Formation of Potholes Associated with Bedrock Gorges on Mesozoic Sandstone of Khari River, Kachchh Mainland, Western India

Kaustubh Sane,Gaurav Chauhan,Mahesh G Thakkar,Deepa Aiyar,Subhash Bhandari

doi:10.4236/ojg.2020.102010

Abstract

The potholes are perceptible erosional features associated with bedrock channels. They play an essential role in bedrock incision studies, but little work has been published on the development of potholes, especially in Bedrock Rivers in India. The present site-specific study aims to analyze the role of physical properties of bedrock and associated structures in the process of development of potholes and to classify the potholes based on their dimensions. The Khari River gorge formed over Mesozoic Sandstone with six bedrock terraces exposed along a confined segment of the river. The site is manifested by strath terraces, grooves, potholes, and knick points. Three stretches of Khari Gorge have been studied in detail for this purpose. The pothole dimensions, joint orientations, rock mass strength, physical properties of rock, and placing of potholes to present active channels were measured. The analysis shows the inverse relationship between the size of pothole and rock properties. The distance of potholes and active channels govern the essential factor and manifest the role of flow hydraulics. The high density of matured potholes near active channels over immature potholes supports primary control of hydraulics of flow over rock properties.

Highlights

Potholes are common erosional features observed in the bedrock channel
The analysis shows the inverse relationship between the size of pothole and rock properties
The present study focuses on the potholes that have developed in a peculiar transect of Khari River, Kachchh

Summary

Introduction

Potholes are common erosional features observed in the bedrock channel. Potholes usually form via abrasive work, initially in minor bed depression that are weak zones due to the interaction between vertically oriented joints [1] and zones of increased weathering [2] [3]. The bedrock channels have other erosional features such as grooves and immobile boulder obstructions [4]. The turbulent flow of the river develops the eddy current enters these initially minor depressions on the bed form. Stacked grinder particles inside the pothole help in identifying the number of shear flow generation periods in the channel [5]

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Discussion

Conclusion