Impacts of large dams on downstream fluvial sedimentation: An example of the Three Gorges Dam (TGD) on the Changjiang (Yangtze River)

Dai, Zhijun; Liu, James T.

doi:10.1016/j.jhydrol.2012.12.003

Cited by 311 publications

(172 citation statements)

References 24 publications

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“…Although the TGD releases clear water into the downstream section, the turbulent flows cause large amounts of suspended sediments to be moved downstream, changing the morphological evolution of the river channel. Studies have indicated that the riverbed has changed from being accretionary (before the TGD) to erosional, with the riverbed showing strong, intermediate, and weak erosional modes depending on closeness to the TGD [30,31]. In particular, the channel between Yichang and Zhicheng (downstream of the TGD), has been very severely eroded [32], causing a decline in the elevation of the river bed and, correspondingly, an appreciable decrease of water level in the river over time, even though the river runoff has not shown any such trend [30].…”

Section: Hydrological Regimementioning

confidence: 99%

“…At the same time, climate change-driven variations in sea water level and wave conditions potentially affect the dynamic estuarine systems [58,59] River inflows, including the sediment discharge brought with them, are crucial to the environmental conditions, biodiversity, morphological configuration, and development, etc., of the estuary [35,60], and vital for the ecological health and sustainable economic growth of the Yangtze River Delta (YRD), the most developed region in China. Inflows to the Yangtze River estuary are significantly affected by the TGD [30], with data indicating a significant decreasing trend in both total and minimum annual discharges from the Yangtze River to the sea [26,61,62]. These declines can be interpreted as being partially the result of enhanced evaporation of water from the reservoirs and partially due to enhanced rates of water abstraction [62].…”

Section: Hydrological Regimementioning

confidence: 99%

“…For example, sand mining in the Poyang Lake is reported to cause re-suspension of fine deposits, which leads to an increase in the downstream delivery of sediments to the delta [31]. The other is that riverbed erosion decreases with the distance from the outlet of the TGD [12,30], and given the long distance of almost 2000 km, erosion in the estuary is relatively weak. Besides, as we know, estuarine systems are governed by pressures from both the terrestrial and the marine fields, so the significance of drivers from the coastal environment for the evolution of the YRD should not be neglected as well.…”

Section: Hydrological Regimementioning

confidence: 99%

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Impact of the Three Gorges Dam on the Hydrology and Ecology of the Yangtze River

Zhang

Dong

Gupta

et al. 2016

Water

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Construction and operation of the Three Gorges Dam (TGD) has significantly altered the downstream hydrological regime along the Yangtze River, which has in turn affected the environment, biodiversity and morphological configuration, and human development. The ecological and environmental systems of the middle and lower Yangtze River have been affected adversely, with the ecosystems of Poyang Lake and its deltas being among the most damaged. Besides posing a potential threat to the survival of migrant birds and aquatic species, operation of the TGD has also affected the human population, particularly with respect to water and food security. Though the above mentioned effects have been studied in previous papers, a comprehensive discussion has never been conducted. This paper provides the first ever summary of the impacts of the TGD on the downstream reaches of the Yangtze River. The costs and benefits identified provide a constructive reference that can be used in decision-making for sustainable development of water resources in other nations, especially those in the developing world.

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Section: Hydrological Regimementioning

confidence: 99%

Section: Hydrological Regimementioning

confidence: 99%

Section: Hydrological Regimementioning

confidence: 99%

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Impact of the Three Gorges Dam on the Hydrology and Ecology of the Yangtze River

Zhang

Dong

Gupta

et al. 2016

Water

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“…A large body of literature has quantified the sediment load trapped by the dam, and changes in fluvial sediment export, as well as its hydrological and geomorphological consequences for downstream channels (Yang et al, 2005;Yang et al, 2006;Yang et al, 2007;Chen et al, 2008;Dai et al, 2008;Hu et al, 2009;Xu and Milliman, 2009;Dai et al, 2011;Li et al, 2011b;Wang et al, 2011;Luo et al, 2012;Dai and Liu, 2013;Nakayama and Shankman, 2013;Dai et al, 2014;Feng et al, 2014;Jiang et al, 2014;Lai et al, 2014;Yang et al, 2014;Meng et al, 2015;Yang et al, 2015). A recent study estimated that the annual averaged amount of sediment trapped by the Three Gorges Dam ranged from 116 to 234 Mt/yr during 2003-2012, with an average of 118 Mt/yr (Yang et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Flow regulation manipulates contemporary seasonal sedimentary dynamics in the reservoir fluctuation zone of the Three Gorges Reservoir, China

