REVIEW

Problems caused by the Three Gorges Dam construction in the YangtzeRiver basin: a reviewKaifeng 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 varioussizes have been constructed in the Yangtze River basin, with many other dams proposed to be constructed by 2020. Damconstruction has played significant roles in flood control, irrigation, navigation, and energy supply; however, the enormousnegative effects, such as landslides, ecological problems, andwater quality decline, could surpass positive gains. Although a longand complicated evaluation process had been carried out and the countermeasures for numerous foreseen negative impacts ofthe Three Gorges Dam (TGD) had been implemented, many uncertainties and debating opinions on the benefits and costs of thisproject still exist. In this review, we synthesize the negative impacts that have occurred as a result of the TGD, includingreservoir-triggered seismicity, landslides, water quality control, ecological problems, siltation, and sediment discharge declineto 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 ouvragesprévus d’ici 2020. La construction des barrages a joué un rôle important pour le contrôle des inondations, l’irrigation, lanavigation et l’apport en énergie, mais les énormes effets négatifs comme les glissements de terrain, les problèmes écologiqueset le déclin de la qualité de l’eau pourraient dépasser les gains. Bien qu’on ait appliqué un long et complexe processus etd’évaluation et que l’on ait appliqué des mesures pour prédire les impacts négatifs du barrage des Trois-Gorges (BTG), il subsistede grandes incertitudes et des opinions contradictoires sur la balance coûts-bénéfices. Les auteurs synthétisent ici les impactsnégatifs occasionnés par le BTG, incluant la génération d’une séismicité accrue par le réservoir, les glissements de terrain, lecontrôle de la qualité de l’eau, les problèmes écologiques, l’envasement et la décharge de sédiments entachent l’assurance d’uneopération environnementale acceptable du BTG ainsi que du développement durable régional dans le bassin de la rivièreYangtze, 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.

IntroductionDam is an example of human's attempt to control nature. Since

the construction of dams as far back as 3000 years ago in theFertile Crescent (WCD 2000), dams have played an important rolein human development throughout the world, providing water,controlling floods, irrigating crops, facilitating navigation, creat-ing recreational opportunities, and generating electricity. By theend of the 20th century, about 45 000 large dams (>15m in height)and an estimated 800 000 small dams had been built worldwide,generating altogether about 19% of the world's electricity and sup-plying water for 30%–40% of the irrigated croplands (Rosenberget al. 2000; WCD 2000). Until recently, large dams are still per-ceived as a symbol of progress in hydraulic engineering and eco-nomic development, but this image has waned steadily in the pastseveral decades in the face of increased recognition of their failureto provide the expected economic benefits, along with increasedawareness of their detrimental effects on the environment(Milliman 1997). As a consequence, some developed nations, suchas France and the United States, have suspended their construc-tion and, in some cases, have even initiated their demolition(WCD 2000; McCormack 2001). While benefits of dam are signifi-cant and should be recognized, negative effects can be huge andoften surpass the positive ones, especially for large dams (WCD

2000). The list of problems associated with large dams is long,highlightingenvironmental and social consequences,mainly includ-ing increased incidence of earthquakes and landslides, modifyingriver flow, water quality decline, natural habitat fragmentation, im-pacts on aquatic and terrestrial biodiversity, as well as problemslinkedwith forced human resettlement and associated changes intheir livelihoods, loss of cultural heritage, and spread of somediseases.

Flood disasters have been devastating in the Yangtze River ba-sin since the earliest civilizations. This has been particularly no-table post-1978, following rapid development and populationgrowth, resulting in increasingly severe losses. Along with a rapidclimb in energy use, China has built more large dams than anyother countries worldwide. More than 22 000 large dams (only22 large dams constructed before 1949) have been built by the endof 20th century, almost half of the world's total (WCD 2000). Forexample, only in the Yangtze River basin, more than 50 000 damshave been built since 1950 (Yang et al. 2005). To meet the energygap between supply and demand, hydropower would become akey developing field in China in the next few decades (Pan and He2000), therefore, dam construction would need to increase toachieve this growing need. The constructions of the Three GorgesDam (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: zhuchengnj@126.com).

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Environ. Rev. 21: 127–135 (2013) dx.doi.org/10.1139/er-2012-0051 Published at www.nrcresearchpress.com/er on 14 May 2013.

started in 1993 and completed in 2009. The dam is a concretegravity type with a height of 185 m. The region between Chongq-ing and Yichang (where the TGD is located) in the Yangtze Riverbasin, a distance of approximately 600 km, is known as the ThreeGorges Reservoir Region (TGRR; Fig. 1). The TGRR covers 19 county-level administrative regions with an area of 58 000 km2 in totaland the reservoir surface water area is over 1080 km2 at a waterlevel of 175 m with the storage capacity of 39.3 × 1010 m3. Conse-quently, as many as 13 major cities, 140 towns, and 326 villageswere submerged inwhole or in part by the impoundment, and thepopulation of resettlement out of the inundated area and ontohigher ground is between 1.0 and 1.2 million (Challman 2000;Wang 2000). The TGD is the world's largest power station with atotal installed hydroelectric capacity of 22 400 MW, equivalent tothe consumption of more than 60 million tonnes of raw coalannually. Other benefits of the TGD include flood control andincreased navigability of the Yangtze River. However, the simul-taneous detrimental effects on the environment and society areattracting extensive attention worldwide.

Although dam construction brings a variety of benefits, it alsosimultaneously produces a large number of man-made negativeeffects. In spite of a long and complicated evaluation process thathad been carried out (nearly half a century from the late 1950s tothe early 1990s; Fu et al. 2010) and the prediction of numerousnegative impacts of the TGD that led to the implementation ofcountermeasures (Wang 2000), large uncertainties and debatingopinions on the benefits and costs of this project still exist (Wuet al. 2004; Fu et al. 2010). What is more worrisome today is thehigh-speed dam construction in China, especially in the upperand middle reaches of Yangtze River (Pan and He 2000). To assurean environmentally friendly operation of the TGD and regionalsustainable development in the Yangtze River basin, especially inthe TGRR, firstly the problems caused by the TGD should beclearly investigated. In this paper, the authors (1) introduced thestate of dam construction in the Yangtze River basin, (2) focusedon the negative environmental effects of the TGD, and (3) madesome suggestions for future monitoring and research of the TGD.

