ABSTRACT
In alpine and piedmont gravel bed Rivers, sand can be transported as bed load or as suspended load over a coarser bed. This explains why most of the monitoring tools, which have been developed for bed load or suspended load, do not adequately measure the sand fraction, which is mainly transported at the transition between these two modes. This difficulty in measuring the sand fraction is a real problem because sand is a major component of the total load transferred from the mountain to the sea. Some techniques have been specially designed for sand measurement; they can be effective but not always easy to deploy. That is why we propose here to test a new method, based on a submerged pump initially developed for hostile environments such as drilling operations, and capable of withstanding high loads of fine sediments. The pumping tests were carried out in the Isère River during July 2019, and compared to a isokinetic flux sampler: the Delft bottle. We present the results and limitations of the method.
