New online maps show storm-based flood potential along Potomac, Anacostia rivers

Published Nov. 21, 2016

New online maps show storm-based flood potential along Potomac, Anacostia rivers – in time for 80th anniversary of historic Potomac River flooding


WASHINGTON – New digital maps allow government leaders, emergency managers, and the public to view potential flood impacts during high-water events along the Potomac and Anacostia rivers throughout the District of Columbia, Northern Virginia and nearby communities. The maps are now live on the National Weather Service’s (NWS) web site.  


This project represents the first interactive flood inundation mapping tool for this region using U.S. Army Corps of Engineers’ (Corps) modeling and mapping, and tied directly to U.S. Geological Survey (USGS) and National Oceanic & Atmospheric Administration (NOAA) water gauges, making it a more accurate and reliable tool for emergency-response decisions.


A public webinar to demonstrate how the tool works will be held Tuesday, Nov. 29, from 6 – 7 p.m.


“The release of this tool is exceptionally timely, as, this year, we marked the 80th anniversary of the devastating Potomac River flooding of 1936, which is one of the worst on record in the District," said James E. Lee, NWS, Baltimore/Washington meteorologist-in-charge. "These maps paint a picture of what our forecast means in the event of an expected flood."


NWS uses USGS and NOAA water gauge data to continuously monitor water levels and uses the Corps’ hydrologic and hydraulic models and corresponding maps to project when and where flooding could occur and how severe it may be. NWS is also using the Corps’ models as a basis for forecast-improvement opportunities for the region - influenced by riverine flows, tides and storm surge.


The District of Columbia has a long history of flooding, dating back to the 19th century. The worst tidal flood in recent history was caused by Hurricane Isabel in 2003, in which the peak storm surge was around 8 feet above normal tide at the southwest waterfront.


“These new maps will enable us to identify the greatest potential impacts of the next major storm," said Tommy Wells, District Department of Energy and the Environment director. “They are also important tools for educating District residents and businesses about flood risks and the preventative steps they can take to minimize these risks.”


The data will be further leveraged by the District as part of a comprehensive risk analysis initiative to inform preparedness, flood mitigation strategy and emergency management plans and operations. Flood depths will be used to estimate physical, economic and social impacts, including future risk attributed to sea-level rise.


Other contributing agencies include National Park Service; Federal Emergency Management Agency; District of Columbia Homeland Security and Emergency Management Agency; and National Capital Planning Commission.


“This tool will prove invaluable for predicting and displaying the extent and depth of flooding for impending storms, so we can better protect human lives and the critical infrastructure in this unique area,” said Stacey Underwood, Corps, Baltimore District, Silver Jackets program coordinator.


The maps show extent and depth of a freshwater flood on the Potomac River, as well as the extent of a tidal flood on both the Potomac and Anacostia rivers. The area mapped encompasses Fletcher’s Cove on Canal Road in Northwest D.C. to the mouth of Broad Creek near Fort Foote, Maryland, and Fort Hunt, Virginia, for a distance of approximately 14 miles. Backwater tributary flooding within this area is also represented, including Four Mile Run, Cameron Run and Oxon Run along the Potomac River; and from New York Avenue in Northeast D.C. to its confluence with the Potomac River for approximately 10 miles along the Anacostia River.


“As someone who spent many childhood weekends playing along these river banks, I've looked forward to the day when residents could have a sense of what areas will flood when the river overflows its banks,” said Peter Ahnert, NWS Middle Atlantic River Forecast Center hydrologist in charge. “Thanks to the excellent modeling and mapping work by the Corps of Engineers and the efforts of the interagency Silver Jackets team, this day has arrived."


Federal and District agencies listed in this release are members of the District of Columbia Silver Jackets Team, which is an interagency team that leverages resources to identify and implement comprehensive, resilient, and sustainable solutions to reduce flood risk around the district and to assist local communities. This project is a D.C. Silver Jackets team project.


D.C. Silver Jackets’ priorities include flood inundation mapping/stream gauges; flood emergency planning; interior drainage flooding; levee certification and accreditation; and communication.


For details on the webinar and to view the tool, visit The webinar recording will also be available on this site within a week of the webinar date, for those who cannot attend.


For more information on the D.C. Silver Jackets, visit:


Sarah Gross
Susan Buchanan

Release no. 16-33