[20170705]IF10627_切萨皮克湾生态系统恢复.pdf

https:/crsreports.congress.gov Updated July 5, 2017Ecosystem Restoration of the Chesapeake BayBackground The Chesapeake Bay is the largest estuary in the United States. Its watershed comprises a 64,000 square-mile area and includes portions of the District of Columbia and the states of Delaware, Maryland, New York, Pennsylvania, Virginia, and West Virginia (see Figure 1). Freshwater enters the bay from several tributaries, including the Potomac and Susquehanna Rivers, and drains into the Atlantic Ocean. The bay supports thousands of wildlife species, commercial and recreational fisheries, recreation activities, shipping, and other commercial activity. The health of the bay ecosystem has been a concern for Congress and stakeholders for many years. The decline of this ecosystem, first noticed decades ago, has been widely attributed to urban and agricultural development and to pollution from the bays watershed. Figure 1. Chesapeake Bay Watershed Source: Chesapeake Bay Foundation. Pollution from point sources, such as sewage treatment plants, and from nonpoint sources, such as agricultural runoff and animal waste, has contaminated the bay waters and ecosystem with excessive nutrients