Simplify the following text for a Grade 9 native English-speaking person.
Original: The island was expanded by approximately 82 a of landfill on its southern side when the Lexington Avenue subway was excavated in the early 1900s .
Simplified: The island was made bigger by about 82 acres ( 33 ha ) of landfill on its southern side when the Lexington Avenue subway was excavated in the early 1900s .