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, wastewater 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 developed a Comprehensive Conservation and Management Plan to protect and restore Long Island Sound.

The LISS partners have made significant strides in implementing the plan, giving priority to reducing nutrient (nitrogen) loads, habitat restoration, public involvement and education, and water quality monitoring.

Nitrogen (Hypoxia) Management

  • 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 to reduce nitrogen loads from human sources. As of 2016, the states have nearly attained the goal, with upgrades to wastewater treatment plants resulting in an annual reduction of 42 million pounds of nitrogen to the Sound  from peak years in the early 1990s.
  • In 2015, EPA embarked on a new Long Island Sound Nitrogen Reduction Strategy with a primary  focus on achieving clean water in harbors, bays, coves, and other embayments to the Sound through efforts to remove nutrient pollution from urban stormwater and turf fertilizer, and from coastal on-site wastewater treatment systems such as septic tanks.  

Habitat Restoration

  • From 1998 to 2015, 1,750 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 2015, 335 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 2016, the program has invested $15 million in 352 projects. With grantee match of $30 million, the program has generated $45 million for locally based conservation. The projects have opened up 157 river miles for fish passage, restored 1,051 acres of critical fish and wildlife habitat and open space, treated 101 million gallons of pollution, and educated and engaged 2.1 million people from communities surrounding the Sound.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

  • The Connecticut Department of Energy and Environmental Protection, on behalf of the Long Island Sound Study, conducts a Long Island Sound Water Quality
    Monitoring Program. Surface and bottom waters are monitored by staff aboard the Department’s Research Vessel John Dempsey.  Testing parameters include water temperature, salinity, dissolved nitrogen, particulate nitrogen, and dissolved oxygen. LISS also provides support to LISICOS, a real-time monitoring program using equipment on buoys at stations thoughout the Sound, and the Interstate Environmental Commission, which monitors the Narrows and Western Sound.
  • 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. Through the Long Island Sound Futures Fund, LISS also supports a pilot study to create a “Unified Water Study” of common standards and methods and produce guidance to inform water quality monitoring of ecological and eutrophic conditions by citizen-science groups working in Long Island Sound embayments and harbors.

To continue progress, LISS’s partners in 2015 totally revised the Comprehensive Conservation and Management Plan to address ongoing and new challenges. The 2015 plan is organized around four themes, each with an overall goal:  

  1. Clean Waters and Healthy WatershedsImprove water quality by reducing contaminant and nutrient loads from the land and the waters impacting Long Island Sound.
  2. Thriving Habitats and Abundant WildlifeRestore and protect the Sound’s ecological balance in a healthy, productive, and resilient state for the benefit of both people and the natural environment.
  3. Sustainable and Resilient CommunitiesSupport vibrant, informed, and engaged communities that use, appreciate, and help protect Long Island Sound; and.
  4. Sound Science and Inclusive ManagementManage Long Island Sound using sound science and cross-jurisdictional governance that is inclusive, adaptive, innovative, and accountable.

The plan sets 20 ambitious, but achievable ecosystem targets for these goals and identifies detailed strategies and actions to drive progress to attain them. 


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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