Qanats

Qanats are traditional underground irrigation channels used to move groundwater from an aquifer in higher ground to villages and fields in arid regions, relying on gravity rather than pumps. By delivering water underground, qanats reduce evaporation and keep the water cooler than surface canals.

Typically, a qanat begins at a water source near the aquifer and proceeds as a gently sloping tunnel excavated toward the settlement. At regular intervals along the tunnel, vertical shafts extend to the surface to provide access for digging, ventilation, and maintenance. The water exits at the end or at a turnout where it feeds a surface ditch, reservoir, or irrigation channel.

Originating in ancient Iran and the broader Persian world, qanats were developed to exploit groundwater in dry climates. They spread along trade routes into the Levant, North Africa, and Central Asia, acquiring diverse names such as kariz, kareez, and karez in different languages. The system supported agriculture and urban water supply for centuries.

Qanats depend on cooperative management and customary water rights. Water users organize maintenance, regulate access, and assign shares for each shaft. Dredging, repairing shaft linings, and clearing silt are ongoing tasks. Their success hinges on stable geology, careful slope, and community governance rather than pumping alone.

Today, many qanats remain in use, while others have fallen into disrepair or been replaced by wells and pumps. They face threats from groundwater depletion, earthquakes, and climate fluctuations, as well as urbanization. Some are preserved as cultural heritage, and modernization projects may rehabilitate or integrate qanat components into contemporary irrigation systems.

Qanats are found across the Middle East, North Africa, and parts of Central Asia, with Iran hosting the largest networks. Similar systems appear in Afghanistan, Pakistan, Turkmenistan, Uzbekistan, and Morocco, illustrating a historic adaptation to water-scarce landscapes that continues to influence water management.