Tang

Bao

et al. 2016

Science of The Total Environment

104

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• Hydrological regime in the reservoir fluctuation zone has been significantly altered.• Grain-size variations are diagnostic for sedimentary stratigraphy differentiation.• Post-dam sedimentation processes were reproduced by chronology determination.• Regular flow regulation controls contemporary seasonal sedimentary dynamics. Since the launch of the Three Gorges Dam on the Yangtze River, a distinctive reservoir fluctuation zone has been created and significantly modified by regular dam operations. Sediment redistribution within this artificial landscape differs substantially from that in natural fluvial riparian zones, due to a specific hydrological regime comprising steps of water impoundment with increasing magnitudes and seasonal water level fluctuation holding a range of sediment fluxes. This study reinterpreted post-dam sedimentary dynamics in the reservoir fluctuation zone by stratigraphy determination of a 345-cm long sediment core, and related it to impact of the hydrological regime. Seasonality in absolute grain-size composition of suspended sediment was applied as a methodological basis for stratigraphic differentiation. Sedimentary laminations with relatively higher proportions of sandy fractions were ascribed to sedimentation during the dry season when proximal subsurface bank erosion dominates source contributions, while stratigraphy with a lower proportion of sandy fractions is possibly contributed by sedimentation during the wet season when distal upstream surface erosion prevails. Chronology determination revealed non-linear and high annual sedimentation rates ranging from 21.7 to 152.1 cm/yr. Although channel geomorphology may primarily determine the spatial extent of sedimentation, seasonal sedimentary dynamics was predominantly governed by the frequency, magnitude, and duration of flooding. Summer inundation by G R A P H I C A L A B S T R A C T a b s t r a c t a r t i c l e i n f o Contents lists available at ScienceDirectScience of the Total Environment j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / s c i t o t e n v natural floods with enhanced sediment loads produced from upstream basins induced higher sedimentation rates than water impoundment during the dry season when distal sediment supply was limited. We thus conclude that flow regulation manipulates contemporary seasonal sedimentary dynamics in the reservoir fluctuation zone, though little impact on total sediment retention rate was detected. Ongoing reductions in flow and sediment supply under human disturbance may have profound implications in affecting sedimentary equilibrium in the reservoir fluctuation zone. The results herein provide insights of how big dams have disrupted the sediment conveyance processes of large scale fluvial systems.

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“…The impacts of the dams construction on hydrologic regime show regional difference, since the effects of dams on magnitude, frequency and timing of streamflow change with the types, operations, storage capacity of dams [16,27,45,46]. For example, the groundwater levels rise significantly below ground surface after dam construction in the Tarim River [47], while the water level in the river decreased appreciably in time after dams construction in Yangtze River, Yellow River, Huaihe River [24,26,48]. Moreover, it has been reported that the pattern of the monthly streamflow change due to damming is location-dependent [7,13,49,50].…”

Section: Introductionmentioning

confidence: 99%

Hydrologic Alteration Associated with Dam Construction in a Medium-Sized Coastal Watershed of Southeast China

Zhang

Huang

2016

Water

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Sustainable water resource management requires dams operations that provide environmental flow to support the downstream riverine ecosystem. However, relatively little is known about the hydrologic impact of small and medium dams in the smaller basin in China. Flow duration curve, indicators of hydrologic alteration andrange of variability approach were coupled in this study to evaluate the pre-and post-impact hydrologic regimes associated with dam construction using 44 years of hydrologic data in the Jiulong River Watershed (JRW), a medium-sized coastal watershed of Southeast China, which suffered from intensive cascade damming. Results showed that the daily streamflow decreased in higher flow while daily streamflow increased in lower flow in both two reaches of the JRW. The dams in the North River tended to store more water while the dams in the West River tended to release more water. The mean daily streamflow increased during July to January while decreased during February to May after dam construction in both two reaches of the JRW. After dam construction, the monthly streamflow changed more significantly and higher variability of monthly streamflow exhibited in the West River than in the North River. The homeogenizing variability of monthly streamflow was observed in both two reaches of the JRW. The earlier occurrence time of extreme low streamflow event and later occurrence time of extreme high streamflow event exhibited after dams construction. The extreme low and high streamfow both decreased in the North River while both increased in the West River of the JRW. All of the indicators especially for the low pulse count (101.8%) and the low pulse duration (´62.1%) changed significantly in the North River. The high pulse count decreased by 37.1% in the West River and the count of low pulse increased abnormally in the North River. The high pulse duration in the post-impact period increased in the two reaches of JRW. The rise rate decreased by 26.9% and 61.0%,and number of reversals increased by 40.7% and 46.4% in the North River and West River, respectively. Suitable ranges of streamflow regime in terms of magnitude, rate, and frequency were further identified for environmental flow management in the North River and West River. This research advances our understanding of hydrologic impact of small and medium dams in the medium-sized basin in China.

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Impacts of large dams on downstream fluvial sedimentation: An example of the Three Gorges Dam (TGD) on the Changjiang (Yangtze River)

Cited by 311 publications

References 24 publications

Impact of the Three Gorges Dam on the Hydrology and Ecology of the Yangtze River

Impact of the Three Gorges Dam on the Hydrology and Ecology of the Yangtze River

Flow regulation manipulates contemporary seasonal sedimentary dynamics in the reservoir fluctuation zone of the Three Gorges Reservoir, China

Hydrologic Alteration Associated with Dam Construction in a Medium-Sized Coastal Watershed of Southeast China

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