City Council
Staff Report
From: City Manager
Report Type: STUDY SESSION
Lead Department: Public Works
Meeting Date: October 26, 2026
Report #:2610-6871
TITLE
Review of 2026-2027 Winter Storm Preparedness Activities
RECOMMENDATION
Staff has prepared the following report to inform the City Council of actions being taken in preparation for the upcoming 2026/2027 El Niño winter storm season; CEQA Status – Not a Project
EXECUTIVE SUMMARY
With a very strong El Niño climatic condition forecast for the upcoming winter, staff is taking a number of steps to prepare for winter storms and the potential for creek flooding. While minor nuisance flooding is possible in many locations, the largest risk is an overflow of San Francisquito Creek, as occurred most recently in 1998 and 2022. Capital improvement program projects completed by the San Francisquito Creek Joint Powers Authority and by the City of Palo Alto have increased the capacity of San Francisquito Creek and the ability of the City’s storm drain infrastructure to convey creek water that may overflow. However, flooding from the creek is still a significant concern and it is important for the City and community members to be prepared. This session provides an opportunity to increase public awareness of work by the City and partnering agencies as well as steps residents can take to prepare.
BACKGROUND
El Niño Winter Forecast
Over the past several months, the National Weather Service has identified a pattern of increasingly elevated sea surface temperatures in the Pacific Ocean, creating a climatic condition known as El Niño. Based on the dynamics of the pattern to date, the Weather Service has predicted a strong to very strong El Niño likely through January – March 2027. Typically, El Niño is characterized by ocean temperatures greater than or equal to +0.5°C above average while La Niña ocean temperatures are less than or equal to -0.5°C. A strong El Niño (defined as measured sea surface temperatures at least 1.5°C (2.7°F) above average typically results in above-average rainfall for the Bay Area and the rest of California. Recent temperatures in the Niño region 3.4 were measured as 2.4°C above average.
This year’s El Niño conditions are the strongest since winter of 2015-16 and previously the winter of 1997-98, which produced widespread flooding throughout California and the flood of record for San Francisquito Creek. Although forecasters cannot reliably predict weather patterns beyond 7 to 10 days, the Weather Service’s Climate Prediction Center (CPC) issues probabilistic long-term forecasts based on multiple computer weather models. Two such forecasts are provided for reference as Attachment A, and are from September 17, 2026, the most recently released three-month outlook prediction. The first map depicts the CPC’s prediction that for the period of Oct-Nov-Dec 2026, there is an equal chance (33%) of aboveaverage precipitation, below-average precipitation, or average precipitation totals for the Bay Area. The second map depicts their prediction that for the period of Jan-Feb-Mar 2027, there is a 40-50% chance of above-average precipitation totals for the Bay Area.
Creek and Storm Drainage System Capacity Improvements Since 1998 Flooding The San Francisquito Creek Joint Powers Authority (SFCJPA) is a regional government agency formed in 1999 by the cities of East Palo Alto, Menlo Park, and Palo Alto, the San Mateo County Flood Control District (now OneShoreline), and the Santa Clara Valley Water District (Valley Water) formed after the flood of 1998, to implement flood control projects along San Francisquito Creek and the Bay. San Francisquito Creek forms the boundary between the Counties of San Mateo and Santa Clara, and the cities of Menlo Park and East Palo Alto to the north and the City of Palo Alto to the south. In coordination with Valley Water, the Reach 1 “Downstream Project” – San Francisco Bay to Highway 101 (Reach 1) was completed in 2019 which resulted in the widening of the creek. The effort included the construction of larger engineered levees and floodwalls in the cities of East Palo Alto and Palo Alto and resulted in more than 22 acres of improved marsh habitat. Reach 1 provides flood protection to 1,700 properties from the 100-year storm event and 3 feet of sea level rise.
Since the major floods of 1998, the City has funded and completed multiple capital improvement programs—financed through voter-approved storm drainage fee measures in 2005 and 2017—to upgrade its aging underground infrastructure, pump stations, and capacity.
An overall map of the 7 projects completed with the 2005 ballot and the 13 projects associated with the 2017 ballot is shown below.
