities and utility conduits. The potential for this is being eliminated in the planned development design by ensuring that utilities are not run through the residual vapor source at the site and by having vapor plugs/seals installed along the utilities. Should you have questions or require clarification of this summary, please feel free to contact me. Sincerely, Paul C. Johnson, Ph.D. RESPONSE TO COLLEGE TERRACE RESIDENTS’ ASSOCIATION    March 18, 2016    SUBJECT: Response to College Terrace Residents’ Association (CTRA) Comments      Summary:  This document provides responses to questions raised by the College Terrace Residents’  Association (CRTA) in its January 26, 2016 letter to the Department of Toxic Substances Control (DTSC)  regarding environmental conditions at the University Terrace development located at  1451, 1501, and  1601 S. California Avenue in Palo Alto, California. Because subsurface chemical impacts were primarily  detected at the 1601 S. California Avenue parcel and it is the focus of the current Preliminary  Endangerment Assessment, this parcel is referred to by its address or as the “Site.” References to the  other parcels that comprise the University Terrace development are referred to by their respective  addresses. The responses to questions asked and supporting information provided below were prepared  jointly among the DTSC; Stanford University, Office of Real Estate (Stanford), the property owner and  developer; and its technical consultant, Haley & Aldrich, Inc.     In its letter, CTRA provides comments and recommendations to address the presence of trichloroethene  (TCE) in the subsurface at the University Terrace development. As indicated in our response below,  which includes supporting information and figures, we have concluded the following:     The Site has been thoroughly investigated and evaluated.   The extent of chemical impacts to soil vapor are defined.   The development plan is protective of human health.   No additional testing at the Site or adjacent properties is needed.    Dr. Paul Johnson, an internationally renowned expert on vapor intrusion, reviewed, evaluated  and concurred with Stanford’s findings and approach to address vapor intrusion.     Questions/Answers:  Specific responses to the nine questions and sub‐questions provided by CTRA are  addressed below with CRTA’s “top‐level” questions shown in italics.    1. HOW CAN WE KNOW THAT THE TCE LEVELS ACROSS CALIFORNIA AVE IN COLLEGE TERRACE, WHERE  HOMES HAVE NO VAPOR INTRUSION MITIGATION, ARE SAFE?    A thorough characterization program was implemented at the Site to evaluate the extent of TCE in soil  vapor. Key points regarding the distribution of TCE in soil vapor are summarized below:     Soil vapor sampling was conducted radially (i.e., extended laterally) and at multiple depths from  the on‐Site source area until the extent of TCE in soil vapor was fully defined.   The sampling pattern and analytical results demonstrate that TCE impacts in soil vapor are  defined and contained within the operational area of the Site.  Response to College Terrace Residents’ Association  March 18, 2016     Page 2         There are 15 soil vapor sampling locations collected parallel to California Avenue and opposite  the College Terrace community in which analytical results show that TCE either was not  detected or detected below the DTSC residential screening level. These results lead to the  conclusion that TCE‐impacted soil vapor does not extend off Site to S. California Ave.   Clayey soil beneath the Site inhibits the vertical and lateral migration of TCE in soil vapor (that is,  vapors have a hard time moving through clay). Borings drilled at the site found the presence of  clayey soil at shallow depths at the northern and western portion of the Site, as well as at other  boring locations throughout the Site. More permeable and discontinuous units were also  observed in the characterization borings located throughout the Site. These coarser grained  units at the Site, where higher concentrations of TCE in soil vapor were detected at some  locations, contain a considerable fraction of finer‐grained (clayey) soil.   A Site‐specific risk assessment identified locations on‐Site where the soil vapor results exceed  the threshold incremental risk level of one in one million (1 x 10‐6) excess cancer risk; the  exceedances are all within and immediately adjacent to the former operational area of the Site.  Stanford will not construct homes over these locations or within an established buffer zone.  A Site conceptual diagram of the environmental conditions relative to the Site development is shown on  Figure 1. No additional investigation or remediation (see CTRA question 2) is necessary for the Site or  surrounding area.    Our response to CTRA question 1 is presented in further detail below.    An iterative approach was implemented, so that the extent of TCE impact was clearly defined in all  directions at depths down to 25 to 35 feet below ground surface (bgs) from the area identified as the  source of the release. At the 8.5‐acre 1601 S. California Avenue parcel, 130 soil vapor samples were  collected at multiple depths from 118 soil vapor probes installed at 51 locations in 2004 and from 2012  to 2015. To evaluate potential sources of volatile organic compounds (VOCs) in the subsurface, soil  samples were collected at 16 locations beneath the building slab and pavement, and 11 samples of  soil/residual sludge were collected from subsurface pipes during building demolition in 2015. Soil  samples were also collected from 23 soil borings advanced to depths between 25 and 35 feet bgs where  TCE‐impacted soil vapor was observed. Finally, a detailed stratigraphic analysis of the unconsolidated  fluvial (stream and floodplain deposits) sediments was performed using boring log data to construct  geologic cross sections.     As presented in the Supplemental Investigation and Risk Assessment (SIRA) Report,1 which has been  reviewed and commented on and is supported by DTSC, data collected at the California Avenue parcels  demarcate the extent of soil vapor impacted by TCE. Based on the sampling and subsequent evaluation  conducted for the Site, soil vapor with TCE at concentrations exceeding DTSC residential screening levels  occurs more than 200 feet east of California Avenue and does not extend to California Avenue. A figure  that shows soil vapor sampling locations parallel to California Avenue and highlights those locations  where risk levels are below the DTSC default residential screening level for TCE is attached (dark blue                                                               1 Haley & Aldrich, Inc., 2015, Revised Supplemental Investigation and Risk Assessment Report, 1601 S. California  Avenue, Palo Alto, California, December 21.  Response to College Terrace Residents’ Association  March 18, 2016     Page 3        circles; Figure 2). This figure additionally illustrates those locations where concentrations were above  screening levels but lower than the de minimis incremental risk level of one in one million (1 x 10‐6)  excess cancer risk (light blue circles), based on the Site‐specific risk assessment performed.  As additionally shown on Figure 2, soil vapor sampling was conducted across the 1601 S. California  Avenue Site in each compass direction to evaluate the distribution of TCE in soil vapor. Soil vapor  samples that did not contain detectable concentrations of TCE also were collected to the west, north  northeast, and east of data point AMEC‐1 on the 1501 S. California Avenue parcel (note that not all of  these soil vapor sample locations are included on the figures developed by CRTA, which are included as  an appendix in their letter).     The College Terrace community is safe with respect to potential vapor intrusion of constituents detected  in soil vapor at University Terrace based on several lines of evidence:     Clayey soil inhibits the migration of TCE in soil vapor. The lithology (soil type) of primarily  fine‐grained soil along California Avenue (cross‐section presented on Figure 3) inhibits  migration of soil vapor.    The investigation data consistently indicate an absence of TCE above screening levels  outside of the operational and nearby area on the 1601 S. California Avenue Site, as shown  on Figure 2.   The release of TCE into the subsurface occurred at least several decades ago and all of the  potential sources of TCE (e.g., plating solution sump) were removed during Site demolition.  Ten years of soil vapor data at shallow depths have consistently demonstrated that  concentrations of TCE are below residential screening levels – levels designed to be fully  protective of human health and the environment ‐ except at some locations within and near  the former operational area of the Site.  CTRA has asked about the screening level used in the analysis of site conditions and whether a lower  screening level may be appropriate. Note that screening levels are used to facilitate an initial evaluation  of site characterization data. If a screening level is exceeded, it does not indicate that a health risk exists,  but rather that additional evaluation is warranted, such as additional sampling or risk characterization.  With respect to the detections of TCE at 1601 S. California Avenue, a thorough site characterization  program and site‐specific risk assessment subsequently were performed. The risk assessment was  performed on a point by point basis, with all sampling locations and analytical data incorporated. The  need for mitigation and/or remediation is determined by the results of this site‐specific evaluation.     The attenuation factor used by DTSC to initially evaluate the presence of TCE in soil vapor is different  than that presented in the U.S. Environmental Protection Agency’s (USEPA’s) 2015 guidance document.  During the January 6, 2016, meeting with representatives of CTRA, Stanford, and the DTSC, Dr. Kimiko  Klein, DTSC Staff Toxicologist, discussed reasons why the USEPA screening level is not used at DTSC‐ regulated sites in California. Dr. Klein stated that there are several limitations to the use of the USEPA  empirical database of paired indoor air and subsurface data points; among them, the database from  which the USEPA derived its factor is from sites across the country, and includes sites where extreme  cold weather conditions enhance vapor migration into homes. Such weather conditions do not exist at  the 1601 California Avenue site and vicinity, or other locations in the Bay Area. Other important factors,  Response to College Terrace Residents’ Association  March 18, 2016     Page 4        such as soil type or sample depth, were not accounted for in the USEPA attenuation factor used to  derive its suggested screening level.     