Hydropeaking in the Indian Himalayas: Interactions between Hydropower Operations, River Dynamics, and Societal Governance

Hydropower supports India’s renewable energy transition by enhancing grid stability amid growing solar and wind penetration. In the Indian Himalayas, hydropower development and operation occur within ecologically sensitive and geographically complex river systems shaped by political, social, and cultural constraints that influence water management and access to hydrological observations, which often rely on manual or low-frequency gauging. Many river basins are transboundary, and hydrological data sharing is constrained by neighboring riparian states as well as broader geopolitical and security considerations, with high-resolution datasets frequently treated as sensitive. These limitations are further compounded by rivers functioning as socially and spiritually significant landscapes. Within this setting, hydropeaking, characterized by rapid sub-daily adjustments of river discharge to meet electricity generation needs, introduces pronounced flow variations in already stressed river systems. Despite its potential consequences and impacts, empirical evidence on hydropeaking impacts in India remains limited and under-represented. This study presents new field-based evidence from a real-time in-situ monitoring station deployed downstream of a hydropower project in the upper Yamuna basin. The observations reveal highly regular sub-daily water-level fluctuations dominated by rapid up- and down-ramping associated with peaking operations, indicating strong operational control over downstream flow regimes. Sub-daily variations in river water temperature are also observed, pointing to additional complexity in regulated river responses and impacts on the riverine ecosystem. Given the cultural and religious use of rivers such as the Yamuna, these hydrological alterations may further influence human–river interactions. Overall, we highlight the need for fine-scale eco-hydrological monitoring and governance approaches that account for political constraints and socially embedded river use when assessing hydropeaking in Himalayan river systems.