Most impactful projects already completed:
▪ San Francisquito Creek Pump Station (SD-06102) – Completed in 2009, the project introduced a new pump station into the City’s storm drain system. At full capacity the station conveys approximately 375 cubic feet per second to San Francisquito Creek, downstream of Highway 101.
▪ Channing and Lincoln Avenues Capacity Upgrades (SD-06101)– Several sequenced projects along Channing and Lincoln Avenues. Phase I replaced 24-inch pipe between Newell Road and Lincoln Avenue with a 5-ft x 4-ft box culvert along Channing Avenue.
Phase II extended the culvert storm drain system on Channing through Alester Avenue and replaced the 12-inch storm drain system on Lincoln Avenue from Channing to Middlefield Road with a new 42-inch pipe. Phase III along Lincoln Avenue from Middlefield Road to Alma Avenue was completed in 2017. This network ultimately drains through a 96-inch pipe into the San Francisquito Creek Pump Station. ▪ Storm Drainage Rehabilitation (SD-06101) – The most recent project was completed in 2026; the project upsized old 12-inch to 36-inch storm drain pipes on Alester Avenue from Hamilton Avenue to Dana Avenue, and installed flap gates on Louisa Court and Newell Place. Several other pipe repairs and/or rehabilitation projects have been completed throughout Palo Alto since 2018, including new fiber network to the cameras and pump stations, pipe lining where a full replacement was not necessary, and replacement of rusted and collapsed pipes.
▪ Matadero Creek Pump Station Improvements – (SD-13003) Completed in 2018, the existing pump station was re-built at the same location. The project included new electrical and fiber optic services, a back-up generator and pumps discharging 375 cubic feet per second. The facility was also raised to be out of the special flood hazard area. ▪ Loma Verde Avenue (SD-19000)- Completed in 2020, the project upsized approximately 1,700 linear feet of an existing 36-inch storm drain system to 48-inch between Sterling Canal to Louis Road. Runoff flows drain into the Matadero Creek Pump Station and ultimately into the Palo Alto Flood Basin.
▪ East Meadow Drive and East Meadow Circle Capacity Upgrades (SD-22000 and SD26000) Completed in 2024, the project replaced 400 linear feet of 36-inch pipe between East Meadow Circle and Adobe Creek pump station with a 48-inch pipe and added 760 linear feet of pipe along East Meadow Circle. This eliminated the localized ponding that occurred on East Meadow Circle when flows in Barron Creek exceeded the height of the flap-gate.
Five projects currently under construction:
▪ Corporation Way System Upgrades and Pump Station (SD-21000) – This project includes installing a 25 cubic feet per second pump station at 3803 East Bayshore Road and approximately 800 feet of 36-inch storm pipes. The closed lane on East Bayshore is anticipated to be open by end of 2026, with the project completion in Spring 2027. ▪ West Bayshore Road Pump Station and West Bayshore Road Trunk Line Improvements (SD-20000 and SD-23000) – This project includes installing a 15 cubic feet per second pump station at 3600 West Bayshore Road and approximately 1,500 feet of 18-inch storm pipes. Construction is anticipated to be completed in early 2027. ▪ Hamilton Avenue System Upgrades (SD-25000) – This project upsizes the smaller existing pipes to 48-in pipe and associated structures, along with the newly installed 36- inch storm pipe installed on Alester Avenue should reduce flooding that occurs during large storm events. To date, new pipe has been installed from Rhodes Drive to Newell Road. The second part of the project is being removed from the existing construction contract due to construction defects found in the first section and will be re-evaluated next year.
▪ Newell Road Bridge Replacement Project (PE-12011) – The project replaced the previous bridge with a new bridge in the same alignment. It removed the abutments that restricted the flows within the creek and widened the creek area as well as raised the bridge and approaches. The work inside the creek is complete and contractor is working on the scope of work outside of the creek banks including street resurfacing. Pending weather conditions, the project will be essentially completed by end of the year.
