What is Virtual Beach?


North Beach (Upper Lake Park), Port Washington, WI
Credit: Dan Ziegler


Beaches provide coastal communities with substantial economic, social and health benefits. Along the U.S. Great Lakes coast, an estimated 8 million people visit beaches each year. Unfortunately, some information commonly used to evaluate water quality, communicate health risks and prioritize remediation efforts are 24 hours old, meaning swimmers can be swimming when conditions are not safe. Conversely, swimmers may be kept out of the water when no current problems exist.

Virtual Beach addresses these short-comings by providing beach managers with a more timely and cost-effective alternative to traditional monitoring. With funding from the EPA BEACH Grant, coastal beaches are periodically monitored for fecal-indicator bacteria; enterococci in marine waters, E. coli in the Great Lakes. The standard approach is to collect water samples, transport them to a lab, and incubate them for 18+ hours, in order to estimate bacteria levels.

The results of overnight lab tests are often not reflective of water quality at the time when advisory decisions are made. An analysis by Mednick and Watermolen, (2014), showed that across the Great Lakes, between 2008 and 2010, nearly one in five decisions to post (or remove) swim advisories or closures were made in error, including nearly



Water Sample collection at Zoo Beach, Racine, WI
Credit: Adam Mednick


3,000 unnecessary advisories/closures and at least 4,500 missed advisories or closures. Moreover, the traditional approach to monitoring can place a financial and human-resource strain on local health departments (Rockwell et al. 2014).

The free Virtual Beach desktop software walks users through the process of developing, evaluating, and operating statistical models to predict (‘nowcast’) water quality in near real-time, based on field-observed and/or remotely-measured environmental conditions. The software was developed by the U.S. EPA’s Ecosystem Research Division, in partnership with the USGS Wisconsin Water Science Center, the Wisconsin Dept. of Natural Resources, and Wisconsin Sea Grant.

Virtual Beach combines advanced statistical methods with a direct connection to the wealth of hydro-meteorological data available via the EnDDaT web portal.


Virtual Beach 3.0
Credit: U.S. EPA Ecosystem Research Division


These tools enable users to develop nowcast models that can estimate water-quality conditions at any time – on both sampled and non-sampled days – at virtually any monitored beach on the Great Lakes Coast.

Recognizing the advantages of nowcast modeling, EPA’s most recent Recreational Water Quality Criteria and National Beach Guidance encourage state and local beach programs to adopt this approach – both to improve advisory decisions and to augment lab-based monitoring. Between 2010 and 2014, the use of nowcast models around the Great Lakes increased from fewer than 10 beaches in 2010 to over 60 beaches in 2014.

Wisconsin Sea Grant and its partners are lowering the barriers to adopting Virtual Beach, through a combination of technical enhancements and cooperative extension directed at local public health professionals, beach managers, and applied researchers throughout the Great Lakes. Future projects will encourage the adoption of VB along the Canadian Great Lakes coast, as well as the U.S. marine coast.