Three years after the dereservation of tram tracks was rolled out with much fanfare, the citys civic managers have suddenly woken up to the fact that concrete is more difficult to dig than asphalt.
In a letter to the transport department, the civic water supply and drainage department has stated that no further concretisation of tram tracks should be allowed if underground water supply and sewer lines are to be maintained.
The departments problem with concrete cover for tram-track surfaces without diversion of underground utility lines is three-fold reaching the underground `is tough; a leak in the water lines cannot be detected easily; there is danger of brick-sewer lines caving in under pressure from the top.
The civic water supply and drainage department has raised these objections over the clearance sought by the Hooghly River Bridge Commissioners (HRBC) from the Calcutta Municipal Corporation (CMC) for concretisation of the 6-km tram tracks from Hazra to Tollygunge and Hazra to Mominpur.
So why was this point not raised during the planning or implementation of the dereservation of tram tracks? Like most other civic matters in the city, no answers are forthcoming.
Mayor Bikash Ranjan Bhattacharyya said: Forget about the blame game. The fact is that ultimately the citizen suffers if there is lack of coordination at the planning and implementation stages. The social cost is enormous.
So who is to blame for this social cost? Everyone involved in the process, stressed Indranath Chakraborty, a water supply expert formerly with CMDA. How was permanent reinforced concrete over sewer lines allowed? It reflects a complete lack of understanding and coordination.
HRBC vice-chairman Sadhan Banerjee said concretisation had been carried out with the CMCs consent.
According to chief engineer (water supply) Bibhas Maity, it would take more than two days to cut through the concrete slab and reach a leak in the water mains five to six feet below the road surface, whereas a bituminous or mastic asphalt surface would take just a few hours to dig.
A leak in the water mains will remain undetected under concrete, causing low pressure in the supply to neighbouring areas.
Also, the century-old brick sewers running under the tram tracks could be in danger of collapsing under concrete pressure, said the civic chief engineer (drainage & sewerage), Tushar Ghosh.