As part of question 1, CTRA commented that TCE was detected in groundwater samples collected at  1601 S. California Avenue as part of the groundwater monitoring and extraction program associated  with a site located on Page Mill Road on behalf of Hewlett Packard (HP). The groundwater investigations  completed at the nearby Page Mill Road site provide important information regarding the depths of  groundwater zones.       Groundwater extraction and monitoring at 1601 S. California Avenue related to the Page Mill  Road site is focused on very deep strata (Lower Santa Clara Formation), at depths greater than  250 feet. Consequently, there is 250 feet of fine‐grained sediments that exist between the deep  VOCs, including TCE, in groundwater and the ground surface, preventing exposure to vapor  receptors.    In 2013, the California Regional Water Quality Control Board, San Francisco Bay Region (Water  Board), which is the oversight agency for the Page Mill Road site, determined that VOC  concentrations in the deep water bearing zones beneath the 1601 S. California site were  sufficiently low so that the groundwater monitoring wells located on that site were no longer  needed, and granted its approval to close and remove the wells. The letter and subsequent  email from the Water Board describing the rationale for decommissioning and destroying the  wells is attached.   Note that shallow groundwater beneath the 1601 S. California Avenue site and near College  Terrace is within a different and much younger geologic unit (Quaternary alluvium) than the  deeper strata being addressed as part of the Page Mill Road remediation program. Site specific  geologic analysis, local topography, and regional monitoring data support an overall  groundwater flow direction to the east‐ northeast, that is, away from College Terrace, in the  shallow alluvium beneath the 1601 S. California Ave. site.    Finally, as part of its remediation program, groundwater extraction and treatment is ongoing at  the Page Mill Road site under the regulatory oversight of the Water Board. Groundwater  extraction removes chemical mass from the subsurface and also inhibits further movement of  impacted groundwater. Site remediation will continue until the Water Board deems that site  cleanup is adequate for protection of human health and the environment. This program  provides additional assurance that properties within the vicinity of the Page Mill Road site will  continue to be protected from the historical groundwater impacts.  2. WHY NOT REQUIRE REMEDIATION OF THE TCE CONTAMINATION?    Remediation was performed at the Site to remove TCE sources. The source of TCE in the subsurface, the  former plating solution sump, was excavated and removed on March 19, 2015. In addition, during  building demolition activities (conducted from March 19 to April 17, 2015), chemical storage areas, all  subsurface piping, including process, sewer, and storm drain lines were removed, as well as all  subterranean structures and foundation elements. This means that all potential historic sources of TCE  have been removed from the Site.   Response to College Terrace Residents’ Association  March 18, 2016     Page 5          A Site‐specific human health risk assessment (HHRA) was conducted to evaluate potential human health  risks with respect to future residential development. The results of this HHRA, show there is no  significant public health risk associated with the design of the future residential development of the Site  based on the layout of houses as presented in the University Terrace development plan. For the small  land area where the risk exceeds one‐in‐a‐million, the construction of new homes or other structures  will be prohibited with the adoption of a land use restriction. Finally, no public health risk was identified  for the development or surrounding community.     Our response to CTRA question 2 and sub‐questions is presented in further detail below.    A thorough Site characterization program was implemented during and following building demolition to  delineate and develop an approach to address TCE‐related impacts in the subsurface:     Soil samples were collected beneath the slab and pipes during the removal of the building slab  and associated subsurface utilities in March and April 2015. Specifically, soil or residual sludge  samples were collected where 1) soil or sludge was identified within a subsurface pipe, 2) total  VOCs were measured in soil with a portable photo‐ionization detector (PID), or 3) former  operational features (e.g., utility and process water lines) were previously identified. Sixteen soil  samples were collected from beneath the building slab and pavement and an additional 11  samples of soil/residual sludge were collected directly from subsurface pipes during building  demolition in 2015 to evaluate potential sources of VOCs to the subsurface.   o TCE was detected at a concentration of 2,200 micrograms per kilogram (µg/kg) in one  sample (PVC‐PIPE) of residual sludge collected directly from a polyvinyl chloride (PVC)  pipe at the former plating sump, indicating that a solution containing TCE had passed  through the sump. No visual indications or PID measurements were observed in shallow  soil at the former sump during the removal of sump. Therefore, no additional soil  samples were collected during demolition. However, this area was further evaluated  with the collection of soil samples at 5 foot intervals to a depth of 35 feet bgs from soil  boring EX4‐02, which was advanced at the location of the former sump. The maximum  detected concentration of TCE in soil samples collected at EX4‐02 was 26 µg/kg at 15  feet bgs, which is below the Regional Screening Level (RSL) for residential soil (940  µg/kg) published by USEPA (2015) and endorsed by DTSC (2015).     o TCE was not detected in any of the other 16 soil samples or 10 soil/residual sludge  samples collected directly beneath the building slab or pavement at the utility or  process lines, or where visual indications or PID detections were observed.       Soil samples also were collected from 23 soil borings (including EX4‐02) advanced to depths  between 25 and 35 feet bgs following Site demolition. The analytical results from these efforts  are presented in the SIRA Report. TCE concentrations in soil beneath the former operational  area, where detected, ranged from 4.3 µg/kg (SG‐02 at 5 feet bgs) to 640 µg/kg (EX4‐06 at 35  feet bgs); the Regional Screening Level (RSL) for residential soil published by USEPA (2015) and  endorsed by DTSC (2015) is 940 µg/kg. The results did not indicate the presence of a significant  source of TCE in soil.  Response to College Terrace Residents’ Association  March 18, 2016     Page 6           Finally, it is important to note that no potential sources of VOCs to the subsurface were  identified at the 1451 and 1501 S. California Avenue parcels.    The results of this sampling and monitoring program indicated that excavation of impacted soil is not  necessary at the Site as the analytical results for soil samples did not indicate the presence of a  significant source of TCE in soil; rather it is the soil vapor that is identified as the media of concern at the  Site.      Finally, the approach for addressing residual concentrations of TCE in soil vapor at the Site is consistent  with DTSC guidance. As described in the DTSC risk management framework (2011 Vapor Intrusion  Guidance), several activities are recommended for the ranges of risks and hazards observed at the Site  (i.e., risks between 1x10‐6 to 1x10‐4 and hazards greater than 1.0). In this case, additional risk  characterization was performed and the development plan was reconfigured to mitigate potential risks  to future residents. A Site‐specific HHRA evaluated concentrations of TCE measured in soil vapor to  determine potential human health risks with respect to future residential development. Based on the  results of this HHRA, there is no significant public health risk associated with future residential  development of the Site based on the layout of houses as presented in the University Terrace  development plan; however, Stanford has elected to implement additional protective measures to  guard against vapor intrusion (including engineering and institutional controls) at the University Terrace  development. To be conservative, these measures were not included in the risk calculations presented  in the HHRA. Specifically, the following measures have been or will be implemented:     Clean compacted (95% relative density) engineered fill material was placed on Site in the latter  half of 2015 to raise grade up to 15 feet above the post‐demolition grade. Note that this  material primarily was clean, fine‐grained imported fill from the excavation to construct a  subterranean structure at the adjacent 1451 and 1501 S. California Avenue parcels. Soil at these  parcels is documented as predominantly fine grained clay and silt. Chemical testing of the fill  material showed that it did not contain VOCs and other harmful constituents prior to use. The  additional clean fill material increases the depth to TCE‐impacted soil vapor, compared to the  depth evaluated in the HHRA.    Homes, buffered away from the impacted areas, will be constructed with 10‐inch thick post‐ tension slabs that are more resistant to cracking. Impacted areas overlying greater TCE  concentrations in soil vapor will be designated for outdoor recreational space, which is  considered acceptable per USEPA guidance.2    Future residents will not be permitted to alter the foundation slab of future homes based on  codes, covenants, and restrictions (CC&Rs); Stanford will retain ownership of the land.   Slab penetrations (e.g., pipes) will be sealed and the foundations will be constructed with vapor  barriers designed to prevent indoor vapor intrusion.                                                                2 USEPA, 2015, OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface  Vapor Sources to Indoor Air, Office of Solid Waste and Emergency Response, Publication 9200.2‐154, p. 150, June.  Response to College Terrace Residents’ Association  March 18, 2016     Page 7         Utility corridors that will run through the area where TCE was detected in soil vapor will be  constructed with vapor plugs.  Note that Stanford engaged external peer review of its findings and approach. Dr. Paul Johnson, an  internationally renowned expert on vapor intrusion, reviewed, evaluated and concurred with the Site  conceptual model and Stanford’s approach to address vapor intrusion. A copy of his letter stating his  position is attached.    a. If TCE is not in the groundwater as the Risk Assessment and Stanford state (but we have  reasons to doubt), then why not just dig out contaminated soil?  b. If TCE is in fact in the groundwater, and cannot be remediated by mere removal, why not  mandate appropriate mitigation strategies?    