page_title: District of Columbia Water and Sewer Authority
section_title: DC Water Clean Rivers Project
hierarchical_section_title: District of Columbia Water and Sewer Authority / DC Water Clean Rivers Project
caption_attribution_description: English: View of cutting head portion of a tunnel boring machine used for the DC Water "Clean Rivers Project" in Washington, D.C. The head was built in Germany and is 26 ft in diameter. In 2013 DC Water began a 20-year tunnel construction project to reduce combined sewer overflows to local rivers.
context_page_description: The District of Columbia Water and Sewer Authority provides drinking water, sewage collection and sewage treatment in Washington, D.C.. The utility also provides wholesale wastewater treatment services to several adjoining municipalities in Maryland and Virginia, and maintains more than 9,000 public fire hydrants in the District of Columbia. DC Water was created in 1996, when the District Government and the U.S. federal government established it as an independent authority of the District government.
context_section_description: The District of Columbia is one of 772 older cities in the country with a combined sewer system. The system covers about a third of the city, and was built in the late 19th century to carry both sanitary sewage and storm water in the same pipe.  The system operates well in dry weather. However, during rainstorms, the flow can exceed the capacity of the pipe. To prevent sewer backups and flooded streets, these combined sewers may discharge into the Anacostia and Potomac Rivers and Rock Creek, a phenomenon known as combined sewer overflows (CSOs).
  To date, DC Water has significantly reduced CSOs by eliminating approximately 40 percent of the overflows through a $140 million construction and mitigation program. This investment included inflatable dams to catch and store overflows during rain storms; tide gates to keep river water from flowing into the sewer system; sewer separation to eliminate CSO outfalls; and pumping station construction and rehabilitation to increase flow capacity.
  In 2013 the agency began construction of a deep tunnel system for its "Clean Rivers Project." The $2.4 billion, 20-year project will reduce CSOs by 96 percent overall and 98 percent in the Anacostia River. Once operational, the tunnel system will store the combined sewage during wet weather and release it gradually for treatment at Blue Plains.
caption: Cutting head of a tunnel boring machine used in the Clean Rivers Project
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