Three Gorges Dam: The ecological cost of powering a growing economy

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Written by: Liliana Martis-Geor

China is a country known for its rapid economic growth however, this has often come at a cost to the environment. The nations ongoing coal addiction has left them plagued by air pollution and contributed to the rising greenhouse gases in the atmosphere. Subsequently, harnessing energy from the wild Yangtze river offered a clean and bold alternative to fuelling the increasing energetic demands in China. After all – when you have the third largest river in the world, why not harness its’ power?[1]

For some, the construction of the Three Gorges Dam was hailed as a green initiative, steering the Chinese away from their coal exploitation. In 2020 alone, it set the record for annual power generation, saving around 31 million tonnes of coal, and subsequently reducing carbon dioxide (the dominant greenhouse gas) emissions by approximately 86 million tonnes. [2] While on paper, this seems like a win for the Three Gorges Dam, for many scientists and environmentalists the Chinese governments’ decision to construct the worlds’ largest hydroelectric dam across the Yangtze river sparked outrage.

Figure 1: The Three Gorges Dam, Hubei Province, China. [2]

The Three Gorges Dam spans 2.3 kilometres across the Yangtze River, and towers above the landscape, reaching a height of 185 meters.[3] Situated in the Three Gorges region in South Central China, the dam is nestled in a hotspot for biodiversity, housing a diverse array of endemic and threatened animal and plant species. Subsequently, the flooding of over 600km2 of land to make room for this astronomical project has had major social and environmental consequences[3]. Entire valleys were inundated, and approximately 1.25 million people from within the reservoir area boundary (Figure 2) were re-settled over a 16-year period, prior to 2008.[4] Since this time, the region has been plagued with environmental issues. In a region that is sitting across two major faults and is already vulnerable to earthquakes, the increased pressure from such a large-scale project has intensified landslides in the region, leading to fatalities and scarring the landscape.[5]

Figure 2: The construction of the Three Gorges Dam left entire valleys inundated, and residents located within the reservoir area boundary needed to be re-settled [6].

Additionally, the flow regime of the Yangtze river has been dramatically altered, which has left migratory fish populations highly vulnerable. This has been exemplified by the dramatic decline of four economically significant species of Chinese carp. These species swim upstream to the middle and upper reaches of the Yangtze rivers to spawn during Spring – a phenomenon partly triggered by the rising flow of the river during this season. However, the construction of the dam has created a barrier to migration of these species, and the altered flow regime is interfering with the natural Spring-time flow signals.[7] With a diverse range of species reliant on the ecosystem services the Yangtze River supplies, the enormity of this project has the potential to cause large scale ecosystem crashes.

While a steer towards green energy is much needed, the Three Gorges Dam highlights the importance of fully analysing the ecological consequences of large-scale projects. Sometimes, powering a growing economy can come at a devastating environmental cost, and with the world facing extensive global changes, we need to rehabilitate vulnerable ecosystems to encourage their resilience to the changing climate.

References

[1] Greer, C. E., & Muranov, A. P. (2020) Yangtze River. https://www.britannica.com/place/Yangtze-River

[2] Ruoting, W. (2020). Three Gorges Dam Sets World Record on Annual Power Output. http://en.sasac.gov.cn/2020/11/20/c_6065.htm

[3] Wu, J., Huang, J., Han, X., Xie, Z., & Gao, X. (2003). Three-Gorges Dam – Experiment in Habitat Fragmentation? Policy Forum. 300, 1239-1240.

[3] López-Pujol, J., & Ren, M. X. (2009). Biodiversity and the Three Gorges Reservoir: A troubled marriage. Journal of Natural History, 43(43–44), 2765–2786. https://doi.org/10.1080/00222930903220010

[4] Xu, X., Tan, Y., & Yang, G. (2013). Environmental impact assessments of the Three Gorges Project in China: Issues and interventions. Earth-Science Reviews, 124, 115–125. https://doi.org/10.1016/j.earscirev.2013.05.007

[5] Huan, Z., & Wu, B. (2018). Three Gorges Dam Environmental Monitoring Network and Practice. Springer.

[6] Fu, B. J., Wu, B. F., Lü, Y. H., Xu, Z. H., Cao, J. H., Niu, D., Yang, G. S., & Zhou, Y. M. (2010). Three Gorges Project: Efforts and challenges for the environment. Progress in Physical Geography, 34(6), 741–754. https://doi.org/10.1177/0309133310370286

[7] Cheng, L., Opperman, J. J., Tickner, D., Speed, R., Guo, Q., & Chen, D. (2018). Managing the three gorges dam to implement environmental flows in the Yangtze River. Frontiers in Environmental Science, 6(64), 1–8. https://doi.org/10.3389/fenvs.2018.00064