With respect to specific remediation technologies:    As described above, soil sampling at the Site did not reveal concentrations of TCE in soil that would  warrant deep excavation, and the results of the HHRA in conjunction with the University Terrace  development plan indicate no public health risk on Site or to the surrounding community. Additional  excavation at the Site is not necessary, as analytical results for soil samples did not indicate the presence  of a significant source of TCE in soil, but rather are indicative of TCE in the vapor phase. Additionally,  excavation is not practical due to 1) the considerable depth at which excavation could be required to  remove vapor‐impacted soil (greater than 35 feet below the pre‐development grade3), and 2) the  negative impacts to the surrounding neighborhood. These negative impacts include increased traffic,  dust generation, noise, and a much longer project schedule associated with this type of excavation.    Active remediation technologies, such as soil vapor extraction (SVE), would not likely be effective at this  Site. SVE, a proven technology for remediating coarser‐grained soils, is not practical at this Site due to  the clayey nature of the subsurface lithology which inhibits air flow between soil particles. The lack of air  flow in the subsurface at the Site was demonstrated during Site investigation as no flow conditions4  were encountered during sample collection on at least one occasion at more than 25 percent of the soil  vapor sample probes (that is, a sample could not be obtained due to the lack of soil vapor flow).     3. HOW WIDESPREAD IS TCE ON THE UNIVERSITY TERRACE SITE?    The extent of TCE‐impacted soil vapor at the University Terrace development is defined; Figure 17 of the  SIRA Report graphically illustrates that TCE is not only defined by its location/extent, but also by the  potential incremental excess cancer risk (defined as a 1 x 10‐6 threshold) that soil vapor at that location  could pose to an individual. Additionally, the distribution of soil vapor is discussed in detail in Section 7.2  (titled “Distribution”) of the SIRA Report. In Figure 17, the orange circles represent TCE that would  exceed the residential risk threshold. Note that sample depths are based on the pre‐development grade,                                                               3 Note that the site elevation has been raised by up to 15 feet over much of the area where the higher TCE  concentrations in soil vapor were detected.  4 “No flow conditions” refers to the inability to maintain a minimum soil vapor sampling flow rate.   Response to College Terrace Residents’ Association  March 18, 2016     Page 8        which subsequently has been filled by up to 15 feet of clean fill where higher TCE concentrations have  been detected. Every data point that is not orange represents locations where TCE concentrations in soil  vapor, if present, do not represent incremental health risk above the de minimis 1 x 10‐6 threshold. The  sampling strategy and risk assessment provide the supporting information that demonstrates TCE‐ impacted soil vapor does not extend beyond the 1601 S. California Avenue Site, with the exception of  one soil vapor sample location at 1501 S. California Avenue that is located directly adjacent to the 1601  S. California Avenue parcel. At that one location (AMEC‐1), TCE was detected in soil vapor at depths of  15 and 25 feet bgs at concentrations exceeding the DTSC residential screening level. However, TCE was  detected at a concentration below the DTSC residential screening level in a sample collected at 8 feet  bgs at that location. These results were further evaluated with a site‐specific risk assessment, which  indicated the presence of TCE at that location does not represent incremental health risk above the de  minimis one‐in‐a‐million threshold. TCE was not detected in soil vapor collected at nearby sampling  points at 1501 S. California Avenue at concentrations exceeding the DTSC screening level. The data  evaluation and results for 1501 S. California Avenue are fully discussed and described in the October  2013 report titled “Additional Environmental Investigation Results and No Further Action Request.” For  1601 S. California Avenue, the data evaluation and results are fully discussed and described in the SIRA  Report.    Our response to CTRA question 3 is presented in further detail below.    The attached Figure 2 that is provided with this memorandum illustrates soil vapor sampling locations at  each of the 1451, 1501, and 1601 S. California Avenue parcels (the University Terrace development).  (Note that not all of these soil vapor sample locations, particularly at 1501 S. California Avenue, are  included on the figures developed by CRTA and included as an appendix in their letter). The data  generated from these sampling locations demonstrate that the extent of impacts to soil vapor at the Site  are defined and primarily isolated to the former operational area at 1601 S. California Avenue. An  extensive evaluation of Site lithology has been conducted; the information generated through this  evaluation confirms that vapor concentrations are highest in coarser grained units (that is, coarser‐ grained soil in a clayey matrix) and that the finer‐grained, clayey soil effectively retards the migration of  TCE‐impacted soil vapor in the subsurface. The CTRA letter notes that elevated concentrations of TCE in  soil vapor exist from the sump area in an easterly direction; this distribution of TCE in soil vapor is  consistent with the observed, coarser‐grained lithology.    There is no evidence groundwater is a significant transport mechanism for TCE at the University Terrace  development. As discussed at the January 6. 2016, meeting, a continuous water‐bearing unit has not  been observed in the upper 40 feet of the 1601 S. California Avenue Site, and borings have been  advanced as deep as 68 feet without encountering saturated deposits. Figure 4 illustrates borings that  have been drilled to at least 25 feet below ground surface across the three parcels, i.e., including 1451  and 1501 S. California Avenue, and indicates whether saturated soil/groundwater has been observed  across the overall project Site. Analytical results are presented for these locations on Figure 5, indicating  that TCE was detected in groundwater at two of the nine locations (45 micrograms per liter [µg/L] at  SBA‐9 and 13 µg/L at GW‐20) at concentrations below the Environmental Screening Level (170 µg/L)  Response to College Terrace Residents’ Association  March 18, 2016     Page 9        published by the Water Board for the evaluation of potential vapor intrusion.5 Those results do not  represent a significant impact to groundwater.     At 1601 S. California Avenue, only a thin interval of saturated soil at approximately 29.5 feet bgs was  observed in the borehole (SBA‐9) from which a groundwater sample was obtained. The soil at that  location was documented as “poorly graded sand with clay.” The remainder of the lithology at that  boring location was documented as “clays and clayey sands” (i.e., finer‐grained units) and no other  observations of saturated soil were made.     As described in the response to CTRA question 1, TCE impacts to groundwater reported beneath the Site  as part of the Page Mill Road project were detected at depths greater than 250 feet bgs and were  addressed under the oversight of the Water Board.    4. IS THE TCE FROM THE 1601 CALIFORNIA AVE SPILL(S) IN THE GROUNDWATER?    Yes, TCE has been detected in shallow groundwater beneath the Site, but site data indicate that  concentrations are low, limited in extent, and below the environmental screening levels (ESLs) for  groundwater and would not contribute to vapor intrusion. Fifty‐four exploratory borings were advanced  to assess the nature and extent of VOCs at the University Terrace site. Locations of those borings were  selected based on knowledge of suspected release areas and former site features (e.g., plating solution  sump), to assess potential impacts from off‐Site sources, and to provide general coverage of the area.  Collection of groundwater samples was attempted at 12 locations. Sufficient groundwater from which to  obtain a sample was present in 9 of the 12 borings. TCE was detected at low concentrations in two of  those samples (45 µg/L at SBA‐9 and 13 µg/L at GW‐20). These groundwater data indicate that the TCE‐ impacts to groundwater are limited.     One of CTRA’s comments discussed the possibility of continuous meandering channels beneath the Site  which could serve as potential pathways for aqueous or vapor‐phase contaminant migration. As noted  above, a continuous shallow water‐bearing unit has not been encountered to the depths of borings that  have been drilled at the 1601 S. California Avenue Site, and the distribution of TCE in soil relative to the  Site lithology does not support the existence of a meandering channel. Further, meandering channels,  even if they were present beneath the Site, would not constitute pathways from the 1601 California  Avenue Site to the CRTA neighborhood. Figure 6 presents the locations of historical streams in the  vicinity of the 1601 S. California Avenue Site and the College Terrace community. These streams follow  the general topography of the area. As indicated by the San Francisco Estuary Institute’s Historical  Ecology Atlas and USGS topographic maps (1953), historical streams did not cross the 1601 S. California  Avenue Site or trend from the Site into the College Terrace neighborhood.    In addition to the historical streams, the detailed lithologic information obtained from the numerous  borings at the 1601 S. California Avenue Site did not identify subsurface stream channels that trend                                                               5 The residential groundwater Environmental Screening Level (ESL) for the evaluation of vapor intrusion concerns  (fine‐coarse soil type) for TCE is 170 µg/L (Water Board, 2016, Environmental Screening Level Tables, Interim Final,  February).  Response to College Terrace Residents’ Association  March 18, 2016 Page 10  towards the College Terrace neighborhood. Instead, the discontinuous coarser‐grained units interpreted  as subsurface channels are interspersed within finer‐grained, clayey deposits.  Although a low concentration of TCE (13 µg/L from the depth interval of 52.5to 55.0 feet bgs at GW‐20)  was detected in one groundwater sample collected at the 1501 S. California Avenue parcel, it was below  the ESL6 published by the Water Board for the evaluation of potential vapor intrusion. If groundwater  was a transport mechanism for TCE, then TCE would be expected to be more widely distributed and  detected in soil vapor at 1501 S. California Avenue, and that is not the case, as discussed below.  