New Wave of Three Gorges-Sized Dams Raise Old Fears
As the last of the turbines at China’s Three Gorges Dam was connected to the grid on Wednesday, a dams debate rages over the fate of the Upper Yangtze River and its main western tributary, the Jinsha River.
Known as the “River of Golden Sands,” the Jinsha is slated for a cascade of 25 dams designed to generate as much electricity as four Three Gorges Dams put together. After years of cautious construction and banning projects that either started illegally or had soaring cost overruns due to poor resettlement and environmental management, the government has identified the Jinsha as one of several dam-building hotspots to meet its goal of adding 140 GW of hydropower capacity by 2015.
Scientists and environmentalists in China fear that the cumulative impacts of this dam cascade could spell disaster not only for the health of China’s largest river but also the safety of downstream populations and the future water availability for the region.
Cumulative Impacts on the Environment
According to Mr. Yang Yong, chief scientist at the Heng Duan Shan Society, the 25 proposed dams would slice up the rapidly flowing Jinsha River into a series of stillwater reservoirs. This drastic change to the hydrology of the river basin would fundamentally alter the habitat and lifecycles of state-protected fish like the Chinese paddlefish and the Dabry's Sturgeon.
The river is also one of the three major rivers in a UNESCO World Heritage Site that protects one of China’s most important biodiversity hotspots. The Upper Tiger Leaping Gorge Dam is currently being planned adjacent to the site and would flood the first major bend of the Jinsha River. According to Mr. Weng Lida, former Director General of the Yangtze Valley Water Resources Protection Bureau and a member of the Changjiang Water Resources Commission, hydropower development in China has gotten out of control:
"There are too many dams on the rivers in the southwest, the rivers can hardly breathe."
Cumulative Impacts on Supply and Safety
Earlier studies by geologists have highlighted the seismic, safety, and water security risks of out-of-control dam building in this fragile region. One such study, published last year by Mr. Fan Xiao of the Sichuan Geology and Mineral Bureau, claims that the Yangtze River will run dry because dam developers are planning to build so many dams that their combined reservoir volume would exceed the Yangtze’s flow. The study asserts:
“There would not be enough water for all of the dam projects proposed for the Yangtze to operate simultaneously, ultimately leaving power consumers, river users and the environment to pay the price of unchecked, unwise development.”
Experts also warn against the risk of dam-building in China’s seismically active and flood-heavy southwest, where one dam break could cause a tsunami that creates a domino effect of collapsing dams downstream. This occurred in China in 1975, when a major flood and poor communications caused dam breaks at 62 sites in Henan Province. The catastrophe killed over 26,000 people – more casualties than any other dam failure in history. While such massive floods are rare (this was a once-in-1000-years flood), dam developers have yet to factor in the affects of climate change on extreme weather events such as droughts and floods, which are common in the southwest and have serious implications for dam operation.
The valleys in this region, including those formed by the Lancang/Upper Mekong and Nu/Salween, also experience disastrous landslides during the rainy season due to the steepness of the terrain. These can be exacerbated by the clearing of vegetation for dam construction and by the filling and emptying of reservoirs. The fluctuating water levels of the Three Gorges reservoir, for instance, have destabilized hundreds of miles of slopes and triggered massive landslides. A recent warning sign is the deadly mudslide that occurred on June 28, 2012, at the Baihetan Hydropower Station on the lower Jinsha River (it is under construction by the China Three Gorges Project Corporation). The mudslide killed four people and left 36 more missing – all workers and their families at the dam construction zone. In response to this incident, Mr. Ma Jun, director of the Beijing-based Institute of Public & Environmental Affairs, told the South China Morning Post:
"We believe that China is building too many dams on Jinsha River. Such disturbances of nature can lead to more fatal accidents...We urge the government to seriously reconsider and review its development strategy in this region."
The Cost of Over-damming
On top of these often “hidden” or external costs of dam projects is the actual cost of building the dams and paying for the massive relocation projects that usually accompany such large infrastructure endeavors. In the case of the Three Gorges project, the project's 185-meter dam and 600km reservoir have forced the relocation of at least 1.3 million residents. Reuters reports that the cost of the Three Gorges project has sky-rocketed to a total of RMB 254 billion (nearly US$40 billion), four times the original estimate. The government has also acknowledged that earthquake and landslide risks have also increased in the region, and another RMB 123.8 billion (about US$19.5 billion) has been spent on "follow-up work,” which has included such mitigation measures as wastewater treatment to deal with the industrial pollutants and rubbish that accumulates in the reservoir, and the construction of massive retaining walls to prevent landslides and further soil erosion. Even the Chairman of the China Three Gorges Project Corporation – the state-owned company behind the Three Gorges Dam and a number of other Upper Yantze River projects – is cautious. According to the Chairman, Mr. Cao Guangjing:
“With more dams, the coordination of water storage and drainage will be problematic; you can't squeeze all the value out of every drop of water, you need to consider the environment's needs.”
Early last month, China Three Gorges Project Corporation, the Ministry of Water Resources' Changjiang River Scientific Research Institute, and WWF jointly published a report called "China's Environmental Flows Research and Practice." The report concluded that there were already too many hydropower plants on some parts of the Upper Yangtze River and that untrammelled development was affecting the basin's ecological balance.
Despite these warnings, large-dam cascades are being proposed for several of China's rivers, as well as for river basins in the Mekong, Brazil, and elsewhere. The true cost of over-damming these vital basins would be ecosystem collapse, social upheaval due to massive relocations, the unnecessary risk of dam-related hazards, project cost overruns, and poor returns on investment. When better water and energy solutions exist (in China see for instance Energy Transition Institute), the long-term costs of these risky ventures is just not worth the short-term profits.