Simplify the following text for a Grade 8 native English-speaking person.
Original: The European discoverer of the Lachlan River in 1815 was Acting-Surveyor George William Evans , who named the river after Lachlan Macquarie , the Governor of the colony of New South Wales .
Simplified: The European who found the Lachlan River in 1815 was Acting-Surveyor George William Evans . He named the river after Lachlan Macquarie , the Governor of New South Wales .