Yesterday was a tough day for those fighting to keep five mega hydro-dams out of remote, iconic and stunningly beautiful Patagonia. The proposed HidroAysen project would generate, on average, 18,430 GWh of power, equivalent to 30% of power currently installed on Chile’s central grid, and require 1,400 miles of transmission lines to send the power north to the power grid near Santiago. Despite wide opposition by the people of Chile (polls now show 61 percent of Chileans are against the project), eleven out of twelve Chilean government agencies voted yesterday to approve the dam project on the wild Rios Baker and Pascua in Chilean Patagonia. Bloomberg reports the decision was met with violent protests in the Chilean cities of Santiago and Coyhaique. Colleagues in Coyhaique reported police barricades, tear gas, water cannons, rock throwing and widespread civil unrest.
A strong coalition of locals, along with international scientists, activists and NGOs has been fighting tirelessly to educate investors, governing agencies and politicians about the environmental and social ills of massive dams. The environmental case against large dams is well-documented: Damming is one of the most prominent human alterations of natural river ecosystems worldwide, affecting the biological, chemical, physical, and human components of these systems. Dams interrupt flow patterns, thereby altering sediment and organic loads, and water quality. From greatly reduced sardine catches off the coast of Egypt to the high saline content of the United States’ Colorado River, the consequences of dam installation are wide-ranging and far-reaching.
In this case, not only are the environmental consequences likely to be devastating, but it is not clear that the project is needed. A study by energy experts suggests the HydroAysen project is unnecessary and future demand can be offset by energy efficiency and other renewable sources.
My involvement in the issue stems from an excursion in April 2008, when I was part of an expedition that traveled from source-to-sea in the Rio Baker watershed. We were the first eye-witnesses to the aftermath of a glacial lake outburst flood (GLOF) from Lago Cachet Dos, an axial lake formed by a downstream glacial dam. During this event, water from a lake swelled by increased summer meltwater worked its way through seven kilometers of the Colonia glacier, creating a subglacial tunnel. In about twelve hours, the entire volume of the lake – some seven billion cubic feet of water, exited through this tunnel, exploding from the snout of the glacier and sending a tsunami downstream, leaving behind an empty lakebed, an outwash plain littered with ice shrapnel, and mud lines thirty feet up in the trees along the Baker’s river course. Recorded measurements show the flow of the Rio Baker quadrupled, its water level rose 4.5 meters (14.7 feet) and its temperature plummeted 5◦C (41 ◦F). Observers reported that at the confluence of Rios Colonia and Baker, the Rio Baker actually flowed upstream for a time. We witnessed a vacant lake bed – some five kilometer (3.1 miles) long and one kilometer (0.6 miles) wide – a dramatic pit surrounded by massive sediment slumps and fed by an unstable young river that was ripping beautiful s-turns into failing upstream sediments. Our team was evacuated by helicopter and continued on to float the Rio Baker to the fjords at Caleta Tortel. Approximately 400 livestock were killed, but no people were harmed.
Reports from locals suggested that this was the first time in decades the lake had failed; Lago Cachet Dos has subsequently sent six more GLOFS raging downstream, threatening the lives of those living along the river corridor. While there is debate about the role of climate change in these floods, scientists studying the issue conclude there is a new cycle of activity in GLOFs. Gino Cassasa, director of Glacier and Climate Change Research at the Center for Scientific Studies in Valdivia Chile, says “Glaciers are melting and lakes growing in size throughout Patagonia – a clear sign of global warming.”
Stunningly, the issue of glacial instability related to climate change was never addressed in the Environmental Impact Statement (EIS) developed for the dam project. With my first-hand experience of the GLOF in mind, I brought a group of five MIT graduate engineering students to the region in the winter of 2009 to evaluate the environmental and safety risks of the project. The results of their masters’ theses highlight some of the risks of the proposed dam project. Our team concluded the following:
- While water quality downstream of the dam on the Rio Baker would be similar to that of the un-dammed river, upstream sediment deposition and downstream river bed erosion are likely. Impacts to plants and animals are sure to follow.
- A carbon impact assessment suggests that the transmission line is the most significant carbon generator, accounting for 70% of the dam’s carbon impact. Development closer to Santiago would reduce extensive deforestation and the associated carbon consequences.
- Future lake temperature increases will likely increase peak discharge from Lago Cachet Dos by 500 m3/s (17,657 cfs) above normal summer peak discharge of 1,200 to 2,000 m3/s (42,378 to 70,629 cfs) and lead to a regular occurrence of outburst floods.
- The results of a dam-break analysis show high risk for the population living in the Caleta Tortel area.
- An evaluation of potential alternatives suggests that current operations of the hydropower systems on the Río Biobío are harnessing very close to the maximum amount of power. Only very small gains (from 3 to 11%) can be expected through further optimizing operations. The potential gains for other optimization techniques, such as real-time control with weather forecasting, should be assessed for all large hydropower systems in Chile. Additionally, studies have shown that energy efficiency and renewable energy options are economically feasible for Chile, and these options should be emphasized and explored further, particularly if Chile is to grow its low-carbon economy.
The Natural Resource Defense Council has been leading the charge against this ill-conceived project. (See their blog for a detailed discussion of the issues surrounding the proposed project.) While yesterday’s decision is a defeat, the project is not a done deal. Among other things, the transmission lines have not yet been approved, nor has financing for the $7 billion project been secured. NRDC and others will continue working to demonstrate that more economical and sustainable, and less risky options – including wind, biomass, geothermal and biogas, exist.
Large, unfettered rivers are the precious lifeblood of our planet, and regional biodiversity is inherently linked to their floodplains. If we inundate these river corridors, we drown out the quiet mosaic of biogeochemical reactions that take place in the floodplain, keeping our water clean and providing nutrients and energy to support large ecosystems. To blindly destroy what we can’t see is folly. As one Chilean scientist lamented, “Why can’t we learn from the mistakes of the developed world?” And, frankly, we’ve made plenty. Let’s not make this one too.
You can take action by joining NRDC’s BioGems campaign for wild Patagonia.
 BURRALL, KRISTEN, GIANNA LEANDRO, LAURA MAR, ELISABETTA NATALE, AND FLAVIA TAURO. Analysis of Proposed Hydroelectric Dams on the Río Baker in Chilean Patagonia. Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, Master of Engineering Candidates, 2009.