Dynamics of the Ganga in West Bengal, India (1764–2007): Implications for science–policy interaction

Abstract

Understanding of the fluvial dynamics of the Ganga, especially in its lower reach, is incomplete to present. Questions such as why the river changes its course so frequently, or what are the impacts of major structural intervention at Farakka, have not been addressed properly. Open scientific research is impeded by the governmental attitude to conceal water-related data. The present paper deals with the changing courses of the Ganga in West Bengal since the second half of the 18th century. The source materials of this research are maps published by different agencies since the colonial period and a recent satellite image provided by the National Remote Sensing Agency of India. The Ganga enters the Maldah district of West Bengal after touching the outlier of Rajmahal Hills, and swings across the deltaic plain. In the reach between Rajmahal and Farakka, the Ganga has been flowing through a series of distributaries alternately and those channels have now been abandoned. The sequential maps help to understand how the Ganga has changed its course during the known historical period. Since the construction of Farakka barrage, the Ganga has migrated eastward appreciably and has formed a mighty bend. Trapped sediment load above the Farakka barrage has largely induced the recent change. The continuous oscillation of the Ganga in Maldah district, and also along the Indo-Bangladesh border has posed many problems, including land reallocation, population displacement, and border disputes. There should be a paradigm shift in the governmental attitude to look into the matter, not as a purely engineering problem but also as a social issue.