Preliminary Report on the Tapajós Basin Hydroelectric Inventory

Glenn Switkes
Friday, June 5, 2009
São Luiz Rapids, Tapajós River
São Luiz Rapids, Tapajós River

Photo by EletronorteHydroelectric inventories in Brazil are prepared as the initial step toward construction of series of dams. They identify the "best" sites for damming, initially in engineering terms, and then incorporating cost/benefit analyses, and lastly some environmental indicators.

The Tapajós River is one of the principal tributaries of the Amazon. Inventories have already been carried out for its upper tributaries, the Teles Pires and Juruena Rivers, where multiple dams are also being planned.

1. Seven large dams are being planned for the Tapajós -- São Luiz do Tapajós (6133 MW installed capacity), Jatobá (2338 MW), and Chocorão (3336 MW) on the Tapajós River, and Cachoeira do Caí (802 MW), Jamanxim (881 MW), Cachoeira dos Patos (528 MW), and Jardim do Ouro (227 MW) on its tributary, the Jamanxim River. The total installed capacity would be 14,245 MW (see number two below).

2. The initial plan would be to build the São Luiz Dam just upstream from a series of rapids (near the village of Pimental), diverting most of the river flow via an artificial canal to the power house. The canal would be built within the boundaries of the Amazônia National Park. The objective of this design would be to "preserve" the rapids, but this would be difficult considering the huge scale of the planned construction. The electrical energy regulatory agency, ANEEL requested a study be carried out regarding the alternative of building the dam near the community of São Luiz, downstream from the rapids, which would flood them. It would also mean a greater area of the national park would be affected, but in turn the installed capacity would increase to 6400 MW. In the next step, feasibility studies will be carried out, which will further study the two alternatives.

3. The total area flooded by the seven dams would be 3084.85 km2, an enormous area of the rainforest. The areas flooded by each of the dams would be: São Luiz 784.81 km2; Jatoba 646.3 km2; Chocorão 616.23 km2; Cachoeira do Caí 420 km2; Jamanxim 74.45 km2; Cachoeira dos Patos 116.5 km2; and Jardim do Ouro 426.06 km2.

4. According to the studies, the total number of people directly affected by the dams would be relatively low - 2668 (São Luiz would displace 977 pessoas, Jatoba 1303, Chocorão 18, Cachoeira do Caí 150, and Jardim do Ouro 200). The other dams would supposedly not displace anybody, which is difficult to believe. These numbers do not include impacts, for example, in the community of São Luiz, which being downstream from the dam, is not considered as "affected", even though it would be close to the dam itself. Obviously, if the dam were built downstream from the rapids, the São Luiz community would be displaced.

5. There would be important impacts on indigenous communities - São Luiz would affect the Munduruku and Apiaká communities of Pimental, Akaybãe, e Remédio. The Chocorão Dam would be built within Munduruki indigenous lands, and would flood 121.1 km2 of the Munduruku Reserve, and the Sai Cinza, São Martinho, and Boca do Igarapé Pacu indigenous communities would be within 2.5 km of the dam, and would be severely impacted.

6. There would be other important impacts on conservation units. A total of at least 1,318 km2, or 42.7% of the total area flooded by the dams would be areas guaranteed permanent protection by law:

  • São Luiz - even with the design upstream from the rapids, the reservoir would flood 99 km2 of the Amazônia National Park, besides causing additional impacts by the fact that construction and the worksite would be inside the park's limits. The option to build the dam downstream from the rapids would flood an additional 49 km2 of the national park. It would also flood 0.78 km2 of the Itaituba I National Forest and 204 km2 of the Itaituba II National Forest (total protected areas flooded 303.8 km2, or 352.8 km2 if it were built downstream from the rapids.
  • Jatoba - 27.5 km2 of the Itaituba I National Forest
  • Chacorão - 100.4 km2 of the Juruena National Park
  • Cachoeira do Caí - 156.9 km2 of the Jamanxim National Park, 68 km2 of the Itaituba I National Forest, 204.7 km2 of the Itaituba II National Forest.
  • Jamanxim - Jamanxim National Park, 85 km2
  • Cachoeira dos Patos - Jamanxim National Park, 90 km2; Jamanxim National Forest, 3.6 km2.
  • Jardim do Ouro - Jamanxim National Forest, 147 km2, Altamira National Forest, 10 km2.

Protected areas would suffer multiple impacts: The Itaituba I National Forest would be partially flooded by three of the dams (São Luiz, Jatobá, and Cachoeira do Caí, a total of 9,632 ha. The Itaituba II National Forest would be partially flooded by the São Luiz and Cachoeira do Caí Dams, losing 40,836 ha (9,27% of its total size). The Jamanxim National Park would have 24.204 ha flooded by Cachoeira do Caí, Jamanxim and Cachoeira dos Patos dams. And, the Jamanxim National Forest would have 15,060 ha flooded by Cachoeira dos Patos and Jardim do Ouro dams.

7. The total construction cost of the dams would be US$ 20.76 billion. São Luiz would be the most expensive, costing US$ 9.2 bi. Jatobá would cost $4 billion, Chocorão $4,3 billion, Cachoeira do Caí $1 billion, Jamanxim $984 million, Cachoeira dos Patos $751 million, and Jardim do Ouro $500 million.