Figure 1 is here.
Fig. 1 The Gono River and its tributary (Basen and Saijo
Rivers), the location of the MLIT gauging stations (Green dots) and the
position of the two acoustic stations (T1 & T2) of the FAT system (Red
dots).
In addition, Kawanisi et al., (2016, 2018) performed long-term
streamflow measurements that was located very close to Ozekiyama station
(Fig. 1) using the Fluvial Acoustic Tomography (FAT) system. Hence, as a
novel feature for this work, the available hourly discharge records
measured by FAT from 2016-01 to 2016-06 was used for further comparison
with RC records. Past works had deeply discussed the measurement
principles and discharge accuracy by means of the FAT in details
(Kawanisi et al. , 2013, 2016, 2018; Razaz et al. , 2013;
Bahreinimotlagh et al. , 2016; Al Sawaf and Kawanisi, 2019), thus
this work does not aim to repeat the previous works, rather it considers
the reliable records of streamflow data as observed by the FAT system
for further analysis. However, it is vital to point out that discharge
measured by the FAT is computed using the main flow equation in open
channels as:
\(Q_{\text{FAT}}=u\ \times\ A\times\tan\theta\) (2)
where u and A are the cross-sectional averaged velocity
and oblique cross-sectional area along transmission line, respectively,
and θ is the flow angle. As can be seen in Eq (2), unlike the
discharge estimated by the RC approach, the discharge computed by FAT
comprises both velocity and area (stage) terms.