Climate change impacts
The metropolitan area surrounding Washington D.C. in the United States is susceptible to tidal flooding along two rivers: the Potomac and the Anacostia. Sea levels in the Central Atlantic Coast have risen by nearly 10 inches over the last 80 years, and recently, even small storms and high tides have frequently caused "nuisance flooding" sloshing water over roads and sidewalks. According to a survey by NOAA (Note 1), Washington, D.C., is one of the most flood-prone areas in the nation, with a 373 percent increase since the 1950s. Sewage from all areas of the D.C. metropolitan area flows to a facility called the Blue Plains Advanced Wastewater Treatment Plant, which is located at the lowest elevation of Washington, D.C., and has recently become susceptible to sea level rise.
Adaptation activity
The District of Columbia Water and Sewer Authority (DC Water hereinafter) has implemented two measures to protect advanced wastewater treatment plants from flooding.
First, with the cooperation of government agencies and climate scientists, DC Water helped stakeholders consider how climate change would impact the region over the next few decades. As part of a regional vulnerability assessment, the research group, including climate scientists, used climate projection data to assess potential changes in sea level, high tides, and extreme weather. In addition, a list was created of both physical (e.g., hospitals) and intangible (e.g., tourism economy) urban assets that would be crucial to people’s livelihoods and necessary to protect, confirming what infrastructure may be affected by storms, and establishing the cost of incorporating resilience in monetary terms. As a result, increasing resilience was found to be cheaper than reconstruction after disasters. The Study Group then developed an implementation plan to make cities as resilient as possible to mitigate climate change impacts.
DC Water invested $13.2 million and decided to build a 17 feet (about 5 meters) high seawall around the Blue Plains Advanced Wastewater Treatment Plant (fig.).
In a second initiative, DC Water worked with power companies in the region to construct its own 10-megawatt combined heat and power plant. DC Water pumps 370 million gallons (approximately 1.4 million cubic meters) of wastewater each day and uses a lot of electricity to maintain the pumping system, which also filters and disinfects the water. A combined heat and power supply plant will improve response in the event of a power outage, enabling reductions in carbon emissions and energy costs.
Outputs / Expected benefits
Seawalls can protect advanced wastewater treatment plants of 150 acres (about 610,000 square meters) against 500-year floods. Complete implementation of the proposed program will take years, but DC Water is thinking ahead. Not only is it expected that the combined heat and power facilities will reduce the amount of power used in plants and protect the supply of electricity in emergencies, but there will also be a reduction in power plant carbon emissions by more than a third. This advanced wastewater treatment plant is considered to be Washington D.C.’s most valuable asset, which supports the lives of two million people in Washington, Maryland, and Virginia.
Footnote
(Note 1) National Oceanic and Atmospheric Administration (U.S. Marine and Atmospheric Administration)
