Water quality at Michigan’s beaches has gotten worse since last summer.
According to data from the Michigan Department of Environment, Great Lakes, and Energy's Beach Guard database, about 40% more beach water samples statewide had high levels of E. Coli this year. There were 505 high-E. Coli results by this date last year, and so far this year, there have been 726.
That’s counting the number of samples that show over 300 estimated E. Coli bacteria per 100ml of water, which is the threshold that prompts public water advisories. The dataset comes from local health departments across Michigan, which test beach water and submit reports to Beach Guard.
In northern Michigan, officials are reporting similar findings. The Watershed Center of Grand Traverse Bay, for example, has released 18 advisories this year – they say they normally send out 10 or 11.
Shannon Briggs, a toxicologist at EGLE, confirmed that there have been more advisories out this year. Briggs said she and her colleagues have noticed larger spikes around big rainstorms, which follows the regular trend of stormwater runoff as a driving factor of beach water contamination.
According to Briggs, communities should assess how they manage stormwater, especially during high rainfall events when drains are overwhelmed and can overflow into nearby bodies of water. Some big questions are, she said, “how do we mitigate storm water better? How do we manage stormwater better so that it doesn't impact our beaches so much?”
Sarah U’Ren, Program Director at the Watershed Center of Grand Traverse Bay, said she has also noticed worsening impacts from heavy rainfall. “Most of our advisories were during two major rain events,” she explained. Those rain events, she said, “just so happened a day before sampling.”
U’Ren said it’s far more concerning when the same beach shows up with advisories consistently over time, with or without rain. Spikes after big storms that affect lots of beaches — like those in northern Michigan this summer — usually clear up quickly after a sunny day.
But both Briggs and U’Ren say this data points to the need for stronger stormwater management. U’Ren mentioned two successful methods they’ve installed in the past: underground infiltration trenches that filter water through soil, and microbial filters on storm drains. But for the past few summers, U'Ren hasn't had the funding to expand those projects.
Though they can tie current spikes in beach advisories to heavy rain, they also say it’s important to be able to determine what exactly is contaminating stormwater — and lake water in general. More health departments are performing source tracking tests that use qPCR technology to determine where exactly E. coli contamination is coming from, like pigs, cows, waterfowl, or human sources.
One lab at Michigan State University, run by water microbiologist Joan Rose, has received much attention for its research on microbial source tracking. Rose said in a recent news release that through that source tracking, her lab has determined that contamination from Michigan’s septic tanks has gotten worse in the past decade.
U’Ren said that when the summer ends, she and her colleagues at the Watershed Center will send in the season’s samples for source tracking. That will give them more clarity on the source of E. Coli at the beaches they monitor. Those results are expected in October.