The current dramatic increasing trend of damconstruction in the Yangtze River basin

The Yangtze River is the largest river in East Asia and also the3rd longest river in the world (Fig. 1). It is the mother river ofChina, supporting more than 400 million people. Needless to say,the river is an important waterway in the regions including eco-nomically developed areas in China. To reserve water, minimizeflooding, furnish hydroelectric power, and facilitate irrigation,many dams have been constructed in the Yangtze River basinsince 1950. The total storage capacity of reservoirs in the upperreaches of the Yangtze River in 1950 was only 0.06 × 109 m3, butincreased to 23 × 109m3 by 1990 as a result of dam construction. By1995, 45 628 dams had been constructed in the river basin with atotal storage capacity of 142 × 109 m3, with 64% of the capacityattributed to 119 large-scale reservoirs (>0.1 × 109 m3 storage ca-pacity; CCYRA 1999). By the end of 2002, 143 large-scale reservoirshad been constructed with a total storage capacity of 115 × 109 m3

(CCYRA 2003), which represents a 26.5% increase between 1995and 2002. In this period, seven other large reservoirs were alsounder construction, including the TGD. According to the statisticsof the Yangtze River Water Resources Commission (CCYRA 2006),by 2005, the number of dams in the upper reaches areas ofYangtze River was 12 929 with 23.4 × 1010 m3 of the total waterstorage capacity, while 29 639 dams in the middle reaches areaswith 116.5 × 1010 m3. By 2010, more than 50 000 dams had beenbuilt throughout the Yangtze River basin since 1950 (Yang et al.2011). As of 2000, the Yangtze had 15 dams that exceeded 100 m inheight, with another 20 or more scheduled to be constructed by2015 (Yang et al. 2011).

Today, the growing trend of building hydropower stations inthe upper and middle reaches areas of Yangtze River is moreprominent. For example, the Shennongjia Nature Reserve, locatedin Hubei Province with an area of 3253 km2, is rich in animalresources and encompasses three vertical vegetation zones. For itsecological value, it is known as the heart of the middle reaches ofYangtze River. However, it is estimated that 90 dams have been

Fig. 1. Map of the Yangtze River basin (adapted from Yang et al. 2006).

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built including one with 96 m in height (Lei 2011). Furthermore,another 10 dams are under constructionwith an additional 4 damsscheduled for future construction. Because the runoff in the upperandmiddle reaches was stored in reservoirs, in recent years it wasobserved that the downstream section of the riverbed has experi-enced periods when it dried up from days to even weeks per year.For example, in 2007, the 30.5 km long Xiangxi River, an impor-tant river in the Shennongjia Nature Reserve, has experienceddrying up of 10.5 km of the riverbed in the main stream (Lei 2011).Under these circumstances, there is huge danger for the biodiver-sity and environment of the Shennongjia Nature Reserve.

By the end of the 20th century, more than 22 000 large damshad been built in China, almost half of the world's total (WCD2000). China is the largest country of dam construction and hasthe 2nd most dams (WCD 2000). Incredibly, only 22 large damsexisted prior to the founding of the People's Republic of China in1949 (WCD 2000), illustrating the rapid progress and huge energydemands in China. According to the data published in Pan and He(2000), the total installed hydroelectric capacity of China was72.97 million kW by the end of the 20th century. However, by2020, it is estimated to be 210 million kW in mainly developpedareas for hydropower centralized in the southwest area of Chinawhere the upper and middle reaches of the Yangtze River arelocated. Therefore, dam construction in the Yangtze River basin isgrowing at an alarming rate, and in the next few decades, thespeed of dam construction in China is expected to be higher.

Negative effects of the TGD

Reservoir-triggered seismicity and landslidesThe geology of the TGRR consists of two major components: a

pre-Sinian crystalline basement and a Sinian–Jurassic sedimen-

tary cover (Wu et al. 2001). The former is composed of magmaticand metamorphic rocks, with sporadic outcrops throughout thearea. The latter is widespread and comprises interbedded carbon-ate, sandstone and shale formation. Regional geological struc-tures dominantly trend NE–SW and are associated with majoranticline–syncline fold systems. The numerous fault zones thatfollow the NE–SW orientation of these fold systems tend to formweaker zones of tectonically stressed rock with high slope insta-bility, rock-collapse, and the other geological disasters (Xue andMan 2008; Chen and Man 2011). Karst landform is extensive andwidespread around the TGRR covering more than 1200 km2, dueto it being easily soluble under the warm subtropical and temper-ate climate in southwest China. For example, there is a doline inFengjie county, with 666.2 m in depth and 626 m in diameter, thedistance to the TGD is less than 30 km. Some underground riversthat are dozens of kilometres in length also distribute in Fengjiecounty (Fig. 2). In addition, the development for cave mines israpid andmanymine caves are excavated. Because the water stor-age elevation and storage capacity of the TGD are 175 m and 39.3 ×1010 m3, respectively, the TGD has resulted in the formation of areservoir with a total water surface area of 1080 km2 in the Yang-tze River between Chongqing and Yichang (Fig. 1). Under this sit-uation, the reservoir water may pour into natural limestonecaves, underground rivers, and mine caves distributed in theTGRR and the adjacent areas, which can lead to the caves becom-ing unstable and ultimately collapsing, triggering collapse-typereservoir earthquakes. For example, there have been 19 cases ofreservoir-induced seismicities, and most cases of reservoir-induced seismicity occurred in the southern regions of China thatkarst terranes are predominant (Chen and Talwani 1998).

Fig. 2. Karst landforms of (a) doline, (b) ground fissure, and (c) underground river distributed in the Three Gorges Reservoir Region (photostaken by C. Zhu).

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Reservoir-triggered seismicityEarthquakes triggered by artificial water reservoirs were first

pointed out by Carder (1945) at Lake Mead in the US. Since then,more and more earthquakes occurred in reservoir area have beenrecorded. Large reservoirs can cause seismic events because theimpoundment of a reservoir can reduce the strength of rocks byreducing the coefficient of friction or reducing the cohesivestrength of rocks. And the occurrence of earthquake is also in-duced by karst cavity collapse as a result of dissolution of thecarbonate rocks and the added load of the reservoir (Chen andTalwani 1998). Reservoir-induced seismicity is ubiquitous in reser-voir regions worldwide (Gupta 2002). The result from engineeringinvestigation in the TGRR (Chen and Man 2011) shows that thedam is located on a highly stable rigidmassif with no regional andactive faults present, and there is no record of strong earthquakesin the dam site and nearby counties and cities for over 2000 years.According to Chen and Talwani (1998), the TGD is built on a gra-nitic rock. It forms a core within carbonate rocks and the up-stream area of the reservoir lies on both the granitic core and theupstream limestone beds, with an active fault separating them.Therefore, the situation in the TGRR is not optimistic. There is anevidence of an increase in mild earthquakes during the impound-ing process of the Three Gorges Reservoir (TGR), which weremainly distributed in the region adjacent to the TGRR (MEP 2010).At 16:01 of 22 November 2008, an earthquake with amagnitude of4.6 occurred in Zigui county of Yichang with the focal depth andthe distance to the TGD of only 7.5 and 30 km, respectively. Fol-lowing the Wenchuan earthquake of 2008, seismologists in andoutside China speculated that this may have been human in-duced. It was only during the trial impoundment in 2008 thatthere was a notable rise in the frequency of minor earthquakeswith the epicenter at Badong–Zigui region (MEP 2010). This lead tothe conclusion that the presence of faults in the granitic core ofthe TGD and of natural and artificial carbonate rocks caves in-creases the possibility of moderate earthquakes to be induced bythe TGD in the future.

