Washington DC and the climate change
Washington, DC, formally the District of Columbia, is situated on the banks of the Potomac and Anacostia Rivers, wedged between the states of Maryland and Virginia. The capital of the United States is one of the most densely populated cities in the US with an estimated population of 672,228 as of July 2015 and a resident density of 11,000 people per square mile. During workweeks, commuters from the surrounding suburbs raise the city’s population to over one million.
This large population needs protection against the dramatic consequences of climate change that confront the city to an increasing extent. Three types of flooding are expected to have a dramatic impact if the authorities fail to take preventive measures and key stakeholders fail to improve coordination:
- riverine flooding, caused when excessive river water flows into a floodplain area;
- tidal and storm surge flooding, caused by high tides and coastal storms that drive surge and wave up the Potomac River from the Chesapeake Bay and the Atlantic Ocean;
- interior flooding, caused when stormwater drainage systems are overwhelmed during extreme precipitation events. According to the Köppen climate classification, Washington, DC is located in the humid subtropical climate zone. This means that winters are mild to cool, summers are hot and humid, and precipiation is generous throughout the year.
Specifically low-lying areas of Washington, DC are at sea level and are subject to major Potomac River and Anacostia River floods, hurricane storm surge floods from the Chesapeake Bay, and interior floods.
Washington, DC commits to sharing its knowledge, experiences and best practices in activities related to stormwater and flood risk management, including collaborations through the so-called DC flood risk management (‘Silver Jackets’) team, the RiverSmart programme and ongoing watershed, wetland and stream restoration projects.