General layout design of Dongping Hydropower Station

Dongping Hydropower Station is built on Zhongjian River,the tributary of Qingjiang River,and is the lowest one of the planned 3-stage development scheme.Dongping dam site is at Zhongwudang gorge,which is characterized as steep slope,narrow river valley and poor construction-site condition,in the upstream of the dam axis,there is a gully at left bank of upper dam axis,the river channel turns right abruptly 310 m in the downstream of the dam,and the river bed elevation is 20 m plus lower than the normal water level of Shuibuya Reservoir.The rock mass at dam site is weak and easy to be scoured,and the mountain after the abrupt bend is a toppled creep mass,which make difficulties for the design of flood discharge structures.The hydro-junction is consisted of thin double-curvature arch dam with height of 135 m,flood discharge orifices,plunge pool,water diversion system at left bank and underground powerhouse(installed capacity of 2×55 MW) etc.The project has been running successfully since the power generation of first unit.We mainly describe the design of general layout.