Morphological adjustment of the Qingshuigou channel on the Yellow River Delta and factors controlling its avulsion

Shan, Z.S.; Han, Shasha; Guang-ming, Tan; Xia, Junqiang; Wang, Baosheng; Wang, Kairong; Edmonds, Douglas A.

doi:10.1016/j.catena.2018.03.009

Cited by 27 publications

(18 citation statements)

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“…The impoundment of the XLDR in October 1999, especially impoundment according to the Water-Sediment Regulation Scheme with a controlled release of flood waters by the Yellow River Conservancy Committee since June 2002, has significantly changed the natural flow regime, trapping 3 billion m 3 of sediment by 2017, and has caused a sharp decrease in the sediment load entering the LYR (Wang et al, 2010;Yang et al, 2010). The river channel downstream from the XLDR has experienced continuous erosion, and the corresponding riverbed morphology has changed significantly with the increase in the grain sizes of the suspended sediments, leading to an important impact on the eco-environment and evolution of the estuary (Wu and Li, 2008;Wang et al, 2010;Xia et al, 2016;Zheng et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015

Wang

Zhong

2020

J. Geogr. Sci.

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Based on the measured discharge, sediment load, and cross-sectional data from 1986 to 2015 for the lower Yellow River, changes in the morphological parameters (width, depth, and cross-sectional geomorphic coefficient) of the main channel are analyzed in this paper. The results show that before the operation of the Xiaolangdi Reservoir (XLDR) from 1986 to 1999, the main channel shrunk continually, with decreasing width and depth. The rate of reduction in its width decreased along the river whereas that of depth increased in the downstream direction. Because the rate of decrease in the width of the main channel was greater than that in channel depth, the cross-sectional geomorphic coefficient decreased in the sub-reach above Gaocun. By contrast, for the sub-reach below Gaocun, the rate of decrease in channel width was smaller than that in channel depth, and the cross-sectional geomorphic coefficient increased. Once the XLDR had begun operation, the main channel eroded continually, and both its width and depth increased from 2000 to 2015. The rate of increase in channel width decreased in the longitudinal direction, and the depth of the main channel in all sub-reaches increased by more than 2 m. Because the rate of increase in the depth of the main channel was clearly larger than that of its width, the cross-sectional geomorphic coefficient decreased in all sub-reaches. The cross-sectional geometry of the main-channel of the lower Yellow River exhibited different adjustment patterns before and after the XLDR began operation. Before its operation, the main channel mainly narrowed in the transverse direction and silted in the vertical direction in the sub-reach above Aishan; in the sub-reach below Aishan, it primarily silted in the vertical direction. After the XLDR began operation, the main channel adjusted by widening in the transverse direction and deepening in the vertical direction in the sub-reach above Aishan; in the sub-reach below it, the main channel adjusted mainly by deepening in the vertical direction. Compared with the rates of decrease in the width and depth of the main channel during the siltation period, the rate of increase in channel width during the scouring period was clearly smaller while the rate of increase in channel depth was larger. After continual siltation and scouring from 1986 to 2015, narrow and deep. The pattern of adjustment in the main channel was closely related to the water and sediment conditions. For the braided reach, the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with suspended sediment concentration (SSC) during the siltation period. By contrast, the cross-sectional geomorphic coefficient was positively correlated with discharge and negatively correlated with SSC during the scouring period. For the transitional and meandering reaches, the cross-sectional geomorphic coefficient was negatively correlated with discharge and positively correlated with SSC.

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Section: Introductionmentioning

confidence: 99%

Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015

Wang

Zhong

2020

J. Geogr. Sci.

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“…The modern YRD has been built by rapid sedimentation and frequent avulsions after a major avulsion in 1855, when the lower Yellow River switched to a more northerly course and emptied into the Bohai Sea (Figure 1). Annual sediment transported to the YRD was 0.677 billion tons during 1950-2016, and between 50 and 70% of incoming sediment was deposited on the delta or near the shoreline due to a weak coastal dynamic environment (Saito et al, 2001;Wang, 2010;Zheng et al, 2018a). The delta progradation rate is about 2-3km/yr at channel mouths and approximately 5,400km 2 of new land has been accreted on the modern YRD since 1855.…”

Section: The Yellow River Deltamentioning

confidence: 99%

Geomorphic evolution of the Qingshuigou channel of the Yellow River Delta in response to changing water and sediment regimes and human interventions