Furthermore, AMEC concluded that it is likely that the presence of TCE in soil vapor at 1501 S. California  Avenue is attributed to limited vapor migration from 1601 S. California Avenue, as no source for TCE  impacts was identified at the 1501 S. California Avenue parcel. Importantly, DTSC reached the same  conclusion and noted that the sump at 1601 S. California Avenue was the likely source of the soil vapor  impact.   Finally, the conclusion that groundwater is not a significant transport mechanism is supported by soil  vapor samples collected at AMEC‐1 and the surrounding area at 1501 S. California Avenue. TCE was not  detected at a concentration exceeding the DTSC residential screening level in the soil vapor sample  collected at 8 feet bgs at AMEC‐1, and TCE was not detected in soil vapor at the surrounding locations.  Those results indicate that:  The proximity to TCE‐impacted soil vapor at 1601 S. California Avenue and lithology at this location (AMEC‐1) allowed for the migration of TCE in soil vapor. The migration of TCE in soil vapor is inhibited by fine‐grained, shallow soil. TCE‐impacts to soil vapor do not extend beyond AMEC‐1. The absence of TCE in soil vapor beyond AMEC‐1 provides additional evidence that groundwater is not a transport mechanism for TCE. Thus, TCE detected in soil vapor samples at AMEC‐1 are not indicative of a groundwater source.   5.IS THERE A POTENTIAL TCE CONTAMINATION FROM STORM WATER RUN‐OFF? No. There is no possibility for TCE detected in soil and soil vapor to impact storm water runoff at the  Site, as described below. Stanford is managing storm water runoff at the University Terrace  development under a general permit issued by the Water Board. Storm water was tested on January 27, 2016 prior to off haul,7 which was required to meet a storage capacity issue. As expected, no VOCs,  including TCE, were detected. Stanford provided the Storm Water Unit of the Water Board this  information in support of this conclusion on February 3, 2016.   6 Water Board, 2016, Environmental Screening Level Tables, Interim Final, February.  7 Ground Zone Environmental Services, 2016, Letter regarding potential for TCE contamination to be released to  storm water during construction activities at 1501 and 1601 California Avenue, Palo Alto, California, February 2.  Response to College Terrace Residents’ Association  March 18, 2016     Page 11        Soil  The presence of TCE in soil was explored by collecting soil samples at multiple depths at 26 locations in  and around the operational areas of the Site.      At those locations where TCE was detected in soil, clean fill ranging in thicknesses from 5 to 15  feet has been placed atop as part of the surface grading for the development (the average depth  of the fill is approximately 12 to 13 feet over these sample locations).   No fill has been placed over 4 of the 26 sampling locations; at three locations, no TCE was  detected in soil. At the fourth location, the first detection of TCE in soil was detected at a depth  of 10 feet below ground surface.    Soil Vapor  With respect to storm water runoff, there is not a complete pathway for impacted soil vapor to come  into contact with storm water runoff at the Site. During rain events, surficial soil is saturated—the pore  spaces between soil particles are filled with water. TCE in soil vapor cannot migrate through saturated  soils and into storm water runoff.     At the Site, the area over which higher TCE concentrations in soil vapor have been detected also are  covered with clean  fill that ranges up to 15 feet. Rain in contact with the ground surface will not take up  TCE from subsurface soil or soil vapor.     6. COULD BUILDING DEMOLITION HAVE IMPACTED THE TCE LOCATIONS?    No. Building demolition would not impact the distribution of TCE in soil vapor at the Site. It is possible  that building demolition could have caused some vibration; however, the subsurface structure of the  clayey soil would not be altered by this vibration, and the TCE, which moves by diffusion through the soil  pores, would not be triggered or enhanced by this short‐term vibration. The clay would continue to  effectively retard the migration of TCE impacted soil vapor.    7. WHAT WAS OR WERE THE SOURCE(S) OF THE TCE CONTAMINATION DISCOVERED AFTER THE 1601  CALIFORNIA AVE BUILDINGS (1962 ORIGINAL AND 1988 ADD‐ON) WERE VACATED AND  DEMOLISHED?  a. Sump?  b. Is there any documentation that Granger’s plating solution contained TCE?  c. Chemical Storage Source Area?  d. Did HP follow hazardous waste practices between 1971‐1977? If so, those records should reveal  how much TCE was trucked away from the site. Have those records been uncovered during the  risk assessment process?  e. Degreaser in the Model Room?    Response to College Terrace Residents’ Association  March 18, 2016     Page 12        Potential sources, including the model room, were evaluated to get a clear picture of the Site before  redevelopment. The sampling strategy and results are discussed above. Note that all of the operational  areas of the Site, inclusive of subsurface features such as utility and process water lines within the area,  were evaluated as potential sources. In addition to the extensive sampling program within and outside  of the operational area, an environmental technician was on Site during the demolition activities to  observe, monitor, and collect ambient air and soil samples where indications of potential contamination  existed. Upon advisement by the environmental technician, soil samples were collected at locations  where 1) soil or sludge was identified within a subsurface pipe, 2) total VOCs were measured in soil with  a portable PID, or 3) former process features were previously identified. Sixteen soil samples were  collected beneath the slab and pipes; an additional 11 samples of sludge/soil were collected directly  from exposed, subsurface pipes. TCE was detected at a concentration of 2,200 µg/kg in one sample  (PVC‐PIPE) of residual sludge collected directly from a PVC pipe at the former plating solution sump. TCE  was not detected in any other soil or residual sludge samples that were collected during the demolition  activities.     Observations made during demolition of specific feature locations (e.g., plating solution sump location),  along with historical plans that indicated locations of specific features (see Figure 3 in the SIRA Report)  were incorporated into the sampling strategy and design. The distribution of TCE at and near these  potential source areas is well‐defined.    As discussed in the response to CTRA question 2, additional information regarding potential sources was  explored following Site demolition. Soil samples also were collected from 23 soil borings advanced to  depths between 25 and 35 feet bgs where TCE‐impacted soil vapor was observed. The analytical results  from these efforts are presented in the SIRA Report. TCE concentrations in soil at and in the vicinity of  historical operational features did not identify additional potential sources of TCE to soil vapor.     8. IS THE CURRENT MITIGATION PLAN FOR SOME NEW HOMES ON THE 1601 CALIFORNIA AVE SITE  ADEQUATE?    Yes. The elective mitigation measures based on our redesign for the Site include not building homes  over and near the area with elevated concentrations of TCE in soil vapor, and placing plugs along utility  corridors that traverse or are near the impacted area. Additional measures that will be taken by  Stanford, which include installing vapor barriers beneath homes and placing fill (as part of the  development plan grading requirements), were not required mitigation measures, but provide an  additional level of protection. The placement of clean engineered fill and vapor barriers were,  conservatively, not incorporated in the HHRA.     The proposed 50‐foot buffer for the University Terrace development is appropriate and supported by:     The detailed knowledge of Site lithology relative to the distribution of TCE in soil vapor;   The density of soil vapor sampling locations and analytical results that delineate the extent of  TCE in soil vapor; and  Response to College Terrace Residents’ Association  March 18, 2016     Page 13         The release of TCE into the subsurface occurred at least several decades ago and all of the  potential sources of TCE (e.g., plating solution sump) were removed during Site demolition. Ten  years of soil vapor data at shallow depths have consistently demonstrated that concentrations  of TCE are below residential screening levels ‐ levels designed to be fully protective of human  health and the environment ‐ except at some locations within and near the former operational  area of the Site.    Dr. Paul Johnson, an internationally renowned expert on vapor intrusion, has reviewed, evaluated and  concurred with the Site conceptual model and Stanford’s approach to address vapor intrusion. A copy of  his letter stating his position is attached.    9. WHO IS RESPONSIBLE?    Stanford owns the 1601 California Avenue parcel, but did not operate the former facilities located at this  Site. In its environmental analysis for, and required by, the Mayfield Development Agreement, Stanford  investigated environmental conditions at each of the three parcels – 1451, 1501, and 1601 S. California  Avenue – that comprise the development area. Following its initial evaluations, Stanford has diligently  and responsibly worked to identify and address environmental conditions on the 1601 California Avenue  Site. Information regarding these efforts is included in the SIRA and the Remediation Completion  Report8 and Addendum.9    By entering into a voluntary agreement with the DTSC, Stanford has engaged regulatory oversight to  confirm that Site conditions meet current standards and are safe for future residents. In addition,  Stanford retained Dr. Paul Johnson to perform an independent peer review of the investigation and  analysis performed by Haley & Aldrich. Dr. Johnson concluded that this multiple mitigation approach   protects human health and the environment and goes well beyond industry standard.     Attachments:    Figure 1  Conceptual Site Diagram  Figure 2  Soil Vapor Sample Locations  Figure 3  Cross Section X to X’  Figure 4  Depth to Saturated Soil  Figure 5  Groundwater Analytical Results  Figure 6  Surface Drainage Displayed on 1953 USGS Map   April 23, 2013 Well Decommissioning Request from Stantec Consulting Services to the Water Board,    July 24, 2013 e‐mail from Roger Papler of the Water Board to Paul Paschke of Hewlett Packard  approving request for well decommissioning   Letter from Dr. Paul Johnson to Annette Walton of Stanford dated January 5, 2016                                                               8 Haley & Aldrich, Inc., 2015, Remediation Completion Report – Excavation of Soil Containing Polychlorinated  Biphenyls, 1601 S. California Avenue, Palo Alto, CA, July.   9 Haley & Aldrich, Inc., 2015, Addendum to the July 2015 Remediation Completion Report – Excavation of Soil  Containing Polychlorinated Biphenyls, 1601 S. California Avenue, Palo Alto, California, 1 December.  