Journal of the Japan Society of Erosion Control Engineering, Vol.65,No.2, 2012

Development of an automatic opening pit bedload sampler

Takeshi KIRYU, Kenji NAGAI, Akihiro TAKEUCHI, Nobuhiro USUKI, Hisatoshi SANO,
Tomoaki EGUCHI, Naoki NISHIMURA and Takahisa MIZUYAMA


In the observation of bed load transport using a hydrophone, a bed load measuring pit is often installed for the calibration of the hydrophone's pulse data. A small pit, however, poses a problem as it tends to fill up before a flood event reaches its peak. Because past observations have revealed a tendency for bed load to exhibit different flow patterns before and after the peak of a flood, we need to establish a relationship between the hydrophone pulses and bed load transport after the peak. For this purpose, a device for measuring bed load transport has been developed with a mechanism that opens the slit of the measuring pit automatically at the peak of a flood. This device uses water|level measurements obtained by an ultrasonic water gauge as a trigger to activate a hydraulic jack which moves the lid installed over the slit so as to allow the pit to start collecting bed load in the middle of a flooding event.

Key wordsFautomatic opening pit bedload sampler, hydrophone, Osawagawa river

Japan Society of Erosion Control Engineering
Sabo Kaikan Bekkan 3F, 2-7-5 Hirakawa-cho, Chiyoda-ku, Tokyo
Phone +81-3-3222-0747 Fax +81-3-3230-6759