LandsidesThere have been frequent landslides in the Three Gorges area

extending from Yichang to Chongqing along the Yangtze River inthe historical records of China (Han 1988; Guo 1991; Li and Zhang1993). According to the results of related investigations (Han 1988;Guo 1991; Li and Zhang 1993), there have been about 428 land-slides with more than 1.0 × 105 m3 of one single landslide involume. The total volume of landslides along the major streamand the 31 major tributaries is about 2.79 × 109 m3, in which304 landslides with a total volume of 1.40 × 105 m3 occurred in themajor stream of Yangtze River and 124 landslides with a totalvolume of 1.39 × 105 m3 occurred in tributaries (He et al. 2009).

Slope instability links to geological and socioeconomic envi-ronments. After reservoir impoundment and the associated re-settlement to higher ground, the frequency and magnitude oflandslides are expected to increase through the reactivation of oldlandslides and triggering of new ones (Fourniadis et al. 2007). Inthe process of the TGD construction, engineering activities havenotably increased, mainly including reconstruction of countiesand towns for resettlement of local residents onto higher ground(Fig. 3) and highway construction from Yichang to Chongqingalong the Yangtze River. As a consequence, an evident slow in-crease of landslide occurrence on valley slopes of the YangtzeRiver is found, with an increase in the casualties and homelessfamilies from individual landslide event (Wu et al. 2001). Accord-ing to the statistics (Yin and Yuan 2009), by the end of 2008, over1.2million people had been resettled, only about 0.21millionwereresettled outside the TGRR (Liang 2009) and the remainder werelocally relocated onto higher ground in the TGRR, where the orig-inal vegetation was seriously destroyed (Fig. 3). The first impound-ment of the TGR began from 95 m on 1 June 2003 and reached

135m in 2weeks on 15 June. Shortly after thewater reached 135m,many slopes began to deform and some landslides occurred(Wang et al. 2004).

Water quality control and ecological problemsEnvironmental pollution and ecological problems are becom-

ing the major issues in the TGRR and the TGD downstream areas.The construction of the TGD has significant impacts on the hy-drological regimes of the Yangtze River. The river processes andtheir associated ecosystems and environments have been notablyinfluenced by the TGD construction including loss of biodiversity,inundation of cities and agricultural land, slow tributary flow, andchanges inwater chemistry. As one of the economically developedand densely populated areas in China, there is no doubt thatenvironment quality control is essential for sustainable develop-ment in the Yangtze River basin.

Water quality controlThe sources of pollutants in the TGR are primarily from

(1) natural runoff from the upper streams of the Yangtze, (2) indus-trial and domestic wastewater and agricultural runoffs in theTGRR, (3) waste materials from shipping, and (4) internal sourcesof pollutants from toxic industrial sediments left behind as theTGD filled in (Zhu et al. 2006). Because of the impoundment ofthe TGD, the flow velocity of the Yangtze River has been slow andthe self-purification ability has declined. As a consequence, thewater resources pollution is constantly exacerbated.

In 2006, the industrial and domestic wastewater released intothe TGR was 1.124 × 1010 tonnes and the ones from fertilizer andpesticide application in the region were 154 000 and 655.47 tonnes,respectively (Zhu et al. 2006). Research suggests that the YangtzeRiver receives a large part of its nutrient burden from the drain-age area upstream of the TGD (Zhang et al. 1999). Since the fillingof the TGR, algal blooms consistingmainly of dinoflagellates haveoccurred in 22 tributaries in the TGRR (Fu et al. 2010), which aredirectly linked to slow tributary flow and changes in water chem-istry caused by the TGD (Ye et al. 2006), as well as to land-use andmanagement changes driven by regional economic development(Ye et al. 2009). An alarming signwas also observed in 2006 regard-ing the increasing amounts ofmajor nutrients and trace elements(e.g., As, Hg, Ti, Cd, Cr, Cu, and Zn) in the middlestream anddownstream of the Yangtze River compared with the data ob-tained 20 years ago (Muller et al. 2008). Eutrophication has be-come a major problem of aquatic ecosystem degradation in theTGRR. Moreover, large amounts of toxic sediment from factories,mines, and garbage dumping sites remain on site after the reset-tlement. It is predicted that there would be an increasing internalsource of toxics pollution including arsenic, sulfides, cyanides,and mercury from these sources (Yu et al. 2006; Ye et al. 2010). Arelated investigation has proved this prediction, as 100 or moreorganic compounds have been identified in water samples fromthe rivers in Chongqing (located in the TGRR), including a varietyof organic chlorine compounds, esters, ketones, phenols, hetero-cyclic, benzene, and its derivatives (Guo et al. 2006). Moreover,after the reservoir filled, the navigability has increased with anincrease in shipping that added an additional 3.8 million tonnesof waste materials into the reservoir (Zhang and Lou 2011). Conse-quently, there has been a remarkable decline inwater quality. Themonitoring results indicate that the water quality of the mainstreams in the reservoir were rated as grade II and III (e.g., grade I,II, and III are suitable for drinking) when the TGR reserved waterfor the 1st time in 2003 (Fu et al. 2010). However, after the com-pletion of the TGD, the water quality in some sections of the TGRRhad deteriorated to grade IV, and in some cases to grade V, in 2009(MEP 2010).

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Ecological problemsThe TGD lies in a region which is considered to be one of the

three richest flora centres in China (Ying 2001) and also one of the25 biodiversity hotspots in the world (Myers et al. 2000). The TGRRhas a large number of terrestrial and aquatic species (Table 1). Oneexceptional feature of biodiversity in this region is the abundanceof ancient, rare, endemic, and endangered species. For example,there are as many as 177 endemic fish species in the TGRR, ofwhich 25 already are in endangered status (Yue and Chen 1998).The environmental impacts of the TGD on biodiversity and eco-logical processes have raised concerns to scholars in related fieldsworldwide. The dam and associated environmental alterationsmay result in a wide range of regional changes in terrestrial andaquatic biodiversity, as well as in ecosystem structure and func-tioning.

