China’s dam environmental problem

Author: Alison Singer, Appalachian State University

As the global leader in hydropower, China must adopt environmental policies that account for methane and carbon emissions as well as ecosystem disruptions and erosion potential.

Taking the lead in financing and building hydroelectric infrastructure in Southeast Asia, whilst also implementing domestic dam projects, China has funneled a vast amount of money into projects in Laos, Cambodia and Myanmar, as well as developing extensive systems of dams in its own waters. But while dams can provide relatively cheap, clean energy (hydroelectric power provides almost 20 per cent of the world’s electricity, more than any other alternative energy source), the associated ecosystem destruction and human relocation issues have triggered protests and concerns across China.

A new study by the Bertelsmann Foundation’s Sustainable Governance Indicators (SGI) project reported that the majority of states in the region, including China, have introduced substantial regulatory measures aimed at strengthening environmental impact assessment and planning capacities. Indeed, due to internal and external pressures, China has become apparently more focused on environmental issues. China introduced environmental assessment legislation in 2002, and increased investment in green technology by 18 per cent in 2011.

However, despite making headway in its resource efficiency as it introduces cleaner technologies, China still lags behind many of its Asian counterparts. Though efforts to reduce emissions and utilise alternative energy resources are promising, the rapid development of nations like China demands massive increases in energy, construction and resultant emissions. Indeed, China appears to be increasing its per capita CO2 emissions. The SGI experts hold that China’s environmental policy has largely failed to protect and preserve the sustainability of natural resources and quality of the environment.

For example, the Three Gorges Dam in China displaced over one million people, flooded hundreds of towns and villages, and is full of industrial pollution from upstream sources, as well as pollutants from the submerged mines, dumps and factories. Scientists are also concerned about increased seismic activity, erosion, and the exacerbation of drought conditions resulting from the reservoir and its new microclimate.

Though the Chinese government has acknowledged the extensive environmental issues resulting from the Three Gorges Dam, the Ministry of Environmental Protection has given the green light for the construction of the world’s tallest dam: a 314-metre-high project that will produce about 8 billion kWh of energy annually. The dam is part of a shift in China’s energy portfolio, as the nation seeks to increase non-fossil fuel sources to 15 per cent of its total energy. While applauding the intention behind the effort, environmentalists are disappointed by the Ministry’s consent due to the potential environmental dangers, arguing that the dam will interfere with fish spawning and migration, submerge parts of nature preserves, and possibly contaminate downstream waters. 

Additionally, Brazilian scientists estimate that approximately 4 per cent of human-caused climate change is due to methane and carbon dioxide emissions from reservoirs, which can occur during reservoir drawdowns. Reservoir drawdowns (which involve the rapid lowering of water levels) are instigated to increase power generation, for routine maintenance activities, or to provide irrigation or flood control. During drawdown periods, decaying organic matter is exposed and massive amounts of methane are released into the atmosphere. Researchers have found that methane emissions during drawdowns can be up to 36 times higher than under normal reservoir levels. The Three Gorges reservoir is routinely partially drained to remove silt, and scientists have found that the newly exposed marshland emits high levels of methane, particularly during the July summer peak. As methane is 20 times more potent than carbon dioxide, this risk and the results of further research in this area should be central to future policy considerations.

Additionally, dams require huge amounts of concrete, the production of which involves extreme heat. Studies suggest that cement, the primary ingredient in concrete, accounts for as much as 5 per cent of global CO2 emissions. The Three Gorges Dam required more than 27 million cubic meters of concrete for its 181-metre wall, and the future Shuang Jiang Kou Dam will surely require even more for its 314-metre wall. China is responsible for over 45 per cent of the world’s cement, and this vast industry accounts for a large portion of the nation’s carbon emissions.

Though hydropower offers cleaner energy, and is generally politically and economically viable, its environmental impacts remain uncertain. And as China continues to build upon its already vast network of dams, it is imperative that it utilises scientific research to develop best practices. As a global leader in hydropower, China has a responsibility to provide a model of environmentally safe development that accounts for methane and carbon emissions, ecosystem disruptions, and erosion potential.

Alison Singer is a postgraduate student at Appalachian State University and writes for the blog Is Sustainability Still Possible? of the Worldwatch Institute.

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