Morphometric study of selected river basins from the Meghalaya Plateau — implications for the hydrodynamics of the eastern part of Indian subcontinent

Meghalaya Plateau is a unique geomorphologic feature, being the only elevated landform in the Himalayan foreland in the eastern part of the Indian subcontinent. The elevation difference of the plateau with the Assam valley in the north and Bangladesh plains in the south has led to the development of an intricate network of drainage streams. Due to its geographical position, it receives the maximum rainfall in the world, caused by the monsoon winds. The impervious/semi-pervious rock strata of the plateau steer a huge volume of rain water as runoff through the network of streams into Assam and Bangladesh. In the absence of a robust water resource management program, the huge volume of water running down from the Meghalaya Plateau worsens the annual flood conditions in this part of the subcontinent. The Geographic Information System-based morphometric analyses of selected basins from the Meghalaya Plateau have been used to interpret the development of stream network that carries the monsoonal discharge. The calculated morphometric parameters have been used to explain the effect of vegetation, tectonics, and lithology on the development of the drainage pattern. Subsequently, a regional water divide has been established, which plays a pivotal role in the monsoonal discharge budget between Assam valley and Bangladesh plains. The work explains the contribution of the geomorphology of Meghalaya Plateau towards the development of the Brahmaputra and the Meghna rivers systems, which control the hydrodynamics in the Sundarban deltaic region.