For the past few days, residents along the Adyar River have been noticing an increase in the water level. While environmental experts say it is caused by a tidal effect, residents have demanded that the mouth of the river be dredged properly to prevent inundation.

Residents of Ururkuppam said the water level in the river increased during this time of the year and in winter. Last year, the area was flooded as the sand accumulated in the river's mouth was not removed periodically, they said.

Officials of the Water Resources Department said the water level may rise by up to one metre as the impact of high tide was strong during June following the change in wind direction.

Due to reduced flow, the tidal effect would help in flushing the sewage from the river, they said. “We have stationed an equipment to sustain an open mouth and periodically remove accumulated sand,” an official said.

Environment experts said the sediment gets transported from the south to the north. However, its movement is affected due to the construction of the harbour.

L. Elango, Professor of the Department of Geology, Anna University, said, as the movement of the sediment gets obstructed, sand bars get accumulated.

If not removed regularly, it would result in stagnation of sewage in the river and result in mosquito menace and inundation, he added.