One obvious impact of the TGD is the unprecedented change inbiodiversity due to reservoir environments. All along the ColoradoRiver in the US — one of the most regulated bodies of water inthe world — the habitat for fish, birds, and other wildlife is nearcollapse (Kelly 2006). It has been reported that inundation andresettlement would affect a total of 22 vegetation types, includingfour wood communities, nine shrub communities, and nine grasscommunities (Tian et al. 2007). A field study by Xie et al. (2006)found that two species, Myricaria laxiflora and Adiantum reniformevar. sinense, would have their entire distribution inundated and

became extinct in the wild. Following 156-m impoundment in2007, the phytoplankton diversity index was observed to havedecreased from �85.52% to �32.32% in tributaries of the TGRR,although phytoplankton compositional changes were not ob-served (Zhu et al. 2009). The effects of the TGD on fish species havebeen the focus of many studies, as dam construction has animportant impact on biodiversity of freshwater fish species(Dudgeon 2000; Xie 2003). This is due to inundation of habitat, iso-lation of fish populations, and interruption of migratory paths. Inthe region of the TGD, loss of fish species has already been expe-rienced. The construction of the Gezhou Dam in 1981, 38 kmdownstream from the TGD, led to sharp decline in the popula-tions of three endemic ancient fish species, Chinese sturgeon(Acipenser sinensis), river sturgeon (A. dabryanus), and Chinesepaddlefish (Psephurus gladius) (Fu et al. 2003) and up to 40 fishspecies have been affected because of the interruption of theirmigratory paths and the loss of spawning grounds (Dudgeon 2000;Fu et al. 2003). A related study by Xie (2003) predicted that thedecline in thewater flowbelow the TGDwouldmost likely destroythe only breeding ground available for fish. Consequently, thedestruction of spawning grounds and the obstruction of migra-tion routes have resulted in a large population decline of fishspecies such as four domestic Chinese carps (Ctenopharyngodonidella, Myloparyngodon piceus, Hypophthalmichthys molitrix, andHypophthalmichthys nobilis) (Gao et al. 2009). Only a few months

Fig. 3. Photos of new Wushan city under construction including road construction. (a), (b), and (c) are the status of vegetation deteriorationcaused by resettlement of the Three Gorges Dam; and (d) is the landslide caused by road construction in the Three Gorges Reservoir Region(photos taken by C. Zhu).

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after impoundment, a shift of fish communities from lotic tolentic components has occurred in the upper reaches of theYangtze River (Gao et al. 2010). In fact, some aquatic mammal andendemic fish species are currently near extinction, including theChinese river dolphin (Lipotes vexillifer), the finless porpoise(Neophocaena phocaenoides asiaorientalis), and the Chinese paddle-fish (P. gladius) (Stone 2008). It is reported that the Chinese paddle-fish (P. gladius) was declared extinct in 2007 and there are only�920 finless porpoises (N. asiaorientalis) still living in the YangtzeRvier (ScienceNet 2013).

Dams usually result in large-scale habitat fragmentation andecosystem alterations that adversely affect both terrestrial andaquatic biodiversity (Dynesius and Nilsson 1994; Wu et al. 2003,2004). When water levels rise to 175 m, besides the obvious loss ofhabitat through inundation, dam also has significant impact onits surrounding habitats. Impoundment transforms free-flowingrivers into reservoirs, which are subject to vastly different pro-cesses by nature (New and Xie 2008). This can result in new sedi-ment processes leading to changing landforms, affecting thenutrient composition of both terrestrial and aquatic environ-ments, and creating island habitats and habitat fragmentation(New and Xie 2008). Wu et al. (2004) reported that, when the totalinundated area in the TGRR is about 1080 km2, more than100 mountaintops and ridges would become landbridge islandswith an estimated total number and total area of land-bridge is-lands of 47–102 and 58.70–80.67 km2, respectively. Aside from theloss of vegetation through inundation, exotic species suitable forlakeshores environment as well as rare local species that has beenpreviously linked to lakeshores exposed to high levels wouldthrive (New and Xie 2008). Bai et al. (2005) predicted that theformer arid species of aquatic plants found at the lower level andwaterline would be replaced by water-tolerant species such asCynodon spp. and Hemarthria spp. or other aquatic plant speciesthat can persist because of wave action or revive after desiccationduring periods of drawdown in the riparian zone of the TGR. Todate, there are no studies on plant species biodiversity throughfield investigations in the TGRR, but a related study suggests thatthe vegetation cover has changed in mountainous areas of theTGRR with an increasing trend of normalized difference vegeta-tion index from 2001 to 2010 (Li et al. 2011a). In addition to changesin floral biodiversity, significantly increased intra- and inter-specific competition among local animal populations has beendetected in newly isolated islands in the TGRR that is predicted tolead to further changes in species composition and biodiversity inthe reservoir region (Wang et al. 2010).

The TGD not only affects terrestrial and aquatic biodiversityand ecosystems in the TGRR, downstream areas from the TGD, butalso the Yangtze River mouth and the adjacent shelf region. Mod-ified river flows and changed amount and composition of sedi-ment and nutrients have altered the habitats of the flora, fauna,and microorganisms in the riverine and coastal ecosystems (Fuet al. 2010). Some studies (Li et al. 2005; Yu et al. 2011) have shownthe impacts of the TGD impoundment on the vegetation in down-stream wetlands and found that the TGD has indeed played a rolein vegetation growth in downstreamwetlands, with simultaneousnegative and positive effects at different times. A comparativeanalysis of before-and-after the TGD impoundment using remoteimages found that, to date, the impacts of the TGD on terrestrialplants in downstream areas are not obvious (Chen and Shen 2011).The impacts of the TGD in the Yangtze River mouth and the adja-

cent shelf region have been the focus of many studies. Generally,dam results significant changes in shoreline vegetation by affect-ing the diversity and composition of plant communities as well asaltering structural patterns (New and Xie 2008). In June 2003,sluice gates on the TGD were closed for water reservoir; and afterthe TGD filled one third of its storage capacity of 39.3 × 1010 m3 in10 days, the flow at the Yangtze River mouth into the East ChinaSea dropped 27%. A low discharge of runoff from the upper catch-ment area into the estuary resulted in abnormal salinity levels inthe estuary of the Yangtze River that occurred in the 2nd im-poundment phase of the TGD (Dai et al. 2011). Xie (2003) predictedthat the extinction of fish species at the estuary may result higherlevels of salinization. The salinity changes by the reduction offreshwater discharge would result in an enhanced nutrientconcentration in the shelf waters, consequently, harmful algalblooms or red tides may occur more (Gao 2007). In the 1st im-poundment phase of the TGD in 2003, phytoplankton communitystructure (Wang et al. 2009), zooplankton community structure(Liu et al. 2007), and ichthyoplankton community structure (Shanet al. 2005) have also undergone notable changes. Moreover, stud-ies indicate that in a dry season the water discharge to the sea isgreatly reduced resulting in strong saltwater intrusions in theestuary (Chen et al. 2001; An et al. 2009; Yu et al. 2009). This wouldlikely lead to the downstream effect of a saltwater intrusion in theriver delta. Furthermore, the soil and groundwater salinization inrainy seasons of dry years would be aggravated because the riverlevel in the Yangtze River Estuary would significantly change; andduring the water storage period of the TGD from October toDecember, the risk of soil salinization in the estuary would in-crease (Yu et al. 2009).

