MCA on mechanism of river bed potholes growth: a study of middle Subarnarekha River basin, South East Asia

Pothole is an exceptional dynamic micro-fluvial erosional landform of the river bed. Subarnarekha River is a rejuvenated antecedent river and occupies a significant part of the Chotanagpur Plateau. The river bed of the Subarnarekha River and the confluence zones of Subarnarekha-Lokjoriya and Subarnarekha-Kharsoti have favourable conditions for the development of potholes. Geological (joint and fracture on river bed) and hydrological (stream power, water discharge, flow velocity) parameters are taken into consideration to understand the mechanism of pothole growth. Multi-criteria analysis (MCA) has been done to understand the governing factor influencing the mechanism of pothole development. The results are analysed in a quantitative way, and the micro-scale field observations have been represented using ArcGIS10.2.2 and IBM SPSS 22. Using the MCA it has been inferred that joint length' is the prime contributing factor responsible for pothole formation in the middle Subarnarekha River basin, Ghatsila. The main significance of this research work is the study of micro-geomorphic landforms mechanism near confluence and other places of the river bed.