116 3rd St SE
Cedar Rapids, Iowa 52401
A hot, dry summer — particularly in northern Iowa — has created favorable conditions for more harmful algae blooms in Iowa lakes.
The Iowa Department of Natural Resources reported 24 swim advisories at state park beaches this summer because of microcystins, toxins generated by harmful algae. These toxins, if ingested, can cause gastroenteritis, allergic responses and potentially-fatal liver damage.
This is double the 12 microcystin advisories in 2020.
“It goes back to the drought,” said Mary Skopec, director of the Iowa Lakeside Laboratory on West Lake Okoboji. “When it’s stagnant and still and hot and dry, that is perfect growing conditions.”
Most of the northern half of Iowa is in moderate to severe drought, according to the most recent U.S. Drought Monitor map released Thursday. In June, 90 percent of the state was at or near drought conditions. Climate change also has increased the likelihood of severe storms, which can bring heavy rains that wash manure and fertilizer off farm fields and into streams and lakes.
Overall, the Iowa DNR reported 106 swim advisories at 39 state park beaches after conducting weekly tests from Memorial Day weekend through Labor Day. This is down from 118 advisories in the summer of 2020. The bulk — 88 — of this year’s warnings were for E. coli, bacteria that indicates the presence of feces in the water. A handful of beaches had weeks with advisories for both E. coli and microcystin.
Three Eastern Iowa beaches had the highest number of advisories of all of Iowa’s state park beaches.
Lake Darling State Park, near Brighton, had 12 of 15 weeks this summer when water at the beach did not meet state standards for recreation. For all of July and the first week of August, the beach had advisories for both E. coli and microcystin.
Backbone State Park Beach, near Dundee, had 11 advisories for E. coli, starting in early July and lasting for the rest of the summer.
Lower Pine Lake Beach, near Eldora, had nine weeks with swim warnings, including four weeks when levels of both E. coli and microcystins were too high.
Twenty-two Iowa state park beaches had at least one week with a swim warning this summer; 16 had no advisories. The Iowa DNR did not do water testing at Lake Ahquabi, near Indianola, because of renovations there.
The Iowa Environmental Council, based in Des Moines, would like to see more genetic testing for E. coli contamination to understand whether the bacteria are coming from geese, humans or livestock, said Ingrid Gronstal, water program director for the group.
The council is working with the Iowa DNR to improve warning signs, including by having signs also in Spanish, posting cautionary signs when there is a visible algae bloom, but before weekly sample results are back, and posting signs at boat ramps.
Skopec, who supervised Iowa DNR water monitoring for years, thinks this is a good idea.
“I knew back when I was working at the DNR that we needed to improve our signs,” she said. “They were kind of wordy and don’t necessarily grab people’s attention.”
Skopec would like to see the Iowa DNR recognize water recreation doesn’t stop at Labor Day and maybe post signs advising people to watch for algae blooms and don’t let pets drink lake water.
The Environmental Council has regularly reported on swim advisories this summer to make Iowans more aware of how polluted water affects their recreational options.
“As the pandemic has shown, opportunities for the public to get outside and experience nature are vitally important to quality of life, and we must protect these resources so that they are safe for people and pets to enjoy,” Gronstal said.
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