Small Hydroelectric Dams Not So Green

RIO DE JANEIRO -- The combined impacts of numerous small hydroelectric dams in one river basin can be at least as harmful as one large dam, warn experts, environmental activists and indigenous groups, who face a flood of new projects along the rivers of the western Brazilian state of Mato Grosso.

Hydraulic energy from small dams "is interesting because of its low environmental costs, but everything has its limits," says André Villas-Boas in reference to their proliferation along the tributaries of the Xingú River, in the Amazon.

At least six small dams are concentrated on the rivers in northeast Mato Grosso, points out Villas-Boas, coordinator of the Xingú Programme of the non-governmental Socio-Environmental Institute (ISA). Two have already been built and a third has been given the green light by the energy and environmental authorities for the Culuene River alone, the main tributary of the Xingú.

Such projects should not be authorised without an integral assessment of the river basin in its environmental and social aspects, for a planned exploitation of the water resource as a whole, and limits on the number of hydroelectric dams, according to Villas-Boas, who notes that more than half the area of the Xingú is indigenous territory.

The dams are located around the Xingú Indigenous Park, a symbol of Brazil's indigenous policy that is home to some 5,000 people from 14 different ethnic groups.

Often included among "clean" sources of energy, small hydroelectric dams have become an attractive business for the "soft legislation" under fiscal and financial control and incentives, without duly considering that "they seriously alter biological dynamics" if there are many in one watershed, says Villas-Boas.

As a result, there are 240 small hydroelectric dams planned in Brazil, according to the National Electric Energy Agency (ANEEL). The 81 dams already under construction will produce 1,342 megawatts, or 17.29 percent of the total power supplies.

An example of a more unsustainable panorama is the Juruena River, according to Raul do Valle, an attorney who coordinates ISA's political and legal actions. In the Juruena basin, in northwest Mato Grosso, 83 hydroelectric dam plans have been registered. ANEEL suspended 30 projects in early July and decided to pursue integrated environmental assessments for them.

There have been several cases where indigenous people have taken government officials or construction company employees hostage, in a bid to bring the work on dams on the Juruena and the Culuene rivers to a halt. In other efforts, lawyers have tried to do so through legal channels, obtaining temporary suspensions of construction permits. There are many cases where a final decision is still pending.

"We predict that there will be fewer fish" as a result of the energy projects on local rivers, begun around 10 years ago, because the dams "block the fish from swimming upriver to breed," said Paulo Kamaiurá, who has taken as his surname the name of his tribe, who live in the Xingú Park.

The affected rivers, which are already polluted by agro-chemical runoff, flow towards the Park where they form the Xingú River, and as a result "the problems will be aggravated," said Kamaiurá, adding that it is essential to mobilise indigenous communities to raise awareness about the threats.

Because of their presumed limited ecological impact, environmental permits for small hydroelectric dams are granted by state, not federal, agencies. And the state bodies are more vulnerable to local economic pressures, says Valle.

But the permits must be issued by the national Brazilian Environmental Institute when the projects affect Indians, he explains. In the case of northern Mato Grosso, it is a matter of survival of native peoples, who rely on fish for subsistence, he adds.