HomeMy WebLinkAboutStaff Report 321-09TO: HONORABLE CITY COUNCIL
FROM: CITY MANAGER DEP ARTMENT: PUBLIC WORKS
DATE: JULY 20, 2009 CMR:321:09
REPORT TYPE: REPORTS OF OFFICIALS
SUBJECT: Recommendation to the San Francisquito Creek Joint Powers
Authority Regarding a Preferred· Alternative for an Initial Flood
Protection Project on San Francisquito Creek
EXECUTIVE SUlVIMARY
The San Francisquito Creek Joint Powers Authority's (JPA) comprehensive watershedwwide
flood control project will require several more years of study and design, as well as substantial
amounts of federal and local funding. In an effort to provide some tangible benefit in the near
future, the JPA has been pursuing the implementation of an Initial Flood Protection Project that
would provide incrementally improved flood protection to the communities in the watershed by
the end of the year 2012. The JPA retained engineering consultant Philip Williams & Associates
to assess the feasibility of two types of Initial Flood Protection Projects: 1) detaining storm
water runoff in the upper watershed in order to reduce flood flows in downstream reaches, and 2)
providing increased flow capacity in the reach of creek downstream of Highway 101.
As for upstream projects, the consultant identified three potential detention sites on Stanford
University land that could each provide a moderate reduction in the downstream flow rates
during a 1% (lOO-year)l flood event. Construction of a detention basin on any of these sites
would require resolution of several logistical challenges, including but not limited to high cost,
land acquisition, disposal of excavated soil, impacts to endangered and threatened species, and
impacts to archaeological resources. Staff recommends that the JP A defer further consideration
of the upstream detention alternatives at this time, but that the JP A and the City continue a
dialogue with Stanford University regarding potential acquisition of land for future detention
basin construction.
As for downstream projects, the consultant investigated flood protection alternatives for the
reach of San Francisquito Creek downstream of Highway 101 utilizing two basic design
approaches: 1) increasing the conveyarice capacity of the channel (widening the channel), and 2)
diverting a portion of the creek flow through the Palo Alto Municipal Golf Course. Staff
believes that the channel widening alternatives are superior to the Golf Course bypass channel
alternative due to their significantly lower cost and reduced impacts to the Golf Course. Staff
1 A 1% (lOO-year) flood event has a 1% chance of being equaled or exceeded in any given year. Over a very long
period of time, this event would occur an average of once per one hundred years.
CMR:321:09 Page 1 of7
recommends the following key issues be considered in evaluating project alternatives: level of
flood protection to be provided by the project; whether or not to include provision of levee
freeboard (a factor of safety by building the top of the levee higher than the expected water
surface) in the design; project cost; and the level of impact to the Palo Alto Municipal Golf
Course. Based on these factors, staff recommends that that Council recommend channel
widening downstream of Highway 101 as the preferred alternative for the San Francisquito
Creek JPA's Initial Flood Protection Project.
RECOMMENDATION
Staff recommends that Council 1) review the upstream and downstream project alternatives and
recommend the downstream flood protection alternatives for the San Francisquito Creek Joint
Powers Authority'S (JPA) Initial Flood Protection Project, and 2) if the downstream project
alternatives are preferred, recommend channel widening downstream of Highway 101 as the
preferred downstream alternative for the JPA's Initial Flood Protection Project and direct Mayor
Drekmeier to advocate for this alternative as Palo Alto's representative to the JPA Board of
Directors.
BACKGROUND
In April 1999, the cities of Palo Alto, Menlo Park, and East Palo Alto, the Santa Clara Valley
Water District, and the San Mateo County Flood Control District formed the JPA in order to
cooperatively pursue a flood damage reduction and ecosystem restoration project for San
Francisquito Creek. Due to the substantial cost and complexity of a comprehensive watershed-
wide flood control solution for the creek, the JP A has partnered with the U.S. Army Corps of
Engineers (Corps) on a General Investigation (GI) project to plan and implement the
improvements. The GI project will require several more years of study and design, as well as
substantial amounts of federal and local funding. In an effort to provide some tangible benefit in
the near future, the JP A has been pursuing the implementation of an Initial Flood Protection
Project that would provide incrementally improved flood protection to the communities in the
watershed by the end of2012. This initial project would be eligible for future credit towards the
JPA's required local contribution towards the cost of the ultimate GI project and would not
negatively impact the costlbenefit analysis that will be performed by the Corps to determine
whether the federal government will participate in the construction of the GI project.
