Attachment 13PREPARED BY: JENNIFER ARMER
Associate Planner
Reviewed by: Planning Manager and Community Development Director
110 E. Main Street Los Gatos, CA 95030 ● 408-354-6874
www.losgatosca.gov
TOWN OF LOS GATOS
PLANNING COMMISSION
REPORT
MEETING DATE: 05/10/2017
ITEM NO: 2
ADDENDUM
DATE: MAY 8, 2017
TO: PLANNING COMMISSION
FROM: JOEL PAULSON, COMMUNITY DEVELOPMENT DIRECTOR
SUBJECT: ARCHITECTURE AND SITE APPLICATION S-15-056, CONDITIONAL USE
PERMIT APPLICATION U-15-009 AND ENVIRONMENTAL IMPACT REPORT
EIR-16-001. PROJECT LOCATION: 401-409 ALBERTO WAY. PROPERTY
OWNER: CWA REALTY. CONTACT PERSON: SHANE ARTERS, LP
ACQUISITIONS, LLC.
REQUESTING APPROVAL TO DEMOLISH THREE EXISTING OFFICE
BUILDINGS AND CONSTRUCT A NEW, TWO-STORY OFFICE BUILDING WITH
UNDERGROUND PARKING ON PROPERTY ZONED CH. APN 529-23-018.
REMARKS:
The geotechnical peer review report, prepared by the Town’s consultant (Amec Foster
Wheeler) is attached as Exhibit 43.
Exhibit 44 includes additional public comment received between 11:01 a.m. Friday, May 5, 2017
and 11:00 a.m. Monday, May 8, 2017.
EXHIBITS:
Previously received under separate cover:
1.Draft Environmental Impact Report
Previously received with August 10, 2016 Staff Report:
2.Location Map
3.Required Findings and Considerations (two pages)
4.Required CEQA Findings of Fact (24 pages)
5.Recommended Conditions of Approval (15 pages)
6.Letter of Justification/Project Description (15 pages), received July 15, 2016
ATTACHMENT 13
PAGE 2 OF 3
SUBJECT: 401-409 ALBERTO WAY PROJECT/S-15-056, U-15-009 AND EIR-16-001
MAY 8, 2017
N:\DEV\PC REPORTS\2017\AlbertoWay401-409 05.10.17 ADD.docx 5/8/2017 1:32 PM
7.Project Construction Details (three pages), received August 3, 2016
8.Letter of Outreach Conducted (40 pages), received February 10, 2016
9.Second Letter of Neighborhood Outreach (26 pages), received August 3, 2016
10.Consulting Arborist’s Report (41 pages), dated September 26, 2015
11.Architectural Consultant’s First Report (five pages), received September 10, 2015
12.Architectural Consultant’s Final Report (five pages), received March 18, 2016
13.Conceptual Development Advisory Committee Meeting minutes, June 10, 2015 meeting
(four pages)
14.Public Comments
15.Final EIR and Mitigation Monitoring and Reporting Program, dated June 29, 2016
16.Development Plans (37 pages), received July 15, 2016
Previously received with August 10, 2016 Desk Item:
17.Comments received from 11:01 a.m. on Thursday, August 4, 2016 to 11:00 a.m. on
Wednesday, August 10, 2016
Previously received with August 24, 2016 Staff Report:
18.Comments received from 11:01 a.m. on Wednesday, August 10, 2016 to 11:00 a.m. on
Thursday, August 18, 2016
19.Applicant’s Response Letter, received August 19, 2016
Previously received with August 24, 2016 Desk Item:
20.Comments received from 11:01 a.m. on Thursday, August 18, 2016 to 11:00 a.m. on
Wednesday, August 24, 2016
21.Applicant’s Response Letter, received August 24, 2016
Previously received with October 26, 2016 Staff Report:
22.Communication from the applicant, received October 10, 2016 and October 19, 2016
23.Public comments received from 11:01 a.m., Wednesday, August 24, 2016 to 11:00 a.m.,
Thursday, October 20, 2016
Previously received with January 11, 2017 Staff Report:
24.Communication from the applicant, received November 11, 2016
25.Public comments received from 11:01 a.m., Thursday, October 20, 2016 to 11:00 a.m.,
Thursday, January 5, 2017
Previously received with March 22, 2017 Staff Report:
26.Communication from the applicant, received February 28, 2017
27.Comments received from 11:01 a.m. on Thursday, January 5, 2017 to 11:00 a.m. on
Thursday, March 16, 2017
PAGE 3 OF 3
SUBJECT: 401-409 ALBERTO WAY PROJECT/S-15-056, U-15-009 AND EIR-16-001
MAY 8, 2017
N:\DEV\PC REPORTS\2017\AlbertoWay401-409 05.10.17 ADD.docx 5/8/2017 1:32 PM
Previously received with April 12, 2017 Staff Report:
28.Revised Required Findings and Considerations
29.Revised Conditions of Approval (21 pages)
30.Comments received from 11:01 a.m. on Thursday, March 16, 2017 to 11:00 a.m. on
Thursday, April 6, 2017
31.Applicant’s Response Letter (23 pages), received March 17, 2017
32.Architectural Consultant’s Report on Revised Plans (six pages), received February 22, 2017
33.Applicant’s Response letter to Architectural Consultant’s Report (three pages), received
March 16, 2017
34.Architectural Consultant’s Second Report on Revised Plans (eight pages), received March
17, 2017
35.Traffic Consultant Letter (eight pages), received April 6, 2017
36.Revised Development Plans (35 pages), received March 17, 2017
Previously received with April 12, 2017 Addendum Report:
37.Communication from the applicant, received April 10, 2017
38.Public Comment received between 11:01 a.m. Thursday, April 6, 2017 and 11:00 a.m.
Tuesday, April 11, 2017
Previously received with May 10, 2017 Staff Report:
39.Applicant’s Supplemental Response Letter, received April 24, 2017
40.Town Consultant Peer Review of Transportation Report, received April 28, 2017
41.Project Information Sheet, prepared by the Parks and Public Works Department
42.Public Comment received between 11:01 a.m. Tuesday, April 11, 2017 and 11:00 a.m.
