The Tamil Nadu State Department of Archaeology (TNSDA) has identified a brick structure exposed in the Kollidam riverbed at Koogur near Lalgudi in Tiruchi district as a Sangam-period water regulation structure. It lies about 100 m from the northern bank of the Kollidam, close to the ancient Kallanai. Its bricks, measuring about 39–43 cm × 20–22 cm × 6–7 cm, resemble those unearthed at Arikamedu, Keeladi, Mangulam and Poompuhar. Experts link it to the Kurampu, an ancient check-dam-like structure, which may have regulated Cauvery water flowing into the Kollidam through the Ullar.