The FEMA floodplain is a geographic area that has been defined as having some level of flood risk. The floodplain is separated into different flood zones based on the level of flood risk. Some areas shown on the FEMA flood maps have been determined to have no risk, as they are not considered to be in the FEMA floodplain. Other areas on the flood maps have low to moderate risk and are in the floodplain. Flood insurance is optional in low and moderate risk areas, and some of these areas are not subject to floodplain regulations. High risk areas are defined on the maps and are subject to floodplain regulations and flood insurance purchase requirements.

The Special Flood Hazard Area (SFHA) is any area on the FEMA flood maps that is anticipated to be flooded by the 1-percent annual chance flood or the base flood. Properties located partially or fully in the SFHA are subject to floodplain development regulations and flood insurance purchasing requirements.  The SFHA is determined from historic weather data, local topography, computer modeling, and the best available data at the time the flood maps are created.

The base flood is also referred to as the 1-percent annual chance flood. Sometimes this is referred to as the “100-year flood”, which can be misleading because it is possible to have two 1-percent annual floods within a year or none for over 100 years. The base flood is the flood event that has a 1-percent annual chance of occurring, which means that statistically there is a 1 % chance every year that there will be a flood that looks like the one on the FEMA maps showing the Special Flood Hazard Area. 

The Base Flood Elevation (BFE) is the elevation that the base flood is anticipated to rise to during the 1-percent annual chance flood. The BFE will be unique in each area of the floodplain and can be determined from the FEMA Flood Insurance Rate Maps (FIRMs). The BFE is required information when preparing an Elevation Certificate. 

The floodplain provides a valuable function by storing floodwaters. When earthwork fill or buildings are placed in the floodplain, the flood storage areas are lost and flood heights will rise because there is less room for the floodwaters. Compensatory storage provides an equal volume of flood storage at equal elevations to replace what is lost. Providing compensatory storage is required for projects that are located in the Special Flood Hazard Area and include fill or buildings being placed in the floodplain. 

Auburn has a unique landscape, with large areas of the City located in a valley between two hills. While much of the valley is considered “floodplain”, the areas that are designated as the high-risk Special Flood Hazard Area (SFHA) are mostly found in areas along the Green and White Rivers. Areas on each side of SR 167 where Mill Creek flows through the City, and portions of the north valley between SR 167 and the Green River, are also determined to be within the SFHA. You can see the SFHA by following the link below to the City’s interactive map. Just turn on the “Special Flood Hazard Area” layer under “Regulatory Floodplain”.

• City of Auburn Interactive Map

There are several City of Auburn staff members who are Certified Floodplain Managers (CFM®). These staff are happy to help you determine if your property is located partially or fully within the SFA and what development regulations may apply to your project. You can visit the Permit Center at 1 E Main St in Auburn, or call 253-931-3020. 

Floodplain management regulations require that structures associated with new development within the floodplain are elevated above the BFE and that other measures are taken to protect against flooding. If the structures on your property are existing and you do not have plans on redeveloping, there are still steps you can take to protect your property in the event of a flood. FEMA provides several resources to assist residential property owners with mitigating future risk:    

• Elevating Your House (PDF)
• Homeowner’s Guide to Retrofitting (PDF)

Flood management has been used in the region for over a hundred years. It is possible that you have never experienced flooding on your property. Some of the more significant projects to manage floods in this area are the Howard A. Hanson Dam on the Green River and the Mud Mountain Dam on the White River. There are also numerous levees on the Green River within Auburn that are managed by the King County Flood Control District. Prior to these flood control measures, the valley in Auburn experienced annual flooding. With these structures there is reduced risk, however, significant rain events can still surpass the protection provided by the dams and levees. The FEMA floodplain is determined using measured ground elevations and historical rainfall records to determine where water would go under specific scenarios. The likelihood of flooding on your property is still present, even if it has not happened recently. Being aware of the risk is helpful in preparing for the possibility of flooding and preventing damage or loss of life.

FIRMs are available on FEMA’s Flood Map Service Center webpage. You also can obtain the FIRM for your area by contacting the City of Auburn Permit Center at 253-931-3020 and asking to speak with someone in the Floodplain Management group. You can also visit  the Permit Center at 1 E Main St in downtown Auburn. City staff can assist you in reading the map or you can use the FEMA How To Read a Flood Insurance Rate Map Tutorial to learn how to interpret the information.