ANALYSIS
The following is a summary of winter preparedness activities undertaken to date and planned for the duration of the winter storm season:
1. Storm drain system and tree maintenance performed by the Public Works Public Services Division:
a. Ongoing Tasks
i. Hydroflushing of storm drain pipelines (on-schedule) ii. Catch Basins – inspection/cleaning
iii. Minor repairs to damaged pipelines and catch basins iv. Wet well cleaning (first full round completed)
v. Trash racks (first full round completed)
vi. Inspection and pruning of street trees (on schedule) vii. Inspection and clearing of tree branches around overhead electric lines (ahead of schedule)
b. Completed Tasks
i. Inspection of all storm drain outfalls and servicing of flap gates ii. Culverts – inspection/cleaning
iii. Pressurized storm drain manhole covers – inspect/retorque bolts iv. Inspection and cleaning of all trash capture devices v. Testing of all storm water pumps and motors
vi. SFC Pump Station – underwater pump maintenance/service vii. Pump Stations – generator maintenance/service
viii. Pump Stations – pump/instrumentation/electrical maintenance/service ix. Large Trash Capture Devices – inspection/cleaning/maintenance x. Small Trash Capture Devices – inspection/cleaning
c. Upcoming Tasks
i. Inspection and cleaning of all storm water pump station wet wells (second round by 11/1)
ii. Inspection and cleaning of all storm drain catch basins (by 11/30) iii. Replace one broken portable water pump (by 11/30)
iv. Inspection and cleaning of Palo Alto Flood Basin tide gate hatch (by 11/30)
2. Equipment procurement and readiness
a. Two additional vacuum trailers rented
b. Excavator for advance placement at Pope/Chaucer bridge rented c. Discussions ongoing with SFCJPA partners about potential excavator for advance placement at West Bayshore bridge
d. Equipment readiness - small equipment service and replaced as needed e. Fleet readiness – critical vehicles & large equipment needed for storm response identified and serviced
3. Set-up and stocking of filled or self-service sandbag stations by November 1, 2026 (see sandbag station map – Attachment B)
a. Palo Alto Airport (stocked by Valley Water).
b. Mitchell Park, behind Little League field (stocked by CPA Public Works) c. Rinconada Park tennis court parking lot, Hopkins Ave. at Newell Road (stocked by CPA Public Works)
d. Pope/Chaucer Area – this will be a supplementary sandbag station to be located in the vicinity of the Pope/Chaucer Bridge this year (exact location to be determined; stocked by CPA Public Works)
e. City staff have already purchased the seasonal quantity of 5,000 filled sandbags and have purchased an additional 2,500 filled sandbags with the prediction of a strong El Nino this year. Empty sandbags and loose sand will also be available at the sandbag locations.
4. Creek clearing and vegetation management
a. Santa Clara Valley Water District (Valley Water)
i. Responsible for creek maintenance where they own right-of-way or hold flood control easements granted by City or private property owners ii. Maintains improved creek reaches (most of Matadero, Barron, and Adobe Creeks, and San Francisquito Creek downstream of Marlowe Street)
iii. Applied water-safe herbicide to manage vegetation in lined channels iv. Responds to downed trees and blockages during storm events b. San Francisquito Creek Annual Maintenance Walk with JPA and other Regional Partners/Agencies
i. The creek maintenance walk occurred on August 25 and 27. The purpose of the walk is to identify items such as downed trees and other large debris in the channel that could obstruct flows during large winter storm events. Items that need attention are tagged and assigned to the appropriate entity for removal or modification.
ii. 23 items were identified and assigned to the appropriate regional jurisdictions for removal, modification, or monitoring. Work included cutting and removing fallen trees blocking the channel, removing brush and vegetation, monitoring bank erosion, and removing trash and debris. iii. 7 items were assigned to Palo Alto. Staff also independently identified four additional areas requiring attention. All work was completed by September 30.
c. Private property owners
i. Responsible for maintenance of creek segments on their property if they have not granted a flood control easement to the Santa Clara Valley Water District
5. Baylands Nature Preserve Resilience
a. Community Services staff have been working with BCDC on a permit to raise the levee trail by Lucy Evans Nature Center 6-8” to prevent over topping with the goal to have the work completed before the November King tides. If the permit is not received by that time, staff will proactively place sandbags at this location. b. Open Space staff will also place sandbags around sensitive areas near Byxbee Park and the horizontal levee.
c. Staff are tracking higher water levels during high tides, about 0.5 - 0.75 feet higher than the tide charts, possibly due to Kelvin waves which is a phenomenon occurring with El Niño. As with past flooding incidents, if water levels go over Embarcadero Road, staff will close the Baylands Nature Preserve. d. Staff will share details with the community in advance of any closure, if there is time to do so. Staff traditionally adds signage, asks the public to avoid the area, and shares details via City websites.
