The Lincoln Memorial Reflecting Pool will be drained after 80 ducks were found dead in the span of two days due to a water-borne parasite.

The pool is slated to be drained starting Sunday to eradicate the parasite that sickened the ducks from May 20 to May 21, a press release from the National Parks Service said.

“Necropsy performed on the ducks by the U.S. Geological Survey’s National Wildlife Health Center suggests the cause of death was high levels of parasites that develop and grow in snails that live in the pool,” the National Parks Service said. “Chemical treatments alone are not sufficient to fully reduce the parasite and snail population, so the pool must be drained and cleaned.”

The parasite is not dangerous to humans, the service said. If people do come in contact with it, a rash called “swimmer’s itch” could form, but it does not normally require medical care.

The pool will take about two days to drain, and then it will be cleaned on Tuesday, June 13. The whole process should be finished by Friday, June 16. The service said it will check the pool’s water to avoid another incident.