Assessment of urbanization impact on groundwater resources in Hanoi, Vietnam.

In this study, the impact of urban development on groundwater resources of Hanoi City was assessed in terms of: (1) change of land use practice, and (2) increasing groundwater abstraction due to urban population growth. To this end, a coupled hydrological rainfall-runoff and groundwater flow simulation with WetSpa and MODFLOW codes was carried out with a set of spatial and temporal data of meteo-hydrology, land use, groundwater abstraction, population growth, and losses from the city water supply and sewerage system. The results of the simulation indicate that infiltration from rainfall contributes with 53.6% to the recharge of the groundwater system in Hanoi City, followed by seepage from rivers and lakes (31%). The remaining 15.4% was attributed to leakage from the municipal water supply and sewerage networks. This study also suggests that the main cause of groundwater level's decline in the city is the extensive groundwater abstraction, while an increase of the urban impervious areas due to urbanization only causes a slight decrease of groundwater recharge.