Field and laboratory calibration of impact plates to measure coarse bedload

摘要

During 2008-2009, an array of impact plates instrumented with either accelerometers or geophones was installed over a channel spanning weir in the Elwha River in Washington, USA. The impact system is the first permanent installation of its kind in North America. The system was deployed to measure the coarse sediment transport evacuated from two reservoirs following the removal of the upstream Elwha and Glines Canyon dams. It has been estimated that, collectively, 21 million m~3 of sediment was accumulated in the reservoirs (Hilldale et al. 2015). The focus of this manuscript is to discuss recent studies to better understand signals generated by accelerometer plates. Calibrated accelerometer plates will provide additional means to obtain a surrogate measurement of the mass of coarse sediment load passing the weir and potentially measurements of particle sizes in transport. A basic description of recent in-situ and laboratory experiments including data processing methodology will be discussed.