The Grand Anicut, also known as the Kallanai, is an ancient dam built on the Kaveri
River in the state of Tamil Nadu in southern India.
Kallanai Built By Karikalan, A Chola King. (This image also shows 19th century additions
to the ancient dam).
It was built by the Chola king Karikalan around the 1st Century and is considered
one of the oldest water-diversion or water-regulator structures in the world, which
is still in use.
The Kaveri River forms the boundary between the Erode and Salem districts. The Bhavani
River joins the Kaveri at the town of Bhavani, where the Sangameswarar Temple, an
important pilgrimage spot in Tamil Nadu, was built at the confluence of the two
Sweeping past the historic rock of Tiruchirapalli, it breaks into two channels at
the island of Srirangam, which enclose between them the delta of Thanjavur (Tanjore),
the garden of Tamil Nadu.
The northern channel is called the Kollidam (Kolidam); the other preserves the name
of Kaveri, and empties into the Bay of Bengal at Poompuhar, a few hundred miles
south of Chennai (Madras). On the seaward face of its delta are the seaports of
Nagapattinam and Karaikal. Irrigation works have been constructed in the delta for
over 2,000 years.
The Kallanai is a massive dam of unhewn stone, 329 metres (1,080 ft) long and 20
metres (60 ft) wide, across the main stream of the Kaveri.
The purpose of the dam was to divert the waters of the Kaveri across the fertile
Delta region for irrigation via canals. The dam is still in excellent repair, and
supplied a model to later engineers, including the Sir Arthur Cotton's 19th-century
dam across the Kollidam, the major tributary of the Kaveri.
The area irrigated by the ancient irrigation network is about 1,000,000 acres (4,000