Calcutta’s Pulta Water Works: 150 years of silent service

Abstract

Calcutta (Kolkata) served as the capital of colonial India from 1757 to 1911. It fundamentally resembled the urban setting of London. For over three centuries since its inception as an urban centre, Calcutta observed huge growth, endured political events, survived disasters, absorbed the influx of refugees and is now one of the most congested cities in the world. Prompted by its growth as a regional hub in the early nineteenth century and recognising the pressing need for an organised water supply system, the authorities started implementation of the very first surface-water-based supply scheme in Asia. Despite being situated next to River Hooghly, Calcutta’s water supply was designed to draw water from 22 km upstream. Pulta Water Works started operation in 1868 with only 27·3 million litres per day (mld) capacity, having simple water abstraction, treatment, supply, storage and distribution techniques. Now, this waterworks has an installed capacity of 1182 mld and employs advanced treatment technologies to serve more than half of the larger city area. This paper summarises the history of inception and development of Pulta Water Works, which still serves Calcutta and stands out as an emblem of sustainable urban water supply.