The music festival took place during the weekend and featured performances by Foo Fighters, Eminem, Coldplay, Lady Gaga, My Morning Jacket, Big Audio Dynamite, The Kills and Cee-Lo Green.
"This is probably one of the worst [aftermaths]," Bob O'Neill, president of the Grant Park Conservancy, told the Chicago Sun-Times. "The turf damage is substantial, bushes were trampled ... there's a little bit of damage to some gardens."
A Chicago Park District spokeswoman told the newspaper the event's promoter, C3 Presents LLC, based in Texas, will foot the bill for the cleanup of garbage and repair of damage to the fields.
Estimates on restoration costs aren't expected until later in the week, but last year's restoration cost more than $200,000. O'Neill said repairing Hutchinson Field alone could cost as much as $80,000 this year, the Sun-Times reported.