SOIL VAPOR CONCENTRATIONS NOT DETECTED OR BELOW RISK-BASED RESIDENTIAL TARGET OPEN SPACE BUFFER ZONE 10-15 FT. COMPACTED FILL CLAYEY SAND CHANNELS IMPACTED AREA ~ ~ RESIDUAL SUBSURFACE VAPORS CLAYEY FLOOD PLAIN DEPOSITS SOIL VAPOR CONCENTRATIONS NOT DETECTED OR BELOW RISK-BASED RESIDENTIAL TARGET ~15-20 FT. UNIVERSITY TERRACE FIGURE 1 1451, 1501 AND 1601 S. CALIFORNIA AVENUE PALO ALTO, CALIFORNIA SITE CONCEPTUAL DIAGRAM MARCH 2016 NOT TO SCALE @@A @@A @@A @@A @@A@@A@@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A@@A@@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A@@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A @@A@@A @@A @@A @@A @@A @@A @@A@@A@@A @@A @@A@@A @@A @@A @@A @@A @@A @@A@@A @@A@@A @@A @@A @@A 1601 S. CALIFORNIA 1501 S. CALIFORNIA 1451 S. CALIFORNIA RESIDENTIAL AM H E R S T S T R E E T BO W D O I N S T R E E T DRAKE W A Y S CALIFORNIA AVE AM H E R S T S T BO W D O I N S T CO L U M B I A S T DAR T M O U T H S T AMEC-10 SG-19 AMEC-7 SG-16 SG-17 SG-25 SV-8 SV-6 SV-7 SG-37 SG-18 SG-20 SV-1 SVA-2 SV-2 SV-3 SV-4 SV-5 SVA-14 SVA-12 SVA-15 SVA-10 SVA-9 SVA-7 SVA-6 SVA-4SVA-3 SVA-5 SG-39 SG-42 SG-31 SV-1 SV-10 AMEC-11 SV-9 SV-3 AMEC-12 SV-2 AMEC-2 AMEC-4 AMEC-9 SV-1 SV-3 SV-4 AMEC-3SV-11 SV-6 SV-7SV-8 SV-9 SV-10 SV-12 SV-4 SV-13 SV-7 SV-15 SV-5SV-6 SV-14 SV-8 SV-11 SG-36 SG-30 AMEC-6 AMEC-13 SG-15SG-24SG-21 SG-26 SG-27 SG-29 AMEC-1 AMEC-8 SG-14 SG-38 SG-41 SG-23 SG-28 SG-35 SG-34 SG-40SG-32 SG-33 NOTES 1. THE 1451, 1501, AND 1601 S. CALIFORNIA AV ENUE PARCELSCOM PRISE THE UNIV ERSITY TERRACE PROJECT. 2. DEV ELOPM ENT PLAN SOURCE: W ILLIAM HEZ M ALHALCHARCHITECTS INC., REV ISED SITE PLAN, 9-23-2015. 3. µg/m 3 = M ICROGRAM S PER CUBIC M ETER 4. AERIAL IM AGERY SOURCE: ESRI 1451, 1501 AND 1601 S. CALIFORNIA AV ENUEPALO ALTO, CALIFORNIA SOIL V APOR SAM PLE LOCATIONS FIGURE 2SCALE: AS SHOW NFEBRUARY 2016 LEGEND @@A DENOTES TCE W AS NOT DETECTED IN ANY SAM PLES AT ACONCENTRATION EXCEEDING THE RESIDENTIALSCREENING LEV EL (480 µg/m 3) @@A DENOTES TCE W AS NOT DETECTED IN ANY SAM PLES AT ACONCENTRATION EXCEEDING AN ESTIM ATED LIFETIM EEXCESS CANCER RISK OF ONE-IN-A-M ILLION (1X10 -6 ) @@A DENOTES TCE W AS DETECTED IN AT LEAST ONE SAM PLE ATA CONCENTRATION EXCEEDING AN ESTIM ATED LIFETIM EEXCESS CANCER RISK OF ONE-IN-A-M ILLION (1X10 -6 ) PROPERTY BOUNDARY 0 100 200 SCALE IN FEET 110 100 90 80 70 60 50 40 30 20 10 110 100 90 80 70 60 50 40 30 20 10 EL E V A T I O N ( F E E T A B O V E M S L ) EL E V A T I O N ( F E E T A B O V E M S L ) x x’ 01020 0 50 100 VERTICAL SCALE SCALE IN FEET HORIZONTAL SCALE SV-1 SV-2 SG-20 SG-31 SG-18 SG-17 SV-8 SV-10 AMEC-11 AMEC-12 EB-8 EB-14 EB-3 SG-19 44 W 49 W 43 E 4 W 2 E 6 E 47 E 3 W 2 W 35 E 51 E 19 E 16 W 24 E SV-1 48 W SV-2 1 E SO I L C O N D I T I O N S N O T L O G G E D SO I L C O N D I T I O N S N O T L O G G E D SO I L C O N D I T I O N S N O T L O G G E D SO I L C O N D I T I O N S N O T L O G G E D GROUND SURFACE ELEVATION ALONG SECTION LINE (SEE NOTE 4)<8 <8 <8 <8 <8 <8 <8 <8 <8 <8 <8 <8 <100 <100<100 NF <8 <7.1 <8 29 13.8 11.4 23.2 NF NF NF NF NF SVA-4 0 <100 1451, 1501 AND 1601 S. CALIFORNIA AVENUE PALO ALTO, CALIFORNIA CROSS SECTION X TO X' FIGURE 4SCALE: AS SHOWN FEBRUARY 2015 32016 SV-10 2 W <100 GEOLOGIC EXPLANATION BOREHOLE SYMBOLS FILL SILTS AND CLAYS (FINE GRAINED UNITS) CLAYEY GRAVELS AND SANDS (COARSE GRAINED UNITS) BORING DESIGNATION OFFSET DISTANCE BETWEEN BORING AND CROSS SECTION LINE (FEET) STRATUM BOUNDARY NO FLOW CONDITIONS DURING SOIL VAPOR SAMPLING MAXIMUM DETECTED SOIL VAPOR CONCEN- TRATION OF TRICHLOROETHENE (TCE) IN MICROGRAMS PER CUBIC METER TCE NOT DETECTED IN SOIL VAPOR SAMPLE. CONCENTRATION INDICATED IS THE TEST DETECTION LIMIT SG-17 16 W NF 300 <8 NOTES: 1. REFER TO FIGURE 1- SITE VICINITY WITH DEVELOPMENT PLAN AND CROSS SECTIONS, FOR PLAN LOCATION, DESIG- NATION, AND ORIENTATION OF SUBSURFACE SECTIONS AND AS-DRILLED EXPLORATION LOCATIONS. 2. TEST BORING GROUND SURFACE ELEVATIONS WERE ESTIMATED AND SHOULD BE CONSIDERED APPROXIMATE. 3. SATURATED SOIL CONDITIONS WERE NOT ENCOUN- TERED IN ANY OF THE TEST BORINGS SHOWN ON THIS SECTION. 4. BORINGS SHOWN ABOVE AND BELOW THE GROUND SURFACE ELEVATION ARE PROJECTED ONTO THE SECTION. THE TOP OF BORING REPRESENTS THE GROUND SURFACE ELEVATION AT THE LOCATION WHERE THE BORING WAS DRILLED. CROSS SECTION LOCATION PLAN LIMITS OF 1601 S. CALIFORNIA PROPERTY LIMITS OF 1501 S. CALIFORNIA PROPERTY LIMITS OF 1451 S. CALIFORNIA PROPERTY @A @A @A @A@A @A @A @A @A @A @A @A @A@A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A@A @A @A @A @A @A @A @A @A @A @A @A @A@A @A @A @A @A @A @A @A @A@A @A @A @A @A &( &( &( &( &(&( &(&(&( &( &( &( &( 1601 S. CALIFORNIA 1501 S. CALIFORNIA 1451 S. CALIFORNIA RESIDENTIAL AM H E R S T S T R E E T BO W D O I N S T R E E T DRAKE W A Y SG-16 25 SG-2425 SG-2625 EX4-0835 EX4-02 35 EX4-0435 EX4-0535 EX4-07 35 EX4-0935EX4-06 35 EX4-10 35EX4-0135 SG-3335 SG-2325 SG-3125 SG-3525.5 SG-3625.5 SG-3435 SG-4025.5SG-3235 SG-3035 SBA-640 SG-1925 EB-625 AMEC-625.5 AMEC-725.5 AMEC-1325.5 SG-1525 SG-1725 SG-2525 EB-225 SG-2125 SG-2725 SG-2925 AMEC-125.5 AMEC-825.5SBA-837 SG-1425 SG-3740 EX4-0335 SG-1825 SG-2025 SBA-3755 SBA-3549 SBA-3366 EB-125 EB-325 EB-525 EB-425SG-3825 SG-4125.5 SG-3925.5 SG-4225.5 SG-2825 EB-1425 AMEC-1225.5 EB-825 EB-1225 AMEC-225.5 AMEC-425.5 AMEC-925.5 S CALIFORNIA AVE AM H E R S T S T BO W D O I N S T CO L U M B I A S T DAR T M O U T H S T SBA-9 : 29.5 (NOTE 5) SBA-11 : 37.5 (NOTE 4) GW-2 : 31.4 GW-1 : 39.8 SB-9 : 34.5SB-10 : NOTE 7 SB-11 : 35.7 SB-12 : NOTE 7 SB-13 : NOTE 7 GW-20 : NOTE 6 EB-9 : 31.9 (NOTE 8) EB-15 : 26 (NOTE 8) EB-16 : 24.8 (NOTE 8) NOTES 1. THE 1451, 1501, AND 1601 S. CALIFORNIA AV ENUE PARCELS COM PRISE THEUNIV ERSITY TERRACE PROJECT. 2. DEV ELOPM ENT PLAN SOURCE: W ILLIAM HEZ M ALHALCH ARCHITECTS INC.,REV ISED SITE PLAN, 9-23-2015. 3. DATA BASED ON BORING LOGS AND DOCUM ENTED INFORM ATION ININV ESTIGATION REPORTS FROM GEOM ATRIX CONSULTANTS, AM EC AND HALEYAND ALDRICH. 4. AT SBA-11, SATURATED SOIL W AS ENCOUNTERED, HOW EV ER SOILS W ERE NOTSUFFICIENTLY TRANSM ISSIV E TO ALLOW FOR COLLECTION OF A W ATER SAM PLE. 5. AT SBA-9, SATURATED AND COARSER GRAINED SOIL W AS OBSERV ED IN A LENSEXTENDING FROM APPROXIM ATELY 29.5 TO 30 FEET BGS. NO OTHER SATURATEDSOIL W AS OBSERV ED TO THE TOTAL DEPTH OF THE BOREHOLE. 6. AT GW -20, A GRAB GROUNDW ATER SAM PLE W AS OBTAINED FROM 50 TO 55FEET BGS. DATA FOR DEPTH TO FIRST SATURATED SOIL W AS NOT AV AILABLE. 7. AT SB-10, SB-12, AND SB-13, GRAB GROUNDW ATER SAM PLES W ERE OBTAINEDFROM W ELL SCREENS THAT EXTENDED FROM 28 TO 43, 16 TO 45, AND 27 TO 45FEET BGS, RESPECTIV ELY. DATA FOR DEPTHS TO FIRST SATURATED SOIL W ERENOT AV AILABLE. 8. THE PRESENCE OF GROUNDW ATER W AS DOCUM ENTED IN BORINGS EB-9, EB-15AND EB-16, W HICH W ERE DRILLED AS PART OF THE GEOTECHNICALINV ESTIGATION, AT THE DEPTHS SHOW N. 9. AERIAL IM AGERY SOURCE: ESRI 1451, 1501 AND 1601 S. CALIFORNIA AV ENUEPALO ALTO, CALIFORNIA DEPTH TO SATURATED SOIL FIGURE 4SCALE: AS SHOW NM ARCH 2016 LEGEND PROPERTY BOUNDARY &( LOCATION OF BORING AT W HICH SATURATED SOIL W ASENCOUNTERED OR THE PRESENCE OF GROUNDW ATERW AS DOCUM ENTED (DEPTH SHOW N INDICATES DEPTHBELOW GROUND SURFACE TO SATURATED SOIL ORGROUNDW ATER) LOCATION OF BORING ADV ANCED TO DEPTH INTERV ALNOTED BELOW ; SATURATED SOIL NOT ENCOUNTERED @A UP TO 25.4 FEET BELOW GROUND SURFACE (BGS) @A 25.5 - 35.4 FEET BGS @A 35.5 - 45 FEET BGS @A M ORE THAN 45 FEET BGS 0 100 200 SCALE IN FEET 25.0 DEPTH INDICATED IS TOTAL BOREHOLE DEPTH 36.7 @A @A @A @A@A @A @A @A @A @A @A @A @A@A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A@A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A @A@A @A @A @A @A @A @A @A &( &( &( &(&( &(&(&( &( 1601 S. CALIFORNIA 1501 S. CALIFORNIA 1451 S. CALIFORNIA RESIDEN TIAL AM H E R S T S T R E E T BO W D O I N S T R E E T DRAKE W A Y SBA-9SCREEN INTERVAL: 26-46TCE CONCENTRATION: 45 GW-20SCREEN INTERVAL: 52.5-55.0TCE CONCENTRATION: 13 SB-9SCREEN INTERVAL: 31-46TCE CONCENTRATION: <0.50 GW-1SCREEN INTERVAL: 36-41TCE CONCENTRATION: <0.50 SB-12SCREEN INTERVAL: 16-45TCE CONCENTRATION: <0.50 SB-11SCREEN INTERVAL: 31-46TCE CONCENTRATION: <0.50 SB-10SCREEN INTERVAL: 28-43TCE CONCENTRATION: <0.50 GW-2SCREEN INTERVAL: 27.5-32.5TCE CONCENTRATION: <0.50 SB-13SCREEN INTERVAL: 27-45TCE CONCENTRATION: <0.50 SG-23 SG-35 SG-36 SG-34 SG-40 SG-32 SG-30 SBA-6 SG-19 EB-6 AMEC-6 AMEC-7 AMEC-13 SG-15SG-16 SG-17 SG-24 SG-25 EB-2 SG-21 SG-26 SG-27 SG-29 AMEC-1 AMEC-8 SBA-8 SG-14 SG-37 EX4-08 EX4-03 EX4-02 EX4-04 EX4-05 EX4-07 EX4-09EX4-06 EX4-10 SG-18 SG-20 SBA-37 SBA-35 SBA-33 EX4-01 SG-33 EB-1 EB-3 EB-5 EB-4 SBA-11 SG-38 SG-41 SG-39 SG-42 SG-28 SG-31 EB-14 AMEC-12 EB-8 EB-9 EB-12 EB-15 EB-16 AMEC-2 AMEC-4 AMEC-9 AM H E R S T S T BO W D O I N S T CO L U M B I A S T DAR T M O U T H S T S CALIFORN I A A V E NOTES 1. THE 1451, 1501, AN D 1601 S. CALIFORN IA AV EN UE PARCELS COMPRISE THEUN IV ERSITY TERRACE PROJECT. 2. DEV ELOPMEN T PLAN SOURCE: W ILLIAM HEZ MALHALCH ARCHITECTS IN C.,REV ISED SITE PLAN , 9-23-2015. 3. DATA BASED ON BORIN G LOGS AN D DOCUMEN TED IN FORMATION ININ V ESTIGATION REPORTS FROM GEOMATRIX CON SULTAN TS, AMEC AN D HALEYAN D ALDRICH. 4. AT SBA-9, SATURATED AN D COARSER GRAIN ED SOIL W AS OBSERV ED IN A LEN SEXTEN DIN G FROM APPROXIMATELY 29.5 TO 30 FEET BGS. N O OTHER SATURATEDSOIL W AS OBSERV ED TO THE TOTAL DEPTH OF THE BOREHOLE. 5. AT GW -20, A GRAB GROUN DW ATER SAMPLE W AS OBTAIN ED FROM 50 TO 55FEET BGS. DATA FOR DEPTH TO FIRST SATURATED SOIL W AS N OT AV AILABLE. 6. AT SB-10, SB-12, AN D SB-13, GRAB GROUN DW ATER SAMPLES W ERE OBTAIN EDFROM W ELL SCREEN S THAT EXTEN DED FROM 28 TO 43, 16 TO 45, AN D 27 TO 45FEET BGS, RESPECTIV ELY. DATA FOR DEPTHS TO FIRST SATURATED SOIL W EREN OT AV AILABLE. 7. THE RESIDEN TIAL GROUN DW ATER EN V IRON MEN TAL SCREEN IN G LEV EL (ESL)FOR THE EV ALUATION OF V APOR IN TRUSION CON CERN S (FIN E-COARSE SOILTYPE) FOR TCE IS 170 µg/L (REGION AL W ATER QUALITY CON TROL BOARD, SANFRAN CISCO BAY REGION , 2016). 