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FEMA Updating Flood Insurance Rate Maps

Updated January 11, 2011

Latest Update
(January, 2011)

Redwood Shores Levee Project: Construction Complete
Levee improvements around Redwood Shores have been fully completed. The levee pathways have been restored and construction staging areas have been cleared.

Concurrent with this work, the City has been seeking FEMA certification of the levee improvements, which in turn will result in the removal of the flood zone designation for Redwood Shores. The certification plans were submitted to FEMA in May. In mid-July FEMA notified the City that the package was under review, and that the final determination would be made by FEMA’s Risk Analysis Division in Washington DC. The City is very confident that levee certification is imminent, which would remove any requirement for flood insurance - FEMA has continued to assure the City that when their new flooed maps are issued, Redwood Shores will be classified as protected by levees.

In addition to the levee improvements, residents have noticed some additional signage and fencing along certain levee access points. These are being installed at the direction of the U.S. Fish and Wildlife Service (USFWS) as part of that agency’s requirement for the City to protect the habitat of special status species such as the California Clapper Rail and the Salt Marsh Harvest Mouse. As a reminder, the segment of levee facing Bird Island, from the sewage treatment plant to the new Preserve at Redwood Shores development, is closed to the public, as mandated by the USFWS. We’re told by the USFWS that public access to other parts of the levee may be jeopardized if trespassing onto the restricted sections of levee continues.

The City would like to thank Redwood Shores residents for their patience during the levee improvements, and for complying with the levee access restrictions implemented by the USFWS.

(Fall, 2010)

In September, 2009, Redwood City shared its plan for the Redwood Shores levee improvement project. Those improvements were needed to meet levee certification requirements of the Federal Emergency Management Administration (FEMA), in order to prevent the imposition of mandatory flood insurance for Redwood Shores residents.

The key structural elements and necessary levee elevation have been completed, and we’re now moving forward with certification to meet FEMA’s flood zone map deadline, as well as cleanup and restoration of the paths atop the levees.

We will restore the levee to a condition suitable for its prior recreational use. Timing of the cleanup and restoration, though, is problematic since federal regulations prohibit the use of machinery atop the levee until September 1st, the end of the Clapper Rail nesting season. So the final work will not take place until September.

This work was accomplished despite an extremely short construction window, permit obstacles, and a series of intense storms that threatened to cause insurmountable delays.

We had originally anticipated getting the necessary permits by November and then beginning construction in December. This would have provided a full two months of work before January 31st, the start of the Clapper Rail nesting season, during which construction on the levee is prohibited by the US Fish & Wildlife Service.

However, due to the complexity of the permitting process, permits were not obtained until December 30th, and only after considerable effort and assistance from Congresswoman Jackie Speier’s office, the Bay Planning Coalition, and our City Council. This left only about one month to build levee improvements that typically require two months to complete in the dry season.

We made good progress during early January, with a rapid pace of construction on the levees around Redwood Shores, by the South Bayside System Authority treatment plant, and adjacent to the San Carlos Airport. As you know, this included weekend and night work in order to complete construction before January 31st, and we truly appreciate the understanding of nearby residents who endured noise, construction activity, and unusual work hours.

Then, during the week of January 18th, a series of intense storms forced a complete halt to construction. Faced with the critical deadline, and despite the weather’s significant impact to the already condensed construction schedule, crews managed to complete construction of the structural elements required for levee certification. With the elevation achieved, we can proceed with FEMA certification.

Please be assured that the levee surface will not be left in its current state. We will restore the levee to a condition suitable for its prior recreational use. Timing of the cleanup and restoration, though, is problematic since federal regulations prohibit the use of machinery atop the levee until September 1st, the end of the Clapper Rail nesting season. However, as a temporary measure we plan to utilize hand tools and manually restore the levee surface. Ironically, after the near-feverish pace of work to get to this point, the cleanup and restoration will be a slower operation and we thank you for your continued patience. After September 1st we’ll proceed with finalizing the surface restoration work.

