High‐frequency streamflow acquisition and bed level/flow angle estimates in a mountainous river using shallow‐water acoustic tomography

Abstract

Abstract:The acquisition of reliable discharge estimates is crucial in hydrological studies. This study demonstrates a promising acoustic method for measuring streamflow at high sampling rate for a long period using the fluvial acoustic tomography system (FATS). The FATS recently emerged as an innovative technique for continuous measurements of streamflow. In contrast to the traditional point/transect measurements of discharge, the FATS enables the depth-averaged and range-averaged flow velocity along the ray path to be measured in a fraction of a second. The field test was conducted in a shallow gravel-bed river (0.9 m deep under lowflow conditions, 115 m wide) for 1 month. The parameters (stream direction and bottom elevation) required for calculating the streamflow were deduced by a nonlinear regression to the discharge data from the well-established rating curve. The crosssectional average velocities were automatically calculated from the acoustic data, which were collected on both riverbanks every 30 s. The FATS was connected to the internet so that the real-time flow data could be obtained. The FATS captured discharge variations at a cut-off frequency of approximately 70 day À1 . The stream exhibited temporal discharge changes at multiple time scales ranging from a few tens of minutes to days.

A Mountainous River Flow Fluctuation Analysis Using Shallow-Water Acoustic Tomography System

“…This finding demonstrate fluctuation characteristics observed by FATS is almost similar with other conventional measurement methods. In other words, this finding support the other works of Kawanisi, et al 9),10),11), 12) , who proved the feasibility and high performance of automatic monitoring of streamflow at a high temporal resolution by the use of FATS.…”

“…The flow rate computed by both approaches were almost similar. Kawanisi et al 12) studied the uncertainties of discharge measurement by FATS in comparison to RC, they demonstrated that the relative difference between QFATS and QRC does not exceed 6% and discharge obtained by FATS is reliable. The results of the high-frequency scaling exponents are presented in Fig.…”

“…M-sequence (Maximum length sequence) is a pseudo-random sequence. Further details about FATS's measurement method and the competitiveness of the obtained data can be found in the literatures of Kawanisi et al 9),10),11), 12) .…”

Applicability of recurrent neural networks to retrieve missing runoff records: challenges and opportunities in Turkey

“…Moreover, according to the DSI records, stage-discharge readings were performed one time per month. As a result, establishing robust relationships between stage and discharge would not be guaranteed (Di Baldassarre & Montanari, 2009;Kawanisi et al, 2016;McMillan et al, 2010). In this regard, McMillan et al (2017) proved that in Europe the costs of developing a new discharge rating curve costs roughly €10,000, consisting of one day's work for a hydrometric consultant team to do discharge measurements (€3000) and the cost of stepped water releases over the desired flow interval (average additional release of 3 m 3 /s for 10 h; cost €7000).…”

Influence of Suspended Sediment Concentration and Particle Sizes on the Sound Attenuation of the Fluvial Acoustic Tomography Technique

“…The principle of the streamflow measurement by FATS is presented by Kawanisi et al (2016). Briefly, the streamflow is determined by solving the following equations [21]:…”