HYDE PARK — Four South Side beaches are getting an extra round of testing for harmful bacteria this summer, but it’s not because they are dirtier.
The Chicago Park District is piloting a new water quality test at four South Side beaches — Calumet, Rainbow, South Shore and 63rd Street — and Montrose beach on the North Side.
The new test will search for traces of DNA from harmful bacteria, a method developed by the University of Illinois at Chicago that promises results within a few hours. In the past, test results would come back after 18 hours, meaning beaches could be closed based on bacteria levels that might no longer be present.
“With speed is greater accuracy,” said Cathy Breitenbach, director of natural resources for the Park District.
She said the Park District will continue to run its current tests, which take water sample cultures to see if harmful bacteria like E. coli are present and run models to predict when bacteria levels reach unsafe levels.
“We found at times we were a little behind, even though we were following all the guidelines, and it was frustrating,” Breitenbach said of the current water testing methods.
She said the South Side beaches were chosen not because they are particularly dirty, but because unique mixes of landscape, currents and weather patterns make it harder to predict when bacteria levels will spike.
Breitenbach said that two of the beaches, 63rd Street and Rainbow, have made significant progress and are closed less often than in the past.
She said using trained border collies to chase off seagulls, one of the main sources of bacteria, has been hugely successful at 63rd Street Beach.
A new filter designed by the Illinois Institute of Technology that keeps animal waste from flowing into the lake from the parking lot during rainstorms at Rainbow Beach also is expected to limit closures this year.
“There were a lot of geese hanging out in the parking lot,” Breitenbach said.
Volunteers at Rainbow Beach were excited to be a part of the pilot program.
“It makes sense. I think it’s smart,” said Marion Brown, president of the Rainbow Beach Park Advisory Council.
She said the beach has a reputation for being clean, and it’s helpful to be able to prove that’s the case.
Breitenbach said beachgoers can help keep bacteria levels in the water low by not feeding birds at the beach, putting children in swim diapers and picking up trash and other food that feeds birds.
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