[1][2] The dam was built primarily as a source of hydroelectricity and second for navigation between the upper and lower Tocantins River.

Communities in Northeast Brazil would also benefit as well, such as Belém, São Luiz, Marabá, and later Eastern Amazonia.

In 1975, the consortium formed by the Brazilian companies Engevix and Themag were hired to draw up the basic and executive designs.

Phase I called for the construction of the main dam, its dikes, the power house, spillway and upper portion of the navigation locks.

The navigation lock that is part of the dam's design was only partially completed during Phase I with only the upper portion.

This phase called for the construction of the new power house for 11 x 375 MW (503,000 hp) Francis turbines and the completion of the navigation lock-system.

[7] Silva was a staunch protester of tropical damming, working as a regional coordinator for the Movement of Dam-Affected Peoples, and spent much of her time exposing the fact that while hydroelectric power is lauded as a sustainable energy source, the Tucuruí Dam's location meant it was not environmentally friendly.

[8] In 2007 a series of street demonstration organized by the Movement of Dam Affected People, Movimento dos Trabalhadores Rurais Sem Terra, and Via Campesina resulted in protesters occupying the Tucuruí plant for two days.

[9] In 2007 Movimento dos Trabalhadores Rurais Sem Terra occupied a ranch in Piratininga, São Paulo as a protest to the destruction of lands as a result of the Tucuruí Dam's construction.

Through a process referred to as grilagem (translates to land-grabbing from Portuguese), which could be compared to a more violent form of gaining squatters rights in other countries, the protesters were able to occupy the land.

In the wake of the dam's completion the region it inhabits underwent eutrophication, the process of soil becoming too nutrient rich, making it a breeding ground for malaria carrying mosquitos and ideal habitat for excessive aquatic plant life growth as a result.

[12] The Tocantins watershed was, historically, an important access point for freshwater amongst the humans and animals living in the region.

As a result of construction, however, the water quality of the Tocantins River Basin has been jeopardized due to discharge of industrial effluents, residues of agricultural uses, and untreated sewage disposal.

The addition of the Mojú and Caraipé earth-fill dikes increases the total length to 12,515 metres (41,060 ft).

The main dam's Creager-type service spillway is the second largest in the world with a maximum capacity of 110,000 cubic metres per second (3,900,000 cu ft/s).

The completion of Phase I in 1984 led to a large amount of unemployment among its 20,000 employees and subsequent migration from the area.