Wetlands in West Bengal’s Murshidabad district are disappearing at an average rate of 2.1 per cent per year — about one-and-a-half times higher than India’s national average and almost three times the global average, according to a new study.
The paper examined 14 major wetlands in the district and found a loss of two-thirds of the wetland area over 35 years. The combined area of these wetlands had declined sharply to 1,700.2 hectares (ha) in 2025, from 5,524.7 ha in 1990.
The study, conducted by Subhasis Das of Raja Narendralal Khan Women’s College (Autonomous) under Vidyasagar University, along with Pravat Kumar Shit, Assistant Professor of Geography, was based on satellite image analysis from 1990 to 2025, and was supported by field surveys conducted between 2019 and 2025.
Fourteen major wetlands were studied, including Ahiron Lake in Suti-II block, Bonsabati Beel, Balagachhi Reservoir in Sagardighi, Chhatiyani Beel in Beldanga-II, Chaltia Beel in Berhampore, Bishnupur Beel, Bilpatan, Bil Belun and Char Sujapur.
West Bengal state has around 150 natural wetlands, with Murshidabad hosting the highest number of wetlands in the state. The wetlands in the district, often described as the ‘kidneys of south Bengal,’ regulate water flows, recharge groundwater, support fisheries and agriculture, and sustain thousands of rural households.
The study found that more than half of the wetlands in Murshidabad were now severely degraded, choked by invasive aquatic weeds, silt deposition and pollution.
The researchers assessed wetland health based on habitat condition, landform stability and ecosystem services. Wetlands such as Chaltia Beel, Bishnupur Beel, Bil Belun and Bilpatan were classified as being in ‘very poor’ to ‘poor’ condition, while Ahiron, Chhatiyani and Balagachhi Beel were assessed as ‘below normal’.
Only a few wetlands showed relatively stable ecological conditions.
A critical concern highlighted by the study is the collapse of natural river-wetland connectivity. Of the 14 wetlands surveyed, 13 were historically connected to nearby rivers. However, today, only four — Shial Lake, Balagachhi, Char Sujapur and Chhatiyani Beel — retained functional connections.
Changes in river courses, embankment construction and large-scale encroachment have severed these links, resulting in stagnant water, reduced flushing and declining biodiversity.
While indigenous fish species were disappearing and the availability of aquatic plants like shaluk, water chestnut, kalmi shak and gima shak, important for household nutrition and supplementary income, has declined sharply, the economic consequences too were visible.
Using data from 2019 and 2025, the study estimated the value of ecosystem services, such as fisheries, crop production, water supply, fodder, jute retting and tourism, provided by wetlands.
The total ecosystem service value declined from $89.75 million per hectare per year in 2019 to $86.96 million per hectare per year in 2025, reflecting an annual loss of about 0.46 per cent. Researchers warned that this gradual erosion translates into long-term livelihood losses for wetland-dependent communities.