The sand-deposition impact of artificial gravel beds on the protection of the Mogao Grottoes

Gravel beds can prevent sand-dust emission and weaken sand-dust flux. We used wind-tunnel experiments and field observations on artificial gravel beds above the Mogao Grottoes to quantify their impact. In the report, we identified a significant correlation between gravel roughness and its ability to trap wind-transported sand. The optimal combinations of gravel diameter and coverage were determined. The greatest roughness is achieved when small gravel coverage is 75%, medium 40% and large 45%. We found that initial wind speed and gravel coverage are the key factors controlling the amount of sand trapped by the gravel beds.