MINNEAPOLIS — Contaminated water led to a record number of beach closures in Minneapolis this summer, the city’s park and recreation board said.

Half of the city’s 12 beaches were not safe to swim in at various times during the summer — the most since Minneapolis started a water sampling program in 2003, said Deb Pilger, the director of environmental management for the Minneapolis Park and Recreation Board.

Heavy rainfall was part of the problem, Minnesota Public Radio reported.

“When we have a rain event, it brings in a lot of storm water runoff and that runoff brings in a lot of debris and bacteria from streets, yards, yard waste,” Pilger said.

But officials said goose droppings also contaminated the water at some beaches, as well as people with an illness that got in the water.