河床変動に対応した河川流量観測システムの開発と実河川実験

抄録

The river flow discharge measurement system under the condition of riverbed evolution has been developed. In the system, flow velocity, water level and local riverbed elevation are measured continuously, and cross section and calibration factor of the river channel are estimated both from the measured riverbed elevation and riverbed shapes previously detemrined by numerical calculations. Flow discharge is then obtained by multiplying the measured flow velocity, estimated cross section and calibration factor. Field experiments were carried out at Ozaki located upstream of Kambara Ozeki weir in the Shinano River. Investigations of the riverbed materials indicated that bed load could have moved after the special gate operation for migration of salmon at October 1st when reservoir water level was drawn down by opening gates of the weir and flow velocity was increased. The mean riverbed elevation was fallen down by 16cm from September to December. It was confmned that the developed system can measure the river flow discharge within +/- 10% of that estimated by an Acoustic Doppler Current Profiler.