Evaluation of the role of rock properties in the development of potholes: A case study of the Indrayani knickpoint, Maharashtra

Abstract

The most conspicuous erosional features associated with constricted bedrock channel reaches and knickpoints are potholes. The presence and morphology of potholes have been attributed to a number of factors by earlier researchers. Amongst these factors, the role of substrate rock properties has received very little quantitative attention. The main objective of this study is to quantitatively evaluate the physical properties of bedrock in order to test the possible influences of rock properties on the occurrence and morphology of potholes. The area selected for this study is a large scabland area developed by the Indrayani river at Shelarwadi near Pune. This site is ideally suited for the study since it is featured by wide straths, multiple inner channels and several hundred potholes. A transect-based quadrat method was used in this study. Within each quadrat, the pothole dimensions, the joint length, joint direction, the rock mass strength and the distance from active channel were measured. The analysis reveals a weak correlation between pothole size and rock properties. The distance from the active channel emerges as the most significant factor, suggesting that the hydraulics of flows is the key factor and substrate characteristics play only a secondary role. © Indian Academy of Sciences.