Simplify the following text for a Grade 8 native English-speaking person.
Original: Rainfall varies across the catchment of the Macquarie River , genrally the peaks and tablelands receive higher rainfall due to the shadowing effects of the surrounding ranges .
Simplified: Rainfall varies across the area drained by the Macquarie River . The mountain the peaks and tablelands receive higher rainfall due to the shadowing effects of the surrounding ranges .