Reservoir-induced changes to fluvial fluxes and their downstream impacts on sedimentary processes: The Changjiang (Yangtze) River, China

Gao, Jian; Jia, Jianjun; Kettner, Albert J.; Xing, Fei; Wang, Ya Ping; Jun, Li; Bai, Fenglong; Zou, Xinqing; Gao, Shu

doi:10.1016/j.quaint.2015.03.015

Cited by 42 publications

(23 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Given this background trend, the decrease in PAH concentrations in the ECS sediments suggests a decrease in PAH flux into the sea due to decreased sediment loads discharged from the Changjiang River, because transported PAHs are mainly adsorbed onto fine‐grained particles. After the impoundment of the TGD, approximately 131 ± 46 Mt year −1 of sediments were intercepted by the TGD, comparable to the average annual sediment discharge of the Changjiang River into the ECS (Gao et al, ). Meanwhile, large amounts of terrestrial materials were also intercepted by dams elsewhere in the catchment, shifting their burial site from the ECS margin to terrestrial reservoirs.…”

Section: Resultsmentioning

confidence: 81%

“…The ECS is also considered an important sink for PAHs with relatively high deposition and burial flux (Wang et al, ); a previous study estimated that the Changjiang (Yangtze) River discharged more than 232 t yr −1 of particulate PAHs into the ECS (Wang et al, ). However, this situation has changed since the 1980s because terrigenous material discharge into the ECS has changed substantially (Gao et al, ), especially given the >50,000 reservoirs constructed in the river's catchment (Yang et al, ) that intercept sediment at a rate of 453 Mt year −1 (Gao et al, ). For example, sediment loads discharged into the ECS decreased from 511 Mt year −1 in 1956–1968, to 450 Mt year −1 in 1968–1985, to 340 Mt year −1 in 1986–2002, then to 145 Mt year −1 in 2003–2012 (following construction of the Three Gorges Dam, TGD), and finally to 118 Mt year −1 in 2013–2015 (following construction of the Cascade Dams) (Yang et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…Such drastic reductions in sediment discharge have caused significant changes in the sedimentary environment and hydrodynamics of the ECS's estuarine‐inner shelf regions (Gao et al, ; Wang et al, ; Yang et al, ). In addition, reservoir interception of coarse‐grained sediment from upper reaches has induced channel erosion in the middle and lower reaches, substantially changing the sediment component reaching the ECS (Gao et al, ; Yang et al, ). These changes have directly influenced the particulate PAH flux discharged into the ECS, which decreased from 232 t year −1 before the construction of the TGD (Wang et al, ) to ~140 ± 40 t year −1 afterward (Wang et al, ), inevitably affecting the distribution and transport of particulate PAHs in the estuarine‐inner shelf areas of the ECS.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Shifts in the Distribution and Fate of Sedimentary Polycyclic Aromatic Hydrocarbons Within the Estuarine‐Inner Shelf Areas of the East China Sea: Response to Human‐Induced Catchment Change

et al. 2020

Self Cite

View full text Add to dashboard Cite

Human-induced changes in river catchments, such as damming, can affect estuarine depositional settings and further affect the transport of sediments and associated pollutants. Polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the East China Sea (ECS) at two time nodes (2006 and 2018) were compared to understand the response of PAHs to human-induced catchment changes. PAH concentrations in the ECS ranged from 8-414 ng g −1 (dry weight), with a mean value of 112 ± 77 ng g −1 , relatively low than that in 2006 (38-308 ng g −1 , with a mean of 122 ± 60 ng g −1 ). Sharp decreases in sediment loads have triggered erosion in subaqueous delta and changed the distribution of sediment components, which may eventually influence the distribution pattern of PAHs. The obvious spatial differentiation of PAHs between 2006 and 2018 suggested that the depositional center of PAHs shifted from the estuary to the inner shelf area. PAH deposition patterns in the ECS were primarily influenced by riverine input before 2006 but are now dominated by winnowing processes related to long-distance transport due to sharply decreased sediment loads. Dam construction in the river catchment intercepted large amounts of sediments and PAHs, shifting the Changjiang-derived PAH depositional center from the ocean to reservoirs. Overall, depositional patterns of PAHs in the ECS were largely altered by human-induced catchment changes, which may cause significant impacts on the region's biogeochemical cycles and ecosystem health. Plain Language SummaryCoastal oceans are usually considered important sinks of terrestrial materials, especially river-dominated coastal margins. However, river-derived terrestrial materials have decreased drastically in the last several decades worldwide, due to intensified human activities that have changed the local sedimentary environment. In this study, changes in the surface sediment grain size within the East China Sea from 2006 to 2018 indicated that the sedimentary environment in this region was clearly altered. Similarly, the distributions and compositions of PAHs in surface sediments changed from 2006 and 2018. Based on combined analysis of grain size and PAHs, we found that PAH dynamics in this region were primarily influenced by riverine inputs before dam construction in the Changjiang (Yangtze) River basin but are now dominated by winnowing processes related to long-distance transport due to sharply decreased sediment loads. Therefore, intensified human-induced catchment changes have significant influenced the fate of PAHs in the East China Sea.

