Base-level and Litho-structural Controls on the Incised Sinuous Bedrock Rivers of the Jawhar Plateau, North Konkan, India

ABSTRACT The coastal rivers draining the mid-altitude Jawhar Plateau in north Konkan display some unusual drainage and channel characteristics. These rivers, especially in their middle reach, are highly sinuous and deeply incised in bedrock basalt. In this study, various geomorphic indices were calculated and interpreted for five such bedrock meandering rivers, namely Purna, Ambika, Auranga, Par and Damanganga. Morphometric data reveal that in spite of more drainage basin area in the mid-elevation category, the rivers are not only deeply entrenched within bedrock basalt, but also have unusually high sinuosity. There are indications of subtle to significant control of dykes and lineaments on the channel planform morphology and channel bed profile. However, various other geomorphic evidences suggest that an increase in the regional slope, induced by a fall in the erosional base-level, has most likely played an important role on longer timescale in the initiation and formation of the incised bedrock meanders in this part of the Deccan Traps region.