Evolution of wetlands in lower reaches of Bagmari-Bansloi-Pagla rivers: a study using multidated images and maps

Numerous seasonally flooded wetlands in the lower Gangetic floodplain offer unique natural habitat for many migratory bird species due to their geographical location and hydro-ecological functioning. The various developmental projects change the riverine flow regime and cause hydro-ecological modification in the Gangetic floodplain wetland system. This study presents a comprehensive spatio-temporal monitoring of wetland dynamics in the lower segment of the Bagmari-Bansloi-Pagla sub-basin of the Ganga-Bhagirathi rivers using image classification technique and some fragmentation indices. Our results reveal that the land-use conversion and fragmentation processes that affect the wetland landscape are generally represented as the evolution, and consecutive drying and squeezing of wetland patches over the study area. The water-spreading area of the wetlands was highest during 1975 after the construction of the Bhagirathi feeder canal. The situation has worsened since 1980 due to cumulative effects of agriculture after the Green revolution, and the whole landscape has become a fragmented, isolated and agronomically managed wetland.