show abstract

Section: Resultsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Shifts in the Distribution and Fate of Sedimentary Polycyclic Aromatic Hydrocarbons Within the Estuarine‐Inner Shelf Areas of the East China Sea: Response to Human‐Induced Catchment Change

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…In recent decades, the increasing construction of dams and res-ervoirs on rivers has changed the natural hydrologic regime of many rivers dramatically (Dynesius and Nilsson, 1994;Darwish et al, 2017). This situation has also altered the hydraulic connections between the trunk river and its tributary lakes (Guo et al, 2012;Gao et al, 2015). For example, reduction of runoff in Changjiang River due to the operation of the Three Gorges Dam has caused more outflow from its tributary lakes and has significantly lowered the water levels in those lakes, such as the Lake Dongting and the Lake Poyang, in southern China (Guo et al, 2012;Liu et al, 2013;Zhang et al, 2013b).…”

Section: Introductionmentioning

confidence: 99%

The effect of the Changjiang River on water regimes of its tributary Lake East Dongting

Dai

Gao

2018

J. Geogr. Sci.

View full text Add to dashboard Cite

The blocking or reversing effect of the downstream trunk river on its tributary lakes is an essential aspect of river-lake hydraulics. To measure how and the extent to which a trunk river can influence its tributary lakes, we made a case study in Changjiang River and one of its tributary lakes, Lake East Dongting (Lake ED) during a 35-year study period . Specifically, we investigated Lake ED's discharge ability into Changjiang River using stage-discharge relationship curves, and hence the changes of the lake discharge ability under different hydrologic conditions of the Changjiang River. The results show that (1) the Changjiang River does exert a huge impact on the water regimes of Lake ED. And this impact varies seasonally. A variation of 3000 m 3 /s in Changjiang River's runoff would change the lake water level by about 1.1 m in dry seasons, by 0.4 m in wet seasons, and by 0.6 m during severe summer floods. (2) Changes in the Changjiang River runoff triggered by the Three Gorges Dam since 2003 have led to dramatic water regime variations in Lake ED. Other factors, including reduction of lake inflow and the lake bed erosion, also exacerbated the water regime variations in Lake ED.

show abstract

“…Numerous case studies, even in recent past, dealt with the issue of river response to dam regulation (Gao et al ., ; Adib et al ., ; Zhang et al ., ; Zheng et al ., ). However, a consensus is building on the need of predictive mechanisms that can forecast possible channel response to dam building and operation.…”

Section: Introductionmentioning

confidence: 99%

Predicting dam‐related downstream geomorphic response with widely available stream gauge data: A case study of the Godavari River Basin, India

Sanyal

Kanae

2020

Singap J Trop Geogr

View full text Add to dashboard Cite

Dam-related downstream adjustments of riverbeds are normally investigated by analysing the trend in sediment supply and high flow events during the pre-and post-dam periods. The required data for existing predictive models is not measured at river gauges, which limits the application of these tools. We derived the frequency of sediment-transporting streamflow events (T*) and upstream sediment supply (S*) in the pre-and post-dam periods with widely available gauged records and predicted changes in the downstream riverbed by adapting an existing model. Ten gauging stations in the Godavari River Basin, India, located downstream of dams, were chosen as study sites. Annually surveyed cross-sections at each site validated the accuracy of the predicted dam-related downstream changes. Then, a regression equation (R 2 = 0.75) was established between T*/S* (independent variable) and changes in the downstream bed elevation (dependent variable) for the Godavari Basin. We recommended that similar local empirical equations be formulated for larger river basins. Models of large-scale rainfall-runoff and sediment transport processes that can account for the influence of dams, such as the Soil & Water Assessment Tool, can be paired with the proposed regression equation to estimate dam-related downstream erosion and deposition with globally available data.

show abstract

Reservoir-induced changes to fluvial fluxes and their downstream impacts on sedimentary processes: The Changjiang (Yangtze) River, China

Cited by 42 publications

References 35 publications

Shifts in the Distribution and Fate of Sedimentary Polycyclic Aromatic Hydrocarbons Within the Estuarine‐Inner Shelf Areas of the East China Sea: Response to Human‐Induced Catchment Change

Shifts in the Distribution and Fate of Sedimentary Polycyclic Aromatic Hydrocarbons Within the Estuarine‐Inner Shelf Areas of the East China Sea: Response to Human‐Induced Catchment Change

The effect of the Changjiang River on water regimes of its tributary Lake East Dongting

Predicting dam‐related downstream geomorphic response with widely available stream gauge data: A case study of the Godavari River Basin, India

Contact Info

Product

Resources

About