The JP A retained engineering consultant Philip Williams & Associates to assess the feasibility of
several Initial Flood Protection Project alternatives for San Francisquito Creek. Specifically, the
consultant was asked to study the feasibility of two types of potential projects: 1) detaining
storm water runoff in the upper watershed in order to reduce flood flows in downstream reaches,
and 2) providing increased flow capacity in the reach of creek downstream of Highway 101. The
consultant presented preliminary findings to the JP A Board at the May 28, 2009 meeting
(Attachment A). This presentation was the beginning of a two-month process of outreach and
discussion with governing bodies of the JP A member agencies, neighborhood groups, and the
community at-large regarding potential Initial Flood Protection Projects to be implemented by
the JP A. JP A Executive Director Len Materman presented the consultant's preliminary findings
to Council at a study session on June 8th, with particular emphasis on potential impacts to City
of Palo Alto residents, businesses and City-owned properties. Mr. Materman also made a
presentation to the members of the Crescent Park Neighborhood Association (CPNA) and the
CMR:321:09 Page 2 of7
Duveneck/St. Francis Neighborhood Association at the CPNA)s annual meeting on June 23rd•
The consultanf s San Francisquito Creek Flood Reduction Alternatives Analysis Report will be
finalized on July 17th, and copies will be provided to Council members at places at the July 20th
Council meeting. IP A staff will be asking the JP A Board to authorize the issuance of a Request
for Proposals for design and environmental review consultant services for a specific Initial Flood
Protection Project at the JPA Board meeting on July 23, 2009.
DISCUSSION
JPA member agencies have assigned staff members to participate on a JPA Management Team
that provides advice and guidance to the JPA Executive Director on creek-related matters.
Public Works Department staff representing Palo Alto on the Management Team have taken an
active role in reviewing the report prepared by Philip Williams & Associates to assess the
feasibility of various Initial Flood Protection Project alternatives and in the discussion of the pros
and cons of each alternative. Public Works staff has also met with Planning, Community
Services, and Administrative Services representatives to solicit their input and concerns. Staff's
findings and recommendations regarding the JPA's Initial Flood Protection Project and the Philip
Williams & Associates report are summarized below.
Upstream Detention Alternatives
One potential approach to reducing the flood risk along San Francisquito Creek is to detain water
in the upper watershed and release it in a controlled manner that will reduce peak flows in the
lower reaches of the creek. Due to the large amount of open land required for a detention basin,
the only areas available for detention are upstream of Junipero Serra Boulevard, which is much
less densely developed than the lower watershed. Philip Williams & Associates explored
opportunities for detention that could significantly reduce downstream peak flow rates. Initially,
they sought detention sites that could provide enough flow reduction to allow the then less
than 1 %. flow (the amount of runoff statistically estimated to have a 1 % chance of occurring in
any given year -now estimated to be 9200 cubic feet per second) to pass safely beneath the
Middlefield Road bridge, the most upstream bottleneck along the creek. Achieving this level of
detention would allow 1 % flood protection to be achieved in the future for the entire watershed
without the need to replace the Middlefield Road bridge. Ultimately, this goal was found to be
infeasible, and a lower flow reduction target was adopted for detention alternatives. The
consultant identified three potential detention sites that could each provide between 7 and 14
percent reduction in the downstream flow rates during a 1 % flood event and could provide 20
percent flow reduction if all three detention basins were constructed. All three of the potential
detention basin sites are located on land owned by Stanford University (see site map, Attachment
B). Construction of each of the basins is estimated to cost between $20 million and $30 million,
excluding land acquisition and substantial soil disposal costs. Construction of a detention basin
on any of these sites would require resolution of several logistical challenges, including but not
limited to land acquisition, disposal of excavated soil, impacts to endangered and threatened
species, and impacts to archaeological resources.
