14 natural streams in Arunachala Hills cleaned to discharge excess rainwater into Then Pennai river

The Tiruvannamalai Corporation has cleaned of 14 natural streams, also known as ‘Odai’, in Arunachala Hills near Arunachaleeswara Temple in Tiruvannamalai town to ensure a smooth flow of excess rainwater from the hills and to prevent inundation of the temple town during Northeast monsoon.

Corporation officials said that the natural streams in the hills are under the control of the civic body for many years. These streams are key to prevent waterlogging in the town during monsoon. “Regular inspection of streams in the hills is being done to identify any blockage that could prevent the free flow of rainwater downstream. New drains are also being built to connect the streams with nearby irrigation tanks,” S. Ravi, Assistant Engineer (AE), Tiruvannamalai Corporation, told The Hindu.

Along with Corporation officials, Collector K. Tharpagaraj inspected the foothills of Arunachala Hills on Thursday to assess the condition of the rocky terrain. He directed the civic officials to take precautionary measures to prevent land slips in the hills. On December 1, 2024, seven persons died after heavy rain triggered a landslide in the hills.

Corporation officials said that each stream varies between 1.2 km and 1.8 km in length from the hillock to the town. Each stream, on an average, is 15 metres wide and seven metres in depth. In the downstream, especially the town area, streams are connected to large drains to discharge the excess rainwater into irrigation tanks, which are maintained by the Water Resources Department (WRD), before draining into Then Pennai river.

Most of the drains, that are connected to streams, have been desilted. These drains, on an average, are seven feet wide and in depth. New drains are also under construction, especially on Sattanaickan Street and Pei Gopuram area, at a cost of ₹2.8 crore under the 15th Finance Commission scheme by the civic body. “Desilting of the Vengaikal irrigation tank should be done to prevent inundation of areas around the Collectorate. Many streams from the hills flow into the tank during monsoon,” said K. Sampath, a resident.  

On its part, the Highways Department has constructed retaining walls at two identified spots in the hills to prevent land slips during monsoon. Each wall is 20 metres long and 10 feet in height. Open areas at the foothills are also being levelled to enable the free flow of rainwater from the hills.

Forest officials said that the Arunachala Hills come under the Adi Annamalai Reserve Forest, with over 900 hectares, spreading nine km radius. The hill, located at 2,668 feet-high from the mean sea-level, is where a fire is lit atop the hillock as part of the Maha Deepam festival every year. The land around the foothills, to a distance of six kms, belongs to the Revenue Department while the remaining area in the hills are forests.