How to view the IFM Flood Maps:
The IFM Flood Maps can be viewed on the interactive DC Flood Risk Tool.
- Find instructions for the DC Flood Risk Tool and learn more about its features.
About the Integrated Flood Model (IFM)
Washington, DC, like most cities, has floodplain maps that are developed by FEMA. However, these maps only show flooding along our coastlines, major rivers, and streams. They do not depict flooding that occurs because of heavy rains and overwhelmed stormwater systems; often called stormwater flooding or interior flooding. For much of the District, this represents the most persistent type of flooding. Previous stormwater flood events include the following: 2006 Federal Triangle, 2012 Bloomingdale and LeDroit Park, 2016 Cleveland Park, and 2023 Rhode Island Ave NE.
The District’s Integrated Flood Model (IFM) fills this information gap and maps flood risk across the entire city, not just near bodies of water. For the first time, the IFM allows the District to evaluate flooding caused by limited sewer pipe capacity, in combination with coastal and riverine flooding that can enter through sewer outfalls and back up into communities.
The IFM allows District agencies to better understand how climate change, and the resulting increased frequency and intensity of storms, will impact the District.
- View the Integrated Flood Model Fact Sheet
About the Maps
Although maps show flooding for a specific storm size across the entire District, it is unlikely that the entire city would be flooded in this way given storm paths and varying intensities. Storms are often local, with their greatest impact focused on only one part of the city. It is more likely that a small area of the city might see the most rain, while the rest of the city would see much less and not experience any flooding. The IFM maps are most valuable when zoomed in, to understand what flooding would look like locally if a certain area was the focus of one of the listed storm scenarios.
The DC Flood Risk Tool shows two different storm scenarios: the 1-year storm and the 100-year storm. For each of these scenarios, flooding is shown at a range of depths from 6 inches to 3 feet or greater. To increase confidence in modeled results, only flood patches over 5000 SQ FT have been displayed.
1-year storm scenario: The 1-year storm is a common storm event, expected to occur every year.
This map shows the areas of the city that would experience flooding if the District experienced 2.6 inches of rain in 24-hours. This amount of rain in 24 hours is statistically likely to happen once in any given year -- as a result, this is called the 1-year storm. This is an important map because it highlights areas of the city that are expected to flood frequently (on average about once a year).
100-year storm scenario: The 100-year storm is an infrequent, but intense storm event.
This map shows the areas of the city that would experience flooding if the District received 8.3 inches of rainfall in 24-hours. Because this has a 1 in 100 chance of happening in a given year, it’s referred to as the 1% storm or the 100-year storm. The 100-year storm is also the benchmark that FEMA flood maps use -- like along the Potomac and Anacostia. Creating equivalent maps for stormwater flooding allows us to examine the rest of the city with an equivalent risk tolerance.
An example of differences in flood extent and depths between the 1-year storm and 100-year storm scenarios.
What to do if your property is mapped at risk:
The IFM maps provide the public with free information to understand local flood risk, which is the first step to being Flood Smart. Other Flood Smart steps that residents and businesses can take include:
- Consider purchasing Flood Insurance; homeowner’s insurance does NOT cover flood damages.
- Review the Guide to Flood Insurance in the District to learn more about flood insurance and available offerings.
- Remove valuables and other items from your basement
- Floodproof your home – raise mechanical systems, upgrade low outlets, install backwater valves, purchase removable flood barriers
- Sign up for a free home flood risk assessment with recommendations from the Flood Smart Homes program
- Sign up for severe weather alerts at AlertDC and get Prepared for a Flood with Ready DC. Learn about how to act before, during, and after a flood occurs.
- Apply for the Backwater Valve Rebate Program. Learn what options you have to prevent sewer back-ups and whether you are eligible for a rebate.
- Sign up for RiverSmart Homes to better manage stormwater on your property.
For more information on protecting your home, see our flyers on High Risk Properties and Types of Flooding.
Future Uses of the Integrated Flood Model
Mapping all the types of flood risk is a major step forward for the District since previously stormwater risk was unknown. The IFM is helping DOEE focus outreach to residents who are most vulnerable, and to make sure everyone has access to the best information available. This ensures residents and businesses can make informed decisions on insurance, home purchases or upgrades, and their own safety.
In addition to mapping, the IFM will help the District choose where and how to invest in flood-reducing infrastructure. DOEE will use the IFM to focus investment in the most vulnerable areas, and test proposed designs in the IFM before they are constructed to ensure they will reduce flood risk as planned. Information from the IFM can help property understand the scale of floodproofing systems that they should incorporate into construction plans.
How the IFM was created:
The completion of the Integrated Flood Model is a major milestone for the District and its efforts to reduce risk, protect assets, and plan for a more resilient future.
The IFM came to be with significant help from city leadership, multiple city agencies, and regional organizations. An Integrated Flood Model was first envisioned by DOEE and the DC Silver Jackets, which led to inclusion in the Climate Ready DC and Resilient DC plans. Both the Mayor and the City Council recognized the importance of this effort and provided capital funding in 2020. The importance of the IFM was reaffirmed by the citywide DC Flood Task Force in 2023. Since development on the IFM began in 2022, OCTO and DC Water have been integral partners in its implementation. Thank you to all who have supported this effort.
For general information and FAQ, please view the IFM Fact Sheet.
For More Information
The DC Department of Energy and Environment’s Flood Risk Management program can be contacted at [email protected].