He said that the dam, catering to the irrigation needs of over 60,000 acres in Tirupur and Karur districts of the state, received water from Pambar, Thenaar and Chinnar.
He said the Kerala government has now proposed a dam at Pattichery on Tamil Nadu-Kerala border and the government had laid the foundation stone for the project on Monday.
"If this dam is constructed at a height of 75 ft and width of 440 ft, water flow of about 2 tmcft to Amaravathy dam will be affected," he said in a statement here.
Kerala had not obtained necessary environmental clearance, Vaiko alleged. It was 'illegal' for Kerala to construct a dam without the consent of the lower riparian state Tamil Nadu and urged the state government to take all steps to prevent its neighbour from going ahead with the construction of the dam.