Complex sentence: The Desert Column was responsible for outposts and patrols in the open plain stretching east and south of the eastern flank, and for harassing Ottoman forces at every opportunity, while wells and cisterns were mapped.
Split into simpler sentences: The Desert Column was responsible for outposts and patrols in the open plain stretching east and south of the eastern flank. Outposts and patrols harassed Ottoman forces at every opportunity, while wells and cisterns were mapped.