CHENNAI: The city corporation is now proceeding with the integrated stormwater drain project in the Kosasthalaiyar basin with a revised design after officials found that the initial detailed project report (DPR) did not take into account utility space and field realities in some areas.
Under this project, 767km of stormwater drains worth Rs 3,220 crore in the northern parts of the city under the Kosasthalaiyar basin were taken up by the corporation and around 17% of the work has been completed.
However, the project ran into trouble when residents of some parts, including Manali and Madhavaram, said the drain was being constructed using heavy machinery in narrow roads that spanned 12-15 ft in width, endangering their building structures.
Senior corporation officials told TNIE that the DPR that was originally prepared in 2014-2015 had not taken into account the actual space available for construction minus the space taken up by utilities like the sewage infrastructure.
“In some places, there was a discrepancy between the actual space available for construction and the space that was proposed in the initial DPR. So we now had to calculate the clear width available for construction,” said a corporation official.
Another senior official said in the original design, the stormwater drains in narrow streets were to be constructed in close proximity to the houses in the street that could have resulted in even collapse of houses in the earlier design. It could have also damaged existing underground drainage systems in such cases. Now, the corporation commissioner has asked for opinions of the public and the zonal engineers to be taken into account for construction of redesigned drains. “We ensured minimal disruption to the ongoing project when redesigning. So, there was not much delay in progress of the project,” said a corporation official.
In the six years since the DPR was prepared, there were also new encroachments that had to be taken into account in the revised design. Work on laying the drains has been completed on nearly 200 km so far.