Friday, May 5, 2017
Received with this Addendum Report:
43.Town Consultant Peer Review of Geotechnical Report, received May 8, 2017
44.Public Comment received between 11:01 a.m. Friday, May 5, 2017 and 11:00 a.m. Monday,
May 8, 2017
Distribution:
Shane Arters, LP Acquisitions, LLC, 535 Middlefield Road, Ste. 190, Menlo Park, CA 94025
This Page
Intentionally
Left Blank
May 8 , 2017
Project 0084491960
Mr. Mike Weisz, PE
Associate Engineer
Town of Los Gatos
Parks and Public Works
41 Miles Avenue
Los Gatos, California 95031
Subject: Geotechnical Peer Review
401-409 Alberto Way
Los Gatos, California
Dear Mr. Weisz:
Reference :
amec
foster
wheeler
• Engeo; Supplemental Response to Public Comments ; Hydrology Report;
401-409 Alberto Way , Los Gatos, California, dated March 31 , 2017 .
At your request, Amee Foster Wheeler Environment and Infrastructure Inc. (Amee Foster
Wheeler) has reviewed the reference above pertaining to the proposed construction of a new
office development at 401-409 Alberto Way, Los Gatos, California. We received th is document
from the Town on April 24, 2017. It provides responses to geologic/geotechnical comments
pertaining to the proposed project from the following parties :
• Geissler Engineering (pages 1 through 7);
• Alberto Way Liaison Committee (pages 7 and 8);
• Alberto Way Citizens , Mr. Bob Burke and Pueblo De Los Gatos (pages 9
through 14 );
• Las Casitas (page 14 and 15 );
• Bella Vista Village (page 15); and
• Neighbors of Alberto Way (pages 15 and 16).
We also reviewed A document entitled "Addendum A'', prepared by Geissler Engineering , dated
May 4 , 2017 . We have not seen Engeo's responses to those comments.
Amee Foster Wheeler is familiar with the project because we previously performed a
geologic/geotechnical peer review of the following document submitted for th is project:
• Engeo ; Geotechnical Exploration , 401 Alberto Way , Los Gatos, California, dated
July 17, 2015.
Amee Foster W heeler Environment & Infrastructure, Inc.
180 Grand Ave nue, Su ite 1100
Oakland , Ca lifornia 94612-3066
US A
Tel (510) 663 -4100
Fa x (510) 663-4141
amecfw.co m EXHIBIT 4 3
Mr. Mike Weisz, PE
Town of Los Gatos
May 8, 2017
Page 2
Our comments related to this (July 17, 2015) document were summarized in a letter to you
dated December 4, 2015. In addition to the references , we have reviewed other pertinent
reports and maps. We have not visited the site .
It is our opinion that the March 31 , 2017 responses to geologic/geotechnical comments from the
public prepared by Engeo are appropriate for the conditions anticipated and for the project
planned .
The majority of the comments are related to the elevation of groundwater, and the
corresponding impacts to the proposed development and nearby properties during the
construction and lifespan of proposed below grade parking areas . We note that there are many
examples of concrete structures throughout the Bay Area that have been constructed below the
elevation of the groundwater. Engineering controls and construction techniques specific to those
conditions are available and presumably will be incorporated for this project. We have not
reviewed those details.
Please feel free to contact us should you have questions or require additional information .
Sincerely,
Amee Foster Wheeler Environment & Infrastructure, Inc.
C?-te.A 11. w:,,~
Robert H. Wright, Ph.D., PG , CEG
Principal Engineering Geologist
Direct Tel.: (510) 663-4187
E-mail : bob.wright@amecfw.com
rhw /cjc/ldu
~~c __ L_
Christoph ~r J~utu, ~E . GE
Principal Engineer
Direct Tel.: (510) 663-4156
E-mail: chris.coutu@amecfw.com
x:\8000s\6449 .000\6449.196_alberto way\8449.196_peer review lt_alberto way_050817.docx
Am ee Fos ter Wh eeler
3 1st March 20 I 7
Peter G eissler, Ph.D., P.E.
Consulting Civil Engineer
HYDROLOGY REPORT
401-409 A lb erto Way, Los Gatos, CA 95032
Jennifer T.C. Armer, AICP , Associate Planner ~
Community Development Department
110 E. Main Street · .
Los Gatos CA 95030
And
Los Gatos Commons Homeowners Association
445 Alberto Way
Los Gatos , CA 95032
Project: Hydrology Report re 401-409 Alberto Way Project, Los Gatos , CA 95032
Project
Location:
Affected
Properties:
Ref:
Ref:
Ref:
Ref:
401-409 Alberto Way Project, Los Gatos, CA 95032
Los Gatos Commons, Los Gatos
Bella Vista Village, Lo s Gatos
Pu e blo de Los Gatos, Los Gatos
Las Casitas, Los G a tos
ENGEO Report dated July 17 , 2015, revised August 13 , 2015
401 Alberto W ay, Los Gatos, California, Geotechn ical Exploration, Appendix C ,
D EIR
Architectural Technologies Plans for Project 153948 revised 19 February 2016
Civil Engineering Plans by Architectural Technolog ies in association with Kier &
Wright revised 8 February 201 7
Geiss ler Engineering Project No. E l 6 -2402
TO WHOM IT MAY CONCERN
Geiss ler Engineerin g has been asked to review hydrological and geotechnical data presented in
the ENGEO Report referenced above. In addition , Geissler E ngineering has been asked to
review civil engineering drawings by Architectural Techno lo gies in assoc iation with Kier &
Wright revised 8 February 2017.
EXHIBIT 4 4
The review includes an evaluation of the findings, conclusions and recommendations presented
in the EN GEO Report and renders an expert opinion as to the hydrological impact of the
proposed project on neighboring properties.
In so doing, Geissler Engineering has considered the impact of the proposed construction of a 2-
story underground garage on the residential developments on Alberto Way due to:
(i) The likelihood of life-threatening flooding due to up stream dam failures;
(ii) Soil subsidence caused by temporary dewatering during construction;
(iii) Long-term hydrological effects caused by diversion of subsurface flow of
groundwater following construction of the proposed 2-story underground garage;
(iv) The likelihood of structural cracking (post construction) of the proposed 2-story
underground garage and subsequent seepage of groundwater into the garage;
(v) Long-term dewatering required to discharge the seepage of groundwater into the
underground garage;
(vi) Problems associated with long-term dewatering in the vicinity of the proposed 2-story
underground garage ;
(vii) The likelihood of flooding due to a 125-year storm;
(viii) The hazards associated with the lo cation of the proposed garage located within a
previously mapped Earthquake Fault Hazard Zone;
(ix) The hazards associated with the loc ation of the proposed garage located within a
previously mapped Earthquake Induced Liquefaction Hazard Zone;
(x) The like lihood of flooding of the proposed 2-story underground garage due to
storm water runoff;
EXECUTIVE SUMMARY
The project includes the construction of a 2-story underground garage 20 to 22 feet below grade.
