The maximum discharge of outburst floods caused by the breaching of man-made and natural dams

The sudden release of water impounded in natural and man-made reservoirs has been responsible for some major disasters in mountainous regions of the world. Recent natural damming events and failures of natural dams have illustrated the need to examine the nature and magnitude of outburst floods and the behaviour of debris dams in general. An empirical relationship between maximum discharge (Qmax) and volume of water released during the outburst event (Vmax) is established (Qmax = 0.72Vmax0.53) for man-made dams and the relationship is thought applicable to the breaching of natural debris dams (landslides and moraines). This relationship allows a first-order estimate to be made of Qmax in the vicinity of the breach for a given Vmax during the failure of a man-made dam or a natural debris dam. Key words: outburst floods, man-made dams, natural dams, landslide, dam failure.

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The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure

Earth Surface Dynamics ◽

10.5194/esurf-9-1263-2021 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1263-1277

Author(s):

Xiangang Jiang ◽

Haiguang Cheng ◽

Lei Gao ◽

Weiming Liu

Keyword(s):

Field Data ◽

Failure Process ◽

Landslide Dam ◽

Dam Failure ◽

Dimensionless Length ◽

Channel Changes ◽

Outburst Floods ◽

Characteristics Analysis ◽

Movable Bed ◽

The Relationship

Abstract. Boulder bars are a common form of riverbed morphology that could be affected by landslide dams. However, few studies have focused on the formation and geometry characteristics of boulder bars due to outburst floods triggered by landslide dam failure. In such a way, eight group landslide dam failure experiments with a movable bed length of 4 to 7 times the dam length with 25 boulder bars were carried out. In addition, 38 boulder bars formed in the field triggered by four landslide dam failures were investigated. The aim of this paper is to study the formation and geometry characteristics of boulder bars along the riverbeds. The results show that boulder bars are formed after peak discharge of outburst flow. The number of boulder bars is 0.4 to 1.0 times the ratio of riverbed length to dam bottom length. Besides, boulder bars have the characteristic of lengthening upstream during the failure process. A boulder bar's upstream edge has a more extensive development than a boulder bar's downstream edge. The length of a boulder bar along the channel changes faster than the boulder bar's width and height. After the dam failure, the boulder bar's length is about 8 to 14 times its width. The relationship between the ratio of boulder bar length to width and the boulder bar's dimensionless length could be described with a hyperbolic equation. The dimensionless area of the boulder bar increases linearly with the dimensionless area of the river section, and the linear ratio is about 0.5. With the field data, this demonstrates that the formation and geometry characteristics of boulder bars in tests are consistent with the field boulder bars. Therefore, the results in this paper are credible and can be applied to the riverbed's geomorphological characteristics analysis triggered by overtopped landslide dam failure. The plentiful experimental and field data could contribute to the community boulder bar research.

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Reconstruction of the Catastrophic Outburst Floods of the Diexi Ancient Landslide-Dammed Lake in the Upper Minjiang River, Eastern Tibetan Plateau

10.21203/rs.3.rs-364424/v1 ◽

2021 ◽

Author(s):

Junxue Ma ◽

Jian Chen ◽

Zhijiu Cui ◽

Wendy Zhou ◽

Ruichen Chen ◽

...

Keyword(s):

Tibetan Plateau ◽

Landslide Dam ◽

Peak Discharge ◽

The Tibetan Plateau ◽

Lake Area ◽

Ancient Landslide ◽

Mountainous Regions ◽

Minjiang River ◽

Outburst Floods ◽

Dammed Lake

Abstract Landslide-dammed lake outburst floods (LLOFs) may pose serious safety threats to nearby residents and their livelihoods, as well as cause major damages to the downstream areas in mountainous regions. This study presents the Diexi ancient landslide-dammed lake (DALL) in the Upper Minjiang River at the eastern margins of the Tibetan Plateau, which was known to an estimated previous maximal lake area of 1.1 × 107 m2 and an impounded volume of 2.9 × 109 m3. Then, at approximately 27 ka BP, the ancient landslide dam failed and catastrophic LLOFs occurred. It was determined that the peak discharge of the Diexi ancient LLOFs could be reconstructed using regression, parametric, and boulder competence approaches. The reconstructed maximum peak discharge might be 72,232.66 m3/s, with an average velocity of 17.23 m/s, indicating that the Diexi ancient LLOFs were the most gigantic outburst floods to occur in the Upper Minjiang River Valley since the Late Pleistocene Period. The differences in the widths and slopes within the former and the later reaches of the dam indicated that the geomorphic influences on the river channel resulting from the DALL and its LLOFs have existed for tens of thousands of years. These findings were of major significance in deepening the understanding of the existence and disappearances of important river-knickpoints on a time scale of tens of thousands of years.

