Resumen de Long term recovery rates obtained using RFID technology at a mixed beach

M. Casamayor, Ignacio Alonso Bilbao, Jorge Cabrera Gámez , S. Rodríguez, María José Sánchez García

• Recovery rates were obtained by radio frequency identification (RFID) technology in pebbles and cobbles at SanFelipe beach, Gran Canaria. The aim of this work was to define which factors affected the recovery of taggedgravels. Several tests were performed to determine the detection depth threshold, and 16 field experiments werecarried out over seventeen months after tracer deployment on the beach. Recovery rates are highly variable withtime, ranging from 72.2% in the first recovery session to 25.8% in the last one. Nevertheless, a nearly stablesituation was found for the final eight months. Apart from the effect of time, there were several factors thataffected the recovery rate. Some of these were related to the particle, such as the position of the tag within theparticle, as well as its weight, size and shape. Two environmental factors were considered. First, the elevation ofthe tracer on the beach showed that the recovery rate was higher with particles located above the storm berm.Second, wave height, which showed no relation with recovery rates even though during the experiment significantstorms and periods of calm took place.