Abstract It is inevitable that the building of long deep-buried tunnels in water-enriched area will destroy the original balance of groundwater，which will have negative effects on construction and hydrogeological environment nearby. Water transport in mountain and its influence as well as water inflow into tunnels during excavation are complex three-dimensional(3D) problems influenced by a number of factors. Taking Jinping II hydropower station for example，the transport of groundwater in mountain rock during construction period has been studied. A comparison between the calculated results and the observed data under present circumstances indicates that the method and results are satisfactory，and then the distribution of groundwater after excavation is studied as well as its influence on the two springs(Mofanggou and Laozhangzi springs) nearby and domestic water of local people in construction area. Furthermore，control measures and criteria of water inflow in tunnels are proposed for design and construction.