The ground water varies in depth from year to year depending on annual rainfall during the
previous 5 or 6 years. At this particular location, the depth of the gro und water varies from a
high of 12 feet below grade to a low of 18 feet below grade. [Ref: Section 4.1 and Section 5.13,
ENGEO Report, pages 8 and 20]
ENGEO recommends that for civ il engineering des ign purposes, the groundwater must be
ass umed to be 12 feet below grade. Geissler Engineering concurs. [Ref: Section 4 .1 and Section
5 .13 , ENG EO Report, pages 8 and 20]
Page 2
Therefore, the bottom of the foundation of the proposed 2-story underground garage is to be
constructed I 0 to 12 feet below the water table.
The proposed 2-story underground garage is located within an Earthquake Fault Hazard Zone .
[Ref: California Geologic Survey, State of California Department of Conservation]
The location of the 2-story underground garage has been identified as an Earthquake Induced
Liquefaction Hazard Zone. [Ref: Santa Clara County Hazard Mitigation Plan dated February
21, 2012]
The combined effect of: (i) the likelihood of seismic activity; and (ii) sub grade soils subject to
liquefaction (i.e., sudden loss of strength and bearing capacity in the event of strong vibration),
make this site unsuitable for the proposed underground (and underwater) garage.
In the event of an earthquake, the soils below the 2-story underground garage are likely to
exhibit significant loss of bearing capacity. Loss of bearing capacity is likely to result in
differential foundation settlement with resultant structural cracking of the reinforced concrete
structure. Cracking of the reinforced concrete structure allows significant influx of groundwater.
Geissler Engineering estimates the rate of flow into the (cracked) underground (and underwater)
garage structure could range from 50 gallons per minute to 500 gallons per minute, or more,
depending on the severity of the cracks.
Geissler Engineering holds the opinion that construction of a 2-story underground parking
structure shall cause soil subsidence, differential foundation settlement and cracked slabs at
nearby hous es in Los Gatos Commons, Bella Vista Village, Pueblo de Los Gatos and Las Casitas
developments.
Even in the absence of earthquake activity, EN GEO has admitted that differential foundation
movement is likely due to seasonal shrink-swell activity of expansive s ub grade soils. Such
movement ca n cause leakage at cold joints in und erground concrete walls and floors. Thus even
in the absence of earthquake activity, leakage of groundwater into the underground garage is
likely. The leaka ge of groundwater through cold joints has been estimated by Geissler
Engineering to be on the order of 50 gallons per minute.
Obviously, seepage as small as 50 gallons per minute could be collected in a drainage sump
located within the interior of the garage and pumped out by means of submersible sump pumps.
However , it is not practical to attempt to collect and discharge 500 gallons per minute or more.
The undergro und garage is to be constructed at a location subject to significant sheet flow of
storm water runoff during heavy rains. Thus , surface drainage may also result in floodin g of the
underground garage unless the surface drainage facilities are substantially improved.
The proposed 2-story underground garage is located at a site that ha s been identified as one that
is subject to flooding in the event of an upstream dam failure. [Ref: Section 14.4.2 .2.6, Santa
Page 3
Clara County Hazard Mitigation Plan dated February 21, 2012 Page 14-48; ABAG, 1995. Dam
data from State of California Office of Emergency Services]
Dam failures always pose significant risk to life and property. However, the construction of an
underground garage at a location that has already been identified as one subject to flooding in the
event of an upstream dam failure is beyond the ordinary concept of engineering risk; this is
certain death for everyone inside the garage .
Put simply , the construction of an underground parking garage that is subject to flooding in the
event of a dam failure is wanton disregard for public safety.
The civil engineering drawings by Architectural Technologies in association with Kier & Wright
revised 8 February 2017 are of concern because they show inadequate property drainage.
SOIL CONDITIONS
ENGEO borings show medium dense to dense clayey sands to depths ranging between 10 to 21
feet below grade. Below this level, medium dense to very dense clayey gravels were
encountered to depths of approximately 29 to 33 feet below ground surface. Bedrock was
encountered below the strata of medium dense to very dense clayey gravels. Geissler
Engineering holds the opinion that this description of subgrade soils is accurate.
The surficial clayey sands exhibit adequate strength and bearing capacity to support foundation
loads. Unfortunately, the surficial clayey sands are moderately expansive (i.e., subject to shrink-
swell activity when subject to periodic wetting and drying due to seasonal changes in moisture
content). This can cause heaving and cracking of slabs-on-grade, pavements, and structures
founded on shallow foundations. [Ref: Section 4.3 ENGEO Report, page 8]
The strata of clayey gravels sandwiched between the clayey sands (above) and the bedrock
(below) is subj ect to liquefaction in the event of an earthquake. [Ref: Section 4.13 EN GEO
Report, page 6]
ENGEO estimates the settlements due to liquefaction-induced ground settlement as follows.
Our liquefaction analyses indicate that gravel deposits up to 9 feet thick below the bottom
of the proposed parking garage (estimated to be 20 feet below grade) may potentially
liquefy and result in vertical settlements of approximately 1 inch. Additionally, our
liquefaction analyses indicate that grave l deposits up to 14/eet thick for portions of the
site not within the proposed parking garage may potentially liquefo and result in vertical
settlements of approximately 2 inches. Ref: Section 4.1.4 EN GEO Report, page 7]
ENGEO estimates the potential total and differential settlement as follows.
Assuming the subterranean parking garage extends at least a distance of 20 feet below
grade, we recommend that the foundation design consider 1 inch of total and ~ inch of
Page 4
differe ntial s e ttleme nt associated with liqu efaction-indu ce d settle ment. [Ref: Section
5.7.1 ENGEO REPORT, page 15)
A s ide from an apparent inconsistency in the ENGEO report as regards to the magnitude of
expected settlements, the message is clear. We should expect settlements on the order of 1 inch
or more.
Apprecia te that differentia l foundation settlements on the order of an inch or more shall caus e
significant cracking in the reinforced concrete structure. In an underground (and underwater)
garage, this is likely to allow the influx of substantial flow of groundwater.
