River sediment transport monitoring using time domain reflectometry

River sediment data is essential for watershed management, flood control engineering, and river ecology. A new suspended sediment concentration (SSC) measurement method based on Time Domain Reflectometry (TDR) technique had been developed since 2006. Unlike optical and acoustic methods, TDR SSC method is not affected by the soil particle size or type, and it is more economical, easy to be maintained, and applicable for high SSC monitoring. To further implement the TDR SSC monitoring for river sediment transport, this study aimed to overcome some practical problems, including suppression of fouling, modulization of detachable probe, digitization ofTDR sampler and feasibility ofwater temperature acquisition module to avoid ambient temperature effect. The Current TDR method has a resolution of 1,000 ppm and practically unlimited measurement range. This study also continued to maintain and update existing monitoring stations and added two more demonstration monitoring stations. Full runoff events in 2012∼2013 were monitored to provide full event sedigraphs and evaluate field performance. However, some practical problems, such as interference of trapped debris and sedimentation in the protection pipe, were still observed in the field monitoring program. Further research into continuous improvement of the field construction method and SSC variation investigation in the cross section is recommended.