Reasons for Swim Advisories or Beach Closures
In order to alert the public about potentially unhealthy water quality conditions at Great Lakes beaches, local health departments sometimes post swim advisories. Depending on the severity of conditions, or if there are other safety concerns such as high waves, beaches may be closed. In Wisconsin, cities and counties that receive federal funding for beach monitoring and notification under the BEACH Act are required to report their advisories and closures through the Wisconsin Beach Health Website. On this website you can find all current beach advisories and water quality data. You can also sign-up for advisory email alerts or RSS feeds.
Beginning in 2012, notifications made through the Wisconsin Beach Health Website, email alerts, and RSS feeds will include the principal reason reported for any swim advisory or closure. These include:
A discharge or spill of chemicals or oil has occurred, which could cause unhealthy water quality conditions. The closure is preemptive since lab results will not be immediately available.
Lab results indicate elevated levels of E. coli bacteria in nearshore water. Levels higher than recreational water quality standards or guidelines require either a swim advisory or a beach closure, depending on the levels found. Bacteria levels can fluctuate over several hours and since conventional lab analyses take 18-24 hours, results may not be reflective of present bacteria levels. At some locations, however, rapid lab tests are routinely conducted, with only a 2-4 hour lag.
The results of a predictive model, based on historical observations, indicate a high probability that E. coli levels exceed recreational water quality standards or guidelines. Nowcast predictions are based on a combination of factors correlated to water quality, such as rainfall, wave height, water clarity, nearby river discharge, and lake currents. The advisory or closure is preemptive, since lab results will not be immediately available.
The reason for the posted advisory or closure is not otherwise covered by the above categories. For example, high waves or excessive algae might be the reason for a closure or advisory. In such cases, a narrative explanation is submitted, but is not included in daily notification alerts. These are available after the close of the beach season on EPA’s Beach Advisory and Closing On-line Notification (BEACON) system.
To remove an Advisory or Closure notification, laboratory or modeling results must indicate that bacteria levels are below the water quality standard. The notification may remain posted indicating a “Policy” reason when sample or modeling results are unavailable for the subsequent day.
An ongoing or recent rainfall event (for example, within the past 24 hours) may increase the likelihood of unhealthy water quality conditions due to urban stormwater runoff, agricultural runoff, and/or sewage discharges. The advisory or closure is preemptive since lab res