Abstract: Deep percolation and lateral flow in sandy dunes are closely related to soil water conditions of deep soil layer, ground water and interdune lowlands. In this study, we used a deep percolation and lateral flow monitoring device to measure the quantity of percolation of rainwater into the deep soil, 100 cm below ground, and the quantity of lateral flow in the 0-100 cm soil layer, in four locations of mobile sand dune: at the top, the middle of windward slope and leeward slope, and the bottom of leeward slope, during the growing season (from May to October). The result showed that during the growing season (from May to October), the quantities of percolation of rainwater into the deep soil (100 cm below) reached 44.46, 78.65, 61.84 and 147.6 mm, composing 17.03%, 30.12%, 23.68% and 56.53% of total rainfall at the top, the middle of windward slope, the middle of leeward slope, and the bottom of leeward slope, respectively. The quantities of lateral flow reached 32.35, 96.47 and 82.59 mm, composing 12.39%, 36.95% and 31.63% of total rainfall at the middle of windward slope, the middle of leeward slope, and the bottom of leeward slope, respectively. The quantities of monthly rainfall and the monthly deep percolation was significantly positive correlation at the middle of windward slope (P<0.01) and the top of the mobile sand dune (P<0.05). The quantities of monthly Rainfall and the monthly lateral flow was significantly positive correlation at the middle of leeward slope (P<0.01) and the bottom of leeward slope (P<0.05) of the mobile sand dune.

Key words: mobile dunes, deep percolation, lateral flow, rainfall