by Tathagata Neogi
A couple of days ago a friend invited my wife and me for lunch at one of the elite clubs in Kolkata. We had to oblige the stringent dress code of the club and attend the lunch in full formal attire in the sweltering heat. While we were at lunch, the heavens opened and a torrential monsoon downpour lasted for more than 2 hours. When the rain stopped and we could leave the club, the main roads were waterlogged, alleys submerged, traffic stagnant. Unwilling to pay the skyrocketing Uber fare, we took the metro back half way, and then waded home through knee-deep water in our formal attire. It must have been quite a sight!
Waterlogging is synonymous with the monsoon in Kolkata and many other major Indian cities. Having spent part of my childhood and my college life in Kolkata, waterlogging and related disruptions have become common features of my monsoon experience. While the municipal authorities are working to prevent this predicament by installing pumps and facilitating better drainage, waterlogging continues to affect the older quarters in north, central and south Kolkata. In this post I explore the root of this by traveling back in time and tracing the history of drainage in the Second City of the (British) Empire.
Early drainage system and the problem of waterlogging
The area that is today known as Kolkata used to be a collection of fishing hamlets interspersed with forests, creeks and canals that connected the Hooghly River on the west with the Salt Lakes on the east. These creeks and canals served as the natural drainage system for both rainwater and sewage, which were carried east following the natural incline of the land and deposited in the Salt Lakes. The excess rainwater and sewage were then carried away to the sea by the tides. Apart from the creeks and canals, a large number of tanks in each hamlet collected and stored the excess rainwater, preventing large-scale flooding in the area.
The densely populated areas on the river bank — especially the markets of Barabazar and along the old pilgrims’ way in Chitpore — saw occasional flooding. The fledgling English settlement around the Great Tank (in what is now central Kolkata) also experienced some inundation, leading to deadly bouts of malaria and cholera. However, the presence of the creeks and canals ensured the swift drainage of floodwater out of the city and into the Salt Lakes. However, with the rapid and unplanned growth of the city in the 18th century, especially after the East India Company’s decisive victory at Plassey in 1757, many tanks and creeks were filled in. Newly devoid of a natural drainage route, waterlogging became a major urban problem. Apart from the discomfort, it brought with it more deadly epidemics of cholera, dysentery and malaria, which especially affected the more densely populated “native” quarters of the town in North Kolkata. To address this issue, the small and cash-strapped Calcutta Government excavated some rudimentary narrow sewers to drain sewage and rainwater to the Hooghly River. This plan was ill-conceived, as the flow was against the natural eastward slope of the city, and it led to more stagnation of filth and rainwater during the monsoon.
Wellesley’s Report and the Improvement Committee
In 1803, Lord Wellesley, the then-Governor General of British India published detailed minutes condemning the sad state of municipal affairs in Calcutta. In the report, Wellesley especially condemned the poor condition of drinking water, extremely unhealthy sanitation and faulty drainage system in the city.
“The construction of the Publick Drains and the Water-Courses of the Town is extremely defective…neither answer the purpose of cleansing the Town, nor of discharging the inundations occasioned by the rise of the River, or by the excessive fall of rain during the South-West Monsoon… Experience has manifested that during the rainy season, when the River has attained its utmost height, the present drains become useless; at that season the rain continues to stagnate for many weeks in many parts of the Town, and the result necessarily endangers the lives of all Europeans residing in the Town, and greatly affects our Native Subjects.”
Goode, S. W. (1916). Municipal Calcutta: Its Institutions in Their Growth and Origin.
This report resulted in the appointment of Justices of Peace, early municipal officers, and the formation of an Improvement Committee in 1809 to look into the issues of sanitation, waterlogging, waste disposal and health in Calcutta. The Committee’s recommendations have since been lost; in 1817, the succeeding Lottery Committee reported that they also could not find them. However, it seems that the contribution of the Improvement Committee was limited to excavating the Beliaghata (Circular) Canal along the then-northern and eastern boundary of Calcutta. This canal, which is operational to this day, extended from the inlet of the erstwhile Maratha Ditch in Bagbazar to the Salt Lakes in modern day Chingrighata. The existing open drains of Chitpore, Bagbazar, Sobhabazar and Nimtala were connected to the Beliaghata Canal, and tides from the Hooghly were used to carry sewage and rainwater to the Salt Lakes.
However, this arrangement was not sufficient. To begin with, the open sewage of North Calcutta would dry up during summer, leading to clogged sections and stagnation. These were not cleared regularly and led to an overflow of dirty water and the putrefaction of filth — including human and animal excreta — resulting in more deadly outbreaks of disease. This problem increased manifold during the monsoon. Because of the lack of an underground stormwater drainage network, large volumes of tidal water coming through the canal (from both the river and the Salt Lakes) during the monsoon would fill the open drains and compound the existing problem of waterlogging in the northern part of the city. Finally, the existing drainage system was not comprehensive; there were several parts of the city that did not have proper outlets for sewage and rainwater. The Beliaghata Canal, therefore, did not ameliorate the waterlogging problems of the city.
“After a heavy fall of rain, a canoe was a preferable mode of transit in Chitpore Road.”
Goode, S. W. (1916). Municipal Calcutta: Its Institutions in Their Growth and Origin.
