Problems Caused by the Three Gorges Dam Construction in the Yangtze River Basin: a Review

127 REVIEW Problems caused by the Three Gorges Dam construction in the Yangtze River basin: a review Kaifeng Li, Cheng Zhu, Li Wu, and Linyan Huang Abstract: Dam is an important way of water-resources utilization in large rivers. To date, more than 50 000 dams with various sizes have been constructed in the Yangtze River basin, with many other dams proposed to be constructed by 2020. Dam construction has played significant roles in flood control, irrigation, navigation, and energy supply; however, the enormous negative effects, such as landslides, ecological problems, and water quality decline, could surpass positive gains. Although a long and complicated evaluation process had been carried out and the countermeasures for numerous foreseen negative impacts of the Three Gorges Dam (TGD) had been implemented, many uncertainties and debating opinions on the benefits and costs of this project still exist. In this review, we synthesize the negative impacts that have occurred as a result of the TGD, including reservoir-triggered seismicity, landslides, water quality control, ecological problems, siltation, and sediment discharge decline to assure an environmentally friendly operation of the TGD and regional sustainable development in the Yangtze River basin, especially in the Three Gorges Reservoir region. Key words: dam construction, negative effects, the Three Gorges Dam, the Yangtze River basin. Résumé : La construction de barrages constitue une façon d’utiliser les ressources hydrauliques des grandes rivières. À ce jour, on a construit plus de 50 000 barrages aux dimensions variées dans le bassin de la rivière Yangtze, sans compter les ouvrages prévus d’ici 2020. La construction des barrages a joué un rôle important pour le contrôle des inondations, l’irrigation, la navigation et l’apport en énergie, mais les énormes effets négatifs comme les glissements de terrain, les problèmes écologiques et le déclin de la qualité de l’eau pourraient dépasser les gains. Bien qu’on ait appliqué un long et complexe processus et d’évaluation et que l’on ait appliqué des mesures pour prédire les impacts négatifs du barrage des Trois-Gorges (BTG), il subsiste de grandes incertitudes et des opinions contradictoires sur la balance coûts-bénéfices. Les auteurs synthétisent ici les impacts négatifs occasionnés par le BTG, incluant la génération d’une séismicité accrue par le réservoir, les glissements de terrain, le contrôle de la qualité de l’eau, les problèmes écologiques, l’envasement et la décharge de sédiments entachent l’assurance d’une opération environnementale acceptable du BTG ainsi que du développement durable régional dans le bassin de la rivière Yangtze, surtout dans la région du réservoir des Trois-Gorges. [Traduit par la Rédaction] Mots-clés : construction de barrages, effets négatifs, barrage des Trois-Gorges, bassin de la rivière Yangtze. Introduction 2000). The list of problems associated with large dams is long, Dam is an example of human's attempt to control nature. Since highlighting environmental and social consequences, mainly includ- the construction of dams as far back as 3000 years ago in the ing increased incidence of earthquakes and landslides, modifying Fertile Crescent (WCD 2000), dams have played an important role river flow, water quality decline, natural habitat fragmentation, im- in human development throughout the world, providing water, pacts on aquatic and terrestrial biodiversity, as well as problems controlling floods, irrigating crops, facilitating navigation, creat- linked with forced human resettlement and associated changes in ing recreational opportunities, and generating electricity. By the their livelihoods, loss of cultural heritage, and spread of some end of the 20th century, about 45 000 large dams (>15 m in height) diseases. and an estimated 800 000 small dams had been built worldwide, Flood disasters have been devastating in the Yangtze River ba- generating altogether about 19% of the world's electricity and sup- sin since the earliest civilizations. This has been particularly no- plying water for 30%–40% of the irrigated croplands (Rosenberg table post-1978, following rapid development and population et al. 2000; WCD 2000). Until recently, large dams are still per- growth, resulting in increasingly severe losses. Along with a rapid ceived as a symbol of progress in hydraulic engineering and eco- climb in energy use, China has built more large dams than any nomic development, but this image has waned steadily in the past other countries worldwide. More than 22 000 large dams (only several decades in the face of increased recognition of their failure 22 large dams constructed before 1949) have been built by the end to provide the expected economic benefits, along with increased of 20th century, almost half of the world's total (WCD 2000). For awareness of their detrimental effects on the environment example, only