Complex sentence: There are plans underway to build a sports and recreation centre there because the high altitude is good for professional sports and training (about 3000 feet above sea level on the great dididing) they are going to put a 50 meter pool in-doors.
Split into simpler sentences: There are plans underway to build a sports and recreation centre there because the high altitude is good for professional sports and training (about 3000 feet above sea level on the great dividing range). They are going to put a 50 meter pool in-doors.