[20200108]IF11402_恢复切萨皮克湾水质的工作现状.pdf

https:/crsreports.congress.gov January 8, 2020Status of Efforts to Restore Chesapeake Bay Water QualityBackground For decades, Chesapeake Bay jurisdictions (Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia, and the District of Columbia), multiple federal and local agencies, and others have worked to improve water quality in the Chesapeake Bay. Despite these extensive restoration efforts, poor water quality in the bay and its tidal tributaries persisted, prompting litigation that ultimately required the U.S. Environmental Protection Agency (EPA) to establish a Total Maximum Daily Load (TMDL)or a “pollution budget” for the bay. Established in 2010, the TMDL included interim and final goals for each jurisdiction to achieve by 2017 and 2025, respectively. What Is a TMDL? The Clean Water Act (CWA) requires states to identify waters that are “impaired” by pollution (i.e., not meeting state water quality standards). For those waters, the act directs states to establish a TMDL, which is a calculation of the amount of a pollutant that can enter a waterbody and still allow the waterbody to meet state water quality standards for that pollutant. TMDLs include a quantitative