EART HQUAKE RISK
The project location is located within an earthquake fault rupture hazard zone. [Ref: California
Geologic Survey, State of California Department of Conservation]
_The project location is located within an Earthquake Induced Liquefaction Hazard Zone. The
risk of earthquake induced liquefaction hazard has been determined to be high by the Santa Clara
Planning Department. [Ref: Santa Clara County Hazard Mitigation Plan dated February 21,
2012)
Pla te 1.2 of the Seismic Hazard Zone Report for the Los Gatos Quadrangle (2002) indicates a
likelihood of liquefaction that requires mitigation measures are required as per Public Resources
Code S e ction 2693( c ).
The EN GEO Report admits that the strata of clayey gravels soils at the subject property
(specifically, soils at the location of Boring B3) are subject to liquefaction according to criteria
described in an authoritative research paper. [Ref: Seed, R. B., Cetin K . 0., Moss R. E. S.,
Kammerer A . M ., Wu J., Pestana J.M., Riemer M . F ., Sancio, R. B., Bray J. D ., Kayen R. E.,
Faris A., 2003 , Recent Advances in Soil Liquefaction Engineering : A unified and Consistent
Framework, 26th Annual ASCE Los Angeles Geotechnical Spring Seminar]
GROUNDWATER HYDROLOGY
In 2008, Earth Systems Geotechnologies (ESG) reported encountering groundwater at a depth of
approximately 18 feet at a nearby site located at 55 Los Gatos Saratoga Road. This is
approximately 200 feet away from the proposed construction site. The groundwater is likely to
b e 5 or 6 feet higher following the end of the record drought.
ENGEO did not record the groundwater level in boring Bl or boring B3 .
The EN GEO Report recommends using a design value of 12 feet for the depth of the
groundwater at the project location. Geissler Engineering concurs. ·
Geissler Engineering is concerned that the construction of a 22-foot deep underground garage
may cause diversion of subsurface seepage patterns. The long-term effects of such diversion of
Page 5
subsurface seepage include a rise in groundwater levels in neighboring properties and increase d
seepage flow rates which in tum may cause piping failures in adjacent soil strata.
Geissler Engineering estimates that the so-called "radius of influence" of th e divers ion of
s ubsurface see page i s approximately 250 feet from the underground garage. This estimate of the
radius of influ ence is based upon soil classifications. The permeability of the surficial clayey
so ils estimated to be on the order of 10-8 cm /sec (very low) whereas the permeability of the
gravel strata I 0 -5 cm /sec (very hi gh).
SURFACE HYDROLOGY
The project s ite is located within the FEMA fl ood plane d efined by 0.2% annual chance flood
ha zard . [Ref: FEMA-Santa C lara County DFIRM , 2009]
Thus , the chance of NOT flooding during any I 00-year period is given by the expression :
p = (1 -0 .002)100 = 82%
Accordingly, the chance of flooding during any 100-year period is 18 %.
Based upon the size of the tributary drainage area and the slope of the surface of the ground and
the runoff characteristics of the gro und, Geissler Engineering estimates that the chance of
flooding is 0 .8% annual chance fl ood hazard.
Geissler Engineering calcul ate s the chance of NOT flooding durin g any 100-year period is g ive n
by the expression:
p = (1 -0.008)100 = 45%
Thus, Geissler E ng ineering es tim ates the chance of flooding during any I 00-year period is 55%.
Statistically, thi s is more-or-less e qui va lent to a 125-year flood pla ne.
The usual standard for the assessment of the risk of fl ooding due to annual rainfall is whether or
not the property is located within the so-called 100-year flood plane. This parcel is not located
within th e I 00-year flood plan e.
Geissler Eng ineering hold s the opinion that where, as here, floodin g would result in certain d eath
for anyone ca ug ht inside the und erground parking garage in th e event of floodin g, a hi gher
standard sh o uld be applied by pl anning authorities.
DEWATERING
ENGEO a dvi ses that temporary dewatering during constructi on i s required , as follow s.
Pa ge 6
Based on the anticipated depths of approximately 20 feet for th e planned excavation and
considering groundwater levels encountered during our field exploration and a design
groundwater level of 12 feet, groundwater may be e ncountered above the bottom of the
excavation. Temporary dewatering during construction may be necessary. Assessment of
dewatering s hould be made prior to excavation to determine the level of groundwater
co ntrol and dewatering necessary to address long-term conditions for the depressed
portions of the structure at this site.
Te mporary dewatering during construction may be necessary to keep the excavation and
working areas reasonably dry. If necessary, dewatering should be performed in a manner
such that water levels are maintained not less than 2 feet below th e bottom of excavation
prior to and co ntinuous ly during shoring and foundation ins tallation . As th e excavations
progress, it may be necessary to dewater th e soils ahead of the excavation , such as by
co ntinuous pumping from sumps, to control the tendency for th e bottom of the excavation
to h eave under hydros tatic pressures and to reduce inflow of water or soil.from beneath
temporary shoring. [Ref: Section 5.13 , ENGEO Report , page 20]
During construction, the contractor shall need to construct a cofferdam around the proposed
construction site (i.e., a partial barrier against the influx of ground water) and shall need to
dewater the excavation by means of diesel-powered pumps.
Geissler Engineering estimates the flow of groundwater to be on the order of 250 gallons per
minute (minimum) and 500 gallons per minute (maximum).
During construction, the effect of this local dewatering is two-fold.
First, there is likely to be slight soil subsidence in the near vicinity of the cofferdam due to
dewatering. Geissler Engineering estimates the upper limit of (downward) soil subsidence of
neighboring properties to be as follows .
Di stance to Proposed Excavation Soil Subsidence During Cons truction
5 feet away from excavations I" of soil subsidence
15 feet away from excavations 3/4" of soil subsidence
25 feet away from excavations l 12" of soil subsidence
50 feet away from excavations 3/8" of soil subsidence
100 feet away from excavations l/4" of soil subsidence
150 feet away from excavations 1/8" of soil subsidence
250 feet away from excavations l/16" of soil subsidence
Pa ge 7
Second, the effluent from diesel-powered pumps must be discharged onto the street or other
receiving drainage facility such as a storm drain. Geissler Engineering holds the opinion that
the discharge of 250 gallons per minute (minimum) to 500 gallons per minute (maximum) on a
continuous basi s will negatively impact existing property drainage facilities. At a minimum, this
water is added to existing drainage facilities and , in effect, reduces the capacity of other drainage
facilities (e.g., s torm drains) that serve the neighborhood.
