Assessing the geomorphic response and sensitivity of a Himalayan river to climate change and anthropogenic pressures

Abstract

Understanding river response to external controls and its geomorphic sensitivity is critical for planning sustainable management strategies. The Yamuna River with 1,376 km length and 366,223 km² basin area is a key Himalayan river supporting 341,628 number of people for their agriculture, industry, and urban needs. This study integrates geomorphic characterization, stream power analysis, hydrological modeling, and remote sensing to assess its response to projected climate scenarios and anthropogenic influences. Geomorphic analysis was carried out using the River Styles framework and segmentation analysis of river channel using the Fluvial Corridor Toolkit. Geomorphic attributes for River Styles were analyzed across spatial scales and were used to classify the river system in thirteen different geomorphic classes. Stream power distributions were derived from historical hydrological records and DEM derived longitudinal profile. Future hydrological scenarios were simulated via the Variable Infiltration Capacity (VIC) semi-distributed hydrological model driven by INM-CM5-0 and MIROC6 climate models. Results reveal spatial variability in climate change impacts, classifying river reaches into sensitive and resilient zones. Reach-scale sensitivity map of the Yamuna River system will provide a fundamental dataset to priorities the stream management efforts. Further, 460 km long channel reach from mountain front to downstream of Delhi megacity was analysed with high-resolution (500 m) segmentation of the river using the Fluvial Corridor Toolkit to understand anthropogenic impacts on river channel. Key geomorphic parameters including channel width, braiding index, water width, and vegetation width were quantified for each segment. Results highlight extensive human-induced modifications. Anthropogenic influences, particularly in the alluvial reaches, have surpassed climatic and geological controls, driving geomorphic transformations. Notably, sand mining, dam construction, and encroachment in the Delhi megacity urban corridor have disrupted natural fluvial dynamics. This multi-scale multidisciplinary study highlights the integration of climate, and anthropogenic drivers that shape Yamuna’s contemporary morphology and its future trajectory. The results provide new insight for integrated, multi-scale management strategies. Synthesizing climate projections, hydrological simulations, and geomorphic analyses provide a comprehensive assessment of evolving fluvial dynamics, advocating for proactive interventions to mitigate human-induced disturbances and preserve riverine functionality under escalating environmental pressures.