 Aptly called the Dusi-Mamandur tank, it has a water spread area of 13.5 km2 and a capacity to store 180 million cubic feet of water.This tank is believed to have been constructed in the seventh century A.D. in the reign of the famous Mahendravarman I.The Vaikuntavasa Perumal temple must have once been not only a hub of religious activity but also a socio-economic and cultural centre like many other temples in this region.