Revival of Riverine Wetlands through Re-Establishing Longitudinal Connectivity of Extinct River Systems

Abstract

The Indo-Gangetic Plain exhibits a number of riverine wetlands associated with extinct rivers in the form of interconnected channels, oxbow lakes, meander scars, etc. To develop a model for the revival of these riverine wetlands, the interfluvial zone of the Ganga and Sai Rivers has been taken as the case study area, where, the Bakulahi River is existing an extinct river that has numerous associated riverine wetlands. The SRTM DEM data was acquired from the USGS website, and further, the elevation along the delineated traces of the channels of the Bakulahi River in the DEM map was lowered by 3 m in ArcGIS software, and a modified DEM map was prepared. Applying SWAT to the modified DEM data, a model of the Bakulahi River basin has been developed, which reveals that by excavating along the traces of the Bakulahi River by 3 m, the river can be revived. After the revival, it was found that the catchment area, length, discharge, and number of sub-basins had increased. Out of 125 sub-basins, 14 are notable for high groundwater recharge potential, making them vital for ecosystem conservation and strictly restricted from any construction activities. This model highlights that enhancing longitudinal connectivity not only increases the river’s flow but also reconstructs all the associated wetlands and supports biodiversity. Furthermore, this approach has the potential to serve as a role model for the restoration of Quaternary riverine wetlands in the Gangetic Plain, as well as for similar floodplain systems worldwide facing the threat of extinction.