Integrated approach to evaluate the role of wetland for disaster risk reduction and human well-being: A case study of East Kolkata wetland

Urban wetlands provide vital ecosystem services such as habitat provision, water and purification, flood regulation, climate regulation, food provision, and recreation. However, rapid urban expansion has placed tremendous pressure on urban wetland environments, leading to their shrinkage. East Kolkata Wetland (EKW), a Ramsar site near urban area noted for its high biological diversity. Moreover, this wetland also acts as retardation basin for managing flooding in the neighboring areas and purifies a significant portion of the wastewater received from the city of Kolkata through application of local ecological knowledge (LEK). Despite its high significance, the wetland is facing different threats in terms of encroachment, pollution etc. This study aims to assess possible future changes of the East Kolkata Wetland (EKW) through integrating spatiotemporal data with socio-legal data over the past 23 years. The study uses Shannon's entropy model together with the number of litigation cases. The results indicate that the entropy value increased from 0.394 in 1993 to 0.413 in 2023, suggesting a more dispersed distribution of development, primarily towards the east. This shift is contributing to the conversion of the East Kolkata Wetlands (EKW) into real estate developments. The study also reveals that 95 % of litigation cases in the EKW are related to unauthorized construction and the filling of water bodies. These unsustainable developments can increase Kolkata's exposure to more severe flooding together with loss of food security and biodiversity. The research provides valuable insights for policymakers by offering spatial zones of sensitivity depending upon categories of conversion and suggest steering urban growth away from the east, which could minimize degradation of the EKW and be crucial for Kolkata's long-term sustainability. • The East Kolkata Wetland (EKW) contributes to waste management, food security and flood protection. • Analysis of spatial and socio-legal data was used to predict future degradation of the EKW. • Temporal variation of Shannon's entropy value depicts an increase of dispersed built-up areas. • The eastward growth of the city through real estate developments and illegal encroachments. • The waste management, food security and flood protection function of the wetland is in peril.