Flume experiments on woody debris accumulation at the bridge pier during flood

The probability of debris accumulation near bridge piers during the heavy storm and river flood convert the ‎hydraulic action of flow and increase the scour depth due to the reduction of flow area and the increase in ‎velocity of flow. In this paper, the effects of debris accumulation length, width and submerged depth on ‎scour depth near bridge pier were investigated. An experimental study for three groups of woody debris ‎accumulation was conducted under clear water condition to investigate the effects on maximum scour depth. ‎The results showed that the increase of blocked area of debris ‎to 27% increases the scour depth by approximately 140%. Furthermore, two empirical exponential formulas was proposed to predict the effect of ‎debris on the maximum scour depth and the modification factor required for single pier. Well agreement ‎was obtained for both derived formulas with coefficient of determination (R2) of 0.96. ‎

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Dynamic Responses of Ground-Dwelling Invertebrate Communities to Disturbance in Forest Ecosystems

Insects ◽

10.3390/insects10030061 ◽

2019 ◽

Vol 10 (3) ◽

pp. 61 ◽

Cited By ~ 1

Author(s):

Kayla Perry ◽

Daniel Herms

Keyword(s):

Forest Ecosystems ◽

Environmental Changes ◽

Woody Debris ◽

Canopy Structure ◽

Dynamic Responses ◽

Gap Formation ◽

Invasive Insects ◽

Salvage Logging ◽

Invertebrate Communities ◽

Debris Accumulation

In forest ecosystems, natural and anthropogenic disturbances alter canopy structure, understory vegetation, amount of woody debris, and the properties of litter and soil layers. The magnitude of these environmental changes is context-dependent and determined by the properties of the disturbance, such as the frequency, intensity, duration, and extent. Therefore, disturbances can dynamically impact forest communities over time, including populations of ground-dwelling invertebrates that regulate key ecosystem processes. We propose conceptual models that describe the dynamic temporal effects of canopy gap formation and coarse woody debris accumulation following disturbances caused by invasive insects, wind, and salvage logging, and their impacts on ground-dwelling invertebrate communities. Within this framework, predictions are generated, literature on ground-dwelling invertebrate communities is synthesized, and pertinent knowledge gaps identified.

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Comparison of Large Woody Debris Prototypes in a Large Scale Non-flume Physical Model

E3S Web of Conferences ◽

10.1051/e3sconf/20184005010 ◽

2018 ◽

Vol 40 ◽

pp. 05010

Author(s):

Brian Perry ◽

Colin Rennie ◽

Andrew Cornett ◽

Paul Knox

Keyword(s):

Physical Model ◽

Flood Control ◽

Large Scale ◽

Woody Debris ◽

Water Levels ◽

Mitigation Strategies ◽

Large Woody Debris ◽

Debris Accumulation ◽

The Impact ◽

The City

Due to excessive rainfall in June of 2013, several rivers located in and near the City of Calgary, Canada experienced significant flooding events. These events caused severe damage to infrastructure throughout the city, precipitating a renewed interest in flood control and mitigation strategies for the area. A major potential strategy involves partial diversion of Elbow River flood water to the proposed Springbank Off-Stream Storage Reservoir. A large scale physical model study was conducted to optimize and validate the design of a portion of the new project. The goals of the physical model were to investigate diversion system behaviors such as flow rates, water levels, sediment transport and, debris accumulation, and optimize the design of new flow control structures to be constructed on the Elbow River. In order to accurately represent the behavior of debris within the system due to flooding, large woody debris created from natural sources was utilized in the physical model and its performance was compared to that of debris of the same size fabricated from pressed cylindrical wood dowels. In addition to comparing the performance of these two debris types, the impact of root wads on debris damming was also investigated. Significant differences in damming behavior was shown to exist between the natural debris and the fabricated debris, while the impact of root wad on damming affected the dam structure and formation. The results of this experiment indicate that natural debris is preferred for studies involving debris accumulation.

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