Regulation of dust transport by turbulence intensity over sandy gravelly surfaces

Wind-tunnel experiments were conducted to examine the relationships among gravel coverage (GC), near-surface turbulence intensity (TI), and the dust content (DC) of transported sediment over sandy gravelly surfaces. Wind-speed fluctuations were concentrated near the bed, with 77.70% of the height-wise velocity variance occurring below 0.03 m. Within the tested dataset, the TI–DC observations were more tightly clustered than the mean-wind-speed–DC observations under the adopted descriptive metrics. Sediment transport rate increased nonlinearly with incoming wind speed and generally decreased with increasing GC, whereas profile-averaged DC was relatively low under the 40% and 50% GC treatments but increased again at 60% GC. This non-monotonic response coincided with the recovery of mean wind speed and weaker interlayer TI attenuation and may reflect flow reorganization over the densely covered surface. An empirical GC–TI–DC parameterization described the observed relationships within the experimental dataset, while its applicability beyond the tested conditions requires further validation. The results indicate that gravel-based erosion control should consider both surface coverage and its influence on near-surface airflow and turbulence attenuation under comparable wind-tunnel conditions.