East Kolkata Wetlands and the Regulation of Water Quality

Abstract

The East Kolkata Wetlands (EKW), located on the eastern fringes of Kolkata City, India, are a large network of fish farms with their water supply coming from sewage effluents of Kolkata City. The EKW are spread over an area of 12,500 ha and form a part of the extensive delta of the River Ganges. The wetlands sustain the world’s largest and oldest integrated resource recovery practice based on a combination of agriculture and aquaculture and have been estimated to provide livelihood support to a large, economically underprivileged population of in excess of 20,000 families. The wetland is a mosaic of landforms including predominantly water-dominated areas (fish farms) to terrestrial usages for agriculture and horticulture. Settlements are interspersed between various land uses. The use of sewage as the basis of aquaculture, agriculture, and horticulture production systems provides the rationale for considering the entire system as a single management unit, also referred as Waste Recycling Region (WRR). Based on the significant ecological and sociocultural importance of the site in 2003, the Government of India declared East Kolkata Wetlands as a Wetland of International Importance (Ramsar Site) under the Ramsar Convention.