Based on proximity to the proposed excavation, Geissler Engineering calculations suggest that
all of the Las Casitas development and Pueblo de Los Gatos development are likely to exhibit
cracked slabs as a result of soil subsidence during construction.
ENGEO advises against permanent dewatering. Instead, ENGEO recommends the use of
waterproofing to prevent the influx of groundwater.
Specifically, ENGEO advises:
Permanent dewatering is not recommended and the mat foundation or concrete slabs and
basement walls should b e waterproofed and designed to resist hydros tatic and/or uplift
pressures. [Ref: Section 5.9 ENGEO Report, page 18]
Geissler Engineering holds the opinion that it is impossible to prevent the influx of groundwater
into an underground garage by means of waterproofing alone where, as here, ground settlements
up to 1 inch (vertical) are expected.
Put simply, there is no waterproofing product on the market that will prevent the influx of
groundwater into a reinforced concrete structure that is badly cracked in the aftermath of an
earthquake with earthquake-induced liquefaction settlements.
Like-wise, there is no waterproofing product on the market that will prevent the influx of
groundwater into a reinforced concrete structure when differential foundation settlements due to
seasonal groundwater variations cause differential foundation settlements of Yi" or more.
It is significant that ENGEO recommended that concrete slabs be 8 inches thick at the proposed
development. That shows that EN GEO appreciates the potential for cracked slabs due to
seasonal groundwater variations in expansive subgrade soils. Sadly, this level of protection
against cracking is not afforded neighboring properties' existing slabs.
Geissler Engineering warns that the public safety is at risk.
UPSTREAM DAM FAILURE
The most significant hazard is posed by the possibility of an upstream dam failure.
Built in 1952, the Lenihan Dam (Lexington Reservoir) i s an earthen dam and is maintained by
the Santa Clara Valley Water District. It holds 19 ,000 acre-feet of water and is just minutes
upstream from the project location.
Page 8
A catastrophic failure of Lenihan Dam would cause flooding at the project location within
minutes.
Underground parking amplifies th e risk of drowning in the event of a dam failure.
PROPERTY DRAINAGE
The civil engineering drawings by Architectural Technologies in association with Kier & Wright
revised 8 February 2017 are of concern because there is inadequate property drainage.
The existing and propose d grade e levations are as follows.
• The existing grade on the property at 405 Alberto Way ranges from+ 338.84 (near Las
Casitas) feet to +341.31 feet (near Saratoga -Los Gatos Road).
• The proposed finish grade is +336.63 feet (varies).
• The proposed first floor elevation is + 336.50 feet.
• The s treet elevation at Alberto Way is 339.02 feet (varies).
Put simply, the proposed development is not well draining and is likely to serve as a temporary
storm water retention ba s in (i.e., po nding water) after heavy rains.
T he primary storm water drainage facility shown on the plans Ki er & Wright rev ised 8 February
2017 is a proposed 8" diameter storm drain running towards the northwest corner of the property
but which traverses the southwest corner of the neighboring development, Las Casitas. Geiss I.er
Engineering holds the opinion that the proposed storm drain facility is inadequate to drain the
storm wate r runoff. Geissler Engineering recommends that the storm water drainage must be
redesigned so as to avoid trave rs in g ne ighborin g properties.
Geissler Engin eering holds the opinion that there is inadequate pervious landscape to absorb a
significant fraction of the storm water runoff. The likely result is ponding on the patio areas and
parking areas and pedestrian areas of 405 Alberto Way. Geissler Engineering also holds the
opinion that storm water surface runoff from 405 Alberto Way toward s the southwest corner of
the Las Cas itas property is likely since the northwest corner of 405 Alberto Way is at a slightly
higher elevation than is the southwest corner of the Las Casitas prop e rty .
Geissler Engineering recommends that the p ercentage of pervious landscape surface should be
increased and a hydrology study be undertaken to evaluate the effect of increased stonn water
runoff on neighborin g properties.
Pa ge 9
SANITARY SEWER
The civil engineering drawings by Architectural Technologies in association with Kier & Wright
revised 8 February 2017 show the 6" vitreous clay sewer pipe traversing the southwest comer of
the Las Casitas property. Such a configuration sets the stage for future conflict between the
neighboring property owners. Geissler Engineering recommends that the sewer be redesigned
so as to avoid traversing adjacent properties.
MI TI GA TION MEASURES
ENGEO identifies the risks but the proposed mitigations (e.g., dewatering and waterproofing)
are not sufficient to protect the neighboring properties. (Ref: DEIR 3-80-81)
Geissler Engineering has identified a number of risks associated with the current design. By
simply requiring that all parking remain above grade and be designed as pervious paving, all
these risks can be successfully mitigated.
You are welcome to contact Geissler Engineering if you have questions.
We are pleased to be of service.
Respectfull y submitted,
Peter Scott Geissler, Ph.D., P.E.
Registered Civil Engineer, R.C.E. 44320
GEISSLER ENGINEERING
HYDROLOGY DIVISION
235 Montgomery Street, Suite I 01 l
San Francisco, CA 94920
TEL: (415) 760-5636 (Office)
TEL: (415) 887-8704 (Mobile)
Page 10
FLOODING
HYDROLOGY REPORT
401-409 Alberto Way, Los Gatos, CA 95032
ADDENDUM "A"
Dated 4 May 20 17
• Hydro log ic a l analysis by Geissler E ngineering based on a 100-year flood yields an
elevation for the hi gh water mark at 333 '-6" (NA D 83).
• FEMA Official Flood Maps dated 2017 indicates a high water mark at elevation 333'
(NAD83).
• The project location is located within Flood Zone 6 of the Town of Los Gatos.
Geissler's Commentary:
There is no rational basis for suggestin g th at floodin g cannot occur at the project loc ation . T he
only question is the elevation of the hi gh-wa ter mark?
GROUND WATER
• At th e end of th e recent prolonged droug ht , th e de pth to groundwater at the s ite ranged
from 18' to 20' be low adj acent la nd scape grade; this corre sponds to an e levation of 320'
to 32 2' (NAD83).
• During normal rainy se asons, th e groundwater ca n be expected to range from 10 ' to 12'
below adjacent landscape grad e; thi s corresponds to an e levation of 328' to 330'
(NAD83).
Geissler's Comm e ntary:
Depth to groundwater varies from year to year and throu g hout the year; it is prudent to d es ign
the top of the lowes t garage slab floor so as to b e a bove the groundwater at all times. Therefore,
Geissler Engi nee ring recomm end s tha t th e top of th e lowe st garage s la b floor be designed to
have an elevation of at leas t 330' (NAD 83).