8. SCREEN IN TERV AL SHOW N IN FEET BGS 9. TCE CON CEN TRATION SHOW N IN MICROGRAMS PER LITER (µg/L) 10. AERIAL IMAGERY SOURCE: ESRI 1451, 1501 AN D 1601 S. CALIFORN IA AV EN UEPALO ALTO, CALIFORN IA GROUN DW ATER AN ALYTICAL RESULTS FIGURE 5SCALE: AS SHOW NMARCH 2016 LEGEND PROPERTY BOUN DARY &(GROUN DW ATER SAMPLIN G LOCATION @A BORIN G DRILLED TO DEPTH OF AT LEAST 25 FEET BELOWGROUN D SURFACE (BGS) W ITH N O GROUN DW ATEREN COUN TERED 0 100 200 SCALE IN FEET NOTES 1. ALL LOCATIONS AND DIMENSIONS AR E APPR OXIMATE 2. TOPO MAP SOUR CE: 1953 NW/4 PALO ALTO 15' QUADANGLE LEGEND PR OPER TY BOUNDAR Y 0 1,000 2,000 SCALE IN FEET 1451, 1501 AND 1601 S. CALIFOR NIA AVENUEPALO ALTO, CALIFOR NIA SUR FACE DR AINAGE DISPLAY ED ON 1953 USGS TOPOGR APHIC MAP FIGUR E 6 SCALE: AS SHOWNMAR CH 2016 January 5, 2016 Annette Walton Director - Environmental Management Real Estate Operations 3160 Porter Drive, Suite 200 Palo Alto, California 94304 Dear Annette – As requested, this letter briefly summarizes key points of my review and our discussions related to the health risk assessment and development plans at Stanford’s University Terrace Project, which involves the redevelopment of three former industrial-use properties to a neighborhood consisting of Stanford faculty housing and open park space. No further action letters were issued in 2013 by the California State Department of Toxic Substances Control (DTSC) for two of the properties (1451 and 1501 California Avenue, Palo Alto, CA). Based on environmental reports provided to DTSC, they concluded that neither site posed a significant threat to human health or the environment under residential land use. Thus, my involvement has been focused on the third property at 1601 California Avenue, for which supplemental investigation was conducted to thoroughly assess the potential for significant health risks from post-remediation TCE residuals at depth in the subsurface. That assessment is summarized in the Supplemental Investigation and Risk Assessment Report, 1601 S. California Avenue, Palo Alto, California, prepared by Haley & Aldrich, Inc. Key points from my review and our discussions include the following: Relative to the initial draft, conclusions in the final version of the Supplemental Investigation and Risk Assessment Report, 1601 S. California Avenue, Palo Alto, California were the same, but strengthened by the thorough evaluation of the site conceptual model conducted by Murray Einarson and the expanded range of site-specific inputs that were incorporated by Haley & Aldrich, Inc. in their calculations. These additions increased confidence in the conclusions stemming from vapor intrusion pathway analysis because the selection of defensible site-specific inputs and considering a range of possible scenarios is critical to generating confidence in the results. It was also critical, because subsurface geology is a key controlling factor for vapor migration at this site. There is confidence in the use of the site data for the risk analysis because the historical information, subsurface geology conceptual model, and chemical distribution appear to be self- consistent. The site plan for the University Terrace Project reflects the analysis and conclusions contained in the Supplemental Investigation and Risk Assessment Report, 1601 S. California Avenue, Palo Alto, California. Future residences are placed in areas with projected negligible risks and the relatively isolated area of possible concern is open park space in the plan. The risk assessment report concludes that the future residences will not be exposed to significant health risks under any building construction design and that pre-emptive building-specific mitigation measures are not needed (e.g., sub-slab depressurization systems). The sub-foundation vapor barrier liners being incorporated in the residential construction, therefore, are not necessary, but will add an additional level of protectiveness from vapor intrusion and potential comfort for the occupants. Development plans also address the potential for vapor intrusion via alternative pathways, as we discussed recent studies where vapor intrusion was observed in buildings off-set from subsurface vapor sources as a result of transport along utilities and utility conduits. The potential for this is being eliminated in the planned development design by ensuring that utilities are not run through the residual vapor source at the site and by having vapor plugs/seals installed along the utilities. Should you have questions or require clarification of this summary, please feel free to contact me. Sincerely, Paul C. Johnson, Ph.D. Stantec Consulting Services Inc. 15575 Los Gatos Boulevard, Building C Los Gatos CA 95032 Tel: (408) 356-6124 Fax: (408) 356-6138 April 23, 2013 Mr. Roger Papler California Regional Water Quality Control Board San Francisco Bay Region 1515 Clay Street, Suite 1500 Oakland, CA 94612 RE: Request to Decommission Monitoring Wells MW-135 through MW-138, MW-163 and MW-164 for the Groundwater Monitoring Program at 1501 Page Mill Road, Palo Alto, California Dear Mr. Papler: On behalf of Hewlett Packard Company (HP), Stantec Consulting Services Inc. (Stantec) presents this request to decommission groundwater monitoring wells MW-135 through MW-138, MW-163, and MW-164 located downgradient (i.e., off site) of HP’s 1501 Page Mill Road, Palo Alto, California site facility (Site). Wells MW-135 through MW-138 are located at 1450/1454 Page Mill Road, and wells MW-163 and MW-164 are located at 1601 California Avenue in Palo Alto, California (Figure 1). Three of the wells (MW-136, MW-138, and MW-163) are screened in the Gamma 1 Zone and the remaining three wells (MW-135, MW-137, and MW-164) are screened in the Gamma 2 Zone. Decommissioning of the wells is required to facilitate redevelopment construction activities on those properties by the property owner, Stanford. Stanford intends to redevelop the properties, including the locations where the wells are located, as single family residences in late fall or early winter 2013 and has requested that HP remove the wells from the properties. Wells MW-135, MW-136, and MW-164 are sampled annually as part of the current groundwater monitoring program for the Site. Wells MW-137, MW-138, and MW-163 are not used for groundwater sampling, but have been used for the annual measurement of groundwater level levels in the vicinity of the Site. The six monitoring wells are not considered essential to the monitoring program and decommissioning of the wells would not adversely affect the monitoring objectives of the current monitoring program. Historical analytical data for the wells are presented in Table 1 and a brief discussion of each well follows. Gamma 1 Zone Wells Well MW-136. This well is located on the 1450/1454 Page Mill Road property. Trichloroethene (TCE) is the principal volatile organic compound (VOC) detected in the groundwater at well MW-136. TCE concentrations in the groundwater from this well are stable and have remained below the Federal and State Maximum Contaminant Levels (MCLs; 5 µg/L) since April 1996 (Table 1). Well MW-138. This well is located on the 1450/1454 Page Mill Road property. The well was sampled four times between July 1993 and May 1994. No VOCs were detected in the groundwater from this well, and the well was subsequently removed from the list of wells sampled for the groundwater monitoring program in 1994. The well is currently only used for the measurement of groundwater levels on an annual basis. Mr. Roger Papler April 23, 2013 Page 2 of 2 Well MW-163. This well is located on the 1601 California Avenue. The well was sampled 14 times between August 1993 and July 1997. No volatile organic compounds (VOCs) were detected in the groundwater from this well, and the well was removed from the list of wells sampled for the groundwater monitoring program in 1997. The well is currently only used for the measurement of groundwater levels on an annual basis. Gamma 2 Zone Wells Well MW-135. This well is located on the 1450/1454 Page Mill Road property. Historically, TCE has been the principal VOC detected in the groundwater at this well. TCE concentrations in the groundwater have been relatively stable ranging from 6 to 85 µg/L for the last 10 monitoring events (August 2003 through August 2012). Well MW-137. This well is located on the 1450/1454 Page Mill Road property. The well was sampled nine times between July 1993 and April 1997. No volatile organic compounds (VOCs) were detected in the groundwater from this well, and the well was subsequently removed from the list of wells sampled for the groundwater monitoring program in 1997. The well is currently only used for the measurement of groundwater levels on an annual basis. Well MW-164. This well is located on the 1601 California Avenue property downgradient of 1501 Page Mill Road site. The well has been sampled as part of the groundwater monitoring program since 1993. No volatile organic compounds (VOCs) have been detected in the groundwater from this well. In summary, the six off-site monitoring wells are not considered essential to the monitoring program and decommissioning of the wells would not adversely affect HP’s ability to monitor VOC-impacted groundwater plume. Upon your approval to decommission the wells, the wells will be destroyed to facilitate the proposed redevelopment of the properties at which they are located. The wells will be destroyed consistent with well destruction guidelines of the Santa Clara Valley Water District. Please contact Mr. Paul Paschke of HP at (970) 898-0573 if you have questions regarding this request. Sincerely, STANTEC CONSULTING SERVICES INC. Howard H. Koltermann, PG, CEG, CHG Mark Becker Senior Hydrogeologist Senior Scientist Tel: (408) 356-6124 Tel: (408) 356-6124 Cell: (408) 210-6573 Cell: (831) 246-0711 howard.koltermann@stantec.com mark.becker@stantec.com Attachments: Figure 1 – Site Plan Table 1 – Historical Groundwater Analytical Results for Wells MW-135 through MW-138, MW-163, and MW-164 cc: Paul Paschke, Hewlett-Packard Company Annette Walton, Stanford &A&A %!8%!8 &A%!8 &A&A &A&A %!8%!8&A&A &A &A&A &A&A &A &A&A &A &A &A &A &A &A &A &A &A&A &A&A &A %!8 &A&A &A &A %!8&A&A &A&A&A &A &A &A &A &A &A &A &A &A &A &A &A %!8 &A &A &A %!8&A%! &A&A&A&A &A &A&A&A&A &A&A&A &A&A &A&A %!8 &A&A&A &A%!8%! &A&A%!8&A &A&A&A &A %!8&A &A &A&A&A &A&A%!8&A &A &A&A&A &A&A&A &A &A&A&A%!&A %!8%!8&A %!8%!8&A %!8 %! %! %!8&A&A&A &A %!8 &A&A%!8&A &A&A&A&A&A Pag e M i l l R d Han o v e r S t P eter C o utts Rd Am h e r s t S t Allardice Way Ca t h c a r t W a y Mata d e r o A v e P eter C o utt s Cir Mat a d e r o C t R aim u n d o W a y M e a r s Ct Por t e r D r Sta n f o r d S t S C a l i f o r n i a A v e Former IBM HP 1601 California Ave Tab Tab Alza Alza 1454 Page Mill Rd IBM Former IBM Former IBM Former HP B28C Former HP B28A B1 B3 B2 B4 B5 B6 B6A MW-163 MW-142 EW-6 MW-4 MW-61 MW-63 MW-153 MW-105 MW-136 EW-9 MW-28 MW-23 MW-10 MW-56 MW-88 MW-96 MW-97 MW-62 MW-46 MW-44 MW-144 MW-151 MW-119 MW-141MW-139 MW-121 MW-122 VW-131 MW-120 MW-138 EW-10 MW-27 MW-60 MW-59 MW-65 MW-52 MW-128 MW-109 MW-102 MW-154 MW-135 MW-164 EW-7 EW-5 EW-8 MW-58 MW-94 MW-55 MW-69 MW-146 MW-124 MW-114 MW-137 MW-5 MW-21 MW-84 MW-70 MW-99 MW-145 MW-140 PZ-126 MW-95 EW-3 MW-143MW-116MW-103 MW-118 MW-134 MW-85 MW-76 MW-90 MW-91 MW-92 MW-71 MW-93 MW-87 MW-66 MW-6 MW-64 MW-155 MW-111 MW-104 MW-86 MW-115 MW-25 MW-54 MW-80 MW-51MW-78MW-77 MW-49MW-45 MW-67 MW-68 MW-132 MW-130 MW-110 MW-113 MW-81 MW-72 MW-73 MW-100 MW-8 MW-98 MW-83 MW-89 MW-41 PZ-123 MW-112 MW-106 MW-75 MW-82 MW-74 MW-2A MW-40 PZ-125 MW-10A MW-12A MW-101 EW-1 EW-2 MW-20MW-30 MW-26 MW-15 MW-29 MW-57 MW-32 MW-48 MW-42 MW-50 MW-47 MW-18 MW-117 MW-31 MW-13 MW-14 MW-17 MW-43 MW-19 MW-79 MW-150 MW-127 6082000 6082000 6083000 6083000 6084000 6084000 19 7 6 0 0 0 19 7 6 0 0 0 19 7 7 0 0 0 19 7 7 0 0 0 19 7 8 0 0 0 19 7 8 0 0 0 Client/Project Figure No. Title Site Plan 1 Hewlett-Packard Company 1501 Page Mill Road Palo Alto, Santa Clara County, California October 2012185702501 Notes Legend 1. 