The Lottery Committee and more effective Fever Hospital Committee were successively appointed to address these shortcomings. The Lottery Committee attempted to address the issue of tides by constructing steam-powered lock gates at the mouth of the Circular Canal in Bagbazar. This was the first steam-powered machine in Calcutta and people would flock in large numbers to see it in operation every day.
The Fever Hospital Committee decided that the only effective solution to Calcutta’s waterlogging and sewage problems was to construct an elaborate underground drainage network, including large stormwater drains. Three rival proposals were debated in 1835. The first, which was ultimately adopted, was from Major General (then-Captain) Forbes of the Royal Engineers. He proposed the construction of a masonry aqueduct from Chitpore to South Park Street Cemetery and beyond to the Salt Lakes. This canal, parallel to the Circular Canal, would be provided with sluice gates to admit tidal water from Hooghly and the Salt Lakes. The canal would be flanked by two large covered drains, to which all of the open drains of the city would be connected. These covered drains would, in turn, drain into the masonry canal. The covered drains and all other drains in the city would be flushed by admitting tidal water through additional sluice gates located in different places. The excess rainwater could also be drained into the canal. The canal, Forbes proposed, could also be used by small dinghies (boats) to transport goods against a toll. The water of the canal could also be used to clean roads and supply water to extinguish fires.
The second proposal was from Mr. Blechynden, the Superintendent of Roads of Calcutta. He suggested the construction of a large underground brickwork tunnel running from west to east, from the Hooghly to the Circular Canal near Beliaghata through Nimtala and Maniktala in North Calcutta. Smaller drains would deposit the sewage and excess rainwater into this underground tunnel, and the tunnel will be flushed by the tidal water from the river.
A third and more ambitious plan was proposed by Captain Thomson, an engineer and the Officer-in-Charge of Canals. He proposed the construction of a large underground network of drains and stormwater tunnels to be flushed towards the Salt Lakes by river water, which would be admitted through the Circular Canal and sluice gates at other inlets. James Prinsep, the famous antiquarian and orientalist scholar and an important member of the review committee, vehemently opposed the concept of an underground drainage system and was the only one to reject all three proposals outright. The failure of Prinsep’s own underground drainage scheme at Varanasi had made him skeptical about its implementation in Calcutta. Although Forbes’ proposal was accepted, the Fever Hospital Committee failed to implement it due to a lack of sufficient government funds.
Clark’s Scheme and the foundation of Kolkata’s current sewage system
William Clark, an inventor and civil engineer, expanded on Major General Forbes’ proposal and submitted his plan to the Calcutta Municipality review committee in 1855. In his plan, Clark proposed the construction of three underground main sewers connecting the Hooghly in the west and the Circular Road (erstwhile Maratha Ditch) on the east. These canals would run under Nimtala Ghat Street, Kolutola Street and Dharmatala Street. These main sewers would be intercepted by a north-south oriented sewer from Sovabazar along the Upper Circular Road near Dharmatala. A sewer from the south also met the north-south sewer and the Dharmatala east-west sewer along the Lower Circular Road from Tolly’s Nullah. All open drains in the city first flowed into one of these sewers and then ultimately emptied into one of four stormwater overflows, which had larger capacities than all the intercepting sewers combined, to allow the drainage of excess rainwater during the monsoon. The stormwater overflows carried the sewage (and rainwater) to the Circular Canal at Beliaghata, where a sewage pumping station was located at Palmer’s Bridge. The sewage was then pumped and drained out to Tangra Creek (now the neighbourhood of Science City) on the Salt Lakes. The mechanism continues to this day.
This scheme was sanctioned by the committee in 1857. Between 1858–1859 the Government Drainage Committee took elaborate measurements of the inclines in different parts of the city. Careful readings of the tides were made at Chitpore, Tolly’s Nullah and Chandpal Ghat on the Hooghly and at Bamungahata, Tangra and Dhapa on the Salt Lakes. Additionally, a large brickfield was acquired and cutting-edge brick making machinery was imported from England. The project was cash-strapped from the beginning and had to be halted several times. Due to the rapid increase of population and the city’s area, the plan went through multiple modifications and cost revisions, further crippling the project. Ultimately, in the late 1890s, Clarke’s Scheme was fully implemented and forms the skeleton of the current sewage and stormwater drainage system in Kolkata.
This brings us to the final question: was Clark’s Scheme successful? While the plan looked perfect on paper, there was one crucial flaw at the execution level. The stoneware pipes were fitted invert to invert, rather than soffit to soffit. A soffit-soffit matching in stormwater pipes connected to tidal rivers allows extra room to accommodate excess tidal water during the monsoon at the higher points of the incline. An invert-invert fitting, on the other hand, does not provide that extra room, which leads to overflow and flooding. Although Clark’s Scheme was successful in reducing the incidence of monsoon flooding in Calcutta, and solved the problem of sewage, it could not fully prevent parts of North and Central Calcutta from flooding. In addition, the rapid and alarming shrinking of the East Kolkata Wetlands (the remnants of the Salt Lakes) due to unregulated construction has blocked the natural outflow of sewage from the city. These developments have also altered the natural incline, which made parts of North and Central Kolkata into the new low-lying areas, where the water stagnates and causes flooding after the slightest rainfall. It is, therefore, imperative to put a halt to the rapid destruction of what little remains of the East Kolkata Wetlands for the sake of our beloved city. Until we do that, our fight with the monsoon and waterlogging will continue.