Caverns design for Hong-Jia Du project and its reservoir influence upon environment

Three units with total generating capacity of 540 MW are installed in Bong - Ha Du hydropower station. The reservoir storage capacity is 5.0 GM 3 . Except the rock fill dam with reinforced concrete face, the flood discharge system, draw-off system, diversion system end generating house are located in left mountains, Many questions, such as election of the tunnels’ axis, layout and supporting for the underground cavern group, rock burst, etc., are discussed in this paper. The background investigation, variation and prediction of 36 environmental factors, and the comprehensive evaluation on the reservoir influence upon environment are discussed as well. At the same time, the second pollution of the water mercury is studied in detail.