About the Partnership/Program

Working together to protect and improve the health of Long Island Sound.


What is Being Done to Restore and Care for 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 Partnership (LIS Partnership) 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 LIS Partnership developed a Comprehensive Conservation and Management Plan to protect and restore Long Island Sound. This plan was revised in 2015, and again in 2025, with ambitious goals and objectives to drives further progress through 2035.

Our partner 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 2000, 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. By 2016, the states attained the goal. By 2025, upgrades to wastewater treatment plants have resulted in an annual reduction of more than 47 million pounds of nitrogen to the Sound from peak years in the early 1990s.
  • As a result of nitrogen reductions, water quality is improving. The average maximum summertime area of unhealthy oxygen has shrunk in half.

Habitat Restoration

  • From 1998 to 2024, nearly 2,400 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 2024, nearly 450 miles of river migratory corridors have been restored for anadromous fish passage by removing dams and installing fish passages. .

Public Involvement and Education

  • The Long Island Sound Partnership initiated the Long Island Sound Futures Fund in 2005 through the EPA’s Long Island Sound Office and the National Fish and Wildlife Foundation. Since its inception, the Futures Fund has invested $42 million in 570 projects. The program has generated an additional $54 million in grantee match for a total conservation impact of $97 million. Projects have opened 119 river miles for fish, restored 811 acres of wildlife habitat, reduced 206 million gallons of stormwater pollution, and engaged more than 5 million people in the protection and restoration of the Sound.
  • The LIS 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 on that weekend and on other dates in September and October. Visit the Ocean Conservancy for more information.

Water Quality Monitoring

  • The Connecticut Department of Energy and Environmental Protection and the Interstate Environmental Commission, on behalf of the LIS Partnership, conduct a Long Island Sound Water Quality Monitoring Program. Surface and bottom waters are monitored from staff on board research vessels. Testing parameters include water temperature, salinity, dissolved nitrogen, particulate nitrogen, and dissolved oxygen. lisp also provides support to LISICOS, a real-time monitoring program using equipment on buoys at stations throughout the Sound.
  •  lisp has helped provide financial and technical support to Save the Sound in establishing the Unified Water Study, a new water quality monitoring protocol developed so groups around Long Island Sound can collect comparable data on the environmental health of the Sound’s bays, harbors, covers, and other coastal waters. This groundbreaking water testing program is dramatically increasing available data on the health of Long Island Sound.

To continue progress, the LIS Partnership in 2025 totally revised the Comprehensive Conservation and Management Plan to address ongoing and new challenges. The 2025 plan is organized around four themes, each with an overall goal:  

  1. Clean Waters and Healthy Watersheds – Restore and maintain water quality in Long Island Sound and its watershed.
  2. Thriving Habitats and Abundant Wildlife – Restore and protect the health and resilience of habitats.
  3. Sustainable and Resilient Communities – Empower Long Island Sound communities to plan for and respond to environmental challenges in ways that prioritize well-being for all.
  4. Informed and Engaged Public – Inspire and empower the public to appreciate, value, and protect Long Island Sound and the waters that flow into the Sound.

Under these goals, the plan sets 15 ambitious, but achievable and measurable objectives, identifying specific actions to drive progress to attain them. 

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