DEEP PERCOLATION CHARACTERTISTICS VIA SOIL MOISTURE SENSOR APPROACH IN SAIGON RIVER BASIN, VIETNAM

As a critical factor of the groundwater balance, the deeper percolation rate plays an essential role in determining sustainable yields for groundwater resources, especially in water managements for consecutive drought years. Although, there are many methods to estimate deeper percolation, investigation of deeper percolation somehow remains a challenging task. Hence, the paper focused on to explore deep percolation characteristics of three soil type utilizing Richard's function (Hydrus 1D) and observed soil moisture via field moisture sensors. The maximum deep percolation rate of sand clay loam, sand clay, and clay are estimated to be 4.5 mm/day, 3.5 mm/day, and 2.4 mm/day, respectively. The annual percolation ratios of sand clay loam, sand clay, and clay are 0.34, 0.27 and 0.04, respectively. The average monthly percolation rates of sand clay loam, sand clay, and clay vary 2-4.5 mm/day, 1.5-3.5 mm/day, and 0.5-2 mm/day, respectively with the rainfall intensity of 4-14 mm/day. The experiment gave an insight on deeper percolation characteristics as well as potential land recharge from rainfall utilizing soil moisture approach for future groundwater balance evaluation