in the Yangtze River basin, more than 50 000 dams (Milliman 1997). As a consequence, some developed nations, such have been built since 1950 (Yang et al. 2005). To meet the energy as France and the United States, have suspended their construc- gap between supply and demand, hydropower would become a tion and, in some cases, have even initiated their demolition key developing field in China in the next few decades (Pan and He (WCD 2000; McCormack 2001). While benefits of dam are signifi- 2000), therefore, dam construction would need to increase to cant and should be recognized, negative effects can be huge and achieve this growing need. The constructions of the Three Gorges often surpass the positive ones, especially for large dams (WCD Dam (TGD), the world's largest hydropower project to date, Received 14 October 2012. Accepted 13 May 2013. K. Li, C. Zhu, L. Wu, and L. Huang. School of Geographic and Oceanographic Sciences, Nanjing University, 22 Hankou Road, Nanjing, 210093, Jiangsu Province, P.R. China. Corresponding author: Cheng Zhu (e-mail: [email protected]). Environ. Rev. 21: 127–135 (2013) dx.doi.org/10.1139/er-2012-0051 Published at www.nrcresearchpress.com/er on 14 May 2013. 128 Environ. Rev. Vol. 21, 2013 Fig. 1. Map of the Yangtze River basin (adapted from Yang et al. 2006). started in 1993 and completed in 2009. The dam is a concrete The current dramatic increasing trend of dam gravity type with a height of 185 m. The region between Chongq- construction in the Yangtze River basin ing and Yichang (where the TGD is located) in the Yangtze River basin, a distance of approximately 600 km, is known as the Three The Yangtze River is the largest river in East Asia and also the Gorges Reservoir Region (TGRR; Fig. 1). The TGRR covers 19 county- 3rd longest river in the world (Fig. 1). It is the mother river of level administrative regions with an area of 58 000 km2 in total China, supporting more than 400 million people. Needless to say, and the reservoir surface water area is over 1080 km2 at a water the river is an important waterway in the regions including eco- level of 175 m with the storage capacity of 39.3 × 1010 m3. Conse- nomically developed areas in China. To reserve water, minimize quently, as many as 13 major cities, 140 towns, and 326 villages flooding, furnish hydroelectric power, and facilitate irrigation, were submerged in whole or in part by the impoundment, and the many dams have been constructed in the Yangtze River basin population of resettlement out of the inundated area and onto since 1950. The total storage capacity of reservoirs in the upper higher ground is between 1.0 and 1.2 million (Challman 2000; reaches of the Yangtze River in 1950 was only 0.06 × 109 m3, but Wang 2000). The TGD is the world's largest power station with a increased to 23 × 109 m3 by 1990 as a result of dam construction. By total installed hydroelectric capacity of 22 400 MW, equivalent to 1995, 45 628 dams had been constructed in the river basin with a the consumption of more than 60 million tonnes of raw coal total storage capacity of 142 × 109 m3, with 64% of the capacity annually. Other benefits of the TGD include flood control and attributed to 119 large-scale reservoirs (>0.1 × 109 m3 storage ca- increased navigability of the Yangtze River. However, the simul- pacity; CCYRA 1999). By the end of 2002, 143 large-scale reservoirs taneous detrimental effects on the environment and society are had been constructed with a total storage capacity of 115 × 109 m3 attracting extensive attention worldwide. (CCYRA 2003), which represents a 26.5% increase between 1995 Although dam construction brings a variety of benefits, it also and 2002. In this period, seven other large reservoirs were also simultaneously produces a large number of man-made negative under construction, including the TGD. According to the statistics effects. In spite of a long and complicated evaluation process that of the Yangtze River Water Resources Commission (CCYRA 2006), had been carried out (nearly half a century from the late 1950s to by 2005, the number of dams in the upper reaches areas of the early 1990s; Fu et al. 2010) and the prediction of numerous Yangtze River was 12 929 with 23.4 × 1010 m3 of the total water negative impacts of the TGD that led to the implementation of storage capacity, while 29 639 dams in the middle reaches areas countermeasures (Wang 2000), large uncertainties and debating with 116.5 × 1010 m3. By 2010, more than 50 000 dams had been opinions on the benefits and costs of this project still exist (Wu built throughout the Yangtze River basin since 1950 (Yang et al. et al. 2004; Fu et al. 2010). What is more worrisome today is the 2011). As of 2000, the Yangtze had 15 dams that exceeded 100 m in high-speed dam construction in China, especially in the upper height, with another 20 or more scheduled to be constructed by and middle reaches of Yangtze River (Pan and He 2000).

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