Mayor Subrata Mukherjee faces an uphill task in updating the city’s drainage and sewerage map, as no master guide is available with the Calcutta Municipal Corporation (CMC). The last map dates back to 1930. A committee of experts will be constituted soon to map the drainage utility, at a cost of Rs 20 lakh.
“A number of agencies had worked on the city’s drainage system but none incorporated the changes in the basic map we have,” said Mukherjee.
Technologists of the French Water Club have already taken up the task of mapping the city’s water supply network, but there has been no similar effort on the drainage system. The CMC has the field survey maps of 1784-85 by Lt Col Mark Wood, of 1792-93 by A. Upjohn (Calcutta VII and Its Environ), and a topographical survey map of the Hooghly between Bandel and Garden Reach of July 1, 1841, when Lord Auckland was governor-general. In 1856, Supreme Court member Henry Rickett had prepared a map, which still exists.
However, the map prepared by Englishman Smart between 1909 and 1913 is still regarded as the touchstone. Smart’s map is a collection of 800 sheets, drawn on a 1:600 scale. A micro-level detail of the city landscape for wards 1 to 100 and Garden Reach had been made at an unbelievable scale of accuracy.
But the maps do not deal with underground systems. British engineers started preparing the city’s drainage maps in 1860 and updated them with the changing face of the city till 1930. Then, post-Independence, the Calcutta Metropolitan Planning Organisation took up large-scale infrastructure development. It laid sewerlines and prepared maps for its own use. Subsequently, in 1966, the CMWSA and the CMDA in the 1970s laid sewerlines in different parts of the city. Both agencies worked according to plans and drawings of their own. But the basic drainage maps of the CMC were not updated.