Photograph taken in 1890 by an unknown photographer shows the canal from Tolly's Nullah to the dock. The Calcutta Port is the only major riverine port in India and it constitutes the Calcutta Dock System. 'The construction of wet docks was, for many years the favourite means by which it was proposed to improve the port of Calcutta. Towards the close of the 18th century, General Watson founded a marine yard at Kidderpore, and obtained a grant of land from the King and the East India Company for docking purposes. He designed and actually commenced in 1781 the construction of wet docks between Tolly's Nullah and Kidderpore. To carry out his design General Watson went to the length of diverting the nullah from its old course, but the work...was left uncompleted after General Watson had extended upon it and upon works connected with a dry dock and a shipbuilding yard, on the site of what is now the Govt. Dockyard...' The Tolly's Nullah, constructed by Colonel Tolly in the 1770s from the dried-up bed of Kidderpore Creek, enabled shipping to reach the delta to the east of Calcutta.Source: http://bl.uk