The bedrock river profile fitting and the indicative significance: a case study in Gyirong watershed of the Middle Himalaya

Abstract

Area-slope (AS) Model focuses on quantitative study of bedrock river which has been widely used in the longitudinal profile simulation of bedrock and alluvial rivers, but many applications have failed to carefully consider the mechanism, fitting effect and applicability, resulting in unsatisfactory simulation results. In order to verify the channel profile analysis capability, the study analyzes the oretical basis of AS model and applies to the river channel fitting and knickpoint identification in the Gyirong Watershed in the middle Himalayan Orogen. The results show that, for rivers with different equilibrium status, the fitting curves have different splattering patterns. More than 80% knckpoints locate on the elevation between 4000 –5050 m where coincided with Tibetan Himalayan Unit. Although climate affects the spatial distribution of knickpoints, the structure of Gyirong watershed have developed before modern climate pattern.