Siltation of TGD and sediment discharge declineSediment deposition has become a major problem in about

230 large dams in China, causing an average loss of 14% of theirtotal storage capacity, and in some cases reaching more than 50%(Suo 2004). But silt deposition in the Yangtze River is severe (Wangand Hu 2004) due to the extensive soil erosion experienced in itsbasin in recent decades caused by human activities such as defor-estation and slope cultivation. The problem of siltation in the TGRis a great threat to the TGD. Pan (2003) discovered that the mostcritical material affecting fluvial processes in the upper reaches ofthe Yangtze River is gravel, not sand. Sediment deposition is ex-pected to increase at the tail end of the reservoir because slowwater flow will prevent the flushing out of gravel and pebbles.This might make the port of Chongqing less usable due to thesiltation of the harbour and negatively affect the navigation chan-nel. Zhang et al. (2006) found that the sediment deposits increasedaccumulatively have severely influenced the harbor and the nav-igation of Chongqing.

The Yangtze River has traditionally carried a vast load of sedi-ment from the upper reaches of its watershed to the East ChinaSea, supporting ecological processes in the river delta and theproductivity of fisheries in the Sea. Large quantities of sedimentshave been trapped behind the TGD, which leads to obvious sedi-ment decline and severe downstream channel erosion, addingconsiderable pressure on the Yangtze coast and the East China Sea(Yang et al. 2007; Xu and Milliman 2009). The completion of theTGD has led to a rapid and significant decrease in downstreamsediment load. Before water filling of the TGD, the Yangtze River'smean annual sediment discharge was about 500 million tons.

Table 1. Biodiversity in the Three Gorges Reservoir region (number of species by different taxonomic groups).

Higher plants(MEP 2001)

Insects(Huang 2001)

Terrestrial vertebrates(MEP 2000)

Fish(Huang 2001)

Aquatic plants, plankton, andbenthic organisms (Huang 2001)

6388 3418 (including 368 speciesof butterflies)

552 (including 118 mammals, 342 birds,51 reptiles, and 41 amphibian species)

350 1085

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After the water filling of the TGD in 2006 at Yichang station,downstream of the Yangtze River, the sediment discharge wasonly 64 million tons, only one fifth of its former load (Chen et al.2008). About 172 million tons of sediment were trapped annuallyby the TGD in 2003–2008 with an average trapping efficiency of75% (Hu et al. 2009). Prior to the TGD operation, the subaqueousdelta of the Yangtze experienced accretion (Yang et al. 2003); butsince 2003, net erosion has been observed (Li et al. 2004). Repeatedsurveys of intertidal wetlands at the delta front have revealedrecession since 2003 (Yang et al. 2007). Based on the historicalsediment budget and erosion data from the river delta, scientistsestimate that the delta will be increasingly eroded during the firstfive decades after full operation of the TGD and then approach abalance during the next five decades as sediments start to movethrough the TGR (Yang et al. 2006).

Other negative impacts of the TGDThe TGD consistently supplies water for agriculture, people,

and industries in the vicinity of the dam and to northern China aspart of a major interbasin water-transfer project. Therefore, thewater-level fluctuations caused by the TGD impoundment in theYangtze River have a significant effect on the water available forboth agriculture and human consumption (Gao 2007). Moreover,the changes in infectious disease dynamics can result from thealteration of ecological processes as well as social dynamics. Froman ecological perspective, land-use change, loss of biodiversity,changes in habitat, and alteration of processes, such as nutrientcycling and pathogen dispersion, can significantly affect the dy-namics of disease (Patz et al. 2004). The TGR is situated betweentwo existing areas that are both endemic for schistosomiasis.Marsh areas increased in the TGRR exacerbate the natural condi-tions suitable for schistosoma transmission. Zhu et al. (2008) indi-cated that the TGD can induce a variety of environmental andecological changes in both the TGRR and downstream areas andthese changes carry ambivalent implications for spreading ofschistosoma infections. Furthermore, the magnitude of the damand reservoir is so large that it has already affected local climaticconditions (Wu et al. 2006; Li et al. 2011b). Related studies suggestthat the TGD do have effects on precipitation and temperature inthe vicinity of the TGD (Wu et al. 2006; Li et al. 2011b), but only ona regional scale — 100 km (Wu et al. 2006) — without significanteffects in surrounding regions (Li et al. 2011b).

Concluding remarksWhen utilizing water resources in rivers by dam construction

for flood control, irrigation, navigation, energy supply, etc., wemay solve some problems, but at the same time we create otherproblems, namely man-made problems. The negative impacts ofdam are complex, and the TGD is no exception. Even after a longand complicated evaluation process, there are still many uncer-tainties in evaluating the geological, ecological, and environmen-tal impacts of the TGD. It has always been understood that a goodproject would bring remarkable benefits for human, and a poorone couldmean endless controversy and negative impacts. After along and complicated evaluation process, it is still not possible tosimply conclude the TGD as either a good or poor project. Al-though the analyses suggested both favorable and unfavorableimpacts of the TGD on the ecosystem and environment, differentviews and arguments still exist. This highlights the complexities,difficulties, and unpredictability of the issues under consider-ation and also underlines a lack of knowledge.With the operationof the TGD and the changes to the regional environment in theYangtze River basin, negative and positive effects will continue tobe recognized. Qualifying negative impacts is a long-term chal-lenge that simultaneously gives us good opportunities to investi-gate and research both negative and positive effects of the TGD. Inthe thorough assessment of the TGD's impacts, scientific andmul-tidisciplinary efforts are needed; and adequate information on

geology, hydrology, biodiversity, and ecology in the Yangtze Riverbasin, especially in the TGRR, is also required. Aside from short-term field surveys, a long-term monitoring should also beschemed and implemented, including earthquake, landside,and water-quality. Most importantly, permanent research stationsshould be included, especially for landslide and ecologicalmonitor-ing with different scales. It is estimated that 160–320 new damsare being built worldwide annually (Wu et al. 2003), and the speedof dam construction in China for the next few decades will beextremely rapid (Pan and He 2000). The experiences of the TGDand the related costs and benefits can thus be used as the construc-tive references for sustainable development in other nations or re-gions. With concerted efforts and concrete actions, the negativeeffects could be controlled and the positive effects could be securedin new domestic and foreign projects of dam construction.

AcknowledgementsThis research was funded by the National Natural Science Fun-

dation of China (41171163), the Scientific Research Foundation ofGraduate School of Nanjing University (2012CL02), and the OpenFoundation of State Key Laboratory of Lake Science and Environ-ment, CAS (2012SKL003).

ReferencesAn, Q., Wu, Y.Q., Taylor, S., and Zhao, B. 2009. Influence of the Three Gorges

Project on saltwater intrusion in the Yangtze River Estuary. Environ. Geol.56(8): 1679–1686. doi:10.1007/s00254-008-1266-4.

Bai, B., Wang, H., Li, X., Feng, Y., and Zhi, L. 2005. A comparative study of thefuture water-level-fluctuating zone and the natural water-level-fluctuatingzone in the Three Gorges Reservoir. 2005. J. Southwest Agric. Univ. (NaturalScience), 27(5): 684–691. [In Chinese with English summary.]