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Geomorphic effects of recurrent outburst superfloods in the Yigong River on the southeastern margin of Tibet

Scientific Reports ◽

10.1038/s41598-021-95194-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Kaiheng Hu ◽

Chaohua Wu ◽

Li Wei ◽

Xiaopeng Zhang ◽

Qiyuan Zhang ◽

...

Keyword(s):

Landslide Dam ◽

Upstream Migration ◽

One Dimensional ◽

Landform Evolution ◽

Outburst Floods ◽

Stepwise Method ◽

Large Landslide ◽

Southeastern Margin ◽

Channel Slope ◽

The One

AbstractLandslide dam outburst floods have a significant impact on landform evolution in high mountainous areas. Historic landslide dams on the Yigong River, southeastern Tibet, generated two outburst superfloods > 105 m3/s in 1902 and 2000 AD. One of the slackwater deposits, which was newly found immediately downstream of the historic dams, has been dated to 7 ka BP. The one-dimensional backwater stepwise method gives an estimate of 225,000 m3/s for the peak flow related to the paleo-stage indicator of 7 ka BP. The recurrence of at least three large landslide dam impoundments and super-outburst floods at the exit of Yigong Lake during the Holocene greatly changed the morphology of the Yigong River. More than 0.26 billion m3 of sediment has been aggraded in the dammed lake while the landslide sediment doubles the channel slope behind the dam. Repeated landslide damming may be a persistent source of outburst floods and impede the upstream migration of river knickpoints in the southeastern margin of Tibet.

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Seismic signal characteristics and interpretation of the 2020 “6.17” Danba landslide dam failure hazard chain process

Landslides ◽

10.1007/s10346-021-01657-x ◽

2021 ◽

Author(s):

Yan Yan ◽

Yifei Cui ◽

Dingzhu Liu ◽

Hui Tang ◽

Yongjian Li ◽

...

Keyword(s):

Landslide Dam ◽

Seismic Signal ◽

Dam Failure ◽

Chain Process ◽

Signal Characteristics

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Knowledge Management and Organizational Culture: An Exploratory Study

Creative and Knowledge Society ◽

10.2478/v10212-011-0031-3 ◽

2013 ◽

Vol 3 (1) ◽

pp. 65-77 ◽

Cited By ~ 3

Author(s):

Bing Li ◽

Jianpeng Zhang ◽

Xiaoxia Zhang

Keyword(s):

Organizational Culture ◽

Knowledge Management ◽

Management Practices ◽

Empirical Relationship ◽

Organizational Factors ◽

Equation Modeling ◽

Specific Situation ◽

Knowledge Management Practices ◽

Cultural Traits ◽

The Relationship

Abstract Purpose of the article Knowledge has been considered as the strategic assets and become the source of competitive advantage in organizations. Knowledge management thus receives the extraordinary attention from the top management. Many organizational factors have influences on knowledge management practices. This paper attempts to explore the empirical relationship between knowledge management and organizational culture in the specific situation of China’s commercial banking industry. Methodology/methods The relationship between knowledge management and organizational culture is quantitatively investigated by surveying bank managers. The scale of SECI modes is used to measure knowledge management process and the scale of Denison Organizational Culture Survey (DOCS) is used to measure organizational culture. We explore the underlying relationship by employing the statistical analyses such as correlation, regression and structural equation modeling. Scientific aim The research aims at testing the relationship between knowledge management and organizational culture, and furthermore if there exist linkages between cultural traits and SECI modes. Findings The results of the empirical study confirm the great and positive effect that organizational culture has on knowledge management. Different cultural traits contribute to different SECI modes. Conclusions For obtaining successful knowledge management practices in organizations, it is better to concern about the relationship between knowledge management and organizational culture. The limitation in the paper is the sampling size, which will be solved by an industry-wide survey in our future research.

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Towards a Theory of Suicide: The Case for Modern Fatalism

OMEGA - Journal of Death and Dying ◽

10.2190/mnqb-1rx1-x8eb-ndba ◽

1981 ◽

Vol 11 (1) ◽

pp. 1-14 ◽

Cited By ~ 2

Author(s):

Dennis L. Peck

Keyword(s):

Content Analysis ◽

Empirical Relationship ◽

Social Condition ◽

Case Histories ◽

Specific Population ◽

Suicide Notes ◽

Theoretical Statement ◽

The Relationship

This paper explores the empirical relationship between fatalism and suicide in a population of youthful victims. Content analysis of case histories and suicide notes was conducted for 132 individuals between the ages of twelve and thirty-four. Almost one-third (N = 43) of the youthful suicide victims were found to have experienced fatalistic thought-ways prior to their death. A model of fatalistic suicide based upon salient interdisciplinary observations consistent with a fatalistic explanation of youthful suicide is presented. Results are discussed relative to a specific population of victims in the light of a theoretical statement promulgating the relationship between a fatalistic social condition and youthful suicide.

