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Research & Monitoring


The Long Island Sound Study has launched a new version of the Environmental Indicators section. The data below may be out of date. Please visit and bookmark the new section here to see the most recent data.

Status and Trends: LISS Environmental Indicators

Beach Closures and Advisories

EPA Beacon 2 website, CT Dept. of Public Health and NYS Dept of Health

 Beach Closure and Advisory Days
  CT NY (LI & West.)
1993  60 104  
1994  42 108  
1995  72 230  
1996 188 249  
1997  37 336  
1998 191  94  
1999 113  22  
2000 148  69  
2001  79 136  
2002  57 277  
2003 207 380  
2004 183 352 336
2005 200 301 163
2006 224 676 299
2007 108 606 280
2008 135 685 288
2009 108 772 367
2010 143 350 194
2011 636 878 326
2012 298 954 413
2013 151 732 266
2014 117 347   99
2015 150 909 307
NYC beaches are included as of 2004, and are listed in a separate column


Beach closure and advisory days are a combination of the number of days beaches are closed in a year and the number of days advisories are posted warning beachgoes that condtions might be unsafe for swimming or even for walking..  Beaches are closed to protect swimmers from potential harm or illness caused by pathogens or other contamination. Health departments sample coastal bathing waters to determine whether the water exceeds an acceptable level of 104 CFU (Colony Forming Units)/100mL  for the indicator bacteria, EnterococcusThis bacteria may indicate the presence of pathogens that can lead to gastrointestinal illnesses (GI) among swimmers. Pathogens are disease-causing organisms, including bacteria and viruses. More often, beach managers in Connecticut and New York close beaches preemptively when high rainfall generates stormwater runoff that may contain animal waste, untreated sewage discharge or other contaminants. As of 2012, there were 132 monitored beaches along Long Island Sound’s shoreline in New York and 72 monitored beaches in Connecticut. Yearly variations in closures are a product of rainfall patterns and incidents such as sewer-line ruptures.


Elevated concentrations of this indicator may reflect ongoing problems with pathogen contamination in Long Island Sound and may lead to closed beaches. Closed beaches can have an economic impact because they prevent people from being able to fully enjoy the Long Island Sound shoreline.


Dry summer seasons in 2014 and 2015 resulted in a decrease in the number of beach closures in Long Island Sound. High incidents of closures in Connecticut in 2010 and 2011 were attributed to heavy rainfall and the impact of Tropical Storm Irene (in 2011).  Those years also were  exceptionally high years when one or more sampling stations at a beach reported a single sample Enterococcus result >104 CFU/100mL and at the same time the beach was not under a closure or advisory (source: Connecticut’s 2011 Annual Report for the US EPA Beach Grant) .The high incidents of closures in New York in 2009 were attributed to heavy rainfall. Some health departments also indicate that beach closures have increased since the mid-2000s adoption of a new test for bacterial pathogens for marine waters (the Enterococcus standard). New York City beaches were added to this indicator in 2006.


New York data (NY)  includes Long Island Sound beaches in Nassau, Suffolk, and Westchester. New York City (NYC) beaches in Long Island Sound were added to this indicator in 2004. The indicator uses the EPA Beacon dataset from 2004. Prior to 2004, the information was compiled by LISS staff from county and state health departments.

Regarding the EPA approved marine recreational water quality indicator bacteria Enterococcus, it is important to note that this indicator was shown by EPA through epidemiological study to often associate in a predictable way with swimmer illness most likely caused by pathogens in human fecal contamination. Enterococcus is not considered by EPA to be a pathogen that causes swimmer illness, but may be present when illnesses occur. An indicator bacteria was chosen because directly assaying the concentration(s) of pathogens that may cause swimmer illness has been shown to be very difficult in a timely way. As it is, the analytic methods used to assay the concentration of Enterococcus in marine recreational water require a minimum 24 hours for culturing the bacteria. A water sample collected today will have analytic results reported on the following day (source: e-mail communication with Jon Dinneen, Connecticut Department of Public Health).

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