LITHOLOGICAL CONTROL ON CHANNEL MORPHOLOGY: A STUDY OF KAS RIVER GORGE IN AHMEDNAGAR DISTRICT, MAHARASHTRA, INDIA

Abstract

Gorges and bedrock channels are always the sites of interest for studying fluvial processes. The response and adjustment of the flow to lithological and structural control are also the causes of the several focused studies of bedrock channel. The bedrock channel in the present study also reveals the response to bedrock lithology. The bedrock channel incision affects the evolution of the channel forms while the shapes, size, gradient and plan form of the rocky channels are largely determined by the physical characteristics of bedrock (structure, jointing, resistance to erosion, etc.) rather than the hydraulics and sediment transport characteristics. Since the width and depth of the Kas River George are almost constant therefore the velocity of discharge increases. Hence, the energy available for stream work will be greater in the segments of gorge even at normal flow discharge. Increased velocity helps to maintain the material transportation and/or increases the intensity of erosion processes in the gorge. Kas river also shows variation in the channel width from 40 to 150 meters, channel depth varies unusually from knick towards the confluence. On the basis of channel morphometshows lots of variations in the width and depth in the lower reaches of the stream, which may be the effect of the local controls like bedrock lithology and structure.