Complex sentence: At around 6 a.m. water levels were not so high which allowed to hike back and at 8 a.m. the tourists have reached the mouth of the gorge finding ROP personnel and citizens waiting for them.
Split into simpler sentences: At around 6 a.m. water levels were not so high which allowed to hike back. After two hours the tourists have reached the mouth of the gorge finding ROP personnel and citizens waiting for them.