Staff believes that upstream detention may eventually be a component of the long-term,
comprehensive flood protection plan for San Francisquito Creek, but that it is not a feasible
approach for the IPA's Initial Flood Protection Project. It is unreasonable to expect that the IPA
would be able to generate adequate fmancial resources and overcome the logistical challenges
Page 3
required to implement an upstream detention project in the timeframe envisioned for the Initial
Flood Protection Project. Therefore, staff recommends that the JP A defer further consideration
of the upstream detention alternatives at this time. It is also recommended, however, that the
JP A and the City continue a dialogue with Stanford University regarding potential land
acquisition opportunities in order to preserve the possibility of utilizing upstream detention as a
flood protection strategy for future project phases.
Downstream Channel Improvement Alternatives
In order to pursue alternatives that reduce flood risk by augmenting the flow capacity of San
Francisquito Creek, it is necessary to implement such improvements in a manner that will not
increase the flood risk to others. This constraint necessitates the approach of beginning the creek
capacity improvements at the mouth of the creek and working systematically upstream from that
point. If the lowermost reach of the creek is improved to safely convey larger flows, it will
provide increased flood protection to adjacent residents and businesses without negative impacts
to upstream properties. For the reasons previously cited, the JPA asked Philip Williams &
Associates to investigate flood protection alternatives for the reach of San Francisquito Creek
downstream of Highway 101. The consultant considered two basic design approaches: 1)
increasing the conveyance capacity of the channel (widening the channel), and 2) diverting a
portion of the creek flow through the Palo Alto Municipal Golf Course. Both options are based
on the premise that the JPA will continue to work cooperatively with Caltrans to increase the
flow capacity of the Highway 101 and frontage road bridges over San Francisquito Creek as part
of the California Department of Transportation (Caltrans) structural upgrade project for these
bridges.
Philip Williams & Associates developed three flood protection alternatives for the downstream
reach of San Francisquito Creek (see Attachments C, D, and E respectively). Each of the
alternatives includes the removal of the northern creek levee between the Friendship Bridge and
the mouth of the creek, allowing creek waters to flow out directly into the Faber Tract during
high flow events. Removal of this levee will create additional marsh habitat and increase the
flow capacity of the creek by allowing the creek to equalize with the San Francisco Bay tide
level at the Friendship Bridge instead of having to build up enough depth to push the water out to
its current mouth downstream of the Palo Alto Airport. The alternatives also share as a common
project element, the removal of excess built-up sediment within the existing creek channel down
to mean tide level. Alternatives 1 and 2 are variations on the theme of widening the channel to
allow increased flow capacity. Alternative 3 provides increased conveyance by creating a bypass
channel through the Palo Alto Municipal Golf Course. Creek flow will overflow into the bypass
channel during extreme flood events. The bypass channel will be sized so that the combined
capacity of the existing creek and the bypass channel will safely convey the 1 % flow.
Construction of the bypass channel would require substantial reconfiguration of the Golf Course
due to its large footprint. Construction of Alternatives 1 and 2 are expected to cost under $10
million, while Alternative 3 is estimated to cost nearly $50 million, not including the cost of
reconfiguring much of the Golf Course.
Staff believes that the downstream channel widening alternatives are clearly superior to the Golf
Course bypass channel alternative. The bypass channel alternative is estimated to cost
approximately five times as much as the widening alternative, even without considering the
CMR:321:09 Page 4
substantial costs involved in redesigning and reconstructing a large portion of the Golf Course
and the revenue that would be lost while the course is closed during the construction period.
Furthermore, there are no substantial flood control advantages to the bypass channel alternative
as compared to the widening alternative. Therefore, staff recommends that Council focus on
downstream Alternatives 1 and 2 as the preferred alternatives for the JPA's Initial Flood
Protection Project.
