Wetland degradation of a ramsar site: A study of East Kolkata wetlands of West Bengal, India

Abstract

Wetlands provide various ecological and economic services to sustain biodiversity and livelihood, but they are over exploited around the globe. The East Kolkata Wetlands (EKW) is a crucial Ramsar Site that works as a fully functional natural and organic sewage management system. It is also known as the kidney and lung of the city due to its wise use practices. The East Kolkata Wetlands is a unique site, a network of canals, fish ponds and agricultural fields, treats, retains and drains the sewage of the Kolkata metropolis and provides a sizeable number of fish farming community's livelihood and produces over 10,000 MT of fish per year apart from rice and vegetables. But in the last few decades, illegal land acquisition, wetlands conversion, aquatic species depletion, and siltation have been experienced in different parts challenging the survival of the EKW, which adversely affects the livelihood of the populace which depends on it. In such a scenario, the focus of the study was to investigate the changes in land use/land cover from 1991 to 2021 in the East Kolkata Wetlands to understand the present underlying causes to identify the problems and challenges it faces. The methodology includes preparing a land-use map from 1991 to 2021 using Landsat images. The analysis shows that the area under the settlement build-up has been increased from 22.59 sq km in 1991 to 35.29 sq km in 2021 due to population growth with a consequent decrease of open spaces and water bodies from 12.11 sq km in 1991 to 4.13 sq km in 2021 due to urbanization and developmental activities, consequently hamper the livelihood of dependent communities. The conclusion highlights the approaches of the wetland conservation process and the emergence consequences on the environment and its dependent populace, which would eventually benefit the city herself in the long run and significantly, compound its sustainability.