Massive and widely condemned Chilean dams approved

Elie Gardner in Nature News chronicles the latest on a corrupt-sounding hydro project in Chile: Officials in Chile have approved a controversial US$3.2-billion project to construct five hydropower dams in Patagonia. The HidroAysén project — a collaboration between the country's two biggest energy firms — plans to generate 2,750 megawatts of power by damming two major rivers, the Baker and the Pascua. But it must first seek approval for a 2,300-kilometre transmission line, costing another US$3.8 billion, that would carry power to Santiago.

The project was finally given the go-ahead after an arduous three years in the approval process. The assessment was first presented to the Environmental Assessment Commission of Coyhaique — a regional government body in southern Chile — in August 2008, but the commission wasn't satisfied with it and asked for an addendum.

Dozens of public organizations and thousands of individuals pointed out weaknesses in the study, saying that it lacked crucial information, ignored important issues, used incomplete data, misrepresented facts and contained poor analyses. The project had to submit the assessment three more times, responding to 4,046 comments, before it was finally approved.

Daniel Fernández, executive vice-president of HidroAysén, calls the study the "most extensive and comprehensive environmental assessment in the history of Chile". But those who criticized the original work say that many of their complaints still stand.

Claudio Meier, an engineer at Chile's University of Concepción who has been reviewing environmental-impact assessments for hydropower projects in the country for the past 20 years, was hired by Chile's water authority to review the original document. He says that the assessment was "built around anecdotal data" – for example, the studies on sediment were based on predictions and not actual measurements. What it lacked, in his opinion, was an understanding of ecosystem functions. For instance, the document reported impacts on water temperature, clarity and sedimentation, but did not address how these changes would affect the ecology of the rivers.

Peter Goodwin, founder of the Center for Ecohydraulics Research at the University of Idaho in Boise, says that rigorous scientific methods were not employed and the studies were not conducted over a long enough period to capture environmental variability, a problem made worse by the lack of pre-existing information on the pristine and remote Patagonian ecosystems….