Have additional questions that are not answered here? Contact Foster City Public Works at (650) 286-3270 or email publicworks@fostercity.org.
Improved Levee and Trail
The levee trail is split between the biking lane and the pedestrian use lane. The biking lane is in both directions, so all bikers should use the regular rules of the road, moving to the right of their respective lane to allow others to pass (without going into the pedestrian lane). Within the pedestrian lane, walkers/runners should follow the same rules, staying to the right of the respective lane. If these rules are followed, bikers on the inside bike lane will be facing towards runners/walkers on the inside of the pedestrian lane, and no one should be in danger.
The City currently does not have a regular sweeping schedule. Decomposed gravel on the trail is natural and expected as the trail undergoes normal use.
The trail has posted speed limits, restricting all traffic — e-bikes and scooters included — to 15 MPH or under.
City staff maintains the landscaping on the levee trail in-house and by contract as needed.
The asphalt is expected to wear under normal conditions of use; Erosion of the material along the edges of the trail (the decomposed granite (DG)) is actively being monitored by the City. To extend the life of the DG surface, please remain within the designated bounds of the trail. Use the designated access points to and from the trail, and refrain from using the sides of the trail for ingress/egress. Please do not walk through the landscaping.
The levee design elevation has accounted for wave run-up, and the outer walls at the access points (AP) adjacent to the bay will provide protection from wave run-up and are designed with a concrete floodwall on the bay side of the AP, to be sufficiently long to break the waves before the water finds its way through the AP openings. Elevations along the new trail (bottom of the openings) are generally at least four feet above the current 100-year water level in San Francisco Bay, allowing for future sea level rise. The top of the walls are designed for the wave run-up associated with high winds and high tide levels. Flood barriers are also located at three different locations along the levee: (1) at the Egress bridge (near Rock Harbor Lane); (2) at Baffin Bridge; and (3) on the levee pedway south of San Mateo Bridge.
The overall height of the levee and wall along Beach Park Boulevard from Bridgeview Park to Shorebird Park is on average -6 feet higher than the previous elevation; however, the height of the wall from the walking surface is only about 3.5 feet. The wall is on the bay side of the pathway.
The finished Levee Trail consists of a 12-foot asphalt concrete path, plus a four-foot decomposed granite shoulder on the bay side, and a two-foot decomposed granite shoulder on the inboard (land) side (totaling 18-feet width) with a few exceptions.
The final height of the levee wall varies. From Baywinds Park to the Beach Park Boulevard/Foster City Boulevard intersection, the final height of the wall, including wall cap, is 3.5 feet above the walking surface. For most of the remaining levee structure, the final height of the wall is 2.5-to-3.5 feet or less above the walking surface. There is a short section of the levee wall north of the San Mateo bridge where the concrete wall is nearly four feet, as the trail slopes down to existing grade. Just north of the San Mateo Bridge there is a wall which is 6.5’ high on the inboard side of the trail where we could not raise the levee trail underneath the bridge and maintain required clearances. By placing it on the inboard side, we preserve the bay views and avoid the “tunnel” effect that would result if it was placed on the outboard (bay) side. Some portions of the finished levee do not require a wall.
Striping on the newly paved levee/bay trail is meant to serve as a guide for pedestrians and cyclists. Pedestrians are permitted to walk on the paved asphalt, marked with pedestrian symbols, as well as the decomposed granite paving walkway. While only the asphalt could be marked with symbols, the pedestrian walkway includes the entire width of the trail between the bike lane and the levee wall.
While in the pedestrian lane, pedestrians should exercise caution and use good judgment, including being aware of their surroundings, following any posted signage, and yielding to others when necessary.
Detailed plans are available on the project web page: Documents and Resources. If you have questions about specific design plans for the levee segment nearest to your property, you can contact Foster City Public Works staff at (650) 286-3270. Immediate construction concerns may be reported to the project hotline at (800) 213-6320.
Photos of the new levee are available on the project About page under “Photos of the Completed project“
A natural metal surface was selected for a number of reasons:
- Over time, a painted metal surface will exhibit ‘weeping’ through the coating, leading to streaking and staining of the wall surface, and requiring frequent paint touch-ups to maintain a uniform appearance. New paint over existing sun-worn paint can look uneven and splotchy
- A natural metal surface will age nicely and wear more uniformly than a coated surface, minimizing localized areas of corrosion, and maintaining consistency in the overall condition of the wall. This uniformity and consistency leads to superior longevity than a painted surface.
- The natural metal surface will save money in initial construction costs, and in annual routine maintenance costs. Over its lifetime, a painted wall would need several expensive repaints, in addition to touch ups associated with graffiti removal.
- Removal of graffiti paint from the natural metal surface will result in a more uniform look than paint touch ups, which would be unlikely to match the existing faded paint. To address cases of graffiti, removal techniques would be applied in lieu of paint touch ups, revealing the natural metal surface and allowing it, over time, to return to its patina.
Background and Purpose
The Foster City Levee, owned and maintained by the City, surrounds the majority of the outer bay-front perimeter of the City to provide flood protection. The Levee Improvements Project is the largest public works project in the City’s history and will structurally and aesthetically improve and enhance the levee.
The project will increase the height and width of the levee to improve protection against storm/tide surges, meet sea level rise projections through the year 2050, and make the levee more resistant to earthquakes. Depending on specific location, these improvements will be implemented with conventional sea wall, earthen levee, or hybrid sheet pile wall. Additionally, the project’s associated redevelopment and widening of the Levee/Bay Trail will provide the community with an enhanced, more inviting recreation destination.
