Clean water is the foundation of a healthy Long Island Sound—for human use and recreation, for thriving fisheries, and for productive habitats. The condition of the Sound depends on the quality of the waters draining from the landscapes surrounding it. This connection between the land and water, between healthy, sustainable upland communities and a healthy Long Island Sound is the foundation of the Clean Waters and Healthy Watersheds theme.
While Long Island Sound’s water is getting cleaner, the Sound still suffers from hypoxic “dead zones,” beach closures, and other effects of contamination that keeps the Sound from meeting water quality standards. Addressing these environmental conditions will require integrated approaches to reducing polluted storm and ground water, contaminants of emerging concern, and creating resiliency of infrastructure. There will also be a need for land use planning that protects water resources, which includes adaptation to changing climate, and ensuring the sustainable use of the Sound’s resources. Additional emphasis is needed on assessing and improving the water and habitat quality of the Sound’s embayments, where much of the public goes for recreation and enjoyment.
Controlling nitrogen pollution remains the top priority. The Total Maximum Daily Load Analysis to Achieve Water Quality Standards for Dissolved Oxygen in Long Island Sound (CT DEEP, NYSDEC 2000) set allocations for nitrogen among five watershed states. The plan also identified steps to evaluate additional nitrogen reductions and alternative technologies while continuing monitoring and research programs to assess attainment of water quality standards. Connecticut and New York are now meeting the nitrogen reduction targets for wastewater treatment facilities, the largest source of nitrogen, thanks to recent investments in upgrades. Nitrogen reductions from atmospheric deposition and agricultural sources are also meeting TMDL allocations. Nitrogen from on-site wastewater treatment systems, residential turf fertilizer applications and stormwater runoff, however, have remained level or increased. To continue progress in attaining water quality standards it is necessary to manage adaptively, continuing to seek aggressive and practical nitrogen reductions from all sources while evaluating their effectiveness. This is all the more important due to the changes in the ecosystem brought about by climate change that may make Long Island Sound more susceptible to hypoxia. With new information on the success of reducing nitrogen and the response of Long Island Sound to these reductions, the TMDL target will need to be assessed and revised as appropriate.
The following ambitious, but achievable, ecosystem targets have been developed to drive progress toward attaining the Clean Waters and Healthy Watersheds (WW) goal.
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 Extent of Hypoxia Environmental Indicator
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 Nitrogen Loading Environmental Indicator
Improve water clarity by 2035 to support healthy eelgrass communities and attainment of the eelgrass extent target.
View Water Clarity Environmental Indicator
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 Impervious Cover Environmental Indicator
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 Riparian Buffer Extent Environmental Indicator
Upgrade 5% of the acreage currently restricted or closed for shellfishing by 2035 from a 2014 baseline.
View Approved Shellfish Areas Environmental Indicator
Reduce the area of impaired sediment in Long Island Sound by 20% by 2035 from 2006 baseline.
View Sediment Quality Improvement Environmental Indicator
Find examples below of actions being undertaken by LISS and its partners to achieve outcomes to help meet the ecosystem targets and achieve the Comprehensive Conservation and Management Plan goals for a healthier Long Island Sound.
For More Information
The full description of the actions, strategies, objective and outcomes for Long Island Sound Study can be found in the Comprehensive Conservation and Management Plan.
Making Long Island Sound’s water cleaner by removing excess nutrients such as nitrogen is going to require different solutions. The Nature Conservancy in Connecticut describes many of the choices in its LIS Water Quality website.
Hypoxia, low levels of oxygen, plague coastal waters, including Long Island Sound, every summer. These “dead zones” can force fish and invertebrates to scatter, and make others susceptible to disease. When concentrations are extremely low fish and shellfish unable to flee may die. The video, created by the NOAA Environmental Visualization Lab, describes how high levels of nutrients lead to hypoxia. The setting is the Gulf of Mexico, but much of what is discussed applies to the Sound. The video was produced with support from the Smithsonian Institution, Dalhousie University, and Texas A&M.