Photos of the Long Island Sound

Research & Monitoring

Status & Trends

LISS Ecosystem Targets and Supporting Indicators

Clean Waters and Healthy Watersheds

Clean Water and Healthy Watershed ecosystem targets track progress towards attaining the goal of improving water quality by reducing contaminant and nutrient loads from the land and the waters impacting Long Island Sound.

Extent of Hypoxia

Measurably reduce the area of hypoxia in Long Island Sound from pre-2000 Dissolved Oxygen TMDL averages to increase attainment of water quality standards for dissolved oxygen by 2035, as measured by the five-year running average size of the zone. View Ecosystem Target

Nitrogen Loading

Attain wastewater treatment facility nitrogen loading at the recommended 2000 Dissolved Oxygen Total Maximum Daily Load allocation level by 2017 and maintain the loading cap. Have all practices and measures installed to attain the allocations for stormwater and nonpoint source inputs from the entire watershed by 2025. View Ecosystem Target

Water Clarity

Improve water clarity by 2035 to support healthy eelgrass communities and attainment of the eelgrass extent target. View Ecosystem Target

Impervious Cover

Through green infrastructure, low impact development, and stormwater disconnections, decrease by 10 percent the effective area of impervious cover in the Connecticut and New York portions of the watershed by 2035 relative to 2010 baseline. View Ecosystem Target

Riparian Buffer Extent

Increase the percent area of natural vegetation within 300 feet of any stream or lake in the Connecticut and New York portions of the Long Island Sound watershed to 75% (1,030 square miles of natural vegetation) by 2035 from 2010 baseline of 65%. View Ecosystem Target

Approved Shellfish Areas

Upgrade 5% of the acreage currently restricted or closed for shellfishing by 2035 from a 2014 baseline. View Ecosystem Target

Sediment Quality Improvement

Reduce the area of impaired sediment in Long Island Sound by 20% by 2035 from 2006 baseline. View Ecosystem Target

Industrial Chemical Discharges (TRI data – Total LIS watershed and CT and NY portion of watershed)

This indicator compiles the total amount of discharges of toxic chemicals manufactured and used at industrial facilities that are released into the Sound either by air or by water. View Indicator

Duration of Hypoxia

Hypoxia is a condition that occurs in bodies of water as dissolved oxygen concentrations decrease to levels where organisms become physically stressed and ultimately cannot survive. Duration of hypoxia refers to the number of days in a year during which hypoxia was observed in Long Island Sound View Indicator

Severely Hypoxic and Anoxic Areas

Hypoxia is a condition that occurs in bodies of water as dissolved oxygen concentrations decrease to levels where organisms become physically stressed and ultimately cannot survive. The area of hypoxia in Long Island Sound refers to the number of square miles in which dissolved oxygen concentrations were less than 3 mg/L over the course of a single year. Severely hypoxic areas are less than 2 mg/L and anoxic areas are less than 1 mg/L. View Indicator

Water Quality Index

The water quality index is a calculation that combines several water quality measurements to rate overall water quality in Long Island Sound on an annual basis. View Indicator

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