Preliminary Coastal Flood Maps for Marathon & the Florida Keys

FEMA, Flood Insurance Rate Maps (FIRMs) are used to determine the minimum elevation required for new construction as well as to define construction methods required in certain zones (AE vs VE, and now “Coastal A”).

RELEASE OF NEW PRELIMINARY FLOOD MAPS

On December 27, 2019 the Federal Emergency Management Agency (FEMA) released The Preliminary Maps of the new FIRMs to the City of Marathon and the public. These maps supplant the DRAFT Maps released for review on August 22, 2019.

These maps have been released after a multi-year study of Monroe County’s coastal flood risks and an extensive vetting process and will eventually replace the current flood maps.  The new maps are based upon the best and most recent available data as well as the most advanced possible modeling software.

IMPORTANCE OF THE NEW FLOOD MAPS

Release of the PRELIMINARY Maps officially opens public review and comment concerning the maps.  The City of Marathon, Monroe County, and other municipal jurisdictions want to make sure that all residents and business owners are aware of the potential for a change in flood risk (required flood elevations) for their property.  This will allow individuals to make informed decisions about maintenance or modification to existing structures on their property as well for making decisions concerning potential new construction. 

To emphasize that flood risks are changing and to make sure property owners are aware that new FEMA FIRM maps will be adopted in the near future, the City of Marathon Building Department will be requiring Owner’s to sign a form with permits that acknowledges the issuance of these new PRELIMINARY coastal flood maps and the fact that these maps may indicate a future change to the required elevation of a building currently in the permit process.  This is intended to help homeowners understand that what they are proposing to build today, under the existing flood maps, could become non-conforming when the new maps are formally adopted.  This could make homeowners flood risk and insurance costs greater. Owners should think about designing their improvements to meet the proposed preliminary maps to assure they are addressing potential future risk.

CITY ENGINEERING CONSULTANT – WOODS HOLE GROUP

As the PRELIMINARY maps are rolled out, the City has hired a consultant, Woods Hole Group that is charged with analyzing how flood risks are changing within the City’s municipal boundaries based on the new PRELIMINARY FIRMs and the best available science and technology.  Woods Hole Group will be reviewing the preliminary maps and modeling conducted by FEMA and will be prepared, on the City’s behalf,  to appeal any of the maps that do not appear to be correct.  

To view the City’s PRELIMINARY FIRM maps, please click on the following link Preliminary Maps.  This link will open to an Index map of the Florida Keys which you can then utilize to navigate to individual specific maps concerning your area of the City.  In order to view other PRELIMINARY FIRM maps outside of the City of Marathon, but within Monroe County, please click the following link HERE: DRAFT coastal flood maps.   This link will open a FEMA FIRM Preliminary Maps mapping tool.  Simply click in the FIRM Panel section where your property is located to view the popup containing a link to the Draft Map (PDF).

APPEAL PROCESS
The Federal Emergency Management Agency (FEMA) Preliminary Flood Maps began the 90-day Appeal Period on March 19, 2021. 

The City of Marathon engaged technical consulting firm Woods Hole Group to analyze FEMA's work and submit an appeal on behalf of the community. The community appeal may be favorable to the community but not for a particular property. Any owner or lessee of property in Marathon who believes his or her property rights will be adversely affected by the proposed flood hazard determinations may appeal.  Individual property owners are welcome to hire an engineering consultant or other relevant professionals to help ensure individual property rights are protected. Only appeals of the proposed flood hazard determinations supported by scientific or technical data can be considered before FEMA makes its final flood hazard determination at the end of the 90-day appeal period. The statutory 90-day appeal period cannot be extended.

Woods Hole Group has created draft FIRMS for the appeal of the FEMA Preliminary FIRMS for the City of Marathon.  Those draft appeal maps may be found here: https://www.ci.marathon.fl.us/sites/default/files/fileattachments/planning/page/27847/firm_panels_marathon.pdf

Appeal vs Comment

Appeals explain with extensive science and data research and specialized engineering with alternative modeling scenarios why FEMA’s Preliminary Flood Maps are incorrect. Additions or changes to flood hazard information provided on the preliminary FIRM and in the accompanying FIS report, which may include Base Flood Elevations (BFEs), base flood depths, Special Flood Hazard Area (SFHA) boundaries or Zone designations and/or regulatory floodways, are eligible to be appealed. This flood hazard information is developed by experienced engineers and mapping professionals using the latest engineering methods and computer models. 

