Cholagangam Lake, also known as the Ponneri Lake, was brought into being by Rajendra Chola I as a water pillar of victory. At full water levels, it has a total area of about 130 sq km. The bund is quite high and has a length of more than 5 km. The lake once had a surplus weir as well as input channels from
Kollidam River and Vellar.
