From about Memorial Day through Labor Day, the Iowa Department of Natural Resources (DNR) conducts weekly monitoring of bacterial pollution in Iowa’s 39 state park beaches.
The DNR analyzes water samples from the beaches for certain one-celled microorganisms, known as indicator bacteria, that are visible only under a microscope. High levels of E. coli, a common indicator bacteria, indicate feces is in the water, most commonly in Iowa from livestock sources.
These indicator bacteria are commonly used by state environmental agencies and by the U.S. Environmental Protection Agency to determine the suitability of beaches for swimming-type uses.
Microcystin, a toxin produced by harmful blue-green algae blooms, has also been detected in Iowa’s water bodies.
Due to health risks, when microcystin or E. coli levels exceed certain standards/thresholds, the DNR posts swim advisories telling beach-goers to stay out of the water.
The Iowa DNR and the Iowa Environmental Council track these weekly beach monitoring reports and swim advisories and compare advisory trends from year to year. To review recent trend data, visit the Iowa DNR website.
Twelve beach advisories were issued for Iowa beaches for the week of July 15-22, including 10 for E. coli-related contamination and two for Microcystin-related contamination, and one closure was issued for the risk of Naegleria fowleri, a brain-eating amoeba.
10 Beaches with an E. coli-related Advisory:
Backbone Beach (Dundee, Delaware County, IA)*
Beed’s Lake Beach (Hampton, Franklin County, IA)*
Big Creek Beach (Polk City, Polk County, IA)*
Black Hawk Beach (Lake View, Sac County, IA)*
Emerson Bay Beach (Milford, Dickinson County, IA)*
George Wyth Beach (Waterloo, Black Hawk County, IA)*
Lake Darling Beach (Brighton, Washington County, IA)*
Lower Pine Lake Beach (Eldora, Hardin County, IA)*
Prairie Rose Beach (Harlan, Shelby County, IA)*
West Overlook Beach (Coralville Lake, Coralville, Johnson County, IA)**
2 Beaches with a Microcystin-related Advisory:
Geode Beach (Danville, Des Moines County, IA)*
Green Valley Beach (Creston, Union County, IA)*
1 Beach Closure:
Lake of Three Fires is temporarily closed for swimming.
A Missouri resident that recently swam in Lake of Three Fires has a confirmed infection from Naegleria fowleri, commonly known as the brain-eating amoeba. The U.S. Centers for Disease Control and Prevention and the Iowa Department of Health and Human Services are testing the lake to confirm the amoeba’s presence. The process will take several days, and the beach will remain closed during that time.
*Data from the Iowa DNR State Park Beach Monitoring Program
**Data from the U.S. Army Corps of Engineers, Rock Island District