2. Coordinate System: NAD 1983 StatePlane California III FIPS 0403 Feet Aerial imagery provided by Digital Globe, 2010. 0 150 300ft 1 in = 300 ft South Side Area Alluvium Zone and Santa Clara Zone 1 &A Monitoring or Piezometer Well Location %!8 Inactive Extraction Well Location S-Zone &A Monitoring or Piezometer Well Location %!Active Extraction Well Location %!8 Inactive Extraction Well Location Gamma - A Zone &A Monitoring or Piezometer Well Location Gamma - 1 Zone &A Monitoring or Piezometer Well Location %!Active Extraction Well Location %!8 Inactive Extraction Well Location Gamma - 2 Zone &A Monitoring or Piezometer Well Location %!Active Extraction Well %!8 Inactive Extraction Well Location Gamma - 3 Zone &A Monitoring or Piezometer Well Location %!8 Inactive Extraction Well Location Gamma - 4 Zone &A Monitoring or Piezometer Well Location %!8 Inactive Extraction Well Location \\cd1004-f06\Work_group\01221\active\122140012_data_base_mgmt\Databases\185702367\Drawing\MXD\1501\2012-09-19\185702367_1501_Fig01_SitePlan.mxdRevised: 2012-10-01 By: sstroszkali Table 1 Historical Groundwater Analytical Results for Wells MW-135 through MW-138, MW-163 and MW-164 Hewlett-Packard Company 1501 Page Mill Road Site Palo Alto, California Well ID Sample Flow Sample TCE PCE 1,1,1-TCA 1,1-DCA 1,1-DCE cis-1,2-DCE Benzene Toluene Ethylbenzene Xylenes, Total Other Type Zone Date Constituents MW-135 Gamma-2 Zone 1/21/1993 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 MW-135 Gamma-2 Zone 5/12/1993 14 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 0.98; MW-135 Gamma-2 Zone 6/18/1993 19 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 8/6/1993 27 <0.5 <0.5 <0.5 <0.5 <0.5 ------ --- --- CHLFM = 0.84; MW-135 Gamma-2 Zone 9/23/1994 20 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 0.88; MW-135 Gamma-2 Zone 12/2/1994 <0.5 <0.5 <0.5 <0.5 33 <0.5 --- --- --- --- CHLFM = 1.2; MW-135 Gamma-2 Zone 1/13/1995 18 <0.5 <0.5 <0.5 0.54 1.6 ------ --- --- CHLFM = 1.1; MW-135 Gamma-2 Zone 4/20/1995 37 <0.5 <0.5 <0.5 <0.5 2.2 ------ --- --- CHLFM = 1.1; MW-135 Dup Gamma-2 Zone 4/20/1995 43 <0.5 <0.5 <0.5 <0.5 2.2 --- --- --- --- CHLFM = 1.1; MW-135 Gamma-2 Zone 7/7/1995 30 <0.5 <0.5 <0.5 <0.5 0.86 ------ --- --- CHLFM = 1; MW-135 Dup Gamma-2 Zone 7/7/1995 31 <0.5 <0.5 <0.5 <0.5 1.1 --- --- --- --- CHLFM = 1.2; MW-135 Gamma-2 Zone 10/20/1995 36 <0.5 <0.5 <0.5 <0.5 0.67 --- --- --- --- CHLFM = 0.77; MW-135 Gamma-2 Zone 1/5/1996 24 <0.5 <0.5 <0.5 <0.5 <0.5 ------ --- --- MW-135 Gamma-2 Zone 4/10/1996 19 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 7/9/1996 16 <0.5 <0.5 <0.5 <0.5 <0.5 ------ --- --- MW-135 Gamma-2 Zone 10/9/1996 20 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 1/9/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 4/14/1997 17 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 7/15/1997 15 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 10/9/1997 17 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 1/8/1998 16 <0.5 <0.5 <0.5 <0.5 <0.5 ------ --- --- MW-135 Dup Gamma-2 Zone 1/8/1998 16 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 4/10/1998 20 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 7/9/1998 12 <0.5 <0.5 <0.5 <0.5 <0.5 ------ --- --- MW-135 Gamma-2 Zone 10/8/1998 14 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 1/5/1999 13 <0.5 <0.5 <0.5 <0.5 <0.5 ------ --- --- MW-135 Dup Gamma-2 Zone 1/5/1999 14 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 4/12/1999 13 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 7/14/1999 15 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 10/8/1999 14 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 1/13/2000 14 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 8/21/2000 13 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 8/27/2001 17 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 8/21/2002 22 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Dup Gamma-2 Zone 8/21/2002 24 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 8/19/2003 43 <0.5 <0.5 <0.5 <0.5 3.2 ------ --- --- MW-135 Gamma-2 Zone 10/5/2004 68 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-135 Gamma-2 Zone 8/31/2005 58 <1 <1 <1 <1 <1 --- --- --- --- MW-135 Gamma-2 Zone 8/31/2006 5.9 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 6.3; MW-135 Gamma-2 Zone 8/15/2007 27 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 5.4; MW-135 Gamma-2 Zone 8/20/2008 71 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 1.5; MW-135 Dup Gamma-2 Zone 8/20/2008 63 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 1.3; MW-135 Gamma-2 Zone 8/3/2009 73 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-135 Gamma-2 Zone 8/3/2010 74 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-135 Gamma-2 Zone 8/1/2011 85 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-135 Gamma-2 Zone 8/13/2012 75 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- E:\HP\well_Destructions\20130411 - Table 1 - MW-135-138, MW-163,164.xlsx 185702205.200.044 Page 1 of 4 Table 1 Historical Groundwater Analytical Results for Wells MW-135 through MW-138, MW-163 and MW-164 Hewlett-Packard Company 1501 Page Mill Road Site Palo Alto, California Well ID Sample Flow Sample TCE PCE 1,1,1-TCA 1,1-DCA 1,1-DCE cis-1,2-DCE Benzene Toluene Ethylbenzene Xylenes, Total Other Type Zone Date Constituents MW-136 Gamma-1 Zone 2/21/1993 14 <5 <5 <5 <5 <5 <5 <5 <5 <5 MW-136 Gamma-1 Zone 3/9/1993 46 <5 <5 <5 <5 <5 <5 <5 <5 <5 MW-136 Gamma-1 Zone 5/12/1993 40 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 0.6; MW-136 Gamma-1 Zone 12/3/1994 18 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 4/19/1995 30 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 10/20/1995 11 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 4/13/1996 1.7 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 10/18/1996 0.57 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 4/15/1997 0.7 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 10/9/1997 0.77 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 1/8/1998 0.95 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 4/7/1998 0.53 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 7/7/1998 1 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 10/9/1998 2.9 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 1/7/1999 3.0 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MC = 6.2; MW-136 Gamma-1 Zone 4/7/1999 4 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 7/13/1999 3.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 10/8/1999 2.2 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 1/13/2000 3.7 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 8/28/2000 0.75 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 0.69; MW-136 Gamma-1 Zone 8/28/2001 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 8/9/2002 2 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 0.55; MW-136 Gamma-1 Zone 8/15/2003 2.7 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 0.72; MW-136 Gamma-1 Zone 10/5/2004 3.9 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 8/16/2005 3.4 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- CHLFM = 0.58; MW-136 Gamma-1 Zone 8/31/2006 4.3 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 8/15/2007 4.2 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 8/20/2008 4.1 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-136 Gamma-1 Zone 8/3/2009 3.9 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-136 Gamma-1 Zone 8/2/2010 4.0 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-136 Gamma-1 Zone 8/1/2011 4.3 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-136 Gamma-1 Zone 8/13/2012 4.1 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-137 Gamma-2 Zone 7/20/1993 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 Acetone = 36; MEK = 240; MW-137 Gamma-2 Zone 8/18/1993 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 Acetone = 22; MC = 5.5; MEK = 440; MW-137 Dup Gamma-2 Zone 8/18/1993 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 MC = 5.7; MW-137 Gamma-2 Zone 11/19/1993 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-137 Gamma-2 Zone 3/2/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-137 Gamma-2 Zone 11/20/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-137 Gamma-2 Zone 4/14/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-137 Gamma-2 Zone 10/13/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-137 Gamma-2 Zone 4/12/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-137 Gamma-2 Zone 4/21/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-138 Gamma-1 Zone 7/15/1993 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 MW-138 Gamma-1 Zone 11/23/1993 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-138 Gamma-1 Zone 2/25/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-138 Gamma-1 Zone 5/13/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- E:\HP\well_Destructions\20130411 - Table 1 - MW-135-138, MW-163,164.xlsx 185702205.200.044 Page 2 of 4 Table 1 Historical Groundwater Analytical Results for Wells MW-135 through MW-138, MW-163 and MW-164 Hewlett-Packard Company 1501 Page Mill Road Site Palo Alto, California Well ID Sample Flow Sample TCE PCE 1,1,1-TCA 1,1-DCA 1,1-DCE cis-1,2-DCE Benzene Toluene Ethylbenzene Xylenes, Total Other Type Zone Date Constituents MW-163 Gamma-1 Zone 8/27/1993 <5.00 <5.00 <5.00 <5.00 <5.00 --- 54 50.8 <5.00 <5.00 MW-163 Gamma-1 Zone 8/25/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 11/23/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 1/19/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 4/19/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 7/13/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 10/20/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 1/10/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 4/10/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 7/10/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 10/17/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 1/8/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 4/11/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-163 Gamma-1 Zone 7/16/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 9/17/1993 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 MW-164 Dup Gamma-2 Zone 9/17/1993 <5 <5 <5 <5 <5 <5 <5 <5 <5 <5 MW-164 Gamma-2 Zone 