Police said there was traffic blockade in front of the Uthamapalayam Court and Cumbum on roads leading to Kumili and other parts of Kerala.
The worst affected were Ayyappa devotees whose vehicles had been held up, police said.
Abbas, President of the Mullaperiyar Irrigation farmers association here, protested Kerala MLA E S Bijimol's alleged entry at the dam site yesterday. He pointed out that a committee appointed by the Supreme Court was already monitoring the reservoir.
Executive Engineer Madhavan and the Assistant Engineer Soundar said they were threatened, abused and pushed by some persons on their entry at the dam site yesterday.
With the water level nearing the contentious 142 level mark in the dam, Kerala has urged Tamil Nadu to take steps to reduce it. However, Tamil Nadu Chief Minister O Panneerselvam said the neighbouring state cannot 'interfere' on the regulation of flow from the reservoir.
The two states are locked in a dispute over increasing water level in the dam from 136 feet to 142 feet with Kerala citing safety concerns. The apex court had in May last allowed Tamil Nadu to raise the level to 142 feet, rejecting Kerala's objections.