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A Dynamic Theory of Populism in Power

10.1093/oso/9780197572290.001.0001 ◽

2021 ◽

Author(s):

Julio F. Carrión

Keyword(s):

Regime Change ◽

Dynamic Theory ◽

Empirical Relationship ◽

The United States ◽

Democratic Governance ◽

Theory Of Change ◽

Popular Participation ◽

The Andes ◽

The Impact ◽

The Relationship

The relationship between populism and democracy is a hotly debated topic. Some believe that populism is inherently bad for democracy because it is anti-pluralist and confrontational. Others argue that populism can reinvigorate worn-out democracies in need of an infusion of greater popular participation. This book advances this debate by examining the empirical relationship between populism in power and democracy. Does populism in power always lead to regime change, that is, the demise of democracy? The answer is no. The impact of populism on democracy depends on the variety of populism in power: the worst outcomes in democratic governance are found under unconstrained populism. This book discusses the conditions that explain how populism becomes unconstrained, and advances a dynamic theory of change that shows how the late victories of populists build on early ones, resulting in greater power asymmetries. The book analyzes five populist presidencies in the Andes. In four of them (Bolivia, Ecuador, Peru, and Venezuela), populism became unconstrained and regime change followed. In one case, Colombia, populism in power was contained and democracy survived. The concluding chapter places the Andean cases in comparative perspective and discusses how unconstrained populism in other cases (Nicaragua and Hungary) also lead to the end of electoral democracy. Where populism in power was constrained (Honduras and the United States), regime change did not materialize. This book advances a theory of populism that help us understand how democracies transition into non-democracies. To that extent, the book illuminates the processes of democratic erosion in our time.

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The Relationship between Strength and Abrasion Characterizations in Granite Building Stones

Quarterly Journal of Engineering Geology and Hydrogeology ◽

10.1144/qjegh2020-045 ◽

2021 ◽

pp. qjegh2020-045

Author(s):

A. Cheshomi ◽

M. Moradizadeh

Keyword(s):

Dimensionless Parameter ◽

Empirical Relationship ◽

Building Stones ◽

Brazilian Tensile Strength ◽

Strength Parameters ◽

Empirical Relationships ◽

Quartz Content ◽

Simultaneous Impact ◽

Rock Abrasion ◽

The Relationship

The wear of cutting blades during the preparation of building stones is an inevitable issue that occurs due to the contact of the blade with rock components. The present study aims to investigate the feasibility of proposing experimental relations of strength parameters and mineralogical hardness with Cerchar and LCPC tests. For this purpose, 18 samples of granite building stones were selected and Equivalent Quartz Content (EQC), compressive and Brazilian tensile strength (UCS and BTS), Cerchar, and LCPC abrasivity indices (CAI and LAC) were determined. The results showed the lack of any significant relationship between strength and abrasion properties. However, when evaluating the simultaneous impact of EQC and UCS using the rock abrasion index (RAI=UCS×EQC), significant valid empirical relationships between RAI-CAI and RAI-LAC were derived. To investigate the simultaneous effect of UCS, BTS, and EQC, a dimensionless parameter, i.e. modified rock abrasion index (MRAI=(UCSBTS)×EQC) was introduced. Moreover, it was found that the empirical relationship between MRAI-CAI was more significant and valid than the previous relations. Verification of the proposed relationship with the values of other researchers and 6 new samples for estimating CAI and LAC based on UCS, BTS, and EQC was found to be highly accurate for granite building stones.

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A Study about Factors Influencing the University Performance

Jurnal Teknologi ◽

10.11113/jt.v64.2252 ◽

2013 ◽

Vol 64 (2) ◽

Cited By ~ 1

Author(s):

Rosman Md. Yusoff ◽

Faisal Khan ◽

Asad Mubeen ◽

Kamran Azam

Keyword(s):

Regression Analysis ◽

Empirical Relationship ◽

Decision Makers ◽

High Tech ◽

Data Correlation ◽

Correlation And Regression Analysis ◽

Factors Influencing ◽

University Performance ◽

The University ◽

The Relationship

The purpose of this study is to find out the empirical relationship and influence of Research Environment, Integration of the university with Industry, High-tech Employment and Professional & Managerial Development on the University Performance.A Questionnaire has been used to collect the data. Correlation and Regression analysis were used to determine the relationship and influence of identified dimensions over the University Performance.The findings of the study show that the identified dimensions significantly relate and influence the University Performance. This study would be helpful for the university administration while making policies to upgrade its performance. Less work has been done in Pakistan for the development of universities. This study distinctively identifies and represents the variables and their influence over the university performance. The findings increase the value of the study as it would help the decision makers at the universities to think ‘out of the box’.

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