As previously described, Alternatives 1 and 2 both involve the widening of the existing creek
channel between Highway 101 and the Friendship Bridge. The primary differences between
these two alternatives are the level of flood protection provided and impact to the Palo Alto
Municipal Golf Course. Under Alternative 1, the creek reach downstream of Highway 101
would be able to convey the 1 % flood event out to the Bay, but with the water level up to the top
ofthe levees. Since the Federal Emergency Management Agency (FEMA) requires levees to be
designed with adequate freeboard (additional levee height above the expected water level) in
order to consider them for certification, this alternative would not be sufficient to meet FEMA
standards that would allow for elimination of mandatory flood insurance requirements.
Alternative 2 includes a wider creek section that would provide adequate flow conveyance
capacity for the 1 % flood event and would satisfy the FEMA levee freeboard requirements.
Thus, although the flood insurance requirement for residents and businesses in the downstream
reach could not be eliminated until the tidal levees are also improved, Alternative 2 would lay
the groundwork for future relief from mandatory flood insurance. Alternative 1 would require
the widening of San Francisquito Creek along the western edge of the Golf Course. Moving the
levee closer to the Golf Course may require some course realignment or protective fencing,
although the specific impacts and mitigation measures would not be determined until the design
phase. Alternative 2 includes even more encroachment into the western edge of the Golf Course
and also widens the creek substantially at the Friendship Bridge, completely eliminating the
northwestern comer of the course. The exact impacts on the layout of the Golf Course and the
resultant costs are unknown at this time and would be determined during the project design.
Th £; 11 e 0 owmg matrIX summanzes th h d'ff; e major actors t at 1 erentIate Al ternatlves 1 d 2 an
Factor ALTERNATIVE 1 ALTERNATIVE 2
Flood protection Provides channel capacity for Provides channel capacity for
1 % flood event with no 1 % flood event with freeboard
freeboard (margin of safety)
Floodplain mapping/flood Removal of properties from Lays groundwork for
insurance the FEMA floodplain and removing properties from the
elimination of mandatory FEMA floodplain and
flood insurance purchase eliminating mandatory flood
requirement would require insurance purchase
additional future channel requirement without further
improvements channel improvements
Impacts to west edge of Golf Channel widening results in Channel widening results in
Course minor encroachment into Golf more encroachment into Golf
Course Course, possibly necessitating
redesign of some golf holes
CMR:321:09 Page 5 of7
Factor ALTERNATIVE 1 ALTERNATIVE 2 I
Impacts to northwest corner of Corner still usable as part of Corner converted to marsh and •
Golf Course Golf Course; subject to unusable as Golf Course;
inundation once every seven subject to multiple inundations
years each year
Impacts to Baylands Athletic No encroachment into Channel widening encroaches
Center Baylands Athletic Center into Baylands Athletic Center
overflow parking lot
Habitat value Net increase in marsh habitat Greater increase in marsh
habitat
Cost $8 million $8.5 million
In assessing the best option, staff recommends that Council consider the following key issues:
level of flood protection to be provided by the project; whether or not to include provision of
levee freeboard in the design; project cost; and the level of impacts to the Palo Alto Municipal
Golf Course. Based on these factors, staff recommends that that Council recommend channel
widening downstream of Highway 101 as the preferred alternative for the San Francisquito
Creek lP A's Initial Flood Protection Project and direct Mayor Drekmeier to advocate for this
alternative as Palo Alto's representative to the lPA Board of Directors.
RESOURCE IMPACT
Palo Alto will be an active participant in the design and environmental review process for the
lPA's Initial Flood Protection Project and will contribute staff time as an in-kind service.
However, the City is not being asked to make a financial contribution to the project at this time.
It is estimated that up to 0.1 FTE of staff time may be required to support this activity. The
Santa Clara Valley Water District (District) is providing funding for the project on behalf of the
Santa Clara County portion of the San Francisquito Creek watershed, including the City of Palo
Alto. It is appropriate that the District provide full project funding for the Santa Clara County
portion of the watershed, since the District has primary responsibility for flood control in the
county. The District funds are generated by benefit assessments and special taxes collected from
residents and businesses in Palo Alto and throughout the county for flood control purposes.
