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Understanding flood hazard areas

A functioning floodplain is important for the health of the surrounding ecosystem. It also benefits the local economy and cultural activities.

The changing policy and physical environment is making the management of floodplain resources difficult. Many U.S. communities struggle to find an effective and integrated way to deal with this challenge. We expect floods to increase and become more severe over time. Cities need to better understand the value of floodplains.

Planners are being pushed to think about increasing resiliency and reducing risk to people and property thanks to:

  • litigation on the National Flood Insurance Program
  • changing municipal stormwater rules, and
  • projected impacts of climate change.

The City's Ready Boston initiative aims to educate and empower Bostonians about the hazards they may face. 

Special flood hazard areas

What are Special Flood Hazard Areas?
  • Flood plains that adjoin a river, stream, or other inland or coastal waterway.
  • They are inundated by water during the 1 percent annual chance flood (100-year flood).
What is a 1 percent annual chance flood?

It’s a flood event having a 1 percent chance of taking place in any given year.

Hazard areas on flood maps

These hazard areas are considered a Wetland Resource Area under the Massachusetts Wetlands Protection Act. They are depicted on Federal Emergency Management Flood Insurance Rate Maps as Zones A, AE, AH, AO, AR, A99, V and VE.

Changes to flood insurance and maps

Changes to the Flood Insurance Rate Maps for the City of Boston went into effect on March 16, 2016.

The Federal Emergency Management Agency (FEMA) has been revising flood maps. They’re working to reflect current flood risks in coastal areas nationwide. The revisions use historical data and advanced modeling technology. The goal is to be more accurate when finding current flood risks. The revised maps do not account for future flooding risks. The official map of a community and its flood hazards is known as a Flood Insurance Rate Map.

Maps and buying flood insurance

The revised maps provide more information about flood risks for new and existing developments. Boston adopts these maps so property owners can qualify to buy and keep federally subsidized flood insurance. This insurance is bought through the National Flood Insurance Program. The City is also eligible to receive federal disaster aid in the case of a flood emergency.

The updated maps for Boston are available at the FEMA Map Service Center. Do you need help understanding flood insurance maps? You should consider:

  • finding out if your property will be affected by remapping
  • checking out the FEMA how-to guide, and
  • reading about the resources at the bottom of this page.
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