Impoundment Effects of the Three-Gorges-Dam on Flow Regimes in Two China’s Largest Freshwater Lakes

Lai, Xijun; Liang, Qiuhua; Jiang, Jiahu; Huang, Qun

doi:10.1007/s11269-014-0797-6

Cited by 103 publications

(56 citation statements)

References 30 publications

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“…For example, the water level at Hukou station increased from 7.32 m (11 February 2014) to 18.58 m (26 July 2014). This large water level fluctuation enhances rich biodiversity and the lake's role in ecological conservation (Lai et al, 2014). As one of the world's seven major wetland systems, Lake Poyang is a unique and important ecosystem in the world [21].…”

Section: Study Areamentioning

confidence: 99%

Assessing Aquatic Ecological Health for Lake Poyang, China: Part I Index Development

Huang

Gao

et al. 2018

Water

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Abstract:The development of an ecosystem health index to assess health status in freshwater lakes is urgently needed in China, especially in polluted lakes. This study developed a specific Ecosystem Health Index (LP-EHI) for Lake Poyang in China. LP-EHI quantified lake health from the perspectives of physical, chemical, biological integrity and social service. Physical integrity indices included hydrological conditions (water level and runoff), basic morphometric characteristics (lake area and shoreline), and tributary connectivity. Chemical integrity indices used water quality, nutrition, and toxicity to quantify chemical impairment. Biological integrity indicators covered six major components of the aquatic food chain, namely, phytoplankton, zooplankton, benthic macroinvertebrates, wetland plants, fish, and wintering birds. Social service indices included drinking water, pathogenic potential, flood storage capacity, sand mining, and dish-shaped sub-lake areas under management to measure whether the lake fulfilled the needs of human society. Reference and impaired conditions for each metric were defined by "historical" conditions, "least disturbed" conditions, national standards and expert opinions. The value of LP-EHI ranging from 0 to 1 was divided into five health conditions: excellent (≥0.8), good (0.6-0.8), fair (0.4-0.6), poor (0.2-0.4) and bad (<0.2). The metrics' reliability was further validated using a box-and-whisker plot test. The developed index (LP-EHI) is so far the most comprehensive index to evaluate ecosystem health for Lake Poyang, and is well reflected in the unique characteristics of Lake Poyang. It can enhance our understanding of lake health conditions and thus guide lake management to achieve better health conditions.

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Section: Study Areamentioning

confidence: 99%

Assessing Aquatic Ecological Health for Lake Poyang, China: Part I Index Development

Huang

Gao

et al. 2018

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

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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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“…As the major water bodies of global priority eco-regions [12], Poyang and Dongting Lakes play an important role in maintaining the water resources of the Yangtze River and healthy aquatic ecosystems in the region [13]. During recent decades, however, the water inundations of these two lakes have undergone remarkable spatiotemporal changes [14][15][16] that have resulted in significant hydrological, ecological and economic consequences [7,17,18].…”

Section: Introductionmentioning

confidence: 99%

Mapping Dynamics of Inundation Patterns of Two Largest River-Connected Lakes in China: A Comparative Study

Liu

2016

Remote Sensing

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Poyang Lake and Dongting Lake are the two largest freshwater lakes in China. The lakes are located approximately 300 km apart on the middle reaches of the Yangtze River and are differently connected through their respective tributary systems, which will lead to different river-lake water exchanges and discharges. Thus, differences in their morphological and hydrological conditions should induce individual lake spatio-temporal inundation patterns. Quantitative comparative analyses of the dynamic inundation patterns of Poyang Lake and Dongting Lake are of great importance to basic biogeochemical and ecological studies. In this study, using Moderate Resolution Imaging Spectoradiometer (MODIS) satellite imagery and a geographic information system (GIS) analysis method, we systematically compared the spatio-temporal inundation patterns of the two river-connected lakes by analyses of the lake area, the inundation frequencies (IFs) and the water variation rates (WVRs). The results indicate that there was a significant declining trend in the lakes' inundation area from 2000 to 2011. The inundation areas of Poyang Lake and Dongting Lake, decreased by 54.74% and 40.46%, with an average annual decrease rate of 109.74 km 2 /y and 52.37 km 2 /y, respectively. The alluvial regions near Dongting Lake expressed much lower inundation frequencies, averaged over multiple years, than the alluvial regions near Poyang Lake. There was an obvious spatial gradient in the distribution of water inundation for Poyang Lake; the monthly mean IF slowly increased from north to south during the low-water, rising, and high-water periods. However, Dongting Lake expressed a clear zonal distribution of water inundation, especially in the low-water and rising periods. In addition, the WVRs of the two lakes differently changed in space throughout the year, but were in good agreement with the changing processes of water expansion or shrinkage. The different inundation frequencies and water variation rates in the two lakes may possibly depend on many intrinsic factors, including surface discharges from their respective tributaries, river-lake water exchanges and the lakes' topographical characteristics. These findings are valuable for policymakers because they may lead to different decisions and policies for these two complex river-lake systems.

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Impoundment Effects of the Three-Gorges-Dam on Flow Regimes in Two China’s Largest Freshwater Lakes

Cited by 103 publications

References 30 publications

Assessing Aquatic Ecological Health for Lake Poyang, China: Part I Index Development

Assessing Aquatic Ecological Health for Lake Poyang, China: Part I Index Development

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

Mapping Dynamics of Inundation Patterns of Two Largest River-Connected Lakes in China: A Comparative Study

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