Complex sentence: Before and after the advent of the pioneers, this land was used by the Ute Indians as a camping ground, as water and grass could be obtained on either side of it and enemies could not approach without being seen long before coming to the high ground.
Split into simpler sentences: Before and after the advent of the pioneers, this land was used by the Ute Indians as a camping ground. This is because water and grass could be obtained on either side of it and enemies could not approach without being seen long before coming to the high ground.