Three Gorges Dam: Environmental Impact

The submergence of hundreds of factories, mines and waste dumps, and the presence of massive industrial centres upstream are contributing to some profound environmental impacts of the project.

Emissions: An estimated 366 grams of coal would produce 1 kWh of electricity during 2006, according to the National Development and Reform Commission of China. From 2003 to 2007, power production was equal to that of 84 million tonnes of standard coal.

Erosion and sedimentation: Approximately 80% of the land is facing erosion in that area at current levels, and it resulted in depositing about 40 million tons of sediment into the Yangtze annually. Although the flow is slower above the dam, much of this sediment will settle there instead of flowing downstream; hence there will be less sediment downstream. The absence of silt downstream has effects like – downstream riverbanks becoming more vulnerable to flood, benthic sediment buildup causing biological damage, and reducing aquatic biodiversity.

Landslides: Frequent major landslides are caused by erosion in the reservoir, induced by rising water lead to noticeable disturbance in the reservoir surface, including two incidents in May 2009. When somewhere between 20,000 and 50,000 cubic meters (26,000 and 65,000 cu yd) of material plunged into the flooded Wuxia Gorge of the Wu River and also, there were significant landslides in the first four months of 2010, 97 to be exact.

Waste Management: Over a billion tons of wastewater is released annually into the Yangtze River, which was more likely to be swept away before the reservoir was created. This has caused the water to look polluted, stagnant, and murky. According to the Ministry of Environmental Protection, About 32 landfills were added, which could handle 7,664.5 tonnes of solid waste every day.

Forest cover: The research by the United Nations Food and Agriculture Organization suggested that the Asia-Pacific region would gain about 6,000 km2 (2,300 sq mi) of the forest by 2008. It is a significant change from the 13,000 km2 (5,000 sq mi) net loss of forest each year in the 1990s. It was possible mostly due to China’s massive reforestation effort, which was taken into consideration after the 1998 Yangtze River floods.

Wildlife: The region was known for its rich biodiversity; it is home to 6,388 species of plants, which belong to 238 families and 1508 genera. 57 percent of these plant species are endangered. Surrounding the Three Gorges Dam, the forested area in the region has dropped from 20% in 1950 to less than 10% as of 2002.

The region also provides habitats to hundreds of terrestrial and freshwater animal species. Freshwater fish are more severely affected by dams due to changes in the water temperature and flow regime. Many other fish are hurt by the turbine blades of the hydroelectric plants as well. The Yangtze River basin is home to 361 different fish species, and also accounts for 25% of all endangered freshwater fish species in China, therefore it is especially detrimental to the ecosystem of the region. Other aquatic species have been endangered as well, especially the baiji, or Chinese river dolphin, which is now extinct. Likewise, the Chinese paddlefish is also believed to be extinct due to the dam.

Terrestrial impact: NASA, in 2010 reported that the shift of water mass stored by the dams could potentially increase the length of the Earth’s day by 0.06 microseconds and could have an impact on Earth’s form as well.