Tracking long-term cascade check dam siltation: implications for debris flow control and landslide stability

Landslides ◽  
2021 ◽  
Author(s):  
Zaizhi Yang ◽  
Xingwu Duan ◽  
Jiangcheng Huang ◽  
Yifan Dong ◽  
Xinbao Zhang ◽  
...  
Keyword(s):  
Debris Flow ◽  
Flow Control ◽  
Check Dam ◽  
Landslide Stability

scholarly journals Effectiveness and efficiency of slot-check dam system on debris flow control

2015 ◽  
Vol 3 (9) ◽  
pp. 5777-5804 ◽  
Author(s):  
Y. H. Zou ◽  
X. Q. Chen
Keyword(s):  
Debris Flow ◽  
Flow Control ◽  
River Basin ◽  
Debris Flows ◽  
Check Dam ◽  
Sediment Control ◽  
Sediment Volume ◽  
Check Dams ◽  
Effectiveness And Efficiency ◽  
Set Up

Abstract. Slot-check dam system is commonly used to control sediment transport associated with debris flows and mitigate debris flow hazards. This paper aims to estimate the performance of the slot-check dam system in the field and set up a verification to evaluate the efficiency of a slot-check dam system and each subsystem in debris flow sediment control. Field survey on a group of a series of slot-check dams at Shengou Basin in Yunnan, China reveals that the conserving sediment volume of each dam is related to its relative location in the group, gradually decreasing from upstream to downstream. The cumulative sediment volume within a subsystem of slot-check dams closely related to the characteristics of the catchment controlled by the subsystem. It increases with the controlled catchment area of the most downstream dam in subsystem and the distance from the dam to the upstream most. Evaluation models for the conserving efficiency of a slot-check dam system on debris flow control in a river basin and each subsystem within the group associate to the controlled catchment characteristics have been proposed. The layout principle of a slot-check dam system in a river basin has been developed based on the conserving efficiency of a subsystem of slot-check dams which would allow the slot-check dam system to be designed in a more scientific way.

Quantitative investigation of sediment regulation performance of slot-check dam on viscous debris flow

2021 ◽  
Vol 14 (14) ◽  
Author(s):  
Jinfeng Liu ◽  
Huaquan Yang ◽  
Wenbing Zhou ◽  
Yong You ◽  
Hao Sun ◽  
...  
Keyword(s):  
Debris Flow ◽  
Check Dam ◽  
Quantitative Investigation ◽  
Viscous Debris Flow

Flow Control Using Active Dimples

2004 ◽  
Author(s):  
Natalie Udovidchik ◽  
Sebastien Lambert
Keyword(s):  
Flow Control ◽  
Aerodynamic Drag ◽  
Spherical Shape ◽  
Reynolds Numbers ◽  
Synthetic Jets ◽  
Actuation Frequency ◽  
Flux Change ◽  
Novel Concept ◽  
Smart Surface

In this study, a novel concept of using active dimples for flow control is introduced. It is widely known that dimples on a golf ball dramatically reduce its aerodynamic drag. They are much more effective than surface roughness since the hollow spherical shape produces cavity flow, thus the drag coefficient remains relatively constant at higher Reynolds numbers. It has also been shown by previous studies that by use of circular-arc grooves or dimples, the separation point on a cylinder could be regulated and drag reduced due to the re-circulation occurring in the dimpled surface. Another approach to flow separation that uses the concept of momentum-flux change by near-wall manipulation is an active one, such as synthetic jets or acoustical excitation. The long-term goal of this study is to merge these two approaches and create a continuous smart surface that would have active depressions, which would then be actuated at desired frequencies and conform to a desired shape for optimal results. Current investigation had only touched the tip of the iceberg of this new and unexplored field. In order to begin to comprehend the complexity of the fluid mechanics of the active dimples, a dual focus had been outlined in this study. The first focused on the investigation of a single active dimple on a flat plate, while the latter investigated the effect of a row consisting of such devices on a circular cylinder. The main factors of interest are optimal actuation frequency and dimple positioning relative to the freestream.

scholarly journals A prototype experiment of debris flow control with energy dissipation structures

2011 ◽  
Vol 60 (3) ◽  
pp. 971-989 ◽  
Author(s):  
Zhao Yin Wang ◽  
Lijian Qi ◽  
Xuzhao Wang
Keyword(s):  
Energy Dissipation ◽  
Debris Flow ◽  
Flow Control

Catastrophic disturbances in headwater streams: the long-term ecological effects of debris flows and debris floods in the Klamath Mountains, northern California

2010 ◽  
Vol 67 (10) ◽  
pp. 1596-1610 ◽  
Author(s):  
Matthew R. Cover ◽  
Juan A. de la Fuente ◽  
Vincent H. Resh
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Headwater Streams ◽  
Ecological Effects ◽  
Ecosystem Structure ◽  
Northern California ◽  
Klamath Mountains ◽  
Mountainous Landscapes ◽  
Debris Floods