FEMA uses the most accurate flood hazard information available and applies rigorous standards when developing the FIRMs. Sometimes there are limitations to this information, so small areas may be inadvertently shown within a SFHA even though the property is on natural ground and is at or above the Base Flood Elevation (BFE). Other projects may incorporate fill to elevate structures above the BFE without significant impact to the floodplain. If you disagree with the Flood Insurance Rate Map (FIRM) then you have the right to submit a request for a Letter of Map Change (LOMC) to FEMA at any time. LOMC requests are reviewed by the City's Floodplain Administrator and submitted to FEMA by the applicant. The request is reviewed and approved or denied by FEMA. The City cannot approve a request to revise or change a floodway or floodplain delineation until FEMA has issued a LOMC that approves the change.

There are several types of LOMC that are applicable to different situations. The types of LOMC that you may request are listed below, with brief descriptions for the applicable conditions for each. You can begin the request process by visiting FEMA’s LOMC website, where an online application and information on how to request a change to the flood zone designation is available.

• Letter of Map Amendment (LOMA) – A LOMA is used when the existing natural high ground is higher than the Base Flood Elevation, but the property is shown on the FIRM as inside the SFHA. This is typically for small areas where the scale of the FIRM does not allow for the area to be shown outside of the SFHA.
• Letter of Map Revision (LOMR) – A LOMR is an official revision to an effective FIRM that may change flood insurance risk zones, boundary delineations, and/or the BFE. A LOMR usually results in reprinting a portion of a FIRM. 
• Letter of Map Revision-Based on Fill (LOMR-F) – A LOMR-F is similar to a LOMA, but instead of being based on natural ground elevations the property or structure has been elevated by fill in order to elevate it above the BFE.
• Conditional Letters of Map Change – A CLOMA, CLOMR, or CLOMR-F is used for a proposed project based on the conditions listed above.

• Conditional Letter of Map Amendment (CLOMA) – A CLOMA is a letter from FEMA stating a proposed structure on the natural high ground would not be inundated by the BFE if built. 
• Conditional Letter of Map Revision (CLOMR) – A CLOMR is a letter from FEMA stating that a proposed project would affect the flood zone characteristics and result in modifications of the existing SFHA or the BFE if built. 
• Conditional Letter of Map Revision-Based on Fill (CLOMR-F) – A CLOMR-F is a letter from FEMA stating a parcel or proposed structure that will be elevated by fill would not be inundated by the base flood if built as proposed. 

An Elevation Certificate is an official document that certifies the elevations of buildings on your property and how they compare to the Base Flood Elevation (BFE). This document is used to help determine flood insurance rates, support a request for a Letter of Map Change (LOMC), and show compliance with Auburn floodplain development regulations. Elevation Certificates must be prepared and stamped by a licensed surveyor, engineer, or architect. Once your licensed professional has completed the Elevation Certificate, it must be submitted to the City for review and signature. Your Elevation Certificate must be signed by the City's Floodplain Administrator.

Auburn Municipal Code Chapter 15.68 regulates development in the floodplain. This chapter governs all building in the regulatory floodplain defined by the FEMA flood maps.

Development in the FEMA floodplain is complex and very site-specific. Mitigation of impacts to the regulatory floodplain are required and are based on the nature of the impacts. Changes to flood storage must be mitigated through creating areas of compensatory storage that are hydrologically connected to the existing floodplain outside of the project site. Impacts to endangered species are mitigated through habitat restoration.

Flood insurance is required for all federally funded loans and many lenders require flood insurance even if the loan is not federally funded. If your project is not financed in any way you are not required to purchase flood insurance, however you are not eligible for FEMA assistance in the event of a catastrophic flood. 

Flood insurance is purchased through an insurance agent or insurer who participates in the National Flood Insurance Program (NFIP). For more information on purchasing flood insurance and agent referral resources visit FEMA’s FloodSmart webpage.

The NFIP is the program developed by FEMA to provide affordable flood insurance to property owners, renters, and businesses. The NFIP also encourages communities to adopt and enforce floodplain management regulations. The City of Auburn participates in this program by adopting recommended floodplain regulations as well as preparing for Community Rating System (CRS) audits by FEMA. The City's CRS score allows insurance holders to receive lowered flood insurance rates. Auburn's participation in the NFIP is voluntary, but without participation Auburn residents would not be able to obtain flood insurance.

You can contact the City of Auburn Permit Center at 253-931-3090 and ask to speak with a Certified Floodplain Manager in the Community Development Department. You can also visit the Permit Center in person at 1 E Main St in downtown Auburn.