Author(s): Dorian Shire-Peterlechner; Rolf Rindler; Markus Moser; Helmut Habersack

Linked Author(s): Dorian Shire-Peterlechner, Rolf Rindler, Helmut Habersack

Keywords: PIT RFID tracer; Stationary HDX RFID antenna; Transport length; Transport velocity

Abstract: Estimating bedload transport characteristics gained importance in the last decades, due to technological advances. Most formulae were created referring to steady hydraulic lab conditions. Since hydraulic conditions in alpine streams and torrents are of a highly unsteady nature, tracer-based non-dimensional formulae seem a promising approach. In the past years, tracing single particles by passive RFID technology has proven best usability within alpine streams. Since RFID tags are small, inexpensive, and durable, the use in sediment monitoring applications is evident. Native or synthetic tracer stones can be detected with outstanding recovery rates. Since 2016, the Institute of Hydraulic Engineering and River Research (IWA) has applied RFID technology in two case studies. Both study sites are alpine streams with catchment sizes of 46 km² and 55 km². At one study site a total of seven stationary antennas are in operation in the riverbed subdivided in three different locations. The second study site is equipped with two stationary antennas. Multiple stationary antennas provide a robust measuring setup and enable the measurement of travel velocities between the antennas. Mobile RFID units came into use in multiple search campaigns. Over 1000 native sediments were tagged and traced with mobile and stationary RFID applications in various campaigns. Thereby, the mean tracer velocity at a stationary antenna location was recorded with 1.06 ms-1 (Urslau). Mobile search campaigns result in much lower velocities of max. 5.0E-05 ms-1 (Strobler Weissenbach). Within one event, tracers can be transported over two stationary antennas, resulting in high velocities. In comparison, mobile search campaigns include multiple transport and resting periods, as well as immobile tracers which stay buried for long periods of time. Therefore, the velocities vary strongly.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221542

Year: 2022