8/24/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 11/23/1994 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 1/18/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 4/18/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 7/12/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 10/14/1995 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 1/11/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 4/12/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 7/10/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 10/17/1996 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 1/8/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 4/14/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 7/16/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 10/9/1997 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 10/13/1998 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 10/7/1999 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 8/28/2000 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 9/6/2001 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 MW-164 Gamma-2 Zone 8/9/2002 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Dup Gamma-2 Zone 8/9/2002 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 8/14/2003 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 10/5/2004 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 8/16/2005 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 8/30/2006 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 8/15/2007 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 8/20/2008 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 --- --- --- --- MW-164 Gamma-2 Zone 8/3/2009 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-164 Gamma-2 Zone 8/2/2010 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-164 Dup Gamma-2 Zone 8/2/2010 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-164 Gamma-2 Zone 8/1/2011 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- MW-164 Gamma-2 Zone 8/13/2012 <0.50 <0.50 <0.50 <0.50 <0.50 <0.50 --- --- --- --- E:\HP\well_Destructions\20130411 - Table 1 - MW-135-138, MW-163,164.xlsx 185702205.200.044 Page 3 of 4 Table 1 Historical Groundwater Analytical Results for Wells MW-135 through MW-138, MW-163 and MW-164 Hewlett-Packard Company 1501 Page Mill Road Site Palo Alto, California Well ID Sample Flow Sample TCE PCE 1,1,1-TCA 1,1-DCA 1,1-DCE cis-1,2-DCE Benzene Toluene Ethylbenzene Xylenes, Total Other Type Zone Date Constituents Abbreviations: --- = Not analyzed All results reported in ug/L, except for lead. TCE = Trichloroethene 1,1,1-TCA = 1,1,1-trichloroethene 1,1-DCA = 1,1 dichloroethane 1,1-DCE = 1,1-dichloroethene cis-1,2-DCE = cis-1,2-dichloroethene PCE = tetrachloroethene (perchloroethene) CHLFM = Chloroform MC = Methylene Chloride MEK = Methyl Ethyl Ketone E:\HP\well_Destructions\20130411 - Table 1 - MW-135-138, MW-163,164.xlsx 185702205.200.044 Page 4 of 4 From:Papler, Roger@Waterboards To:Paschke, Paul E (paul.paschke@hp.com) Cc:Walton, Annette; Mark Becker (Mark.Becker@stantec.com); howard.koltermann@stantec.com Subject:HP/PA - 1501 PMR: Comments - Well Decom Request Date:Wednesday, July 24, 2013 6:41:16 PM Hello Paul: Thank you for submitting the 23April13 Request to Decommission Monitoring Wells MW-135 throughMW-138, MW-163 and MW-164 (Request). Regional Water Board staff reviewed the Request and we have the following comments. It is ourunderstanding that the off-property wells were installed during the remedial investigation phase of thesubject site. Since that time, the groundwater monitoring data indicates that the groundwater plumesassociated with the site are within the subject site. Based on well screening data provided by yourconsultant, MW-138 and MW-137 are screened in the Gamma 1 and 2 Zone wells and too deep to beused as sentry wells upgradient of 1050 Mill Road. Based on the above, the Request is acceptable. Please let us know if you need a Regional Water Board letter. Respectfully, Roger W. Papler P.G.Engineering GeologistSan Francisco Bay Regional Water Quality Control Board1515 Clay Street, Suite 1400Oakland, CA 94612   Attachment D Hardcopies were provided to the City Council members and Libraries only This attachment can be reviewed at: http://www.cityofpaloalto.org/news/displaynews.asp?NewsID=2436&TargetID=319 December 16, 2015 Jodie Gerhardt, AICP Current Planning Manager City of Palo Alto 250 Hamilton Avenue, 5th Floor Palo Alto, CA 94301 Re: Submittal of Amended Map for Tract No. 10281, Mayfield California Avenue Residential Dear Jodie: As we have discussed with you and with Michel Jeremias, Stanford University requests an amendment to the Final Map for Tract No. 10281, Mayfield California Avenue Residential. Our proposed amended map is enclosed for City review. This amendment affects only portions of the former 1601 California Avenue site; it does not affect the former 1451 and 1501 California Avenue sites. The reason we request this amendment is as follows. Characterization sampling (soil, soil gas and groundwater) conducted pursuant to the Mayfield Development Agreement Mitigation Monitoring and Reporting Plan (MMRP) revealed an area of isolated elevated TCE concentrations in the form of soil gas under the former footprint of 1601 California Avenue building, where a sump is believed to have been a source contributing to this release. This area was not accessible for TCE testing until after the building was demolished. The isolated TCE in soil gas remains at depth and has not migrated 50 feet beyond this localized area; Also within this isolated area, TCE was found in one perched groundwater sample at a concentration that would not contribute to vapor intrusion; concentrations in groundwater have not migrated from the property. As required by the MMRP, Stanford reported the test results to DTSC. Among other measures, Stanford proposed to DTSC that seven homes originally planned to be located on or near the elevated TCE readings be moved at least 50 feet away from the isolated area thereby eliminating any potential risk of vapor intrusion to future occupants. The isolated area would be used for open space and streets. DTSC agrees that there will not be a risk to future site users with the proposed redevelopment design. This design redistributes 29 residences at the former 1601 California Avenue so that the required 180 homes are still provided; creates a jog in the new Amherst Street to accommodate the redistributed homes; reduces the total square footage of home sites and homes in the affected area; and increases common area open space. Attachment E Jodie Gerhardt December 16, 2015 Page 2 After carefully reviewing the evidence, including this design, DTSC has agreed that “that there will not be a significant risk to future site users with the proposed redevelopment design.” Accordingly, we now seek an amendment to the Final Map for Tract No. 10281 to reflect these changes in the site plan. We request that the City Council consider and approve Stanford’s request expeditiously so that project construction, which is already well under way on the former 1451 and 1501 California Avenue portions of the project site, can be completed as promptly as possible. Section 21.16.280 of the Palo Alto Municipal Code authorizes map amendments. With respect to final maps (as opposed to parcel maps), the ordinance provides: In addition to the amendments authorized by Government Code Section 66469, after a final map … is filed in the office of the county recorder, the recorded map may be modified by a certificate of correction or an amending map if (i) there are changes in circumstances which make any or all of the conditions of such a map no longer appropriate or necessary, (ii) that the modifications do not impose any additional burden on the present fee owner of the property, (iii) the modifications do not alter any right, title, or interest in the real property reflected on the recorded map, and (iv) the map as modified conforms to the provisions of the Subdivision Map Act and Chapter 21. 16 of this title. The decision to approve or deny a modification shall be made by the city council for final maps…. Prior to approval of any modification, notice shall be given as provided in Section 21.12.090. The hearing shall be confined to consideration of and action on the proposed modification. Stanford’s request meets the four requirements of section 21.16.280. First, there are changes in circumstances (elevated TCE readings under seven home sites) that make certain final map conditions (the locations of those homes) no longer appropriate or necessary. Second, the modifications do not impose any additional burden on Stanford, which is the fee owner of the property. Third, the modifications do not alter any right, title, or interest in the real property reflected on the recorded map. Fourth, the map as modified conforms to the provisions of the Subdivision Map Act and PAMC Chapter 21.16. As you know, because this project is subject to the Mayfield Development Agreement and Stanford elected to apply AS2 zoning to it as permitted by that agreement, the project must continue to comply with AS2 Alternative Development Standards. Jodie Gerhardt December 16, 2015 Page 3 We also note that the proposed final map amendment would not result in a substantial increase in the severity of the environmental impacts identified in the Mayfield Development Agreement EIR. During construction, impacts would be the same as under the approved final map. All Mayfield Development Agreement EIR mitigation measures would continue to apply. No additional protected trees would be removed or relocated. Once the project is complete, impacts would be the same, or slightly less than, the less-than-significant impacts identified with the approved final map. The reason for this is that although the amended map still provides for a total of 180 dwelling units at the project (as required under the Mayfield Development Agreement), as noted above, some units will be reduced in square footage and bedroom count, as the house redistribution will be accomplished in part by switching some of the larger house plans to some of the smaller plans, and, in some cases, combining these smaller plans into duplexes. As a result, the project’s total occupancy and, therefore, its total vehicle trips, will likely be reduced compared to buildout under the January 2015 final map. We look forward to working with the City to process this application as expeditiously as possible and welcome any comments or questions you may have. Sincerely yours, Chris Wuthmann Enclosures - Setback Compliance Site Plan - Height Restriction Compliance Site Plan - DTSC Approval email ATTACHMENT F Attachment G Hardcopies were provided to the City Council members and Libraries only Project plans can be reviewed at: http://www.cityofpaloalto.org/news/displaynews.asp?NewsID=3437