El Niño could bring over 50 cm of rain, says Chennai Mayor as GCC races to complete canal improvement works

Chennai Mayor R. Priya has warned that the city could receive more than 50 cm of rainfall in a single spell during the upcoming Northeast monsoon. Although the Greater Chennai Corporation (GCC) has begun works, there has been a delay, she said.

On monsoon preparedness, Ms. Priya told The Hindu: “Because of El Niño, the rain will be heavy. Right now, even the heat is high for us [in Chennai]. Some experts say that the volume of rain could go even above 50 cm. If it comes in a single spell, it will affect Chennai.”

“During the 2023 Michaung Cyclone, the city received up to 45 cm of rainfall. So, they [experts] are saying it could be at that level. Otherwise, the rains might not come at all, and we will be heading into a drought. Either is possible, according to experts at the monsoon preparedness meeting,” she added.

“As far as the canals are concerned, we have to carry out desilting every year. Just because we have done it this year does not mean it will help us next year. It has to be done every year. The GCC had already taken over three canals — Veerangal Odai, Otteri Nullah, and Virugambakkam Canal. The process of removing water hyacinth itself is time-consuming. So, the current government should push for expediting work on waterways with the Water Resources Department as well,” she added.

“This time, the GCC started preparedness work a little late. We usually begin desilting in June. This year, tenders were floated only in July and the work has now begun in August,” she said.

The Chief Minister C. Joseph Vijay conducted a meeting on monsoon preparedness in June, but only officials participated. “There was no invitation even for me or the Deputy Mayor,” she added.

Work in 21 of 33 canals done

According to official data shared by the civic body, the GCC has completed improvement works on 21 of the 33 canals, spanning a total length of 15,868 metres, taken up across the city, with over 14% of the targeted length yet to be finished. Of the 10,529 metres taken up for improvement across canals, 8,985 metres has been completed as of August 1, 2026.

For the Otteri Nullah flowing through the Royapuram, Thiru.Vi.Ka Nagar, and Anna Nagar zones, works estimated at ₹6,500 lakh were planned. As of August 1, works worth ₹2,637.69 lakh had been completed. Improvement of the existing wall is 75% complete, while the construction of new walls is about 25% complete.

For the Virugambakkam Canal in the Anna Nagar, Teynampet, Kodambakkam, and Valasaravakkam zones, more than half of the waterway has been desilted this year. Works worth ₹510 lakh had been completed as of August 1, with over 60% of the existing wall raised, 40% of the new wall constructed, and 20% of the fencing completed.

Low lying areas

The civic body has mapped 294 water stagnation locations and low-lying areas based on last year’s data. The Sholinganallur zone recorded the highest number with 76 locations, followed by Royapuram with 31 and Adyar with 26. The Alandur zone recorded zero water stagnation points.

Across these locations, sump and pump arrangements will be made at 10 sites, with 115 motors to be deployed. Mitigation measures will also be implemented at Metro Rail work sites in the Anna Nagar, Teynampet, and Adyar zones, and in areas affected by Puzhal surplus discharge in the Manali zone.