POLICY IMPLICATIONS
Council approval of a preferred Initial Flood Protection Project is consistent with the following
Comprehensive Plan policies and programs:
Policy N-9: Avoid fencing, piping, and channelization of creeks when flood control and
public safety can be achieved through measures that preserve the natural
environment and habitat of the creek.
. Policy N-lO: Work with the Santa Clara Valley Water District and other relevant regional
agencies to enhance riparian corridors and provide adequate flood control by use
of low impact restoration strategies.
Policy N-11: Preserve the integrity of riparian corridors.
Page 6
ENVIRONMENTAL REVIEW
The JPA will be the lead agency under the California Environmental Quality Act (CEQA).
Environmental review of the proposed JP A Initial Flood Protection Project will be conducted by
the JP A during the project design. The environmental review process will involve significant
input from local residents, businesses, and stakeholders. Due to the federal involvement in the
project, the process will be conducted in accordance with the requirements of both CEQA and
the federal National Environmental Policy Act (NEPA).
ATTACHMENTS
Attachment A: Philip Williams & Associates May 28 PowerPoint presentation to JP A Board
Attachment B: Map of potential upstream detention basin sites
Attachment C: Downstream Alternative 1 site plan
Attachment D: Downstream Alternative 2 site plan
Attachment E: Downstream Alternative 3 site plan
PREPARED BY:
JdETERESI
DEPARTMENT HEAD:
~?igi1 . 4 ... -----
GLENN s. ROBER8i
Director of Public Works
CITY MANAGER APPROVAL: JA)1~?'KEENE / .<' l··'
oi1# Manager
(po'-,l
cc: Len Materman, San Francisquito Creek Joint Powers Authority
Chris Elias, Santa Clara Valley Water District
Alvin James, City of East Palo Alto
Jean McCown, Stanford University
Norman Beamer, Crescent Park Neighborhood Assn.
Karen White, DuvenecklSt. Francis Neighborhood Assn.
CMR:321:09 Page 7
May 28, 2009 PW A
Christie Beeman
c.beeman@pwa-ltd.com
Jeff Haltiner
j.haltiner@pwa-ltd.com
San Francisquito Creek
Flood Reduction
Alternatives Analysis
May 28, 2009 PW A
Presentation Outline
• Introduction
• Downstream project
–Criteria
–Alternatives
• Discussion
• Upstream project
–Criteria
–Alternatives
• Discussion
May 28, 2009 PW A
Downstream Project Criteria
•Hydraulic performance in 100-year event
–Contain Q100 throughout the project reach
•Compatibility with potential future
project(s) that might:
–Deliver Q100 to the project reach and/or
–Reduce peak flows delivered to this reach
•Minimize impact to infrastructure
•Net habitat/ecology benefit
May 28, 2009 PW A
Downstream Project Reach
May 28, 2009 PW A
Project Alternative Components
• Widen channel
– Increases channel capacity
• Create bypass channel through Golf Course
– Increases conveyance capacity
– Removes water from main channel
• Remove levee between the channel and
Faber Tract portion of Baylands Preserve
– Allows water to spill into Faber Tract
– Flood flows meet Bay tide level sooner
May 28, 2009 PW A
Project Alternative Components
• Increase channel capacity
– Terrace lowering
– Levee setback
– Floodwall
May 28, 2009 PW A
Alternative 1
May 28, 2009 PW A
Alternative 2
May 28, 2009 PW A
Alternative 3
May 28, 2009 PW A
May 28, 2009 PW A May 28, 2009 PW A
Historical Ecology
May 28, 2009 PW A
Ecological Opportunities and Constraints
•Existing floodplain terrace habitat is degraded -
dominated by invasive wetland and upland weeds
•Excavation of these terraces could restore high quality tidal wetlands within the creek channel