FIRST FLOOR ELEV A TION
• Plans dated 9 March 2017 sho w the fir st-sto ry s lab floor to be at e levati o n 336.5'
(NAD83).
Geissler's Commentary:
The e levation of the first-story s la b flo or is above th e high water mark during a 100-year fl ood.
That is 0.K.
Page 11
GARAGE FLOOR ELEV A TION
• Plans dated 9 March 2017 show the top of the PI-level garage s lab to be at elevation 326.
Ft. (NAD83).
• Plans dated 9 March 2017 show the top of the P2-level garage slab to be at elevation 317'
(NAD83).
Geiss l er 's Commentary:
The elevation of the groundwater varies from year to year and throughout the year; during
normal rainy seasons the groundwater is l ike ly to be at an elevation of 328' to 330' (NAD83).
Therefore, Geissler Engineering recommends that the top of the garage slab floor be designed to
have an e levation of at least 330 ' (NAD83). The proposed design calls for the P2-level garage
slab to be submerged 13' during a normal rainy season. ln the absence ofunintemipte d pumping
of groundwater, this may result in as much as 13 ' of standing water within the garage. This is
unsafe.
LIQUEFACTION
• Liquefaction analysis by Geissler Engineering based on Seed, R. B., et al., 2003, Recent
Advances in Soil Liquefaction Engineering: A untfied and Consistent Framework, 26th
Annual ASCE Los Angeles Geotechnical Spring Seminar confirms that the site is subject
to liquefaction in the event of strong shaking due to a nearby earthquake.
• The project site is located within a Liquefaction Hazard Zone as per Santa Clara County
Geological Hazard Zones Map dated 17 September 2012 .
• The project is located in a (former) creek bed . The creek was relocated to the other side
of Highway 17. However, the original soil conditions remain , namely alluvial soi l
deposits that are subject to liquefaction in the event of strong shaking due to a nearby
earthquake.
Geissler's Commentary:
There is no logical basis for the claim that the site is not susceptible to liquefaction in the event
of strong shaking due to a nearby earthquake.
When eva luatin g the likelihood of liquefaction in the event of strong shaking due to a nearby
earthquake, EN GEO does not take into proper account the fact that the subject property is a
(former) creek bed . This omission represents a significant departure from the standard of care in
the engineering profession.
DIFFERENTIAL FOUNDATION SETTLEMENT
• Structural analysis by Geissler Engineering based on the architectural plans dated 9
March 2017 shows that a mat s lab foundation cannot be uniformly supported by subgrade
Page 12
soils subject to liquefaction in the event of strong shaking due to a nearby earthquake
unless the mat foundation exceeds 4 ' in thicknes s.
• Structural analysis by Geissler Engineering based on the architectural plans dated 9
March 2017 shows that the proposed 1' thick mat slab shall be subject to differential
foundation settlement in the event of strong shaking due to a nearby earthquake.
• Structural analysis by Geissler Engineering based on the architectural plans dated 9
March 2017 shows that the proposed 1' thick mat slab is likely to exhibit significant
cracking in the event of strong shaking due to a nearby earthquake.
• Hydrological analysis by Geissler Engineering based on the architectural plans dated 9
March 2017 shows that the proposed 1' thick mat slab is likely to permit groundwater to
seep into the garage with a flow rate that cannot be pumped out by sump pumps.
Geissler's Commentary:
Put simply, earthquakes cause liquefaction; liquefaction causes loss of sub-grade support below
the building; loss of support allows the garage slab floor and walls to settle and crack;
differential foundation settlement causes structural cracks; the cracks allow the massive influx of
groundwater.
SUMP PUMPS
• Percolation analysis by Geissler Engineering based on the like ly performance of a I '
thick garage slab floor subject to liquefaction in the event of strong shaking due to a
nearby earthquake would allow the influx of approximately 500 gallons per minute into
the underground garage. This amount of water leakage cannot be controlled by the use of
sump pumps.
• Percolation analysis by Geissler E ng ineering based on the likely performance of a 4 '
thick garage s lab floor subject to liquefaction in the event of strong shaking due to a
nearby earthquake would allow the influx of approximately 50 gallons per minute into
the underground garage. Contrariwi se, thi s le sser amount of water leaka ge can be
controlled by the use of sump pumps. However, it is unwise to rely upon sump pumps
for prolonged periods.
Geissler' s Commentary:
Geissler Engineering has 35+ years of experience in the design and construction of foundations
below the groundwater. Geissler Engineering recommends the use of a 4 ' thick garage mat slab
foundation and 2' thick garage walls for the required strength and rigidity. The impermeability
afforded by a 4 ' thick mat slab and 2 ' thick garage walls plus good quality exterior
waterproofing plus the installation of several submersible sump pumps and backup electric
generators would re sult in an underground partially submerged garage that is safe for occupancy.
Page 13
CONSTRUCTION PROBLEMS
• The maximum groundwater elevation during construction is not likely to exceed 330 '
(NAD83). The elevation of the garage slab floor is 317' (NAD83). The elevation at the
bottom of the 4 ' thick garage s lab mat slab is 313' (NAD83). Therefore, the depth of
construction is likely to me a maximum of 17' below the groundwater.
• Excavations 17' below the groundwater require prolonged de-watering and can cause soil
subsidence of adjacent properties.
• Geissler Engineering estimates that s ignificant settlement is likely to be caused by
prolonged dewatering during construction.
Geiss ler's Commentary:
Geissler Engineering recommends that the underground garage be rai sed above the groundwater.
DAM FAILURE
• According to the Town of Los Gatos, "Wh ile the Lenihan Dam at Lexington Res ervoir is
considered to be structurally sound and is carefully maintained by the Santa Clara Valley
Water District, the fact that th e lake 's 19,000 acre feet of water is just minutes upstream
from downtown Los Gatos, makes it a concern to Los Gatos emergency managers. "
• Alberto Way is located in Floor Zone 6 in the Los Gatos Flood Evacuation Plan.
[Reference Link: ht!ru;)/w~w.lo..§.fil!tosca.gQv /Docuwent Ce nte1 :/..Jjom~(_yj_~.~j..f_0_ilJ ]
• Dam failure is the like ly result of s trong shaking due to a nearby earthquake.
• Unlike seepage of groundwater, flooding from a dam failure is a sudden and catastrophic
event. Flooding of the underground garage occurs with l 00% certainty under these
circumstances, as is the death by drowning of everyone in the underground garage.
