Observations
Observations
- Sediment production and debris flow initiation at the Hiru dani stream
- Observation flume at the Ashiarai dani river
- Observation at the Ashiarai dani watershed
- Debris flow observation at Kamikami horizawa creak
Sediment production and debris flow initiation at the Hiru dani stream
In the Hiru dani stream, we conduct observations of sediment production and transportation. A branch stream flows into the main stream at the middle reach. In the branch stream, active sediment production and transportation are observed, and in the main stream, on the other hand, there are a little sediment production and transportation is observed. We have focused our observation on upmost part of the branch stream, middle reach confluence part and the lower reach check dam.
Upstream of the Hiru dani
We have conducted sediment production and transportation by video monitoring in long term perspective at the upmost part of the Hiru dani branch stream.
Middle reach of the Hiru dani
At the confluence part in the middle reach, we have conducted the water level and turbidity monitoring. At 200 m upstream part from the middle reach station, a tipping bucket rain gauge is installed and rainfall monitoring has been conducted. We also conduct video monitoring similar to the upmost observation station.
Downstream of the Hiru dani (Hiru dani check dam)
At the check dam in the lower reach, water level, turbidity, electric conductivity, and rainfall have been observed. Sediment deposition are constantly measured to estimate total sediment transport in a long term perspective. We also conduct experiments to improve sediment flushing techniques from dam reservoir.
Observation flume at the Ashiarai dani river
We have conducted bedload monitoring by Japanese pipe hydrophone, plate hydrophone and Swiss plate geophones, and comparing their performances. We also installed a vertical type pipe hydrophone to improve the accuracy of the bedload measurement.
Observation at the Ashiarai dani watershed
The Ashiarai dani river consists of four tributaries, Hiru dani, Waru dani, Kuro dani, and Shiramizu dani streams. Besides the observation flume at the lower reach of the Ashiarai dani, water level and bedload monitoring are conducted at the Hiru dani, Waru dani, Kuro dani and Shiramizu dani streams. Water discharge measurement are constantly performed under various conditions by tracer method using portable EC sensors.
Debris flow observation at Kamikami horizawa creak
With the cooperation by Matsumoto Sabo Office, MLIT, we have conducted debris flow monitoring; debris flow velocity, flow depth measurement and video monitoring, at Kamikami Horizawa creak, upstream of the Azusa River, a tributary of the Shinano River watershed. We also conducted the precipitation measurement whole year, with tipping bucket rain gauge heated during winter time.