•Existing, marginal freshwater wetlands adjacent to
the golf course may be impacted by levee setback
•Removing northern levee adjacent to Faber Tract portion of the Baylands Preserve could:
–restore historic connectivity btw Creek & Baylands
–increase tidal circulation & drainage complexity
–replace degraded upland habitat with tidal wetland
May 28, 2009 PW A
Hydraulic modeling approach
•HEC RAS model provided by the Corps
•PWA tested the alternatives using three
flood scenarios:
–Model calibration event (4,010 cfs) ~Q8
–Feb 98 event (7,200 cfs) ~Q45
–Q100 (9,400 cfs)
•Model not calibrated for Q100
–No “existing conditions” Q100 run provided
–PWA modified model geometry to evaluate
project alternative performance for Q100
May 28, 2009 PW A
Hydraulic modeling results – February 2000 event
May 28, 2009 PW A
Hydraulic modeling results – February 1998 event
May 28, 2009 PW A
Hydraulic modeling results – Q100
May 28, 2009 PW A
Q100
Feb
1998Feb2000
Spring
High Tide
May 28, 2009 PW A
Q100 Feb 1998Feb 2000
Spring High Tide
May 28, 2009 PW A
Comparison of Modeling Results
•All three alternatives perform well at Q8 relative to
existing conditions
•All three alternatives contain Feb 98 event
•For Q100 water levels:
–Alt 1 may not contain Q100 at Hwy 101
–Alt 2 provides the greatest reduction at Hwy 101
(~1 foot below existing levee tops)
–Alt 3 provides greatest reduction along golf course but not necessarily at Hwy 101
•Design-level analysis required to determine performance relative to FEMA standards
–FEMA typically requires 3 feet of freeboard above the Q100 water surface profile
May 28, 2009 PW A
Opinion of Probable Construction Costs
ALT 1 ALT 2 ALT 3
Cut cy 131,000 142,000 140,000
Fill cy 108,000 112,000 830,000
Net (cut-fill) cy (23,000) (30,000) 690,000
Excavation $20/cy $ 2,620,000 $ 2,840,000 $ 2,800,000
Grading/Levees $20/cy $ 2,160,000 $ 2,240,000 $ 16,600,000
Flood Wall Const. $333/lf $ 654,000 $ 654,000 $ 654,000
subtotal $ 5,434,000 $ 5,734,000 $ 20,054,000
Fill Import $20/cy $ 13,800,000
Fill Disposal $10/cy $ 230,000 $ 300,000
subtotal $ 5,664,000 $ 6,034,000 $ 33,854,000
Contingency 30% $ 1,699,000 $ 1,810,000 $ 10,156,000
Escalation (2011) 10% $ 566,000 $ 603,000 $ 3,385,000
total $ 7,929,000 $ 8,447,000 $ 47,395,000
• Construction cost estimate based on estimate of unit costs and quantities provided for comparison purposes
• Costs associated with land acquisition, design, permitting, monitoring, maintenance etc. not estimated May 28, 2009 PW A
Downstream Project Discussion
May 28, 2009 PW A
Detention Site Screening Methodology
•Identify flood reduction screening criterion– Minimum 10% reduction in Q100 peak flow at Middlefield Road
– Q100 = ~9,200 cfs
– 10% reduction = ~8,300 cfs– Middlefield capacity = ~6,700 cfs or 27% reduction in Q100
•Evaluate watershed position relative to flood reduction target – Identify locations in the watershed that could meet the flood reduction target.
•Estimate required facility volume – Estimate minimum storage volume needed to meet the flood reduction target.
•Screen out unfeasible areas – Use spatial analysis to screen out unsuitable areas: heavily developed; too far from stream channels; or topographically unable to accommodate the required storage volume.
•Focus site-specific investigation in remaining zone– Identify opportunities for flood detention within the remaining zone.
•Evaluate potential facility locations – Model identified locations to evaluate facility performance and flood reduction potential. Estimate construction quantities and costs for comparison among sites.
