The Nam Ngum 2 Hydroelectric Power Project (NN2 HPP) is located approximately
90 km north of Vientiane in central Laos and approximately 35 km
upstream of Nam Ngum 1 reservoir. A reservoir is impounded by a 182 m high Concrete
Face Rockfill Dam (CFRD). The head of NN2 HPP is 165 m, and its installed
capacity is 615 MW, with three Francis units. The connection between NN2 reservoir
and the powerhouse consists of a intake structure, a 460 m long headrace tunnel,
a manifold and three inclined penstocks as shown in Figure 1