3. Identification of Potential Anthropogenic Barriers to Fluvial Connectivity in the Lower Gangetic Basin of India

The intensifying need of human beings and the corresponding development of infrastructure are increasing the degree of interaction between river systems and anthropogenic constructions like dams, barrages, embankments, roads, railway lines, river crossings, and altering land cover. Therefore, it is essential to identify as well as quantify potential area and degree of interaction over the fluvial landscape, respectively. Freely available geospatial data have been used in the present study to identify such interaction across the Lower Gangetic Basin (LGB). The present study finds that the longitudinal connectivity of rivers of LGB has been disturbed by 96 major dams with their water holding capacity of ~1064 million cubic meters, 21 barrages, and 3548 road-stream crossings. The lateral connectivity is also affected by the alignment of ~28% length of the total transport network of LGB within the active and old floodplains only, which are significantly disconnected about 30% floodplain from its main channel. The proximity analysis shows about 40% area of LGB falls under the proximal distance of 1000 m only. Intensive agricultural practice and construction of built-up areas within the active floodplain are also major causes of fluvial disconnectivity across the LGB.