Our focus is on protecting the Foster City community, and we are in communication with neighboring communities around the common goal of flood protection. Other jurisdictions are in various stages of addressing this need. Foster City is leading the way in implementing these improvements, thanks to the foresight of our community members, who approved Measure P in order to more quickly move forward.
Please visit the project homepage or the menu above for the project description, background, and links to documents and reports related to the Levee Improvements Project.
Other municipalities have unsuccessfully challenged the scientific basis behind hydrodynamic and wave modeling studies FEMA used to determine flood hazards applicable in San Mateo and Foster City. Cities and agencies that have lost their appeals against FEMA’s San Francisco Bay coastal analysis include the City of Alameda, the City of Belvedere, the City of Redwood City, the City of San Bruno, the City of South San Francisco, and the Santa Clara Valley Water District. Results from recent appeals are here: https://www.floodsrp.org/panels/
Because Foster City is moving forward now with the Levee Improvements Project, we are that much closer to completing an improved levee that will better protect Foster City homes, schools, businesses, and essential City services and infrastructure during storms, high tides, and future sea level rise.
Foster City voters passed the Levee Improvement Bond Measure P in 2018, authorizing the City to issue $90 million in general obligation bonds to fund these critical levee improvements. The Measure P levy will start appearing on Foster City property tax bills starting this fall (2020) and will continue for 30 years. The first-year rate will be approximately $36 per $100,000 of assessed property value. Subsequently, the rate will be an estimated $33 annually, with continuing decreases assuming assessed property valuations continue to rise.
On August 5, 2020, the City issued $85 million in bonds. On March 6, 2023, the City authorized issuing the remaining $5 million Measure P bonds and approved the appropriation of $5 million from the City’s Capital Improvement Plan funds.
[Updated 3/7/2023]
Although the levee withstood storm/tide surge challenges, it was in need of critical upgrades and safety improvements. In 2014, the Federal Emergency Management Agency (FEMA) determined that Foster City’s levee system did not meet minimum requirements for flood protection. Further, in order to obtain the necessary permits to implement needed improvements, regional regulations say that construction must meet year 2050 sea level rise protection requirements. If no action was taken, the community would be at heightened flood risk and be designated as a flood zone.
Measure P included fiscal accountability provisions. An independent citizens’ oversight committee ensured all funds were spent as promised on voter-approved projects, and all funds stayed local to improve the Foster City levee system. No funds from the measure was used for administrators’ salaries.
The FEMA seclusion zone designation is ‘indefinite.’ However, in February 2024, the City submitted a Letter of Map Revision (LOMR) request with supporting documentation based on the as-constructed levee system that asks FEMA to return the flood hazard classification within Foster City limits to moderate risk – Zone X Protected by Levee. This process may take six months to a year or more. Flood insurance will continue to be non-mandatory for those with federally backed-mortgages. Anyone can obtain flood insurance, however, and premiums will be significantly lower than they would be if Foster City was reclassified as Zone AE. Questions about typical rates should be referred to lenders.
More information on Foster City’s FEMA status and supplementary documents can be found on this webpage: https://www.fostercity.org/fire/page/foster-citys-local-hazard-mitigation-plan-and-maps
The project will maintain FEMA accreditation of the levee and protect Foster City homes, schools, businesses, and essential City services and infrastructure during storms and high tides, and from future sea level rise. The improved levee will be more resistant to earthquake damage, and will prevent FEMA designation of the City as a flood zone, thus avoiding requirements for homeowners to purchase expensive, permanent flood insurance.
The project includes associated redevelopment and widening of the Levee/Bay Trail, which will provide the community with an enhanced, more inviting recreation destination, maintaining the natural beauty of the levee and our scenic views. The improvements are designed to enhance levee trail access, usability, and landscaping for walkers, runners and cyclists.
The as-built condition of the newly constructed Levee provides resilience against the 100-year flood hazard (stillwater and wave runup) with 3 feet of sea level rise (SLR). The State released updated science and policy guidelines in January 2024. According to those guidelines, 3 feet (1m) of SLR represents “a reasonable upper bound for the most likely range of sea level rise by 2100.”
Construction Activities and Impacts
Construction began in Fall of 2020. The project achieved final completion in February 2024. Please see a Project Construction Timeline graphic on the About page for additional details.
The City received permits for this project from seven different agencies at the federal, state, and regional levels. These permits and associated regulations provided the requirements for protecting wildlife and the environment during the project. The regulations addressed species such as the Ridgeway rail, California black rail, and salt marsh harvest mouse; marine mammals and fish; vegetation and habitat on and around the work areas; bay water and associated wetlands. A biologist was present to monitor temporary impacts to marsh habitat during earthen fill placement, wall installation, and restoration activities.
The new Egress bridge (near Rock Harbor Lane) and Baffin bridge were constructed to provide a permanent connection between Foster City and Belmont/Redwood Shores and Foster City and San Mateo for pedestrians and cyclists. Construction of the bridges has restored tidal action in the Belmont Slough, a condition of the project’s BCDC permit. The restoration of tidal action should have no impact on either trail users or nearby homes, as the backfill and remediation efforts were intended to reduce the risk of flooding.
What is being observed is referred to as exfoliation and is expected to occur. The exfoliation that the wall is experiencing is the result of “mill scale” on the sheet piles that is corroding and becoming disbonded from the piles. Mill scale is essentially an extra surface layer of material that is formed/embedded during the rolling (or metal forming) process of the sheet pile. The layer corrodes and flakes off over time when exposed to the environment.
The project’s corrosion expert is testing the sheet piles to determine the corrosion rate and ensure nothing of significance is occurring. This is part of an ongoing monitoring program that will continue throughout the useful life of the levee.
Current consensus is that the rusting of the mill scale is to be expected.