Climate change-related effects on lake and coastal ecosystems—such as warming waters and intense precipitation—can result in unsafe conditions for recreation. Moreover, because standard E. coli tests can take more than 18 hours, local advisory decisions are frequently incorrect. Virtual Beach, a software package developed by the U.S. Environmental Protection Agency, allows users to generate statistical models to predict levels of disease-causing pathogens such as E. coli and enterococci at specific freshwater/saltwater beach sites. Beach managers can use the tool to help decide when a beach closing is necessary to protect health. Researchers, scientists, engineers, and students interested in studying relationships between water quality indicators and ambient environmental conditions will also find Virtual Beach useful.

Statistical models created by Virtual Beach can be used to "nowcast" water quality based on other environmental conditions. Such "nowcast" models can be used to estimate water quality conditions at any time. Virtual Beach's model optimization and machine-learning capabilities are coupled with the ability to download beach-specific, near real-time data directly into the model.

This decision-support software system walks users through the process of developing, evaluating, and operating "nowcast" models, based on field observations and/or hydrometerological data available from various online data sources. Researchers, students, engineers, and others can also use it to study relationships between water quality indicators and ambient environmental conditions.