Research in Action
Modeling tool helps beach managers protect swimmer's health
EPA scientists have developed Virtual Beach, a software suite that uses data on beach location, local hydrology, land use, wave height, and weather to create models that can predict bacteria and other waterborne pathogen outbreaks at saltwater and freshwater beaches before they happen. Using Virtual Beach, beach managers can issue same-day beach closures or health advisories to protect the health of swimmers and the surrounding community.
When recreational waters are contaminated by bacteria and other waterborne microorganisms, beach managers need to act quickly to protect public health. Additionally, since Americans spend billions of dollars annually in beach communities, beaches that are unnecessarily closed can be costly to local economies. Since the Virtual Beach modeling tool helps beach managers quickly identify when water is unsafe to swim, managers don't need to close beaches as a precaution while waiting for test results, as was done in the past. Virtual Beach’s same day results also allow beach managers to reopen beaches faster when water is once again determined to be safe for swimming.
Background on waterbourne pathogens
Waterborne pathogens at beaches can come from a variety of sources, including urban runoff, waste water treatment plant outfalls, and upstream sources. Local beach conditions — including high numbers of swimmers, dogs or birds — can also affect water quality.
Pathogens can be difficult to detect and measure accurately. Consequently, "indicator" organisms are used by scientists and public health professionals to estimate the likely presence of pathogens. Fecal coliform bacteria and enterococcus bacteria are the indicators most often used because they are found in the digestive systems and feces of both animals and humans.
Version 3.0 of Virtual Beach allows beach managers to use collected water data and meteorological data to develop a statistical relationship between local conditions and concentrations of indicator organisms at beaches. Managers can then make informed decisions on when to close or open a beach to the public. The Virtual Beach modeling tool provides an easy interface for developing statistical models and provides graphs, charts, and tables that guide users toward the best possible predictive model their data can support. Virtual Beach 3.0 has also been enhanced with additional statistical methods to give users more flexibility in modeling their datasets.
The tool has been extensively tested and used at both freshwater and saltwater beaches, including beaches in the Great Lakes region, the Gulf Coast, the Southeastern U.S., and Puerto Rico. The model's predictions have allowed beach managers to act quickly to close beaches when pollutants and pathogens threaten their waters.
EPA Technical Contact