I see that by modern standards a desert well is extremely deep, 1000 feet of more. Where ancient people digging down 1000 feet for there wells?
Up to 900 ft deep, tho many are much shallower. In the middle east Qanats are used to access the water table / underground rivers. These systems, like the landscape they are produced in and the cultures that built them are very old. The systems are impressive to see and interesting to study.
Source: Middle East travel