Vegetative impacts upon bedload transport capacity and channel stability for differing alluvial planforms in the Yellow River source zone

Li, Zhiwei; Yu, Guo; Brierley, Gary; Wang, Zhao Yin

doi:10.5194/hess-20-3013-2016

Cited by 17 publications

(5 citation statements)

References 72 publications

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“…Riparian vegetation area increases the river resistance and effectively reduces the flow velocity [1], greatly reducing the sediment carrying capacity [2], thus affecting the sediment transport and deposition process [3,4] and final river bed morphology. The flow tends to shift to the main channel with minimal resistance [5], increasing channel brush depth and reducing the channel curvature, straightening the meandering channels [6,7].…”

Section: Introductionmentioning

confidence: 99%

Experimental Analysis of River Evolution with Riparian Vegetation

Yang

Bai

2018

Water

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Studying the effects of different riparian vegetation densities on river channel evolution has practical significance for predicting the river channel evolution process during flood periods and ecological river engineering via the artificial planting of vegetation. In this study, we simulated the formation and evolution processes of river channels under different riparian vegetation coverage rates in laboratory conditions. The riparian vegetation coverage rates were set as 0, 20, 40 and 80%, on unilateral and bilateral sides of a river channel bank. Given the same flow and sediment boundary conditions, experiments were carried out in a 4 × 1.5 m tank. This paper focuses on the comparative analysis of main stream stability characteristics, bend migration characteristics, river bank erosion characteristics and sediment transport intensity. The results showed that different amounts of riparian vegetation cover created different characteristics of river channel evolution and strongly impacted the stability of the banks and bed. River channel evolution under unilateral vegetation cover is often accompanied by alternate development of the main stream and branch, and the bend stability under unilateral riverbank vegetation cover is worse than under bilateral cover. For a bilateral vegetation-covered river channel, a narrow and deep regime channel more easily forms with a higher vegetation coverage rate; the curvature of the stable river bend is smaller, but the adaptation period of the flow to the river channel bed increases. Planting of riparian vegetation played a positive role in the erosion resistibility, which effectively reduced the lateral migration rate of the riverbank. The higher the vegetation coverage rate, the greater the flow shear stress needed for the same river channel migration rate. While effectively reducing lateral migration, riparian vegetation coverage increased the vertical migration and led to a trend in overall scour depth along the riverbank.

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Section: Introductionmentioning

confidence: 99%

Experimental Analysis of River Evolution with Riparian Vegetation

Yang

Bai

2018

Water

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“…China's recently formed Sanjiangyuan National Nature Reserve, for example, foregrounds the ecological values of the Qinghai-Tibetan Plateau (see Li et al, 2012). While reports of controls on river morphology have emphasised the role of temperature gradients in controlling vegetationstream responses on the Plateau (Li et al, 2016;Yu et al, 2014), these relationships exist in a context of up to 8800 years of grazing by nomadic Tibetan herders (Miehe et al, 2008(Miehe et al, , 2009. A focus on conserving the region's naturalness, made explicit in the reserve's name, along with concerns for soil loss and river sedimentation, drove efforts to concentrate herders into fixed settlements after grassland degradation was linked to changes in pastoral regime (Xin, 2008).…”

Section: Which Nature?mentioning

confidence: 99%

What’s wrong with healthy rivers? Promise and practice in the search for a guiding ideal for freshwater management

Blue

2018

Progress in Physical Geography: Earth and Environment

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It is easy to talk of improving river condition. It is more difficult to pin down exactly what this means. Emerging from ecology, the concept of river health presented an attempt to provide a broad framework for freshwater management incorporating both natural and human values. Initially criticised as subjective and unscientific, river health was nevertheless mainstreamed through being rendered quantifiable. Tracing the (re)definition of river health from a holistic but hazy ethic of environmental care to prescriptive indicators for intervention, I examine how common-sense understandings of river condition were first challenged by, and then incorporated within, the scholarly and political project of river health. Arguing that the search for objectivity entrenched assumptions that naturalness was both desirable and attainable, I explore the potential value of a reimagined, revitalised river health as a constructive platform for renegotiating and broadening what matters for freshwater.

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“…The results of the physical model experiment showed that a substantial reduction in the flood frequency of the river flow after dam construction caused the river to gradually develop from meandering to straight [33]. In addition to water and sediment conditions, vegetation is also considered an important factor affecting sediment transport and the morphological development of river channels [34,35]. The latter has also been noted to promote meandering and alter the meander scale in numerical simulations of river meandering.…”

Section: Introductionmentioning

confidence: 99%

Main Flow Migration in the Middle Yangtze River Influenced by Cascade Reservoirs: Characteristics, Controlling Factors, Trends, and Ecological Impact

Zhu

2023

Land

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The main flow migration in the middle Yangtze River occurs in most river sections and is affected by factors such as incoming water and sediment, riverbed boundaries, and channel shapes, leading to a complex riverbed evolution. Revealing the controlling factors and analyzing the developmental trends are important for addressing the adverse ecological impacts caused by these changes. Based on a large amount of observational data since the impoundment of the Three Gorges Reservoir, the characteristics of the main flow migration in the middle Yangtze River under different flow conditions were analyzed, and its correlation with the nodes and bars at the inlet, the plane shape of the river, and riverbed morphology were determined to identify the key controlling factors. The results showed that it is characterized by the displacement of the main flow zone during the middle-flow period. The key factors controlling the main flow migration include the deflecting action of the nodes and sidebars at the inlet, relaxation of the channel plane shape, and resistance difference caused by the riverbed morphology between the branches. The trend analysis suggests that the main flow migration in the middle Yangtze River may become more frequent after the operation of the cascade reservoirs in the future and may threaten the ecological environment.

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Vegetative impacts upon bedload transport capacity and channel stability for differing alluvial planforms in the Yellow River source zone

Cited by 17 publications

References 72 publications

Experimental Analysis of River Evolution with Riparian Vegetation

Experimental Analysis of River Evolution with Riparian Vegetation

What’s wrong with healthy rivers? Promise and practice in the search for a guiding ideal for freshwater management

Main Flow Migration in the Middle Yangtze River Influenced by Cascade Reservoirs: Characteristics, Controlling Factors, Trends, and Ecological Impact

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