Geissler's Commentary:
Geissler Engineering appreciates that we assume risks in the built environment. Earthquakes,
windstorms, flood s and dam failures occasionally do occur. It is the responsibility of planners
and policy makers to decide what risks are worth taking. It it is the responsibility of professional
engineers to avoid unnecessary and unreasonable risk.
Geissler E ngi neering holds the opinion that the permitting of an underground garage in an area
that is subject to the inundation of floodwaters in the event of an upstream dam failure represents
unnecessary and unreasonable risk.
Pa ge 14
STORM WATER RUNOFF FROM HWY 17
The fundamental problem with the civil engineering design is that the slightest amount of soil
eros ion on the verge ("shoulder") of the northbound Highway 17 on-ramp is likely to cause
s torm water runoff directly onto the subject property. [See red circle in Figure, below.]
®
Page 15
Geissler's Rebuttal to ENGEO on Geissler 1
Geissler Engineering Comment 1
The likelihood of life-threatening flooding due to upstream dam failures .
Page 8, Upstream Dam Failure Section , "A catastrophic failure of the Lenihan Dam
would cause flooding at the project location within minutes. Underground parking
amplifies the risk of drowning in the event of a dam failure ."
To Geissler 1, ENGEO responds:
In December 2012. Terra/GeoPentech prepared a Seismic Stability Evaluation on Lenihan Dam
for the Santa Clara Valley Water District. According to the report, the likelihood of significant
cracks forming in the crest and other areas during the Maximum Considered Earthquake (MCE)
is considered very low, and no seismic remedial measures are deemed necessary at the
Lenihan Dam . Additionally, the report indicates that the Division of Safety of Dams (DSOD)
performed their own independent analyses and concurred that no seismic remedial measures
were necessary.
Based on the informat ion ENGEO reviewed, the risk of inundation as well as the likelihood of
life-threatening flood at the project site is low and the hazard to the project is no greater than
that of any other parcel within the mapped inundation zone in the Town of Los Gatos.
Geissler's Rebuttal to ENGEO on Geissler 1
Leniham Dam is located adjacent to the Fault Rupture Hazard Zone. Strong shaking in the
Earthquake Fault Rupture Hazard Zone is likely to cause the earthen dam to fail.
The 20 J 2 Terra I GeoPentech report does not take into account the close proximity between
Leniham Dam and the Earthquake Fault Rupture Hazard Zone. Therefore, ENGEO's unfounded
reliance upon the findings and conclusions of the 2012 Terra I GeoPentech report represents a
failure to comply with the standard of care of the engineering profession .
Page 16
Geissler's Rebuttal to ENGEO on Geissler 2
Geissler Comment 2:
Comment 2:
Soil subsidence caused by temporary dewatering during construction .
Page 6, Dewatering Section: "First, there is likely to be slight soil subsidence in the near
vicinity of the coffer dam due to dewatering. Second, the effluent from diesel-powered
pumps must be discharged onto the street or other receiving drainage facility such as a
storm drain ... At a minimum, this water is added to existing drainage facilities and, in
effect, reduces the capacity of other drainage facilities (e.g. storm drains) that serve the
neighborhood ... Geissler Engineering calculations suggest that all of the Las Casitas
development and Pueblo de Los Gatos developments are likely to exhibit cracked slabs
as a result of soil subsidence as a result of construction."
ENGEO Response to Comment 2
Geissler Engineering did not provide its calculations to support its letter. Temporary dewatering
during construction will drawdown groundwater in the vicinity of the excavation and result in an
increase of vertical stresses in surrounding soils. When vertical stresses increase in soil,
settlement may occur in soft compressible clayey deposits and loose sandy or gravelly deposits.
Contrary to Dr. Geissler's comments, the soils encountered below the design groundwater level
of 12 feet at the project site are medium dense to very dense clayey gravels. The risk of
settlement (subsidence) in dense soil deposits as a result of temporary dewatering is low.
Please see Chapter 3 .5 of the Draft EIR for a description of the existing Project site soil
characteristics.
Additionally, groundwater was encountered at a depth of roughly 21 feet in June 2015, which is
below the historic high groundwater level of 12 feet bgs. Based on this data, the project site and
vicinity has already experienced the effects of a lowered groundwater level. We are not aware of
signs of subsidence reported in the area as the groundwater level fluctuates . This also indicates
that the soils in the project area are not prone to subsidence as a result of lowered groundwater
levels.
Geissler's Rebuttal to ENGEO on Geissler 2
ENGEO intentionally misleads the reader into thinking that seasonal fluctuations in groundwater
mimic the effects of construction dewatering. That is not true. Seasonal fluctuations in the depth
of groundwater can cause foundation settlement but not differential foundation settlement. By
contrast, construction dewatering induces differential foundation settlement. Cracked slabs are
associated with differential foundation settlement not uniform settlement.
Page 17
Geiss ler's Rebuttal to E NGEO on Geissler 3
Geissler Comment 3:
Comment 3:
Long-term hydrologic effec ts caused by diversion of subsurface flo w of groundwate r following
construction of the proposed 2-story underground garage .
Page 5, Groundwater Hydrology Section: "Geissler Engineering is concerned tha t the
construction of a 22-foot deep underground garage may cause diversion of subs urface
seepage patterns . The long-term, effects of such dive rsion of subsurface seepage
include a rise in groundwater levels in the neighboring properties and i ncreased seepage
flow rates which in turn may cause piping failures in adjacent soil strata . Geissl er
Eng ineering estimates that ... the di version of subsurface seepage is approx imate ly 250
feet from the underground garage . . . The permeability of the surficial clayey soils
estimated to be on the order of 10·8 cm/sec (very low) whereas the permeability of the
gravel strata 10-5 cm/sec (very high)."
ENGEO Response to Comment 3
Diversion of subsurface groundwater flow occurs when an impermeable structure , such as a
slurry cut -off wall, is constructed across high groundwater flow gradients, such as along the
center of a dam or levee, to increase flow paths and reduce the risk of pip ing . The groundwater
level encountered at the project site is similar to nearby areas, indicating that the hydrauli c
grad ient in the area is relatively flat. In the absence of steep hyd raulic gradient in subsurface
flow, diversion of g rou nd water is unlikely . The groundwater level s urround ing the basement is
expected to stabilize to a level similar to the surrounding area after dewater ing wells are
decommissioned .
