Ancient Brickwork Unearthed in Kollidam River Reveals Sangam‑Era Water Management

When the waters of the Kollidam receded last month, a curious brick outline emerged from the silty riverbed near Koogur, a small village close to the historic Kallanai dam. At first glance it looked like the remains of a forgotten wall, but a swift investigation by the Tamil Nadu State Department of Archaeology (TNSDA) turned the mystery into a story that reaches back over two millennia.

On August 22‑23, 2026, a team led by Joint Director V.P. Yathees Kumar, along with academic adviser K. Rajan, Assistant Director Prabhakaran and Archaeological Officer Vasanthkumar, went out with sonar gear, diving equipment and a healthy dose of curiosity. Their goal? To see whether the exposed bricks were an isolated oddity or part of something larger hidden beneath the river’s surface.

Using sonar, the researchers traced faint outlines suggesting that the visible portion was just the tip of an underwater structure. Trained divers then slipped beneath the water, documenting brick sizes, mortar patterns and the overall layout. What they found was surprisingly systematic – two distinct sections, each bent in a gentle ‘L’ shape, hinting at a purposeful design rather than a random construction.

The first section stretches roughly six metres east‑west before turning north for another 8.3 metres. It stands about 1.75 metres wide and just over a metre high, with thirteen visible courses of well‑fired bricks. The northern part of this segment is still buried under sand, waiting perhaps for another low‑water season to reveal itself.

A short distance away – about 11 metres – lies the second section. Parallel to the first, it measures around 2.15 metres in width, runs six and a half metres east‑west, and then arcs north for roughly 4.5 metres. Here, six brick courses are visible on the western side, while three can be seen on the east. Slight differences in the riverbed’s elevation between the two banks add a subtle nuance to the whole layout.

All these details, the team says, line up neatly with known engineering practices of the Sangam period (circa 3rd century BCE to 3rd century CE). Back then, sophisticated water‑regulation works were essential for agriculture, especially in the fertile delta of the Cauvery and its distributaries. The proximity to the ancient Kallanai – the world’s oldest functioning dam – further strengthens the argument that this brickwork formed part of a larger network of irrigation and flood‑control measures.

"It’s like finding a missing piece of a puzzle that our ancestors left behind," Kumar remarked, adding that the structure’s design suggests it could have diverted or slowed water flow during the monsoon, protecting nearby fields from inundation.

While the exact function – whether a weir, a sluice, or a combination of both – remains under discussion, the discovery shines a spotlight on the ingenuity of Sangam engineers. It also underscores how much of our past still lies hidden, waiting for the river to lower its guard.

For now, the brick formation stands as a silent reminder of a time when sophisticated hydraulic projects were already shaping Tamil Nadu’s landscape. As water levels rise again, archaeologists hope to revisit the site, perhaps with more advanced imaging tools, to map the full extent of this ancient water‑management marvel.