| One of the goals of the International Bedload Surrogates Monitoring (IBSM) Workshop was to identify potential new technologies for safe and continuous monitoring of bedload in rivers. Here is a summary of the main technologies, along with their state-of-development:
I. Discrete-impact sensing devices with passive acoustic sensors – Several devices of this nature are currently deployed in Europe and in Japan. The devices include: 1) a flat steel plate with attached geophone or piezoelectric sensor and 2) an air-filled steel pipe with microphone. Each of these devices operate by detecting and recording discrete impacts of gravel on the device.
II. Hydroacoustic sensors– The gravel-to-gravel impact during bedload transport generates sound that can be detected by hydrophones. Development of this technology is underway and has great potential for monitoring bedload.
III. Active acoustics devices – Using focused, high-frequency sound has good potential for accurate, continuous monitoring of bedload transport. Research and development is ongoing. Technologies include Acoustic Doppler Current Profiler (ADCP) and pulse-echo sonar systems.
IV. Electromagnetic devices – In systems where rocks have high magnetite content, electromagnetic monitoring has been tested. In addition to mineralogical constraints of the rock, this technology needs further development before it can be deployed on a large scale.
V. Tracer Methods – As sensors become smaller and cheaper, the potential for rock tracer methods grows. Passive and active Radio Frequency Identification (RFID) are examples of potential tracer methods for studying bedload transport.
The IBSM Workshop, which was broadcast live over the Internet, involved presentations and discussions on all of these technologies. To see any of the presentations, please visit the webstream archive. | 
