Automated Real-Time Streamflow Acquisition in a Mountainous River Using Acoustic Tomography

Abstract

Acquiring discharge estimates is crucial in hydrological studies, extreme event analyses, and water resources management. This study demonstrates the improved fluvial acoustic tomography system (FATS), a promising approach for automatically measuring streamflows with high temporal resolution for a long period. Unlike past hydroacoustic systems, the FATS enables continuous capture of the depth- and range-averaged water velocity with a single transducer set. Streamflow measurements were performed on November 26, 2015, in a mountainous river (depth: 0.8 m under low-flow conditions, width: 115 m). This paper presents a 127-day record of the flow. The average stream velocities and streamflows are automatically estimated from the acoustic data and water level data. The real-time flow data can be monitored by the Internet access. The continuous FATS estimates indicate that the streamflow does not change smoothly with the river stage. Analyses reveal that the streamflow may not be estimated accurately from a smooth rating curve (RC). The relative biases of RC reach ∼±20% even under higher flow conditions. The FATS captures short-wave irregularities in the streamflow time-series.