Venting of turbidity currents approaching a rectangular opening on a horizontal bed

Chamoun, Sabine; Cesare, Giovanni De; Schleiss, Anton

doi:10.1080/00221686.2017.1289266

Cited by 13 publications

(13 citation statements)

References 32 publications

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“…To avoid reflection or stagnation effects caused by the end of the wall, the experiment was continued for 100 s after opening the gate, before the head front had reached the end of the flume. More precise details of the experimental set-up can be found in Oehy & Schleiss (2007), Oehy et al (2010) and Chamoun et al (2017). The experiment was performed twice to confirm that an identical flow was produced each time.…”

Section: Facilities and Experimental Proceduresmentioning

confidence: 99%

Sediment mass movement of a particle-laden turbidity current based on ultrasound velocity profiling and the distribution of sediment concentration

Nomura

Hitomi

Cesare

et al. 2018

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Particle-laden flows or turbidity currents along the seafloor are important to the formation and erosion of submarine topography. To understand the mass-transport process, flume tests were carried out with a continuous supply of quartz-laden suspension. The vertical and horizontal velocities were extracted by two pairs of ultrasound Doppler velocity profilers installed at different angles with respect to the bed-normal direction. Due to the head intrusion into the ambient water, the sediment in the suspension was continuously lifted up and mixed, leaving lobes and clefts. The velocity-maximum layer acted as the main sediment conveyor and divided the body into wall and jet regions. The concentration distribution was also quantified based on the relationship between the fluid density and the intensity of light attenuation obtained using a video recording. An area of high sediment concentration was observed just behind the head frontal area. Analysis of the velocity and concentration distribution demonstrated that sediment in the turbidity current was transported mainly by head movement and that continuous sedimentation took place in the wall region. The results indicate that a turbidity current proceeds while maintaining an ordered inner dynamic structure.

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Section: Facilities and Experimental Proceduresmentioning

confidence: 99%

Sediment mass movement of a particle-laden turbidity current based on ultrasound velocity profiling and the distribution of sediment concentration

Nomura

Hitomi

Cesare

et al. 2018

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“…Estimation of the suspended sediment loads (SSLs) is important in the design and operation of water structures and in the planning of sediment management (yield reduction, routing and removal) to preserve their live storage capacities [1][2][3][4][5]. The temporal variations and changes in SSLs are also an important indicator of the effectiveness of existing watershed management practices or tectonic and land-sliding activities in the catchment area.…”

Section: Introductionmentioning

confidence: 99%

Variability and Trend Detection in the Sediment Load of the Upper Indus River

Ateeq-Ur-Rehman

Bui

Rutschmann

2017

Water

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Water reservoirs planned or constructed to meet the burgeoning energy and irrigation demands in Pakistan face a significant loss of storage capacity due to heavy sediment load from the upper Indus basin (UIB). Given their importance and the huge investment, assessments of current UIB sediment load and possible future changes are crucial for informed decisions on planning of optimal dams' operation and ensuring their prolonged lifespan. In this regard, the daily suspended sediment loads (SSLs) and their changes are analyzed for the meltwater-dominated zone up to the Partab Bridge and the whole UIB up to Besham Qila, which is additionally influenced by monsoonal rainfall. The gaps between intermittent suspended sediment concentration (SSC) samples are filled by wavelet neural networks (WA-ANNs) using discharges for each site. The temporal dynamics of SSLs and discharges are analyzed using a suite of three non-parametric trend tests while the slope is identified using Sen's slope estimator. We found disproportional spatio-temporal trends between SSLs and discharges caused primarily by intra-annual shifts in flows, which can lead to increased trap efficiency in planned reservoirs, especially upstream of Besham Qila. Moreover, a discernible increase in SSLs recorded at Partab Bridge during summer is being deposited downstream in the river channel. This is due to a decrease in river transport capacity in the monsoonal zone. These findings will not only help to identify these morphological problems, but also accurately anticipate the spatio-temporal changes in the sediment budget of the upper Indus River. Our results will help improve reservoir operational rules and sediment management strategies for existing and 30,000-MW planned dams in the UIB.

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“…Based on previous results of LVE and VEI obtained on the horizontal bed (Chamoun et al, 2017), venting turbidity currents reached the highest efficiency for F ¼ 100%. In other words, the highest sediment release was obtained with the lowest water loss for this venting degree.…”

Section: Local Venting Efficiency In Timementioning

confidence: 99%

“…These definitions were initially introduced and detailed in a previous publication (Chamoun et al, 2017). All equations corresponding to the above mentioned concepts can be found in the appendix attached to the present article.…”

Section: Analysis Conceptmentioning

confidence: 99%

“…Examples include the Dez Dam in Iran (Schleiss et al, 2010), the Iril Emda reservoir in Algeria (Raud, 1958), the Elephant Butte reservoir in the USA (Lara, 1960), and the Großs€ olk reservoir in Austria (Schneider et al, 2007) among others. However, systematic research on venting turbidity currents is still lacking and very few experimental studies (Chamoun et al, 2017;Fan, 1986;Lee et al, 2014;Yu et al, 2004) were carried out and published. Dam operators still miss the required knowledge needed for an optimal performance of venting operations.…”

Section: Introductionmentioning

confidence: 99%

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Management of turbidity current venting in reservoirs under different bed slopes

Chamoun

Cesare

Schleiss

2017

Journal of Environmental Management

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a b s t r a c tThe lifetime and efficiency of dams is endangered by the process of sedimentation. To ensure the sustainable use of reservoirs, many sediment management techniques exist, among which venting of turbidity currents. Nevertheless, a number of practical questions remain unanswered due to a lack of systematic investigations. The present research introduces venting and evaluates its performance using an experimental model. In the latter, turbidity currents travel on a smooth bed towards the dam and venting is applied through a rectangular bottom outlet. The combined effect of outflow discharge and bed slopes on the sediment release efficiency of venting is studied based on different criteria. Several outflow discharges are tested using three different bed slopes (i.e., 0%, 2.4% and 5.0%). Steeper slopes yield higher venting efficiency. Additionally, the optimal outflow discharge leading to the largest venting efficiency with the lowest water loss increases when moving from the horizontal bed to the inclined positions.

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Venting of turbidity currents approaching a rectangular opening on a horizontal bed

Cited by 13 publications

References 32 publications

Sediment mass movement of a particle-laden turbidity current based on ultrasound velocity profiling and the distribution of sediment concentration

Sediment mass movement of a particle-laden turbidity current based on ultrasound velocity profiling and the distribution of sediment concentration

Variability and Trend Detection in the Sediment Load of the Upper Indus River

Management of turbidity current venting in reservoirs under different bed slopes

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