The Michigan Department of Natural Resources announced the temporary closure of swimming areas on Belle Isle Park after detecting high levels of bacteria in the Detroit River.
Samples taken on July 10 found elevated amounts of E. coli, which can be harmful if ingested or exposed through skin contact.
Tests found an average of 920 of E. coli per 100 milliliters. That’s more than triple the allowed level. Belle Isle’s beaches are generally safe to swim in, except after heavy rains.
Orange barrels were placed at the water’s edge, along with signs notifying visitors of the closure. The beach parking lot was also closed, and staff were instructed to notify visitors as they enter the park and anyone who gets in the water that swimming is not allowed.
Tom Bissett, the DNR’s urban district supervisor, said a cause hasn’t been determined, but E. coli outbreaks are often connected to rain events that flush bacteria into the stormwater system and the river.
“I can’t tell you exactly what the source was, but it seems like whenever we have a very large rain event , that is associated with water quality,” Bissett said.
The beach will remain closed until the average sample returns to 300 per 100 milliliters. Bissett said the state is working with the Detroit Health Department.
A new round of samples were taken on Monday. It typically takes two days to receive results, Bissett said.
“We just basically keep sampling until the average is is at the acceptable level,” he said.
The most common side effect of swimming in water with E. coli is acute gastrointestinal illness like diarrhea and vomiting, according to the Centers for Disease Control and Prevention.
An emergency alert was issued Monday morning. Sign up here to receive alerts from the text update system.
Belle Isle’s beach was closed in 2023, twice in 2021 and twice in 2017 due to high bacteria levels.
Surprised no one has mentioned that Detroit Water and Sewerage Department releases raw sewage into the Rouge water when rain events overwhelm the plant capacity. I’m not a hydraulic engineer, so I can’t say if the waste from Detroit toilets is polluting Belle Isle, but no doubt this same practice happens upstream from Belle Isle as well.