The elevated water tank at Tala (just on the northern fringe of Kolkata) is the largest elevated water tank made of steel.
Supported on steel columns, the capacity of the tank is nine million gallons (almost 41,000 m3) with a staging height of 33 m. It can hold more water than that required to fill up 16 standard size Olympic swimming pools.
The square tank measures 98 m on one side with 5 m side water depth and is supported on 295 steel columns. It is supplied by a single 1.50 m (60 inch) diameter mild steel water main and has four separate compartments with isolation facility.
The bottom steel of the tank sits on wooden planks supported by steel beams without any anchorage. Tala tank was erected in the year 1911 and has served the city of Calcutta (Kolkata) for over a century.
The structure was conceived in 1901 by Mr. Arthur Peirce (AMICE), Assistant Engineer of Calcutta Corporation, who wanted to ensure round the clock water supply.
The idea was to provide an elevated balancing reservoir with only a single supply/delivery pipe which would receive water by pumping during off-peak hours, store, and supply during maximum demand.
This concept, now being used all over the world in urban water supply, was at that time innovative and met with the approval of the Chief Engineer, Mr. W B MacCabe, MICE.
The foundation of this huge structure was prepared by M/s T K Mukherjee and Co. It was a challenge to support the immense weight of water - 41,000 ton - and also its steel components weighing 8,500 ton.
Sir R N Mukherjee’s company M/s Martin and Co. laid the concrete foundation for this structure and M/s Clayton, Son and Co. was responsible for providing, fabricating, and erecting the steel members and tank that were brought from Middlesbrough, UK.
Cover for the tank was provided by Arracon Co. and Babu Kali Shankar Mitter. The tank was completed in two years and it was commissioned in May 1911.
In 1978-79, the Calcutta Metropolitan Development Authority undertook extensive repair work.on the tank. However, lately, this magnificent structure has showed signs of deterioration .
The Kolkata Municipal Corporation has now taken up a project to rehabilitate this century-old structure and return it to its original glory.
The project will cost almost £ 1 million, and steps are being taken to make this structure sustainable for decades to come.