The dense to very dense sand and gravel deposits encountered at the project site are confined
in a clay matri x. The cla y matrix will reduce the permeability of s ite soils . Considering the
density of the soil deposits, the low permeabil ity as a resu lt of the cla y m atri x and lack of
hydraulic flow gradient, the risk of piping is very low.
It is our expert opin ion that the construction of a subsurface garage will not dramatically impede
groundwater flow, and the risk of piping as described by Ge issler Engineering is extremel y
unlikely.
G eiss ler's R ebu tta l to ENGEO on Gei ss ler 3
T he prop osed underground garage is both w ide and d ee p; of c ourse it sha ll di vert the fl ow of
subsurface seep age . The di ve rsion of sub surface seepage is comple te; a ll of the sub surface
see page is di ve rte d a round th e impermeabl e struc tu re.
EN GE O sta tes," ... th e co nstru cti on of a subsurface ga rage w ill not dra matica ll y imp ede
ground water fl ow." Ge iss ler E ng in ee ring respec tfully poin ts ou t that the constru ction of a
sub surface garage nece ssaril y imp ede s gro undwa ter flo w; the fl ow of gro undwate r is di ve rted
around th e und er ground parking garage. There is an in creased leve l of groundwater on th e
upstrea m si de of th e underground parkin g garage and a decreased leve l of groundwater on the
d ownstream s id e of th e und er gro und parkin g garage . T hi s is a n economic iss ue rath er th a n a
Page 18
safety issue. Cracked slabs in neighboring buildings must be repaired at considerable expense to
the neighbors. However, thi s problem poses no safety ri sk to the public.
Pa ge 19
Geissler's Rebuttal to ENGEO on Geissler 4
Geissler Comment 4
Comment4:
The likelihood of structural cracking (post-construction) of the proposed 2-story underground
garage and subsequent seepage of groundwater into the garage.
Page 3, Executive Summary Section : "In the event of an earthquake, the soils below the
2-story underground garage are likely to exhibit significant loss of bearing capacity. Loss
of bearing capacity is likely to result in differential foundation settlement with resultant
structural cracking of the reinforced concrete structure. Cracking of the reinforced
concrete structure allows significant influx of groundwater. Geissler Engineering
estimates that the rate of flow into the (cracked) underground (and underwater) garage
structure could range from 50 gallons per minute (gpm) to 500 gpm ."
Page 4, Soil Conditions Section : "Appreciate that differential foundation settlement on
the order of an inch or more shall cause significant cracking in the reinforced concrete
structure. In an underground (and underwater) garage, this is likely to allow the inffux of
substantial flow of groundwater.
Page 8, Dewatering Section: "It is significant that ENGEO recommended that concrete
slabs be 8 inches thick at the proposed development. That shows that ENGEO
appreciates the potential for cracked slabs due to seasonal groundwater variation in
expansive subgrade soils. "
ENGEQ Response to Comment 4
The proposed office structure should be supported on a structural mat foundation designed in
accordance with recommendations provided in the Geotechnical Report, summarized as follow :
• Tolerate up to 1 inch of total liquefaction settlements
• Tolerate up to Y:i inch of differential liquefaction induced settlement
• Withstand an edge cantilever distance of 6 feet
• Withstand an interior span distance of 15 feet
When designed based on the above criteria , the foundation mat is rigid enough to span
localized irregularities without suffering from structural damage. We do not anticipate severe
cracking of the structure and associated water intrusion as described by Geissler Engineering
on a foundation mat designed in accordance with the above criteria. We also note that the
above mentioned foundation design criteria are not exceptional to projects constructed in the
San Francisco Bay Area.
Seasonal moisture fluctuation on expansive so il may impact surficial secondary slabs such as
walkways , patio and driveway slabs. Sin ce the foundation is below the water table, moisture
variations which would cause shrink and swell of expansive clay cannot occur at the foundation
subgrade level so expansive soil will have no long-term effect on the below-grade foundation .
Additionally, the 8-inch-thick slab recommendation noted by Geissler Engineering is for concrete
pavement design and is intended to provide support to traffic loads. Geissler Engineering has
misunderstood the purpose of the 8-inch-thick concrete pavement section referenced in the last
quoted statement in Comment 4 above .
Pa ge 20
Geissler 's Rebuttal to ENGEO on Geissler 4
Geissler Engineering stands corrected as to ENGEO's recommendation of an 8-inch slab.
Architectural drawings dated 9 March 2017 specify a 12-inch concrete slab for the garage slab
floor not an 8-inch thick slab .
Geissler Engineering holds the opinion that a 12-inch thick slab floor is too flexible to span over
areas of soil subsidence caused by liquefaction and too weak to prevent cracking. In comparable
situations in San Francisco where liquefaction causes soil subsidence, Geissler Engineering
specifies the construction of a 48-inch thick mat slab. A thick slab affords protection against
differential foundation settlement and cracking in saturated sandy and silty soils in the event of
strong seismic shaking.
Provided the top of slab of the underground garage is located above the groundwater, the
cracking of the underground parking structure is primarily an economic problem. Contrariwise,
if the top of slab of the underground garage is located below the groundwater then the influx of
groundwater into the cracked underground parking structure is a matter of public safety because
water floods the damaged and submerged underground garage.
Page 2 1
Geissler's Rebuttal to ENGEO on Geissler 8
Geissler Comment 8
Comment 8:
The hazards associated with the location of the proposed garage located within a pre
mapped Earthquake Fault Hazard Zone.
Page 5 , Earthquake Risk Section : The project location is located within an earthqu
fault rupture hazard zone [Ref California Geologic SuNey, State of Ca/ifo.
Department of ConseNation]"
ENGEO Response to Comment 8
We disagree wi1h Geissler Engineering on the statement quoted under Comment 8 . The
site is not located within State of California Fault Rupture Hazard Zone (Los Gatos Quad
1991) as shown on Figure 2.
Figure 2: State of California Special Studies Zone Map,
Los Gatos Quadrangle, 1991
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State of California Fault
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Page 22
Geissler's Rebuttal to ENGEO on Geissler 8
ENGEO is incorrect because ENGEO used an outdated map dated 1991. The more recent 2002
map shows that the proposed development is located within the Fault Rupture Hazard Zone and
the Liquefaction Zone.
CONCLUSION
Geissler Engineering stands by its original conclusion. All the risks originally identified with
this design remain. By simply requiring that all parking remain above grade and be designed as
pervious paving, all these risks can be successfully mitigated.
Page 23
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