A source tracking framework for attribution of reservoir fluxes in multi-reservoir systems

•Framework quantifies the contribution of diverse water sources to reservoir releases.•Apply the concept of virtual storages for source tracking.•Analyze a water transfer project from Godavari to Krishna basins in Southern India.•Show possibility of increased transferred water to contribute to environmental flows during monsoon season.•Show that transferred water mainly satisfies demands from other reservoirs further downstream of the recipient.