Douglas County waters have been a cool, clean haven from the heat this summer. The Douglas County Health Department has the tests to prove it.
The county monitors five inland beaches (Lyman Lake, Lake St. Croix, Lake Nebagamon and two sites on Lake Minnesuing) and 12 beaches along Lake Superior for E. coli bacteria.
"We can't test for every known virus or pathogen," said Pat Heiser, environmental health supervisor for the Douglas County Department Health and Human Services Department, so E. coli is used as an indicator. If it shows up in higher levels, that means higher quantities of other harmful bacteria could also be present.
Test results fall into three categories -- safe, advisory and closure. Safe levels indicate 235 colony forming units (CFU) of E. coli or less in a water sample. Advisory levels run from 235-1000 CFU. An amount greater than 1000 CFU triggers an automatic closure. When a beach is closed or put on advisory, the waters are retested until levels of E. coli drop.
Beach monitoring along Lake Superior has led to 26 advisories and only three closings to date, Heiser said. Earlier closings occurred at one of three Brule River beach sites and at the Amnicon River beach.
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Today, one of the four Wisconsin Point beaches monitored was listed as closed. A red sign will be posted in the area until a water test comes back with safe E. coli levels.
Inland lakes have had a good track record this year. There was one beach closing at the county park on Lake Minnesuing June 7 and one advisory at Lake Nebagamon last week. Heiser said a Thursday sample of Lake Nebagamon water showed elevated numbers of E. coli bacteria. A second test Friday showed levels had lowered and the sign was changed to green Saturday. Heiser attributed the higher levels of bacteria in the water to rain that fell Thursday.
Rain is often the trigger that raises levels of E. coli.
"After heavy rainfalls, a lot of places routinely close beaches," Heiser said, because of surface contaminants that are washed into lake waters. "When we get that rain, it makes an impact."
An abundance of rain last summer led to 20 beach closures and 51 advisories along Lake Superior, according to data collected by the county.
Heiser said it's a good idea to avoid beaches for at least a day following a heavy rainfall. In addition, would-be-swimmers should look for signs at the beach to make sure E. coli levels in the water are low. Green signs indicate open, yellow signs mean the beach is under advisory and closed beaches will have a red sign. Another resource is the Beach Health Web site: http://www.wibeaches.us/traverse/f?p=BEACH:HOME:1609103704657215225 . It lists the conditions at all 12 Lake Superior beaches, which are monitored through the Wisconsin Beach Health program funded by the Environmental Protection Agency. None of the five inland beaches are listed on the site.
