anicuts

Anicut, plural anicuts, is a dam or barrage built across a river to regulate its flow and to divert water into irrigation canals. The term derives from Tamil anaikattu, meaning to bind or tie the river, and it is widely used in India and Sri Lanka to describe small- to medium-height barriers that control discharge rather than create large reservoirs.

Historically, anicuts are among the oldest forms of water-regulation infrastructure. One of the most famous examples is the Kallanai Dam on the Cauvery River in Tamil Nadu, traditionally attributed to Karikala Chola in the 2nd century CE. The structure, constructed of masonry and substantially still in use, exemplifies the enduring purpose and design of anicuts: to regulate seasonal flow and to supply irrigation to downstream fields.

Design and operation typically feature a low crest across the river with sluiceways or gates to adjust water flow. The diverted water is channeled into distributary canals that irrigate agricultural lands and, in some cases, support flood management and local water supply. Anicuts are usually built of stone, masonry, or earth and may be maintained or expanded over centuries, incorporating modern gate systems while preserving the fundamental concept.

Geographically, anicut systems are found across parts of the Indian subcontinent, with numerous examples in Tamil Nadu and Sri Lanka. While many ancient anicuts remain in use, some have been modified or replaced by more modern barrages and dam structures. They continue to be valued for traditional irrigation practices, cultural heritage, and regional water management.