Finally, you’ll recall that there is a 500-foot section of the levee near the San Carlos Airport which FAA regulations prohibit from being raised to the FEMA-required elevation, due to aircraft safety issues. Both agencies have expressed that they are open to the possibility of a device which would be deployed during storm/high tide events to temporarily create a higher barrier. We’re confident that our continued work with the FAA and FEMA will result in a solution that meets all our needs.

(August, 2009)

Information meeting scheduled to share construction schedules and the type of work to expect, levee certification timeline and status, and report on overall progress:

Wednesday, August 19, 2009
7 pm
Community Room, Redwood Shores Library
399 Marine Parkway

There has been some solid progress toward certification of the levees protecting Redwood Shores - the City has been working to prevent FEMA from reclassifying the Shores as being within a flood zone, and the resulting increases in flood insurance costs to property owners.

San Mateo County and San Carlos have told Redwood City that they are both fully committed to partnering with Redwood City to achieve timely certification of the Redwood Shores levees including the most challenging segment bordering the San Carlos Airport.

A 400-foot portion of that levee segment is within the Federal Aviation Administration’s (FAA) protected runway safety zone and cannot be built-up due to aircraft landing safety regulations. However, our proposed solution is to use a temporary structure, such as an inflatable bladder, that will deploy only during imminent flood conditions. This would have the effect of temporarily raising the height of that segment of levee, thus completing the flood protection system. During the period the structure is deployed, the airport would have to be closed to comply with FAA regulations.

County airport staff will be coordinating with the FAA to modify airport operations protocols. Parallel to that effort, the City’s project team is in discussion with FEMA regarding acceptance of this solution.

And at the same time, a comprehensive levee maintenance project is underway on the other levees around Redwood Shores, to meet FEMA’s requirements and schedule. Due to wildlife and environmental constraints, the construction window is between September 2009 and February 2010. We will be preparing the FEMA levee certification submittal simultaneously with the levee work. Once construction is complete, the certification package will be ready for submission to FEMA no later than March 2010.

To answer questions and update the Redwood Shores community, the City will be hosting an information meeting at the Redwood Shores Library Community Room on Wednesday, August 19, 2009 at 7p.m. to share construction schedules and the type of work to expect, levee certification timeline and status, and report on overall progress.

Redwood City wishes to express it's appreciation and thanks to the San Mateo County Manager, the County Public Works Director, the San Carlos City Manager and Public Works Director, and the airport staff for their commitment to work together to protect all of the properties in and around Redwood Shores. 

(May, 2008)

The Federal Emergency Management Agency (FEMA) has released new Flood Insurance Rate Maps (FIRMs). These maps show areas that are considered to be in a flood plain, and therefore may require homeowners to obtain flood insurance. Please see for that overview and other updated information.

FEMA’s just-released preliminary maps show Redwood Shores as a flood plain due to the potential of one section of levee, adjacent to the County airport, to allow Bay water into the area. After an on-site inspection with City and County staff, it’s clear that it is the levee height that is in question, and otherwise the levee is in good condition.

It’s important to note that FEMA’s classification is preliminary only, and Redwood City has until spring of 2010 to resolve the situation and have that section of levee certified. Redwood City is happy to report that the City and County staffs are having productive strategy sessions on this issue, with the shared goal of creating a solution that will result in Redwood Shores not being classified as a flood plain in FEMA’s final maps.

The City will continue to work together with FEMA, San Mateo County, and other government agencies toward this objective. Please contact Grace Le with the City’s Engineering & Construction division at (650) 780-7258 or with any questions.

(April, 2008)

As you may know, the Federal Emergency Management Agency (FEMA) periodically updates its Flood Insurance Rate Maps (FIRMs). These maps determine whether an area is considered to be in a flood plain, and therefore may require homeowners in such areas to obtain flood insurance. FEMA is now in the process of updating those maps for San Mateo County for the first time since 1982.

