Des Moines, IA – Despite heavy rainfall in central and northeast Iowa causing some wastewater releases, a few sunny days will likely drop bacteria levels in lakes by the Fourth of July.
“In lakes, bacteria levels from water samples taken earlier this week are elevated a bit in places,” said Mary Skopec of the DNR’s beach monitoring program. “In lakes, if we’ve had some sunny days, the risk of getting ill is much lower. Bacteria attaches to sediment, so in lakes, sunlight penetrates the water and kills the bacteria after the sediment settles out.”
The DNR checks bacteria and algal toxins (mycrocystin) levels at all state park beaches, and at participating city and county beaches at least once per week between Memorial Day and Labor Day. “We are sampling twice at some locations this week because of heavy rainfall and elevated bacteria levels,” Skopec said.
To find test results by lake, search for beach monitoring at www.iowadnr.gov or call the Beach Hotline at 319-353-2613.
As always the DNR recommends not ingesting the water, rinsing off after swimming and washing hands before eating. Fish are safe to eat, but it’s a good idea to rinse them before cleaning. Generally, people and pets should avoid contact with flood waters for at least 24 to 48 hours after flooding ends because bacteria levels could be elevated.
Wastewater discharges have been reported throughout central and eastern Iowa after heavy rains on Monday. When soils are saturated, additional rainfall can overwhelm collection and treatment systems, causing discharges. Cities may also intentionally discharge wastewater after intense rainfall to prevent basements from backing up or to protect the treatment plants.