Carder, D.S. 1945. Seismic investigations in the Boulder Dam area, 1940–1944,and the influence of reservoir loading on earthquake activity. Bull. Seismol.Soc. Amer. 35(4): 175–192.

CCYRA (Compilation Committee for Yangtze River Almanac). 1999. YangtzeRiver Almanac. Yangtze River Almanac Press, Wuhan. [In Chinese.]

CCYRA (Compilation Committee for Yangtze River Almanac). 2003. YangtzeRiver Almanac. Yangtze River Almanac Press, Wuhan. [In Chinese.]

CCYRA (Compilation Committee for Yangtze River Almanac). 2006. YangtzeRiver Almanac. Yangtze River Almanac Press, Wuhan. [In Chinese.]

Challman, D. 2000. The whole dam story: A review of China Yangtze ThreeGorges Dam. Energiea, 11: 1–4.

Chen, D.J., and Man, Z.W. 2011. The research and demonstration of some majorgeological problems of the Three Gorges Project. Eng. Sci. 9(3): 49–56.

Chen, L., and Talwani, P. 1998. Reservoir-induced seismicity in China. Pure Appl.Geophys. 153: 133–149. doi:10.1007/s000240050188.

Chen, P., and Shen, S. 2011. Research on terrestrial eco-environment changingbased on multi-temporal CBERS images. Journal of Yangtze River ScientificResearch Institute 28(2): 69–73. [In Chinese with English summary.]

Chen, X., Zong, Y., Zhang, E., Xu, J., and Li, S. 2001. Human impacts on theChangjiang (Yangtze) River Basin, China, with special reference to theimpacts on the dry season water discharges into the sea. Geomorphology,41(2–3): 111–123. doi:10.1016/S0169-555X(01)00109-X.

Chen, X.Q., Yan, Y.X., Fu, R.S., Dou, X.P., and Zhang, E.F. 2008. Sediment trans-port from the Yangtze River, China, into the sea over the post-three GorgesDam period: A discussion. Quatern. Int. 186(1): 55–64. doi:10.1016/j.quaint.2007.10.003.

Dai, Z.J., Chu, A., Stive, M., Zhang, X.L., and Yan, H. 2011. Unusual salinity con-ditions in the Yangtze Estuary in 2006: Impacts of an extreme drought or ofthe Three Gorges Dam? Ambio, 40(5): 496–505. doi:10.1007/s13280-011-0148-2.PMID:21848138.

Dudgeon, D. 2000. Large-scale hydrological changes in tropical Asia: Prospectsfor riverine biodiversity. BioScience, 50(9): 793–806. doi:10.1641/0006-3568(2000)050[0793:LSHCIT]2.0.CO;2.

Dynesius, M., and Nilsson, C. 1994. Fragmentation and flow regulation of riversystems in the northern third of theworld. Science, 266: 753–762. doi:10.1126/science.266.5186.753. PMID:17730396.

Fourniadis, I.G., Liu, J.G., and Mason, P.J. 2007. Landslide hazard assessment inthe Three Gorges area, China, using ASTER imagery: Wushan-Badong. Geo-morphology, 84: 126–144. doi:10.1016/j.geomorph.2006.07.020.

Fu, C.,Wu, J., and Chen, J. 2003. Freshwater fish biodiversity in the Yangtze Riverbasin of China: patterns, threats and conservation. Biodivers. Conserv. 12:1649–1685. doi:10.1023/A:1023697714517.

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

Li et al. 133

Published by NRC Research Press

Gao, S. 2007. The Three Gorges Project: Development and Environmental issues.Macalester Int. 18: 146–171.

Gao, X., Brosse, S., Chen, Y., Lek, S., and Chang, J. 2009. Effects of damming onpopulation sustainability of Chinese sturgeon, Acipenser sinensis: Evalua-tion of optimal conservation measures. Environ. Biol. Fish. 86: 325–336.doi:10.1007/s10641-009-9521-4.

Gao, X., Zeng, Y., Wang, J., and Liu, H. 2010. Immediate impacts of the secondimpoundment on fish communities in the Three Gorges Reservoir. Environ.Biol. Fish. 87: 163–173. doi:10.1007/s10641-009-9577-1.

Guo, X. 1991. Geological hazards in China and their prevention and control.Geological Press, Beijing. [In Chinese.]

Guo, Z.S., Luo, C.H., Zhang, W.D., Lu, Y., Sun, J., and Cao, J. 2006. The analysis ofthe persistent organic pollution in the Three Gorges Region in Chongqing.Environmental Monitoring in China, 22(4): 45–48. [In Chinese with Englishsummary.]

Gupta, H.K. 2002. A review of recent studies of triggered earthquakes by artifi-cial water reservoirs with special emphasis on earthquakes in Koyna, India.Earth-Sci. Rev. 58: 279–310. doi:10.1016/S0012-8252(02)00063-6.

Han, Z.S. 1988. Landslides and rockfalls of the Yangtze River Gorges. GeologicalPress, Beijing. [In Chinese.]

He, K.Q., Yu, G.M., and Li, X.R. 2009. The regional distribution regularity of land-slides and their effects on the environments in the Three Gorges ReservoirRegion, China. Environ. Geol. 57: 1925–1931. doi:10.1007/s00254-008-1482-y.

Hu, B.Q., Yang, Z.S., Wang, H.J., Sun, X.X., Bi, N.S., and Li, G.G. 2009. Sedimen-tation in the Three Gorges Dam and the future trend of Changjiang (YangtzeRiver) sediment flux to the sea. Hydrol. Earth Syst. Sci. 13: 2253–2264. doi:10.5194/hess-13-2253-2009.

Huang, Z.L. 2001. Biodiversity conservation for the Three Gorges Project. Biodiv-ers. Sci. 9: 472–481.

Kelly, W.J. 2006. Greed Runs Through It. Los Angeles Weekly. March 15.Lei, L. 2011. Prosperity and development of hydropower in Shennongjia Region.

Southern Weekly, September 1. [In Chinese.]Li, Y.S., and Zhang, Y. 1993. Large-scale landslides and rockfalls in the reservoir

of the Three Gorges project of the Yangtze River. Guangzhou Tour Press,Guangzhou. [In Chinese.]

Li, C.X., Yang, S.Y., Fan, D.D., and Zhao, J. 2004. The change in Changjiangsuspended load and its impact on the delta after completion of Three-GorgesDam. Quatern. Res. 24(5): 495–500. [In Chinese with English summary.]

Li, Q., Zeng, G., Huang, G., Zhang, S., Jiao, S., Zeng, T., Wang, L., Xiong, Y., andHe, J. 2005. Effects of Three-Gorge Project on hydraulic gradient and vegetationgrowth in Dongting Lake wetland. J. Safety Environ. 5(1): 12–15. [In Chinese withEnglish summary.]

