A public beach in the town of Linn has been closed, after water sample tests in Geneva Lake showed bacteria levels double what is normally enough to trigger beach closings.
Elevated levels of E. coli bacteria were reported June 24 at beaches in Lake Geneva, Fontana and the town of Linn.
A follow-up test June 25 at Lake Geneva’s Riviera Beach showed a quick drop in bacteria levels — back down below the level associated with beach closings.
The Geneva Lake Environmental Agency collects water sample results at beaches all around Geneva Lake, and alerts local municipalities when bacteria levels are elevated.
Ted Peters, director of the agency, said he recommended that Linn town officials close Hillside Beach because of bacteria reaching the beach from a nearby road construction site.
Peters said he was not recommending any other beach closings around the lake.
The road construction site near Hillside Beach has disturbed two underground streams, and it has resulted in silt and other debris washing out into the beach area, Peters said. If follow-up tests show lower levels of bacteria in the water, he said, he would recommend reopening Hillside Beach in time for the Fourth of July holiday.
E. coli is generally associated with human or animal waste and is a health hazard when people encounter it while swimming in lakes or ponds.
With levels of 1,000 or higher set as the standard for closing a beach, levels were reported June 24 of 1,986 in Lake Geneva, 2,420 in Fontana and 2,419 in the town of Linn.
At a second spot at Lake Geneva’s Riviera Beach, a level of 980 was reported.
The next day, dramatically lower levels of bacteria were reported at the same Lake Geneva sites — down to readings of 67 and 488 respectively.
Lake Geneva City Administrator David Nord said city officials were alerted to the “bad test,” and they were relieved to learn that follow-up tests showed better results.
“Everybody’s calm about it,” Nord said.
Nord said bacteria levels can fluctuate based on such factors as rainy weather, windy conditions and maintenance work on the beach.
“Any of those options could have generated those types of results,” he said.
The Williams Bay-based environmental agency tests water sample every week during summer. No elevated bacteria readings were reported this week in Williams Bay.
Peters said sudden spikes in bacteria levels caused by heavy rain are usually short-lived, because the rain washing pollutants into the lake also causes the E. coli to dissipate quickly in the lake water.
Fontana Village Administrator Theresa Loomer said the village was not considering any beach closings, because the Geneva Lake Environmental Agency attributed the bacteria episode to heavy rain.
Loomer said the village will post a warning sign, however, to let beach goers know about the situation.
Regardless of whether it was caused by rain or other factors, high levels of E. coli at a public beach is a health threat, Loomer said.
“I would be concerned,” she added, “if it was there for a long time.”