Drainage Basin Morphometry Analysis in Parts of South Shillong Plateau, Meghalaya: Implications for Landscape Development

The Shillong Plateau is characterised by multiple phases of deformation and number of prominent sets joints/fracture system. The Southern Shillong Plateau unlike the northern part is highly dissected by the scarp faces which are mostly erosional. The area is characterised by deep incising river networks which cuts across many lithological units. To understand the factors influencing the drainage characteristic of the area and landscape development, the present study has been done in context of morphometry, geomorphology and geology of the drainage basin. Fifteen sub basins of 4th order have been selected from the Um Sohrynkew River basin. Drainage morphometry, indices of active tectonism, geology and tectonics and landform features have been worked out for better evaluation of drainage characteristics. The study area forms part of the Meghalaya Precambrian province of upper Proterozoic age. The southern border of the Shillong Plateau is demarcated by Dauki (Also known as Dawki) fault which is a prominent structural lineament. It consists of at least four E-W trending normal faults with occasional reversal. The segment of the Dauki fault in the study area is believed to be active. The present study focuses on the drainage network and the landscape development of the study area where a very strong relationship has been observed between the lithology and structure together with the tectonic activity influencing the drainage pattern in the area.