ShodhPatra: International Journal of Science and Humanities

Spatio-Temporal Change and Anthropogenic Effect For The Decline Of The Saraswati River, Lower Ganga Delta: Integrating Historical Cartography, Hydraulic Morphometry, And Land Use Land Cover Change (1776–2025)

Over time, natural processes and growing anthropogenic interventions have enhanced the degradation of distributary channels in the lower Ganga Delta. The Saraswati River, which was a distributary of the Bhagirathi system of the Hooghly system at one time, has had a great decline in its morphological and hydrological conditions. This paper studies the Spatio-temporal change of the river through the combination of historical cartography, hydraulic morphometry, and Land Use and Land Cover (LULC) dynamics between 1776 and 2025. Georeferences of archival sources, such as the Bengal Atlas, were used to reconstitute the channel patterns in the past, and multi-temporal Landsat (1990, 2005, and 2025) images were interpreted by applying supervised classification methods. Several stations were chosen for this study. Findings show that the downstream channel depth (previously 1.23 m) and discharge (previously 23.70 m3/s) decreased significantly and the width-depth ratio increased (> 45), a sign of widening channels and declining hydraulic efficiency. The LULC analysis shows that the built-up areas are growing at a rapid rate, and fallow land and vegetation are decreasing, which means that the pressure of people in the river corridor increases. This is further indicated by the historical evidence that diversion of the canals and massive interventions, especially under the Damodar Valley Corporation (DVC), have greatly changed the natural flow regimes. It shows a close connection between channel degradation and land use change, and it is necessary to implement an approach to managing rivers and sustainable planning to recover ecological stability in the deltaic river systems.