A fully predictive model for aeolian sand transport, part 3: Verification and application of model for natural beaches

Abstract

This paper presents extensive research results on the verification of a new transport equation for dry and moist sand at field sites and is a continuation of earlier work (Van Rijn and Strypsteen, 2020). A new trap-type instrument (LVRS-sampler) for measuring the sand transport rate of sliding, rolling and saltating particles was designed and used at many natural beach sites in Belgium and The Netherlands. A short mast equipped with three mini wind cup meters was used to measure the velocity distribution in the lowest 1 m of the boundary layer flow. Many new data sets (81 data) of aeolian sand transport for dry and moist beach surface conditions were obtained using the new equipment and used for verification of the new prediction method. Older field data (48 data points) from the literature were also used for verification. The score of the predicted sand transport based on the new VR-method is 87% within a factor of 2 of measured values for dry sand and 91% for moist sand. The modified Bagnold-transport equation was also used for verification of the available field data with scores of 79% and 67%. As a practical example, the new VR-sand transport equation was applied to calculate the annual aeolian sand transport on a Dutch beach site using wind velocity and rainfall data from a local weather station including rain fall effects (moist sand) and conversion of inland wind velocities to beach velocities (upscaling of results).