Han

Rice

Tan

et al. 2020

Earth Surf Processes Landf

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Delta channels are important landforms at the interface of sediment transfer from terrestrial to oceanic realms and affect large, and often vulnerable, human populations.Understanding these dynamics is pressing because delta processes are sensitive to climate change and human activity via adjustments in, for example, mean sea level, and water and sediment regime. Data collected over a 40-year period along a 110km distributary channel of the Yellow River Delta offers an ideal opportunity to investigate morphological responses to changing water and sediment regimes and intensive human activity. Complementary data from the delta front provide an opportunity to explore the interaction between delta channel geomorphology and delta-front erosionaccretion patterns. Cross-section dimensions and shape, longitudinal gradation and a sediment budget are used to quantify spatial and temporal morphological change along the Qingshuigou channel. Distinctive periods of channel change are identified, and analysis provides a detailed understanding of the temporal and spatial adjustments of the channel to specific human interventions, including two artificial channel diversions and changes in water and sediment supply driven by river management, and downstream delta-front development. Adjustments to the This article is protected by copyright. All rights reserved.diversions included a short-lived period of erosion upstream and significant erosion in the newly activated channel, which progressed downstream. Channel geomorphology widened and deepened during periods when management increased water yield and decreased sediment supply, and narrowed and shallowed during periods when management reduced water yield and the sediment load. Changes along the channel are driven by both upstream and downstream forcing. Finally, there is some evidence that changing delta-front erosion-accretion patterns played an important role to the geomorphic evolution of the deltaic channel; an area that requires further investigation.

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“…Riverbed aggradation relative to its floodplain can set up conditions favorable for channel avulsions (Figure 1m). Such conditions can be quantified by a threshold lateral slope advantage or superelevation of the channel bed relative to its floodplain (Mohrig et al, 2000; Zheng et al, 2018). The superelevation hypothesis, which states that avulsion occurs when the superelevation of the channel belt reaches a specified fraction α of the channel depth, h (Chadwick et al, 2019; Ganti et al, 2014; Mohrig et al, 2000; Moodie et al, 2019), was adopted in this study for avulsion setup.…”

Section: Introductionmentioning

confidence: 99%

“…Morphodynamics of deltaic channels such as avulsions play a critical role in the evolution of river deltas and restoration of coastal wetlands and, therefore, have been studied extensively (Chatanantavet et al, 2012; Edmonds et al, 2009; Fisk, 1952; Ganti et al, 2016; Jerolmack & Swenson, 2007; Nienhuis et al, 2018; Smith et al, 1989). Delta progradation can lead to riverbed aggradation with respect to its floodplain, which in turn is thought to increase the likelihood of channel avulsion (Chadwick et al, 2019; Ganti et al, 2014; Mohrig et al, 2000; Zheng et al, 2018). As such, studying the controls on river mouth progradation is critical to better understand channel avulsions (Chadwick et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…The progradation of deltaic channel is subject to downstream controls such as basin water depth and waves (Bijkerk et al, 2016; Wang et al, 2019; Zheng et al, 2018). Among these factors, waves tend to reduce the seaward progradation of deltaic channels when low‐angle waves (i.e., when the angle between wave crests and the shoreline is smaller than 45°) are dominant, which further suppress the aggradation of deltaic channels and thus increase the avulsion timescale (Ashton & Giosan, 2011; Ratliff et al, 2018; Swenson, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Wave Controls on Deltaic Shoreline‐Channel Morphodynamics: Insights From a Coupled Model

Gao

Nienhuis

Nardin

et al. 2020

Water Resources Research

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It is widely recognized that waves inhibit river mouth progradation and reduce the avulsion timescale of deltaic channels. Nevertheless, those effects may not apply to downdrift-deflected channels. In this study, we developed a coupled model to explore the effects of wave climate asymmetry and alongshore sediment bypassing on shoreline-channel morphodynamics. The shoreline position and channel trajectory are simulated using a "shoreline" module which drives the evolution of the river profile in a "channel" module by updating the position of river mouth boundary, whereas the channel module provides the sediment load to river mouth for the "shoreline" module. The numerical results show that regional alongshore sediment transport driven by an asymmetric wave climate can enhance the progradation of deltaic channels if sediment bypassing of the river mouth is limited, which is different from the common assumption that waves inhibit delta progradation. As such, waves can have a trade-off effect on river mouth progradation that can further influence riverbed aggradation and channel avulsion. This trade-off effect of waves is dictated by the net alongshore sediment transport, sediment bypassing at the river mouth, and wave diffusivity. Based on the numerical results, we further propose a dimensionless parameter that includes fluvial and alongshore sediment supply relative to wave diffusivity to predict the progradation and aggradation rates and avulsion timescale of deltaic channels. The improved understanding of progradation, aggradation, and avulsion timescale of deltaic channels has important implications for engineering and predicting deltaic wetland creation, particularly under changing water and sediment input to deltaic systems.

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Morphological adjustment of the Qingshuigou channel on the Yellow River Delta and factors controlling its avulsion

Cited by 27 publications

References 58 publications

Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015

Adjustment in the main-channel geometry of the lower Yellow River before and after the operation of the Xiaolangdi Reservoir from 1986 to 2015

Geomorphic evolution of the Qingshuigou channel of the Yellow River Delta in response to changing water and sediment regimes and human interventions

Wave Controls on Deltaic Shoreline‐Channel Morphodynamics: Insights From a Coupled Model

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