The project was controversial since it had a major environmental impact and during operations released more greenhouse gases than a comparable oil-fuelled plant.

In 1987 the World Bank President, Barber Conable, called the road project "a sobering example of an environmentally sound effort which went wrong.

This could easily be done using the nearby paved road from Ariquemes to Porto Velho, then via Manaus and Santarém to the overseas markets.

[5] With an area / capacity ratio of 2.59 km2/MW the dam compares poorly to most other hydroelectric power plants in the Amazon Region other than Curuá-Una at 2.60 and Balbina at 9.44.

[10] The Samuel power plant was initially designed to supply the cities of Guajará-Mirim, Ariquemes, Ji-Paraná, Pimenta Bueno, Vilhena, Abunã and the capital, Porto Velho.

The assured output of the plant is about 85 MW, but the higher amount was made possible by unusually high rainfall and availability of all five generating units.

[11] In September 2015 the 11th Annual Fishing Tournament was held on the reservoir, attended by fishermen from Rondônia, Acre and Mato Grosso states.

They were demanding a meeting with the state government and city council to address compensation that had not yet been paid to families affected by the Samuel hydroelectric plant.

[3] Although not required by law, Eletronorte conducted a series of environmental studies, but these were later criticized for lack of depth and objectivity.

[3] Satellite images from 1984 and 2011 show a dramatic expansion of deforestation in the areas to the north, west and south of the dam.

(tucunare), Schizodon fasciatus (aracu comum), Hypophthalmus marginatus (mapará) and Serrasalmus rhombeus (piranha preta).