Final answer:
Desert dwellers have historically used systems like qanats for irrigation and accessed fossil groundwater to sustain life and agriculture in arid regions. These ancient methods are still in use today but face challenges due to the non-renewable nature of aquifers.
Step-by-step explanation:
Understanding Ancient Water Systems
Desert dwellers and farmers have historically employed various ingenious methods to harness water in arid regions for their sustenance and agricultural needs. One notable technique is the use of qanats, an ancient irrigation system developed over 2,700 years ago in what is now Iran. These subterranean aqueducts channel water for long distances, facilitating not just irrigation but also providing potable water to tens of thousands. The Qanat system in Gonabad still supplies water to over 40,000 people today.
In arid areas like the Sahara, water scarcity led to reliance on fossil groundwater. Libya, for instance, extracts water from aquifers formed during a past tropical climate era, using it for both agriculture and urban purposes, as in the man-made river project which services major cities. Similarly, the Arabian Peninsula leverages aquifers beneath the sands to support its agricultural production.
The sustainability of such systems, however, is in question, as aquifers are not renewable and intensive usage can lead to aquifer depletion. This necessitates deeper wells or relocation of settlements to seek new sources of water in the future, presenting a significant challenge for maintaining these crucial water supplies.