Fetch‐driven aeolian sediment transport on a sandy beach: A new study

Abstract

This study examines the effect of fetch distance on aeolian sediment transport and the corresponding growth rate of aeolian transport rate on a sandy beach under varying wind speeds. Eight experiments were conducted on both dry and intertidal beach areas, with wind speeds ranging from 9 to 17 m/s. Vertically stacked sand traps were used to measure transport rates over distances up to 100 m, with experiments lasting 20–40 minutes. Results indicate an initial increase in transport rate until the critical fetch distance, followed by a subsequent decrease in sediment transport with further fetch distance. Critical fetch distances, corresponding to maximum transport rates, ranged from 23.8 to 103.5 m. A strong linear correlation was observed between wind speed and critical fetch distance, suggesting that higher wind speeds necessitate longer fetch distances for maximum transport. Furthermore, established formulations by van Rijn and Strypsteen are tested to estimate maximum sediment transport and critical fetch distance based on grain‐related shear velocity. Combining all experiments showed that the growth rate in transport up to the point of critical fetch can be best described by a trigonometric function. These findings contribute to a better understanding of the fetch effect on aeolian sediment dynamics in coastal sandy environments.