Redwood City and our neighboring communities of Foster City, San Mateo, Belmont, San Carlos, and portions of unincorporated San Mateo County all have areas adjacent to San Francisco Bay that FEMA is studying. Key to FEMA’s study is the certification of the system of levees that protect these areas. Certification is established on a levee’s integrity, based on its height, width, and stability.

We’re happy to report that the vast majority of our levees are in a condition that we feel very comfortable with – and we’re confident that we will be able to certify these levees for FEMA.

There are two levees that are currently exceptions, and both may have an effect on Redwood Shores. One is the levee around “The Preserve at Redwood Shores” upcoming development. As part of that development, this segment of levee is scheduled to be improved this summer to certification standard, and we’ve been told FEMA will give it provisional accreditation.

The other levee of concern is adjacent to the County airport, at Steinberger Slough. This levee is actually on County-owned land, with different levee sections within either San Carlos or Redwood City. Due to levee height issues related to the proximity of the San Carlos Airport, there is the potential for Bay water to enter the peninsula at this point. If that were to happen, flood waters would likely enter the Redwood Shores community. It is this aspect that FEMA may use to determine that Redwood Shores is in a flood plain and thereby require flood insurance.

City staff has been working with FEMA over the past year toward excluding the Redwood Shores peninsula from being classified as flood plain, and is also meeting with representatives of San Mateo County to come up with a viable solution.

Although the County has no current budget to improve this levee, it's important to note that we are having productive meetings with County staff and elected officials. City staff is also exploring the possibility of building a new interior levee at the Redwood City limit line to cut off the bay water in the event the existing levee fails.

In the face of these obstacles, we are continuing to put our strongest efforts into ensuring Redwood Shores is not reclassified as flood plain.

FEMA issued the preliminary flood map for San Mateo County on April 18, which classifies Redwood Shores as flood plain. This map is not final and we have time to work more intensively with FEMA to have the flood designation modified. The Effective Map Date is anticipated to be spring of 2010.

Even if flood insurance turns out not to be required, FEMA still suggests that it be purchased if feasible. Flood insurance is sold by insurance agents, but is administered by FEMA so the pricing is set. Still, the pricing structure is very complicated; see for information.

We’ll be sure to keep you informed as this process moves forward. And again, we want to assure you that the City’s sole interests are to protect the Redwood Shores community from flooding, and ensure that Redwood Shores is not reclassified as flood plain. We will continue to work diligently with FEMA, San Mateo County, and other government agencies to find a suitable resolution to this issue.

Please contact Grace Le with the City’s Engineering & Construction division at (650) 780-7258 or with any questions.


FEMA/Levee Q & A

Q: What are Flood Insurance Rate Maps (FIRMs)?

A: It is the official map of a community on which FEMA has delineated the special hazard areas applicable to the community. Private citizens and insurance brokers use the FIRM to locate properties and buildings in flood insurance risk areas. Community officials use the FIRM to administer floodplain management regulations and to mitigate flood damage. Lending institutions and federal agencies use the FIRM to locate properties and buildings in relation to mapped flood hazards, and to determine whether flood insurance is required when making loans or providing grants following a disaster for the purchase or construction of a building.

Q: Why is FEMA issuing new FIRMs?

A: The original FIRMs for the City of Redwood City was issued in 1982 in paper format. In light of new developments, natural environmental changes, and new technologies, FEMA began the process of updating and converting paper FIRMs to digital format. As part of the conversion, FEMA mandates the inclusion of levee evaluations. No maps could become effective without an evaluation of all levees within a community.

Q: What is a levee system?

A: A levee system is a flood protection system which consists of a levee, or levees, and associated structures, such as closure and drainage devices, which are constructed and operated in accord with sound engineering practices.

Q: Why is the Redwood Shores Peninsula protected by a levee system?