May 28, 2009 PW A
Target = 10% reductionTarget = 27% reduction
May 28, 2009 PW A May 28, 2009 PW A
Existing Facilities
•Lake Lagunita
– Existing storage capacity of approximately 360 acre-feet
– Receives runoff from surrounding watershed during large events (fills)– Current diversions pumps 4 cfs; required diversion ~1,100 cfs– 1,100 cfs requires approximately eight 72-inch pipelines– Diversion location approximately 3,000 linear feet from the Lake
– Not viable for flood detention
•Felt Lake
– Existing storage capacity of approximately 1,000 acre-feet
– Diversion situation similar to Lake Lagunita
– Not viable for flood detention
•Searsville Reservoir
– Design storage capacity approximately 1,000 acre-feet
– Sedimentation has reduced capacity by about 90%
– Sediment removal could restore some or all of the storage
• However, significant logistical challenges: dewatering, transportation, etc.– If the dam were removed, this location could provide off-line storage– Not viable as an early implementation project
May 28, 2009 PW A May 28, 2009 PW A
Alternative 1
May 28, 2009 PW A
Alternative 2
May 28, 2009 PW A
Alternative 2
May 28, 2009 PW A
Alternative 3
May 28, 2009 PW A
Comparison of Upstream Alternatives
Alternative DetentionVolume Reduction in Q100 at Middlefield Rd
acre-feet approximate %
Alternative 1 180 up to 7%
Alternative 2 440 up to 14%
Alternative 3 170 up to 7%
Combined 790 up to 20%
May 28, 2009 PW A
Opinion of Probable Construction Costs
Alternative Cut
Volume
Fill
Volume Opinion of probable Construction Cost*
Detention
Volume
Relative
Cost
cy cy $ acre-feet $/acre-ft
Alternative 1 1,310,000 70,000 $27,600,000 180 $153,000
Alternative 2 1,040,000 10,000 $21,000,000 440 $48,000
Alternative 3 950,000 100 $19,000,000 170 $112,000
TOTAL 3,300,000 80,100 $67,600,000 790 $ 86,000
•Cost estimate provided for comparison purposes based on unit cost for earth work of $20/cy
•Transportation and disposal costs not included
•Costs associated with land acquisition,design,permitting,monitoring,maintenance etc. not estimated
May 28, 2009 PW A
Upstream Project Discussion
May 28, 2009 PW A
Christie Beeman
c.beeman@pwa-ltd.com
Jeff Haltiner
j.haltiner@pwa-ltd.com
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San Francisquito Creek Flood Reduction Alternatives Analysis
figure 2
Alternative 1 Conceptual Layout
PWA Ref# - 1965.00
G:\1965_SanFrancisquito\MXDs
±0 750 1,500375
Feet
Friendship Bridge
Palo Alto
Golf Course
Faber Tract
SF Bay
Highway 101
Cross Sections
Levee Lowering
Overflow Bypass Bridge Access
Levee Top
Levee Footprint
Overflow Bypass Terrace
Marshplain Terrace
Overflow Bypass Terrace
RAA T
E
C
D
B
F
A
San Francisquito Creek Flood Reduction Alternatives Analysis
figure 3
Alternative 2 Conceptual Layout
PWA Ref# - 1965.00
G:\1965_SanFrancisquito\MXDs
±0 750 1,500375
Feet
Friendship Bridge
Palo Alto
Golf Course
Faber Tract
SF Bay
Highway 101
Cross Sections
Levee Lowering
Levee Top
Levee Footprint
Marshplain Terrace
Marshland Terrace Bypass
RAA TTT
B
E
D
F
A
C
San Francisquito Creek Flood Reduction Alternatives Analysis
figure 4
Alternative 3 Conceptual Layout
PWA Ref# - 1965.00
G:\1965_SanFrancisquito\MXDs
±0 750 1,500375
Feet
Friendship Bridge
Faber Tract
SF Bay
Highway 101
Cross Sections
Levee Lowering
Water Feature Thalweg
Levee Top
Levee Footprint
Marshplain Terrace
RAADD