Department of Environmental Conservation

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Long Island Sound Study

Long Island Sound is an estuary approximately 110 miles long (east to west) and 21 miles across at its widest point, and covers an area of 1320 square miles with 600 miles of coastline. It is located in one of the most densely populated areas in the United States, particularly along the Nation's coastal areas, within the jurisdiction of two states, New York and Connecticut. Its valuable recreational and commercial uses make it one of the most important estuaries in the nation. In 1985, Congress allocated funds for the U.S. Environmental Protection Agency (EPA) to research, monitor, and assess the water quality of Long Island Sound.  In March 1988, Long Island Sound was identified as an Estuary of National Significance and the Long Island Sound Study (LISS) became a part of EPA's National Estuary Program. In March 1994, LISS released its Comprehensive Conservation and Management Plan (CCMP) to guide restoration and protection activities. In October 2015, the LISS released a new CCMP to incorporate scientific and technological advances, respond to changing community needs, and to address new environmental challenges such as climate change, sustainability, environmental justice, and ecosystem-based management. The new CCMP is organized around four central themes:

  • Clean Waters and Healthy Watersheds
  • Thriving Habitats and Abundant Wildlife
  • Sustainable and Resilient Communities
  • Sound Science and Inclusive Management 

The new CCMP also sets 20 key ecosystem targets for the Long Island Sound to be achieved over the next 20 years. The CCMP was developed through a collaborative process involving federal, state and local governments, university scientists, and interested representatives of business, environmental, and community groups.