This story has been updated.
Algae blooms foul the taste of Bloomington’s drinking water most summers, but some prevention can lessen the effects of the blooms.
Indiana State Parks’ Deputy Director of Stewardship Ginger Murphy said blue-green algae thrives in Lake Monroe when nutrient-rich fertilizer and waste wash into the lake. She said algae blooms can produce toxins that endanger people and animals. She said Lake Monroe is safe for visitors provided they shower after swimming, but dogs should stay out of Indiana lakes.
“It's going to want to lick the algae off its coat and potentially take in some of those toxins,” Murphy said. “And of course, dogs drink water when they're in the lake because they get hot.”
Watershed coordinator for Friends of Lake Monroe Maggie Sullivan said nutrients like phosphorous accumulate over time, leading to worse blooms each year.
“Everything that washes into the lake, particularly sediment, settles down and stays in the lake,” Sullivan said.
Sullivan said people in the watershed should limit fertilizer use and pump septic tanks every few years to keep the lake healthy. Sullivan said Friends of Lake Monroe offers vouchers for Monroe County residents in the watershed to partially cover costs of pumping septic tanks.
Lake Monroe Water Fund also offers septic pumping reimbursements for residents of the Brown County watershed portion. The Water Fund also offers free soil tests for anyone in Brown, Jackson and Monroe counties to determine how much fertilizer is necessary.
Sullivan also said people should think about minimizing nutrient runoff regardless of location.
“Your runoff is going somewhere, it's going downstream, and there's someone downstream from you that will be impacted,” she said.
Another way to reduce nutrient runoff is by planting vegetation between crops and streams. Sullivan said this vegetation filters off nutrients before they enter the lake.
Sullivan said climate change intensifies algae blooms, since hotter and drier summers mean warmer and more still water, which blue-green algae loves.
Lake Monroe’s 60 th anniversary is in October. Sullivan said it needs to be protected to last into the future.
Read more: More blue-green algae could drive up drinking water bills in Indiana's larger cities