Simplify the following text for a Grade 8 native English-speaking person.
Original: On the other side of the watershed , the rivers Tyne , Tees , Wear , Swale , Ure , Nidd , Calder , Wharfe , Aire , Don and Trent also rise in the region but flow eastwards to the North Sea .
Simplified: On the other side of the watershed , the rivers Tyne , Tees , Swale , Calder , Aire , Don , and Trent flow east to the North Sea .