A: The Redwood Shores Peninsula is bordered by Belmont Sough to the northwest, the San Francisco Bay to the north and northeast, and Steinberger Slough to the south and southeast. Since the ground elevations of the peninsula are below the higher tides, a levee system is necessary to prevent potential coastal flooding.

Q: Is our levee system adequate to provide flood protection?

A: Yes. A significant portion of the levee system was improved between 1997 to 2002 according to FEMA and the U.S. Army Corps of Engineers standards and guidelines through the City’s Levee Improvement projects.

The remaining portion of levee slated for upgrade surrounds Area H, and will be improved this summer in conjunction with the Preserve at Redwood Shores development by the developer.

In addition, the City will continue monitoring, patrolling, upgrading, and maintaining the levees through the City’s Levee Operation and Maintenance Program to ensure the integrity of our levee system.

Q: If our levee system is adequate, then why will the new FIRMs designate Redwood Shores Peninsula as “Special Flood Hazard Area” (SFHA)?

A: SFHA is defined by FEMA as a high-risk area in which land would be inundated by a flood having a 1-percent chance of occurring in any given year (also referred to as the base flood). Properties within the SFHA are subject to several requirements:

  • All federally-backed loans must be protected by flood insurance (most lenders require this whether federal or not);
  • All new or substantially improved structures must have the lowest floor elevated above the Base Flood Elevation (BFE), which is usually the one percent occurrence flood elevation.

FEMA recognizes that the City has diligently maintained its levee system. However, a segment of levee on the County of San Mateo Airport property is deficient. According to analysis done by FEMA, this deficiency will cause water to back-flood the Redwood Shores peninsula as well as neighboring areas, resulting in a SFHA designation for this area.

Q: What actions is the City taking to prevent the designation of the Redwood Shores Peninsula as SFHA?

A: FEMA agrees that mitigation of the County Airport segment of the levee will prevent the classification of the Redwood Shores Peninsula as SFHA. City and County staff are meeting to identify and determine a strategy to mitigate the height issues associated with the County Airport levee. We're told that mitigation of the County Airport levee is not feasible due to Federal Aviation Association flight path clearance requirements, environmental restrictions, and budget constraints. The City will continue dialogue with the County regarding the County Airport levee.

As an alternative, the City is also studying the feasibility of a new interior levee in place of the County Airport levee outside of the County Airport Property. If feasible, construction of this “cut-off levee” will prevent the classification of the Redwood Shores Peninsula as SFHA.

Q: What does a SFHA designation mean to the property owners?

A: Property owners with federally-backed loans will have to purchase flood insurance. Most non-federal lenders will also require flood insurance.

Q: What is the cost of purchasing flood insurance?

A: Flood insurance is a federal program administered by FEMA and executed through insurance agents. As such, all rates are determined by FEMA. FEMA encourages property owners to purchase flood insurance before the property is classified as in a flood zone for a discounted rate. Homes built prior to May 17, 1982, the date of issuance of the original FIRMs for Redwood City, will also qualify for a rate discount. More information regarding the flood insurance rate set by FEMA can be found at

 Q: When will the new digital FIRMs (DFIRMs) become effective?

A: FEMA distributed the preliminary DFIRMs to the cities in the County of San Mateo on April 18,2008. City staff will have a number of months to comment on the accuracy of the DFIRMs before FEMA issues the Letter of Final Determination. After FEMA issues the Letter of Final Determination, the DFIRMs will become effective in spring of 2010.

Q: What is the role of the Department of Homeland Security’s Federal Emergency Management Agency (FEMA)?

A: FEMA is one of two federal agencies (the other being the U.S. Army Corps of Engineers) that establish guidelines and design criteria for levees that provide flood control for communities. FEMA sets federal flood management standards, and identifies flood hazard areas throughout the country by producing Flood Insurance Rate Maps (FIRMs).






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