Complex sentence: Ryvarden (2007): 51 Because of the flat terrain, which is only broken by a few hills, it is easy to get lost in the park; lakes and creeks are the easiest way of orientation.
Split into simpler sentences: Ryvarden (2007): 51 Because of the flat terrain, which is only broken by a few hills, it is easy to get lost in the park. The lakes and creeks are the easiest way of orientation.