Reliability of Entropy-Based Telemetry Discharge Estimates in the Himalayan Rivers: A Comparative Study with ADCP and Current Meter

This study evaluates the performance of an entropy-based telemetry river discharge estimation method at two Himalayan river gauging sites – Ganga and Bhagirathi – by comparing its performance with conventional Current meter (CM) and Acoustic Doppler current profiler (ADCP) techniques. Results show strong agreement between telemetry and CM data at the Ganga River gauging site (R2 = 0.97) and between telemetry and ADCP data at the Bhagirathi River gauging site (R2 and NSE > 0.9). To investigate these site-specific differences, sensitivity and Bayesian uncertainty analyses of stage-discharge rating curves for both observation methods were conducted, revealing key differences in method performance. Sensitivity analysis identified stage as the most influential parameter affecting discharge observations. Bayesian uncertainty results indicated that ADCP provide greater accuracy and more robust uncertainty bands, particularly under dynamic, controlled flow conditions where CM performance declined. Overall, the findings demonstrate that the optimal discharge observation method depends on site-specific hydrodynamics, with ADCP offering the most reliable solution for data‑scarce, turbulent environments.