Provide Accurate, Up-to-date Information About Flood Risks and Future Conditions

The Challenge

The cornerstone of the NFIP is the floodplain maps (“Flood Insurance Rate Maps” or FIRMs) that drive rate setting and local land-use regulations. The maps are developed for the purpose of setting insurance rates, but they are used by cities to make decisions that have much longer-term consequences, such as land-use decisions, and decisions on how to design critical facilities and infrastructure. In many cities these maps are outdated, and are developed using only historical flood data. They do not accurately reflect either the current or future flood risks that cities face.

As a result, developers and individuals are using imperfect information to make choices about where to buy and develop. Many homeowners are not adequately informed about the risk of flooding when making decisions about purchasing a home or whether to carry flood insurance after their mortgages are paid off.

Additionally, many state, local and private sector partners struggle to understand requirements for conducting the Hydrologic & Hydraulic studies needed to develop FEMA-compliant Flood Insurance Rate Maps. As a result, other sectors are not able to easily fill the gaps in the FEMA-administered mapping program. The deficiencies in current floodplain maps and mapping practices have been recognized in the literature and in recent legislation, which called for the Technical Mapping Advisory Council to be reconvened to make recommendations on how to improve the NFIP’s mapping program. The process for developing floodplain maps is also costly and inefficient. Contractors are hired to develop maps for different jurisdictions leading to inconsistencies between floodplain maps in neighboring communities.

The Opportunity

Cities, developers, homeowners and businesses all need accurate, future-looking flood risk information to help them effectively understand flood risks, make decisions about where and how to build, and implement projects to mitigate flood risks. The floodplain mapping program should be fully funded and FEMA should be given authority to provide detailed flood hazard information, including information about future conditions and long-term flood risks to help cities make better land use and capital-investment decisions. Options should be explored for the creation of digital platforms that provide tools to better visualize flood hazards, and allow for the integration of data from different federal agencies, and state, local and private sector partners.

Action Steps


Congress should fully fund the floodplain mapping program and Congress should direct FEMA to provide more detailed flood-hazard information, including information about future conditions and long-term flood risks.

Congress should give FEMA authority to create a facility for cost sharing that would allow FEMA to combine funding from other agencies, take in funding from private sources, and use data from other federal agencies, state and local partners, and the private sector. FEMA should coordinate with other federal partners, including USGS, NOAA, the Army Corps and others, to combine data and resources and provide accessible digital elevation maps that help communities better understand their flood risks.

Congress should fund a National Academies study to identify strategies for creating a national flood mapping initiative that coordinates federal efforts, streamlines the process, and creates clear standards for developing floodplain maps.

Considering sea-level rise on floodplain maps
In October 2016, New York City and FEMA announced a partnership to develop new flood maps that account for climate change and sea-level rise, using the bestavailable science as informed by the New York City Panel on Climate Change and in partnership with other federal agencies including NOAA and USGS.17 To protect flood insurance affordability, the city’s FIRMs (which are also being revised) will continue to reflect current flood risk; but the forward-looking maps being developed through this partnership will be used for long-term planning and building purposes, and to help ensure that new investments in New York City are sited and designed with future flood risk in mind. This partnership provides one example of how cities can work with federal partners to identify and apply the best available data and science to inform climate-smart development.


FEMA should continue to partner with other agencies to collect high-resolution digital elevation data; FEMA should be encouraged to develop or build upon existing digital platforms for publishing and visualizing flood-risk information that would allow for inclusion of data from other partners, and that would be compliant with FEMA’s mapping requirements.

FEMA should develop clear and consistent standards for Hydrologic & Hydraulic studies for developing FEMA-compliant floodplain maps. This would allow opportunities for more private, local, and state partnerships in developing risk-based mapping products and data.

Visualization of flood risks
The North Carolina Flood Risk Information System provides an online portal for hosting floodplain maps, but the system also allows for additional data input by local and state governments (such as building elevation data that can be used to develop flood depth damage estimates). A similar system could be rolled out nationally to allow cities to better assess and visualize both current and future flood risks, in a way that is compliant with FEMA’s mapping requirements.

FEMA should develop tools and support efforts to help cities effectively communicate flood risks to individuals, and to help inform their decisions about purchasing insurance or investing in loss-reduction measures, such as home elevation. For example, by simply changing their vocabulary around the “100-year flood”, FEMA could help homeowners better understand that the likelihood of a 100- year flood affecting their home is 1-in-4 over the life of a typical 30-year mortgage (not the 1-in-100 odds that is often assumed). FEMA should also support (and Congress should fund) community-based education projects that will help promote awareness about changing flood hazards, insurance purchase options, and measures that can be taken by homeowners, landlords and businesses to reduce flood losses.

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