6. Public Outreach and Engagement
a. The City distributed its annual “Emergency Preparedness” bill insert in September 2026 with storm preparedness resources. The City’s annual “Winter Storm Preparedness” bill insert to City of Palo Alto Utilities customers will be distributed this month. (Attachment C includes both bill inserts) b. In addition to this study session to inform the City Council and the public, staff is hosting a Storm Preparedness Open House at Fire Station 3 (699 Embarcadero Road) on October 29, 5:30-6:30 p.m.
c. The City issued a community update in early October sharing City storm readiness actions and resources for residents to take before storm season arrives. Find the update at www.paloalto.gov/stormreadiness d. Public Information Officers from JPA member agencies develop an annual informational brochure with flood management projects updates and winter storm preparedness tips. The brochure will be mailed in November/December to all households and businesses in the San Francisquito Creek floodplain and within 1,500 feet of the creek.
e. The City established a unified web page portal for winter storm preparedness and real-time storm information: www.paloalto.gov/stormupdate
7. Contractor resources availability
a. Tree trimming contractors (Street Tree Maintenance contractor & Electrical Line Tree Clearing contractor)
b. Street sweeping contractor (for street debris and mud residue removal) c. Existing street, sidewalk, and storm drain contracts that can be repurposed or additional contingency authorized for emergency grading and paving or storm drain work
8. Inter-Agency Emergency Planning/Response Coordination a. City Emergency Operations Center (EOC) staff use monitoring tools to track creek flows, creek levels, and rainfall during storms, allowing comparison with established triggers for evacuation early warnings through the City’s emergency alert system, should flooding be imminent.
b. Continued implementation of a Multi-Agency Coordination (MAC) framework to coordinate emergency response actions amongst JPA member agency emergency managers and County Office of Emergency Services staff in both counties
c. Part of this framework includes having MAC PIOs meet regularly during storm events to share information and coordinate on messaging to respective communities. This is in coordination with the National Weather Service. d. Established protocol for reciprocal notifications when Emergency Operations Centers are activated
e. Developed protocols for mutual aid among public works departments
9. Emergency Manager/Responder Training
a. Palo Alto Emergency Services Volunteer Program prepared for the season. b. Regional winter preparedness briefing hosted by the Santa Clara Valley Water District
c. City Staff annual Winter Storm Preparedness workshop hosted by City of Palo Alto Office of Emergency Services on November 5, 2026
d. San Francisquito Creek Multi-Agency Coordination Regional Winter Storm/Flood Workshop & Tabletop Exercise to be held December 3, 2026. e. Public Works Public Services Pre-Incident Planning to coordinate with different departments and contractors for assistance during severe flooding. Create secondary operation centers and vehicle/equipment staging if MSC floods.
Overall, the City’s winter storm preparation activities are a robust body of work intended to minimize the risk of flooding, mitigate and respond to any flooding that does occur through infrastructure and staff protocols, and communicate with community members about the City’s activities and what they can do to prepare their homes.
FISCAL/RESOURCE IMPACT
Winter storm preparation activities described in this report are funded through the Fiscal Year 2027 Adopted Operating and Capital Budgets, and do not require additional appropriations at this time.
STAKEHOLDER ENGAGEMENT
Winter storm preparation involves engagement with multiple City departments involved in storm preparation and response, SFCJPA partner agencies, and community members through a variety of coordination meetings, trainings, and community engagement efforts described in this report. Find resources at www.paloalto.gov/stormupdate
ENVIRONMENTAL REVIEW
This update is for informational purposes with no action requested by the Council, and therefore it is not a project subject to review under the California Environmental Quality Act (CEQA).
ATTACHMENTS
Attachment A: Seasonal Precipitation Outlook
Attachment B: Sandbag Station Map
Attachment C: Utility Bill Inserts
APPROVED BY:
Brad Eggleston, Director Public Works/City Engineer