Li, J., Pu, L., Liu, J., Li, Y., and Liu, L. 2011a. The temporal and spatial characteris-tics of vegetation activity in Three Gorges Reservoir Area (Chongqing) from2001 to 2010 and its influencing factors. Resources Science, 34(8): 1500–1507.[In Chinese with English summary.]

Li, Y., Gao, Y.H., Chen, X.Y., and Du, Q. 2011b. The impact of the land use changeassociated with the Three Gorges Dam on regional climate change. Journal ofNanjing University (Natural Sciences), 47(3): 330–338. [In Chinese with Eng-lish summary.]

Liang, F.Q. 2009. The review and consideration on rural immigrant resettlementoutside Three Gorges Reservoir area. Yangtze River, 40: 10–12.

Liu, G., Chen, H., Zhu, Y., and Qi, Y. 2007. Study on the zooplankton communitystructure in the Changjiang River Estuary and adjacent sea area after thefirst-stage storage of the Three-Gorges Project. Periodical of Ocean Universityof China, 37(5): 789–794. [In Chinese with English summary.]

McCormack, G. 2001. Water margins: Competing paradigms in China. CriticalAsian Studies, 33(1): 5–30. doi:10.1080/14672710122114.

MEP (Ministry of Environmental Protection of the People's Republic of China).2000. Bulletin on the Ecological and Environmental Monitoring Results ofthe Three Gorges Project 1999 [online]. Available from http://jcs.mep.gov.cn/hjzl/sxgb/1999/200211/t20021117_83203.htm [Accessed 2 May 2013].

MEP (Ministry of Environmental Protection of the People's Republic of China).2001. Bulletin on the Ecological and EnvironmentalMonitoring Results of theThree Gorges Project 2000 [online]. Available from http://jcs.mep.gov.cn/hjzl/sxgb/2000/200211/t20021117_83211.htm [Accessed 2 May 2013].

MEP (Ministry of Environmental Protection of the People's Republic of China).2010. Bulletin on the Ecological and EnvironmentalMonitoring Results of theThree Gorges Project 2009 [online]. Available fromhttp://english.mep.gov.cn/down_load/Documents/201002/P020100225376514651439.pdf [Accessed20 May 2012].

Milliman, J.D. 1997. Blessed dams or damned dams? Nature, 386: 325–327. doi:10.1038/386325a0.

Muller, B., Berg, M., Yao, Z.P., Zhang, X.F., Wang, D., and Pfluger, A. 2008. Howpolluted is the Yangtze River? Water quality downstream from the ThreeGorges Dam. Sci. Total Environ. 402: 232–247.

Myers, N., Mittermeier, R.A., Mittermeier, C.G., da Fonseca, G.A.B., and Kent, J.2000. Biodiversity hotsposts for conservation priorities. Nature, 403: 853–858. doi:10.1038/35002501. PMID:10706275.

New, T., and Xie, Z. 2008. Impacts of large dams on riparian vegetation: applyingglobal experiences to the case of China's Three Gorges Dam. Biodivers. Con-serv. 17: 3149–3163. doi:10.1007/s10531-008-9416-2.

Pan, Q.S. 2003. Study on the silt of hydro projects in the Yangtze River. ChinaWater Power Press, Beijing. [In Chinese.]

Pan, J.Z., and He, J. 2000. Large dams in China: A fifty-year review. China WaterPower Press, Beijing. [In Chinese.]

Patz, J.A., Daszak, P., Tabor, G.M., Aguirre, A.A., Pearl, M., Epstein, J.,Wolfe, N.D.,and Kilpatrick, A.M. 2004. Unhealthy landscapes: policy recommendationson land use change and infectious disease emergence. Environ. Health Persp.112: 1092–1098. doi:10.1289/ehp.6877.

Rosenberg, D.M., McCully, P., and Pringle, C.M. 2000. Global-scale environmen-tal effects of hydrological alterations: Introduction. BioScicence, 50(9): 746–751. doi:10.1641/0006-3568(2000)050[0746:GSEEOH]2.0.CO;2.

ScienceNet. 2013. Top species are near extinction: what does this mean to theYangtze Rvier? January 13, http://news.sciencenet.cn/htmlnews/2013/1/273912.shtm. [In Chinese.]

Shan, X., Xian, W., and Wu, Y. 2005. Dynamic changes in the ichthyoplanktoncommunity structure after the sluice of the Three-Gorges Dam. Periodical ofOcean University of China, 35(6): 936–940. [In Chinese with English summary.]

Stone, R. 2008. Three Gorges Dam: Into the unknown. Science, 321: 628–632.doi:10.1126/science.321.5889.628. PMID:18669836.

Suo, L.S. 2004. River management and ecosystem conservation in China. InProceedings of the Ninth International Symposium on River Sedimentation.Edited by C.H. Hu and Y. Tan. Tsinghua University Press, Beijing. pp. 3–9. [InChinese.]

Tian, Z., Chen, W., Zhao, C., Chen, Y., and Zheng, B. 2007. Plant biodiversity andits conservation strategy in inundation and resettlement districts of theYangtze Three Gorges, China. Acta Ecological Sinica, 27: 3110–3118. [InChinese with English summary.] doi:10.1016/S1872-2032(07)60065-1.

Wang, R.S. 2000. The environment and resettlement of TGP. Resources andEnvironment in the Yangtze Basin, 9(1): 1–13.

Wang, Z.Y., and Hu, C.H. 2004. Interactions between fluvial systems and large-scale hydroprojects. In Proceedings of the Ninth International SymposiumonRiver Sedimentation. Edited by C.H. Hu and Y. Tan. Tsinghua University Press,Beijing. pp. 39–57. [In Chinese.]

Wang, F.W., Zhang, Y.M., Huo, Z.T., Matsumoto, T., and Huang, B.L. 2004. TheJuly 14, 2003 Qianjiangping landslide, Three Gorges Reservoir, China. Land-slides, 1: 157–162.

Wang, J., Chen, R., and Zuo, T. 2009. Characteristics of phytoplankton commu-nity structure in the adjacent waters of Yangtze River Estuary after sluice ofthe Three Gorges Dam. J. Hydroecology, 2(2): 80–87. [In Chinese with Englishsummary.]

Wang, J., Huang, J., Wu, J., Han, X., and Lin, G. 2010. Ecological consequences ofthe Three Gorges Dam: insularization affects foraging behavior and dynam-ics of rodent populations. Frontiers Ecology and the Environment, 8: 13–19.doi:10.1890/070188.

WCD (World Commission on Dams). 2000. Dams and Development: A NewFramework for Decision Making. Earthscan Publications, London.

Wu, S.R., Shi, L., Wang, R.J., Tan, C.X., Hu, D.G., Mei, Y.T., and Xu, R.C. 2001.Zonation of the landside hazards in the fore reservoir region of the ThreeGorges Project on the Yangtze River. Engineering Geology, 59: 51–58. doi:10.1016/S0013-7952(00)00061-2.

