It is the first large-scale hydroelectric project in the Brazilian Amazon rainforest. The maximum capacity of the 25-unit plant is 8,370 MW. Phase I construction began in 1975 and ended in 1984 while Phase II began in 1998 and is ongoing from delays. The main portion Tucuruí Dam is a 78 m high and 6.9 km long concrete-gravity dam. The addition of the Mojú and Caraipé earth-fill dikes increases the total length to 12,515 m. The reservoir impounded by the dam has a capacity of 45 km³ with a live volume of 32 km³. The main dam's Creager-type service spillway is the second largest in the world with a maximum capacity of 110,000 m³/sec. It is controlled by 20 floodgates measuring 20m x 21m. The 405m x 58m Phase I power house is concrete and is fitted with an intake and penstocks. Phase I's power house contains 12 x 330 MW Francis turbine generators. An auxiliary water intake and auxiliary powerhouse also houses 2 x 20 MW generators. The dam is designed to support two 210m long and 33m wide navigation locks.