Chennai: With the northeast monsoon nearing, stretches of the canal network running through Porur, Iyyappanthangal, Kummananchavadi and Kolathuvanchery show signs of a system under pressure — sections of the waterways are narrow, with silt, plastic and other solid waste accumulating along the bed, thereby reducing flow. The network is a crucial drainage route for excess water from the western suburbs towards Adyar river.The main interconnected waterways along this corridor include Thanthikal Channel, Porur Lake surplus course/Manapakkam Canal and Ramapuram Canal, besides the adjoining feeder and link channels. Thanthikal Channel, about 2.5-km long, carries surplus water from Chembarambakkam reservoir to Porur Lake. From Porur Lake, surplus water moves through the canal system via Moulivakkam, Madanandapuram, Mugalivakkam and Manapakkam before reaching Adyar.The 6.9km Manapakkam Canal passes through densely developed areas, making its carrying capacity particularly important during heavy rain. A metrowater inspection identified 20 sewage outfalls along the canal, with several found carrying sewage during the inspection. Experts say that with sewage outfalls, silt and solid waste, intense rainfall could increase the discharge of polluted water into adjoining low-lying residential areas. Previous flood-management reports have also recorded the vulnerability of the Porur-Iyyappanthangal-Kolathuvanchery belt when surplus-water routes are obstructed.Residents allege encroachments and developments along the banks of the canal have reduced its width by around 5-6 ft in some stretches over the past five years. S Vimala, secretary of Pasumai Karangal and a Porur resident, said the canals required regular maintenance and not just pre-monsoon cleaning. “These channels are treated as isolated stretches, when in reality, they form a connected drainage system. If one portion is narrow or blocked, the impact is felt upstream, particularly in low-lying residential areas. Desilting should be followed by regular inspections to ensure the carrying capacity is maintained,” she said.K Jayakumar of Kolathuvanchery said the 2023 floods exposed the area’s vulnerability. “During Michaung rains, several streets were badly affected, and residents struggled to move around until the water receded. Last year, rainfall was comparatively subdued, but the drainage problems did not disappear. Waterlogging remains a concern even without extreme rainfall, showing that the issue is improper drainage system and not the intensity of rain,” he said. Kanchipuram district collector D Sneha said necessary action would be taken to survey the clogged canals and undertake desilting in the affected areas.
