Effects of land use change on groundwater recharge. A case study in the Day River Basin, Vietnam.

Abstract

The main objective of this study was to “analyze the potential effects of different land use change scenarios on groundwater recharge in the Day River Basin in Vietnam”. The Soil Water and Assessment Tool (SWAT), a spatially distributed model able to predict the environmental impact of land use changes, was applied to the Day River Basin. . Three land use change maps where created, representing three scenarios for the Day River Basin in 2035. Scenario I ’business as usual’ (BAU), scenario II ‘rapid economic growth’ (REG), and scenario III ‘sustainable policies’ (SUS).

The results show that each land use change scenario has different effects on groundwater recharge in the Day River Basin. The BAU scenario, which assumes no implementation of new policies and represents a continuation of current trends, shows decreasing groundwater recharge rates in almost all sub-basins. The same goes for REG scenario where even more rapid urbanization and deforestation processes are at hand, which drastically reduce the rainfall partitioning to groundwater recharge. The SUS scenario shows that sustainable policies, such as, reforestation practices can potentially influence the rainfall partitioning to groundwater recharge in a positive way.

It can be concluded that the sensitivity of groundwater recharge to land use changes is spatially distributed within the Day River Basin. As groundwater resources in the Day River Basin are depleting rapidly, policy effective measurement are needed to address the issue of reducing groundwater recharge as a result of land use changes. Since the effects of land use change on groundwater recharge are significant, land use planners should take into account the effects of their decisions on groundwater recharge, as it is one of the most valuable ecosystem services in the Day River Basin.