Heavy rains over the Memorial Day weekend forced the temporary closure of dozens of Suffolk County beaches as stormwater runoff washed bacteria and contaminants into local waterways, prompting health officials to warn swimmers to stay out of the water until conditions improved.
County officials said the affected beaches were expected to recover following several cycles of high tides, which help flush contaminated water from bays, harbors and canals. Additional testing was being conducted throughout the week as conditions improved.
The Suffolk County Department of Health Services conducts one of the region’s most extensive beach monitoring programs each summer, overseeing water quality testing at more than 190 public bathing beaches from May through September. The primary goal of the program is to protect swimmers from potentially harmful bacteria and pathogens that can enter recreational waters after rain events.
According to the county, stormwater runoff remains the leading cause of elevated bacteria levels at many marine beaches. As rainwater flows across roads, parking lots, lawns and developed areas, it picks up contaminants that eventually drain into local creeks, bays and shorelines. Areas with limited tidal flushing, particularly along portions of the North Shore and South Shore mainland canals and embayments, are especially vulnerable following periods of heavy rainfall.
County health officials test marine beaches for Enterococci bacteria and freshwater beaches for E. coli, both considered “indicator organisms” that signal possible fecal contamination. While the organisms themselves are generally harmless, elevated levels can indicate the presence of disease-causing bacteria, viruses or parasites.
Sampling frequency varies depending on the risk level of each beach. Beaches with a history of poor water quality or proximity to storm drains, creeks or other pollution sources are tested more frequently, often once or twice per week. Additional testing is conducted after heavy rain, sewage spills or other environmental incidents.
Health officials determine whether beaches should be closed or reopened based on federal and state water quality standards, historical data, weather conditions and tidal flushing characteristics.
Exposure to contaminated water can lead to nausea, diarrhea, fever, skin irritation and respiratory illnesses, particularly among children, the elderly and individuals with weakened immune systems. Suffolk County residents can monitor beach advisories and closures through the county’s interactive beach map at www.suffolkcountyny.gov or the hotline: 631-852-5822.