Study on Recharge of Groundwater on the Dunes in the South of Luy River, Binh Thuan Province

Groundwater resources play an important role in supplying water during the dry season in Binh Thuan province. Accurately assessing groundwater recharge makes a significant contribution to protecting and rationalizing the use of groundwater resources in this province. Especially in the sand dunes, groundwater acts as a water reserve during the dry season for the foothills. During the rainy season, rainwater seeps into the sand and reemerges at the foothills in the dry season. Due to the high permeability coefficient, rainwater efficiently replenishes the unpressurized aquifer and recharges groundwater. In this paper, the process of groundwater recharge in the sand dune area of the Southern Luy River, Binh Thuan province, was simulated using a numerical model. The mathematical model comprises three sub-models, including a horizontal 2D model for surface overflow, a vertical 1D soil column model for groundwater flow in the unsaturated zone, and a horizontal 2D model for groundwater flow in the saturated zone. The calculation results have shown the rate of rainwater replenishment. The calculations have also clarified the phase delay of groundwater flow compared to the rainy season.