Understanding dynamics of large rivers aided by satellite remote sensing: a case study from Lower Ganga plains, India

The advent of satellite remote sensing has provided a huge opportunity to geomorphologists to study the temporal dynamics of large rivers. The repetitive coverage of satellite data is an important archive to reconstruct historical-scale dynamics of large rivers and to understand the causal factors. In the lower reaches of the Ganga River around Farakka, natural as well as anthropogenic factors have influenced large-scale dynamics of the river during the last 234 years. The construction of the Farakka barrage was started in 1961 and was completed in 1971 except the feeder canal. The barrage was finally commissioned in 1975 but the serious problems of aggradation both upstream and downstream of the barrage had started much earlier resulting in significant changes in channel morphology and position. The channel upstream of the Farakka barrage has moved towards the east but channel shifting downstream of the Farakka barrage has been erratic. We argue that sedimentological readjustments due to aggradation and bar growth are the major factors influencing the river dynamics in this region.