Rabindra Sarovar: The last oasis in the city of Kolkata, India
S. K Basu1 and P. Zandi2*
1UFL, Lethbridge, AB, Canada; 2Takestan, Iran; *email: firstname.lastname@example.org
Rabindra Sarovar, locally known as Dhakuria Lake or simply Lake is an artificial lake in southern part of the eastern Indian city of Kolkata. Kolkata is a populous, metro city from eastern India and the capital of the east Indian state of West Bengal. The city is plagued with unbalanced growth, huge growing population, regular pressure of migrant workers from rural areas, district towns and adjoining states and industrial pollution. The lake on the southern fringe of the busy and pollutant ridden city is truly an oasis with its spacious pedestrian walks; giant, old rain trees, panoramic view and serenity. The lake serves as an important accessory lung of the city like the East Kolkata Wetlands due to its unique ecosystem and environment, spacious green cover and local flora and fauna. The lake was named by the Calcutta Improvement Trust (CIT) as Rabindra Sarovar in May, 1958 after the legendary Bengali poet and polymath, Nobel laureate Rabindranath Tagore. It has slowly transformed into an important cultural and recreational centre that is of equal interest to pedestrian walkers, joggers, sports, health and environmental enthusiasts, bird watchers, ecologists, botanists, nature photographers local citizens and tourists alike. The status of the lake was later elevated to National Lake due its ecological and environmental significance. However, due to the unfortunate and poor management of the lake and its adjoining premise; lack of education and awareness and severe anthropogenic pressures, the lake is showing signs of rapid degradation in terns of its fragile aquatic ecosystem and local environment.
Factors responsible for the lake pollution
The lake has unrestricted growth of several local species that include Aponogeton, Azolla, Eleocharis, Hydrilla, Hygroryza, Ipomoea, Lemna, Nelumbo, Nymphaea, Potamogeton, Salvia, Utricularia, several aquatic and semi-aquatic species of grasses and sedges in addition to algal bloom most possibly eutrophication. The unrestricted growth of aquatic vegetation transforming into thick floating vegetative mat along with receding water level at several edges and corners of the lake has been a common problem. However, the authorities in charge of the lake do not take enough initiatives to clean and remove the vegetation regularly. As a consequence, a significant part of the lake, particularly along the edge of the shore has accumulated huge vegetation mats trapping a large quantity of floating garbage and slowly deteriorating the water quality of the lake. Several reports and research articles published in recent years have supported this indicating high load of pathogenic bacteria in the water, poor biological and biochemical oxygen demands, increase in alkalinity and turbidity to mention only a handful of detrimental water quality parameters.
Only during monsoon, the pollution level of the water parameters has been found to demonstrate some reduction due to additional volume of water in the lake from the heavy annual precipitation. But during major part of the year, the lake water quality continues to deteriorate due to very high local anthropogenic pressure. Due to deteriorating nature of the water quality both swimming and rowing activities in the lake water has been seriously restricted due to reports of skin allergies and skin rashes. The high pathogenic load in the water has been attributed to direct mixing of animal and human wastes into the lake water promoting eutrophication as well as high loads solid organic matter in the water. Furthermore, the practice of idol immersions by indiscriminate dumping of different idols as part of the Hindu celebration and rituals directly into the lake water has been another important causal factor contributing to serious water pollution through the leaching of synthetic lead-based paints from immersed idols into the water body. In addition the putrefaction of the water due to dumping of flowers, fruits and different synthetic materials associated in the manufacture of the idols causing long term environmental damages to the aquatic ecosystem.
Although the monitoring along the lake premises have improved in recent times; however much needs to be done. Several incidents of mugging, snatching and harassments of ordinary visitors and helpless tourists by local goons have appeared in the local newspapers due to lack of sufficient street lights and security lapses. The pathways surrounding the lake has been paved, cement benches for pedestrians along the paved pathways, latrine facilities and fresh drinking water stalls has also been established. The planting of a number of horticultural and ornaments plants as part of the beautification drive by the local administration is also appreciated. Steps have been taken in regular cleaning of garbage from the lake premise. But unfortunately, the attempts of clean ups are way below the actual need and hence degradation of the lake and adjoining areas continue without interruption. The construction of boundary walls all along the lake premise has been hampered at several spots and hence the illegal encroachments within the campus could not be restricted or restrained efficiently.
One of the biggest nuisances within the lake premise has been the unrestricted access to the lake and the natural resources by the local slum dwellers. These poor communities have developed their slums over decades illegally along the edge of the lake on railways and government land through encroachment. The populations in those make shift slum areas have increased over time way beyond what the limited available facilities could accommodate and as a consequence the helpless communities have turned severely dependent on the lake water and adjoining resources for their daily sustenance. This included regular use of lack water for washing clothes and utensils, illegal bathing, collecting lake water, catching the fishes in the lake, defecation along the edges of the lake premises, using water for washing of different vehicles and indiscriminately dumping waste into this majestic water body.
Unfortunately, both biological as well as non-biological wastes into the water body has continued unrestricted and have been severely contaminating the water and impacting aquatic flora and fauna. These activities have been severely hampering and repeatedly degrading the lake ecosystem and environment. Lack of education, awareness and sensitivity towards local ecology and environment has contributed towards the lack of apathy in conserving it efficiently. Although several non-government organizations, prominent citizens, celebrities, ecologists, environmental and wildlife enthusiast, bird watcher and angler groups, botanical and environmental societies have come close to develop a common platform to protect the local ecosystem and environment and raise awareness; however, still it is far from being successful in transforming into a mass movement in the city.
But the good news is that people are showing some interest in protecting this unique oasis in the heart of a busy city. We sincerely hope that in near future the movement in protecting the important ecosystem of the Rabinda Sarovar; local community members, mostly environmental volunteers and crusaders from the younger generation will come forward to bring visible and meaningful changes for successful environment conservation. This big water resource could be handed to a government monitored fish farming cooperative to cultivate and harvest several local fishes in the water and sell them in the local markets after attaining marketable sizes. There is huge demand for fishes in the local markets and the water body could be used as a potential source for that to successfully cater to the city’s ever increasing demand for fresh fish and fish products. Part of the profit generated in this process could be utilized for annual maintenance and management of the lake ecosystem and protecting the lake premise.
Fig 1. View of lake shore dotted with trees and loaded with aquatic vegetation. Source-Saikat Basu, own work. . Photo credit: S. K. Basu
Fig 2. Drooping branches of a rain tree along the lake shore. Source-Saikat Basu, own work. . Photo credit: S. K. Basu
Fig 3. Lotus bed at the lake edge. Source-Saikat Basu, own work. . Photo credit: S. K. Basu
Fig 4. Plastic dumping on the lake water. Source-Saikat Basu, own work. Photo credit: S. K. Basu