Transformation and risk assessment of the East Kolkata Wetlands (India) using fuzzy MCDM method and geospatial technology

The East Kolkata Wetlands (EKW) is located on the eastern periphery of the city of Kolkata and extends up to the Bidyadhari-Matla River confluence. It is a Ramsar Site and acts as an absorber basin for a large number of con-taminants drained from Kolkata. Agricultural lands, sewage-fed fisheries, garbage dumping fields, horticulture, and built-up areas are included in this protected area, that covers approximately 125 km(2). It reveals that climate change reduces the variety of wetland ecosystem services and increases socio-economic vulnerability and economic stress. The human encroachment, reclamation of land for agriculture, aquaculture, and urban expansion in and around Kolkata has recently adversely threatened the EKW. The remotely sensed data, socio-economic data, and responses of inhabitants have been used to analyse the EKW's risk and vulnerability. We employed geospatial analysis by using the Multi-Criteria Decision Making (MCDM) method using nine risk factors. An in-depth analysis of the EKW using geospatial techniques and the Fuzzy Analytic Hierarchy Process (FAHP) helped to understand the EKW transformations through vulnerability and risk analysis. The results show that the transformation of the wetland to aquaculture, eutrophication and pollution, road proximity, waste dumping, population density, and growth are the main factors for the deteriorating health, quality, and environment of the EKW. It also reveals that quantitative and qualitative evaluations of ecosystem services, wetland degradation, transformation, and cause -effect rapport should be periodically assessed using scientific methods like FAHP, RS, GIS to formulate resilient, integrated plans and strategy for the sustainable management of the EKW.