Wu, J., Huang, J., Han, X., Xie, Z., and Gao, X. 2003. Three Gorges Dam –experiment in habitat fragmentation? Science, 300: 1239–1240. doi:10.1126/science.1083312. PMID:12764179.

Wu, J., Huang, J., Han, X., Gao, X., He, F., Jiang, M., Jiang, Z., and Primack, R.B.2004. The Three Gorges Dam: an ecological perspective. Front. Ecol. Environ.2(5): 241–248. doi:10.1890/1540-9295(2004)002[0241:TTGDAE]2.0.CO;2.

Wu, L., Zhang, Q., and Jiang, Z. 2006. Three Gorges Dam affects regional precip-itation. Geophys. Res. Lett. 33: L13806. doi:10.1029/2006GL026780.

Xie, P. 2003. Three-Gorges Dam: Risk to Ancient Fish. Science, 302: 1149–1151.PMID:14615514.

Xie, Z.Q., Wu, J.Q., and Xiong, G.M. 2006. Conservation ecology of rare andendangered plants in the Three Gorges Reservoir Area. China Water PowerPress, Beijing. [In Chinese.]

Xu, K.H., and Milliman, J.D. 2009. Seasonal variations of sediment dischargefrom the Yangtze River before and after impoundment of the Three GorgesDam. Geomorphology, 104: 276–283. doi:10.1016/j.geomorph.2008.09.004.

Xue, G.F., and Man, Z.W. 2008. Engineering geological investigation and re-search on the Three Gorges Project. China University of Geoscience Press,Wuhan. [In Chinese.]

Yang, S.L., Belkin, I.M., Belkina, A.I., Zhao, Q.Y., Zhu, J., and Ding, X.D. 2003.Delta response to decline in sediment supply from the Yangtze River: Evi-dence of the recent four decades and expectations for the next half-century.Estuar. Coast. Shelf Sci. 57(4): 689–699. doi:10.1016/S0272-7714(02)00409-2.

Yang, S.L., Zhang, J., Zhu, J., Smith, J.P., Dai, S.B., and Gao, A. 2005. Impact ofdams on Yangtze River sediment supply to the sea and delta wetland re-sponse. J. Geophys. Res. 110: F03006. doi:10.1029/2004JF000271.

Yang, Z.,Wang, H., Saito, Y., Milliman, J.D., Xu, K., Qiao, S., and Shi, G. 2006. Damimpacts on the Changjiang (Yangtze) River sediment discharge to the sea:The past 55 years and after the Three Gorges Dam. Water Resour. Res. 42:W04407. doi:10.1029/2005WR003970.

Yang, S.L., Zhang, J., and Xu, X.J. 2007. Influence of the Three Gorges Dam ondownstream delivery of sediment and its environmental implications, Yang-tze River. Geophys. Res. Lett. 34: L10401. doi:10.1029/2007GL029472.

134 Environ. Rev. Vol. 21, 2013

Published by NRC Research Press

Yang, S.L., Milliman, J.D., Li, P., and Xu, K. 2011. 50 000 dams later: Erosion of theYangtze River and its delta. Global Planet. Change, 75: 14–20.

Ye, L., Xu, Y., Han, X., and Cai, Q. 2006. Daily dynamics of nutrients and chlo-rophyll a during a spring phytoplankton bloom in Xiangxi Bay of the ThreeGorges Reservoir. Journal of Freshwater Ecology, 21: 315–321. doi:10.1080/02705060.2006.9665001.

Ye, L., Cai, Q., Liu, R., and Cao,M. 2009. The influence of topography and land useon water quality of Xiangxi Rvier in Three Gorges Reservoir region. Environ.Geol. 58: 937–942. doi:10.1007/s00254-008-1573-9.

Ye, C., Li, S., Bu, H., and Zhang, Q. 2010. Ecologcial risk assessment on heavymetal pollution in the water-levle-fluctuation zone of the three gorgesreservoir. Acta Pedologia Sinica, 47(6): 1264–1269. [In Chinese with Eng-lish summary.]

Yin, Z., and Yuan, Y. 2009. Resettlement planning and design of Three GorgesProject of Yangtze River. Journal of Hydroelectric Engineering, 28(6): 26–31.[In Chinese with English summary.]

Ying, T. 2001. Species diversity and distribution pattern of seed plants in China.Biodivers. Sci. 9: 393–398. [In Chinese with English summary.]

Yu, F., Zhang, C., Zhang, S., Wang, D., and Huang, Y. 2006. Contents and distri-bution of heavy metals in the draw-down zone of the Three-Gorge Reservoirarea. Journal of Southwest Agricultural University, 28(1): 165–168. [In Chinesewith English summary.]

Yu, S., Yang, J., and Liu, G. 2009. Impact on soil salinization in Yangtze Riverestuary by Three-Gorge project. Journal of Liaoning Technical University(Natural Science), 28(6): 1013–1017. [In Chinese with English summary.]

Yu, L., He, L., Zhang, Q., Chen, Y., andWang, X. 2011. Effects of the Three Gorges

Project on the typical wetland vegetations of Poyang Lake. GeographicalResearch, 30(1): 134–144. [In Chinese with English summary.]

Yue, P., and Chen, Y. 1998. China red data book of endangered animals: Pisces.Science Press, Beijing.

Zhang, Q.F., and Lou, Z.P. 2011. The environmental changes and mitigationactions in the Three Gorges Reservoir region, China. Environ. Sci. Policy, 14:1132–1138.

Zhang, J., Zhang, Z., Liu, S., Wu, Y., Xiong, H., and Chen, H. 1999. Human impactson the large world rivers: Would the Changjiang (Yangtze River) be an illus-tration? Global Biogeochemical Cycles, 13(4): 1099–1105. doi:10.1029/1999GB900044.

Zhang, X.J., Mu, D.W., and Zhao, S.Q. 2006. Sediment aggregation and regulationfor Chongqing Reach of the fluctuating backwater district in Three GorgesReservoir. Journal of Chongqing Jianzhu University, 28(5): 13–17. [In Chinesewith English summary.]

Zhu, J., Dong, H., Wang, S., Wang, X., Zhang, H., and Fan, Z. 2006. Sources andquantities of main water pollution loads released into Three-Gorges Reser-voir of the Yangtze River. Adv. Water Sci. 17: 709–713. [In Chinese withEnglish summary.]

Zhu, H.M., Xiang, S., Yang, K., Wu, X.H., and Zhou, X.N. 2008. Three Gorges Damand its impact on the potential transmission of schistosomiasis in regionsalong the Yangtze River. EcoHealth, 5: 137–148. doi:10.1007/s10393-008-0168-y.PMID:18787917.

Zhu, A., Wu, G., Liang, Y., Xie, W., Yu, F., and Hu, X. 2009. Spatial and temporaldynamic of Phytoplankton community in tributary Tongzhuang River estu-ary after 156m impoundment of the Three Gorges Reservoir. Journal ofHydroecology, 2(2): 101–106. [In Chinese with English summary.]

Li et al. 135

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