Anicut

Anicut is a dam or barrage constructed across a river to raise the water level upstream and to divert a portion of the flow into irrigation canals. The name is derived from the Tamil word anaikattu, meaning a dam built across a river to regulate water flow. In common usage, anicuts are masonry structures designed to form a reservoir and to channel water into distributary canals for farming.

Typically, anicuts are built as low barriers of stone or rubble masonry, sometimes with sluice openings to control discharge. They create a stretch of higher water level upstream, from which water can be released through gates into irrigation channels. The design emphasizes reliability and local availability of materials, and many anicuts include multiple sluices to manage varying river discharge.

Historically, the best-known example is the Kallanai Dam, also called the Grand Anicut, on the Kaveri River in Tamil Nadu. Traditionally attributed to the Chola king Karikala around the 2nd century CE, it is one of the oldest river-diversion structures still in use and a landmark in Indian irrigation engineering. Across the Indian subcontinent, numerous anicuts were built or expanded during medieval and colonial periods to support agriculture in river basins such as the Cauvery, Vaigai, and Periyar systems, as well as in neighboring regions.

In modern practice, the term anicut is sometimes used to distinguish earlier, more rudimentary barrage works from larger contemporary irrigation dams and barrages. While some are still critical for local water supply, many have been supplemented or replaced by larger hydrographic schemes, though their basic principle—diverting river flow for irrigation—remains central.