Appellants need to demonstrate better methodologies, assumptions or data exists and provide alternative analyses that incorporate those methodologies, assumptions, or data if appropriate. The results must show an overall change in the flood hazard information shown on the preliminary FIRM and/or in the FIS report. Unless appeals are based on indisputable mathematical or measurement errors or the effects of natural physical changes that have occurred in the floodplain, they must be accompanied by all data that FEMA needs to revise the preliminary version of the FIS report and FIRMs. Therefore, appellants should be prepared to preform coastal, hydrologic, and hydraulic analyses, to plot new and/or revised Flood Profiles, and to delineate revised SFHA zone and regulatory floodways boundaries as necessary.  The data that must be submitted in support of the various types of appeals are discussed in the sections that follow. Link: Criteria for Appeals of Flood Insurance Rate Maps https://www.fema.gov/sites/default/files/2020-02/Appeal_Comment_Processing_Guidance_Feb_2019.pdf

Comments and inquiries regarding data other than the proposed flood hazard determination (examples: incorrect street names, typographical errors, omissions) that are submitted during the appeal period and will incorporate any appropriate changes to the revised FIRM and FIS report before they become effective. Appeal applications that do not provide all data required will be considered a comment. Anything received after the 90th day is automatically reduced to the status of a comment. Comments unrelated to the flood hazard determination also will be considered before the FIRM and FIS report become effective. Requests that changes effected by a LOMA, LOMR-F, or LOMR by incorporated, base map errors and other possible omissions or potential improvements to the mapping will all be considered comments. 

The information above is cited from FEMA’s Appeal and Comments document. To learn more click the link.  https://www.fema.gov/sites/default/files/2020-02/Appeal_Comment_Processing_Guidance_Feb_2019.pdf

PUBLIC COMMENT PERIOD OPEN

MAP REVIEW PROCESS

The public can email comments concerning the PRELIMINARY coastal flood maps to PreliminaryFloodMaps@ci.marathon.fl.us.  However, the public should be aware that any comments must be based upon solid technical data and a solid technical assessment of potential errors in the Maps.  This will require that those making comments must provide such data and analysis to the City in support of any comments made.  The City will be utilizing Woods Hole Group City to review and validate all comments received.

Formal public comments or appeals of the preliminary maps can only be provided to FEMA through local governments like the City of Marathon, other municipalities, or the County.  The City will provide its review of the Maps to FEMA inclusive of all valid comments made by the public.

Once FEMA completes the review of all of the City’s comments and appeals, they will publish the final Flood Insurance Rate Maps (FIRMs).  The FINAL FIRMs will most likely become effective sometime in 2021-2022.  As this happens, the City will formally adopt the maps by ordinance and the maps will then be used when reviewing applications for permits as the current maps are used today, in compliance with the City’s Floodplain Management Ordinance and the Florida Building Code.  For more information about the mapping process call 305-289 4111 or 289-4121.

The following diagram shows the tentative process timeline for the Draft Maps, Preliminary Maps, and Final Maps:

DATUM CHANGE

IMPORTANT:  These maps don't show an additional difference in elevation due to a change in mapping standards between the old and new proposed flood maps (datum NGVD29 to datum NAVD88).  This means that all NGVD29 elevations (e.g., BFE, Lowest Floor Elevation) need to be converted to NAVD88.  While there is no set conversion factor, as it varies throughout Monroe County, on average there is -1.5 foot conversion factor. To account for this change, ON AVERAGE you should add +1.5-feet to any apparent increase. For example: If your building was in an AE-8 flood zone and is still shown in an AE-8 zone, then it actually experienced an increase of 1.5 feet.  Another example: If your building was in an AE-6 flood zone and is proposed to be in an AE-9 zone, the increase appears to be three-feet.  However, the actual increase would be 4.5’-feet.

To convert one vertical datum to another, visit:

https://vdatum.noaa.gov/vdatumweb/vdatumweb?a=094103020190826 or alternatively https://www.arcgis.com/home/item.html?id=4ffd84bc93ce4862bcd642bdb023668e

For more information on vertical DATUMS, read FEMA’s fact sheet at www.FEMA.gov/Media-Library/Assets/Documents/11535.

View current flood maps at FEMA Flood Map Service Center and search by property address.  

The below diagram shows the tentative process timeline for the Draft Maps, Preliminary Maps, and Final Maps: