The Water Resources Department (WRD) would soon clear the lush growth of water hyacinth on the city stretch of the Uyyakondan canal.

The department has called for tenders to carry out the annual exercise. A thick blanket of hyacinth covers the canal on many stretches in the city this year too, especially after the end of the Mettur irrigation season. District Collector Pratik Tayal, along with senior officials, had inspected the canal recently.

Sources said the weeds would be removed on eight stretches, covering a length of about 14 km at a cost of over ₹70 lakh. Tenders have been floated and the work would begin in about a couple of weeks, the sources said.

Farmers and civic activists in the city have long been complaining over water pollution in the canal, especially between the Puthur Weir and Ariyamangalam in the city where sewage is discharged into the canal at various places. This makes it an ideal breeding ground for weeds. A plan to establish sewage treatment plants along the canal remains on paper.

“The thick growth of the hyacinth obstructs water flow in the canal, which still is the lifeline of thousands of farmers. The Tamil Nadu Pollution Control Board, the Tiruchi Corporation, and the WRD should take steps to prevent the pollution,” said R. Subramanian, deputy secretary, Cauvery Delta Farmers’ Welfare Association. He urged S. Ramesh, HR&CE Minister, who represents the district, to convene a joint meeting of the government agencies concerned to find a permanent solution to the problem.

The 1,000-year-old Uyyakondan canal, built by Raja Raja Cholan and renovated by Kulothunga Cholan, has an ayacut of 32,000 acres and feeds 36 tanks. It traverses about 71 km between Pettavaithalai and Vazhavanthankottai tank in Tiruchi district. The Uyyakondan extension canal runs into Thanjavur district feeding some irrigation tanks which are the main source of irrigation for farmers.

Removing the weeds poses a challenge to the WRD as machines cannot enter the canal in the residential areas. Often, the department deploys experienced men to clear the weeds manually.