Debris flows and debris floods are catastrophic disturbances in steep, mountainous landscapes throughout the world, but little is known about the long-term ecological effects of these events on headwater streams. In 10 basins (10–20 km2) in the Klamath Mountains, northern California, USA, we used a space-for-time substitution to infer the long-term (10–100 years) effects of debris flows on stream ecosystem structure. Debris flows mobilized sediment and wood and removed riparian vegetation from large portions of channel networks. Stream temperatures were significantly warmer in streams that had recent debris flows (<10 years ago). Large wood, benthic organic matter, and detritivorous stoneflies were all very sparse in recent debris flow streams, suggesting that allochthonous energy pathways took decades to recover. Rainbow trout ( Oncorhynchus mykiss ) were abundant in recent debris flow streams, but populations of other vertebrates such as coastal giant salamander ( Dicamptodon tenebrosus ) and coastal tailed frog ( Ascaphus truei ) were virtually absent. Increased frequencies of catastrophic debris flows associated with forest management practices can have significant negative impacts on aquatic biodiversity in forested, mountainous landscapes.

scholarly journals Effects of Y-type spillway lateral contraction ratios on debris flow patterns and scour features behind a check dam

2016 ◽  
Author(s):  
Huayong Chen ◽  
Jinfeng Liu ◽  
Wanyu Zhao
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Flow Patterns ◽  
Check Dam ◽  
Mountainous Areas ◽  
Dimensionless Analysis ◽  
Lateral Contraction ◽  
Contraction Ratio ◽  
New Type ◽  
Good Agreement

Abstract. Debris flows often cause devastating damage to property and can injure or kill residents in mountainous areas. The construction of check dams in debris flow valleys is considered a useful strategy for mitigating the damages downstream. In this paper, a new type of spillway structure with lateral contraction was proposed to distribute debris flows after the check dam storage filled up. Four different lateral contraction ratios of the spillway were considered in experiments that investigated debris flow patterns, scour characteristics, and energy dissipation rates when debris flows passed through the spillway. The results indicated that lateral contraction considerably influenced the extension of debris flow nappes. The drop length of the nappe at η = 0.7 (η means lateral contraction ratio) was approximately 1.4 times larger than at η = 0.4. The collision, friction, and mixing forces between the debris flow nappes and debris flows in downstream plunge pools dissipated much of the debris flow kinetic energy, ranging from 42.03 % to 78.08 % at different contraction ratios. Additionally, based on a dimensionless analysis, an empirical model was proposed to predict the maximum scour depth behind the check dam. It indicated that the results calculated by the model exhibited good agreement with the experimental results.

Evaluation and Governance Design of Risk Factor of Debris Flow on Gunmaling

2011 ◽  
Vol 90-93 ◽  
pp. 3151-3154
Author(s):  
Lei Nie ◽  
Li Na Xu ◽  
Yan Xin Yu
Keyword(s):  
Debris Flow ◽  
Correlation Method ◽  
Mature Stage ◽  
Check Dam ◽  
Effect Measure ◽  
Gray Correlation ◽  
Medium Risk ◽  
Reduce Risk ◽  
Total Capacity ◽  
Set Up

Abstract: It is analyzed and obtained the result that the debris flow is currently in mature stage with medium risk and high occurrence through the gray correlation method of fractal research and effect measure of debris flow gully. Therefore, it is necessary to take corresponding governance measures. In this article, check dam is used as main preventive engineering measures to set up two check dams in the passing area of debris flow, with total capacity about 2800m3 and design reservoir capacity of flood once per 50 years. Construction of the check dam will effectively reduce risk of debris flow.

Sediment-trapping effectiveness of check dams with multiple debris-flow surges: Experimental study

2021 ◽  
Author(s):  
Jiangang Chen ◽  
Xi'an Wang ◽  
Huayong Chen
Keyword(s):  
Debris Flow ◽  
Field Investigation ◽  
Sediment Deposition ◽  
Disaster Mitigation ◽  
Check Dam ◽  
Sediment Trapping ◽  
Check Dams ◽  
The Relationship ◽  
Debris Flow Hazard ◽  
Deposition Morphology

&lt;p&gt;A series of check dams were constructed for debris-flow hazard mitigation in China. Based on the results of field investigation, check dam has a significant impact on the geomorphology of debris flow gully, especially the upstream and downstream of a check dam. According to the relationship between the sediment deposition thickness and the check dam height, the running status of a check dam can be divided into three states: without sediment deposition, half of the storage capacity with sediment deposition, and full of sediment deposition. With the accumulation of sediment transport, the running state of a check dam gradually changed and the sediment-trapping effect of check dams has gradually weakened, leading to the loss of part of the disaster mitigation effect, increasing the risk of downstream infrastructure and human security. Therefore, experiments with multi-surges of debris flows were carried out to study the geomorphic and sediment-trapping e&amp;#64256;ectiveness of check dams. The results showed that with the increase of the sediment amount with multi-surges, the deposition slope in the downstream dam approached or even exceeded that of upstream dam. For one surge, deposition morphology has slightly difference in the cascade dams. At last, a method for calculating the reduction coefficient of deposition slope considering the check dam height and sediment amount with multi-surges is proposed.&lt;/p&gt;

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