#Swiss number plate driver#

Progress with passive acoustic sensors over the past 20 years opened new perspectives for the continuous monitoring of bedload transport. However, such traps are often rapidly filled, they affect the hydraulic conditions and provide no detail on the temporal (within events) and spatial (across the section) variations of bedload transport. Meanwhile, measurements of the filling rate of traps dug across streams have provided cross-section integrated estimates of bedload transport rate. Discrete in time and at a point in space, they however failed to quantify the spatio-temporal variability in bedload transport. Д®arly measurements of bedload have used direct sampling with baskets or pressure-difference samplers. These elements particularly matter in Alpine environments where high and spatially-variable gradients in energy are observed, associated to the complex effects of coarse roughness elements on the stream bed, the turbulent and unsteady hydraulics that result, and the frequent reworking of stream bed by erosion and deposition. This is notably due to the complex interactions between the flowing water, the heterogeneous nature of riverbed sediments, the unsteady hydraulics (themselves being a product of mobile channel boundaries), and the sediment transport. ДЄt the same time, bedload transport remains one of the most elusive phenomena to measure and predict. Bedload transport therefore matters for many ecosystems and human activities in the vicinity of rivers, notably in Alpine environments where the rate of climate warming is accelerated and leads to rapid glacier recession and/or an increase in the frequency of extreme hydrological events, which both tend to enhance bedload activity. It can also reduce the efficiency of hydropower facilities and impact fluvial ecosystems both negatively and positively. Bedload has therefore a critical impact on flooding risk, can induce bank erosion and in turn impact infrastructures.

#Swiss number plate driver#

As such, bedload is both a consequence of fluvial erosion and a driver for fluvial deposition.

Results of the experiment over 43 plates at four measuring sites have notably shown (a) that the maximum amplitude (V) recorded by individual plates tends to evolve as a power law function of the impact energy (J), with an exponent slightly larger than 1, for all the plates at all measuring sites (b) that there is a substantial propagation of energy across plates that should be taken into account for a better understanding of the signal response (c) that the response of individual plates is in most cases consistent, which suggests that calibration coefficients are comparable within and in between measuring sites, but site-specific and plate-specific variabilities in signal response have to be considered for a detailed comparison.Д«edload transport in rivers represents the motion of coarse particles of the bed by rolling, sliding and saltation when the shear force of the water flow exceeds the resistance force of the bed matrix. An impact experiment using artificial weights is developed in this paper to assess the variability in individual plate response and to evaluate the extent to which calibration coefficients can be transferred from calibrated plates to non-calibrated plates at a given measuring site and/or to other measuring sites. Acoustic sensors are increasingly used to measure bedload transport in Alpine streams, notably the Swiss plate geophone (SPG) system.