Photos of the Long Island Sound

About Us

About the Long Island
Sound Study

What is Being Done to Restore
and Protect the Long Island Sound?

Since the federal Clean Water Act became law in 1972, investments in water pollution control programs have led to measurable improvements in the water quality of Long Island Sound. Obvious sources of pollution were controlled through permit programs. Tidal wetlands were protected, sewage treatment plants improved, and industrial discharges controlled.

However, to fully restore the health of the Sound, a cooperative effort focusing on the overall ecosystem was needed. As a result, EPA, New York, and Connecticut formed the Long Island Sound Study (LISS) in 1985, a bi-state partnership consisting of federal and state agencies, user groups, concerned organizations, and individuals dedicated to restoring and protecting the Sound. In 1994, the LISS completed a Comprehensive Conservation and Management Plan that identified seven issues:

  1. Low dissolved oxygen (hypoxia)
  2. Toxic contamination
  3. Pathogen contamination
  4. Floatable debris
  5. Living resources and habitat management
  6. Land use and development
  7. Public involvement and education

The LISS partners have made significant strides to restore and protect Long Island Sound, giving priority to hypoxia, habitat restoration, public involvement and education, and water quality monitoring.

Nitrogen (Hypoxia) Management

  • In 1998, the LISS adopted a 58.5 percent reduction target for nitrogen loads from human sources to the Sound by 2014, with interim five- and ten-year targets to assure steady progress.
  • In 2001, the EPA approved Connecticut’s and New York’s plan, called a Total Maximum Daily Load (TMDL), for achieving the 58.5 percent nitrogen reduction from point and nonpoint sources of pollution.
  • Upgrades to wastewater treatment plants have resulted by 2014 in an annual reduction of 40 million pounds of nitrogen  to the Sound  from peak years in the early 1990s.

Habitat Restoration

  • From 1998 to 2014, 1,615 acres of habitat, including tidal wetlands and forest, have been restored in Connecticut and New York in the Long Island Sound watershed.
  • From 1998 to 2014, 317 miles of river migratory corridors  have been restored for anadromous fish passage by installing fishways and removing dams.

Public Involvement and Education

  • The Long Island Sound Study initiated the Long Island Sound Futures Fund in 2005 through the EPA’s Long Island Sound Office and the National Fish and Wildlife Foundation. Through 2014, the program has invested $13 million in 306 projects in communities surrounding the sound. With grantee match of $25 million, the Long Island Sound Futures Fund has generated a total of almost $38 million for locally based conservation in both states.
  • LISS partners hold conferences, summits, and workshops where municipal leaders, research scientists, and educators can share their experiences and highlight their success stories regarding issues such as nitrogen reduction, habitat restoration, research on living marine resources, land use, open space, and smart growth.
  • The International Coastal Cleanup takes place annually on the third Saturday of September. Thousands of volunteers from Connecticut and New York remove and document the trash that they collect along the shoreline and underwater. Visit The Ocean Conservancy for more information.

Water Quality Monitoring

  • A number of organizations and citizen groups monitor water quality to identify how Long Island Sound responds to management initiatives such as nitrogen reduction. Water samples are collected and tested for dissolved oxygen, salinity, temperature, chlorophyll a, and other parameters.

Learn More


Are These Efforts Working?

Is Long Island Sound getting better? Are fish and wildlife populations more abundant? Answers to these questions and more are in theSound Health report, a snapshot of current conditions and trends in the Sound. Keying in on selected environmental indicators, the report highlights water quality conditions, the status of some of the creatures that live in and around the Sound, and trends in land use and development. The complete set ofLong Island Sound Study Environmental Indicators is also available.

LISS Staff

LISS staff clear invasive species (Japanese Knotweed) along the Mill River in Stamford, CT.

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