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. Livestock are the most common source of feces in surface waters in Iowa.
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 often 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.
Thirteen beach advisories were issued for Iowa beaches for the week of July 4.
Ten beaches with an E. coli advisory:
- Backbone Beach (Dundee, Delaware County)*
- Beed’s Lake Beach (Hampton, Franklin County)*
- Denison Beach (Black Hawk Lake, Lake View, Sac County)*
- Lake Darling Beach (Brighton, Washington County*
- Lake Manawa Beach (Council Bluffs, Pottawattamie County)*
- Lewis and Clark Beach (Blue Lake, Onawa, Monona County)*
- Lower Pine Lake Beach (Eldora, Hardin County)*
- Nine Eagles Beach (Davis City, Decatur County)*
- North Twin Lake West Beach (Rockwell City, Calhoun County)*
- Prairie Rose Beach (Harlan, Shelby County)*
Three beach with a microsystin advisory:
- Green Valley Beach (Creston, Union County)*
- Lake Darling Beach (Brighton, Washington County)*
- McIntosh Woods Beach (Clear Lake, Ventura, Cerro Gordo County)*
In addition to the state beaches, three city or county beach exceeds the state’s advisory threshold for E. coli.*
Para ver este aviso en español, haga clic aquí.
*Data from the Iowa DNR State Park Beach Monitoring Program
**Data from the U.S. Army Corps of Engineers, Rock Island District