Bacterial Contamination in Long Island Sound: Using Preemptive Beach Closure to Protect Public Health

Public health officials conduct water quality monitoring at marine beaches to reduce the risk of gastrointestinal illness. Climate change causes increased frequency of heavy rainfall events associated with pathogen-laden runoff, necessitating review of beach closure policies to ensure they are adequate to protect public health. Specifically, the lag of approximately 24-48 hr between collecting the water sample and reporting of assay results represents a period when the potentially contaminated beach remains open. Preemptive beach closure-the shutdown of beaches following a rainfall event of predetermined size-could serve as a solution. We surveyed 15 health departments of Connecticut towns along Long Island Sound and found that only 3 sampled after heavy rainfall events and only 6 practiced preemptive beach closure. We then used historical meteorological and water sampling data in logistic models to develop rainfall thresholds for preemptive closure for four Connecticut coastal towns and identified 2-day precipitation as the primary predictor of enterococci levels. Because preemptive beach closures can cause daily life and economic disruptions and are not widely popular, we engaged with stakeholders, town officials, and the public at each stage of the project. Through collaboration and transparency with communities, preemptive beach closure policies were implemented in two towns.