The rain deficit in the city and its fringes this Northeast monsoon has posed a challenge in portions of the Cooum river. Some stretches continue to be choked by aquatic vegetation despite periodical cleaning.
The Water Resources Department has engaged machinery to clear additional loads of floating vegetation obstructing the flow in the river. It may be recalled that the department had started cleaning the river for a distance of 25 km from downstream of Thiruverkadu before the onset of Northeast monsoon.
However, the river in the urban stretches continue to get covered with aquatic weeds. Officials of the WRD said some of the stretches of the river such as in Maduravoyal and Thiruverkadu are ridden with vegetation. The decrease in river flow this season has led to the weeds from upstream portions clogging the stretches near causeways.
Though Chennai district has received intermittent rains, it has logged in only 42 cm of rainfall, which is short by 28% of its seasonal share of 58 cm so far since October 1. Tiruvallur district too has suffered a rain shortage of 44% this monsoon.
Officials said proliferation of aquatic weeds that suffocate the river indicated sewage pollution, especially in urban stretches lacking in proper sewer infrastructure. Such weeds get washed when the river carried a heavy flow during monsoon every year. However, the river carried only a minimal flow of 1,000 cubic feet per second (cusecs) now.
This has led to clogging of stretches like in Maduravoyal, particularly near causeways. “We are removing a minimum of 10 lorry loads of water hyacinth. The stretches have been cleared of vegetation twice already. The work will be carried out till the year end to allow free flow of water,” said an official.
Prevention of sewage pollution in fast-urbanising areas and replacing causeways with high-level bridges would help resolve such issues, the officials added.
