Simplify the following text for a Grade 11 native English-speaking person.
Original: It is part of the Murray-Darling river system , one of the largest in the world , drains all of New South Wales west of the Great Dividing Range , much of northern Victoria , southern Queensland and parts of South Australia .
Simplified: The whole Murray-Darling river system , one of the largest in the world , drains all of New South Wales west of the Great Dividing Range , much of northern Victoria and southern Queensland and parts of South Australia .