Experimental study of reservoir turbidity currents venting

Ramos-Villanueva, Marielys

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https://hdl.handle.net/2142/90810 Copy

Description

Title

Experimental study of reservoir turbidity currents venting

Author(s)

Ramos-Villanueva, Marielys

Issue Date

2016-04-21

Director of Research (if dissertation) or Advisor (if thesis)

Garcia, Marcelo H.

Department of Study

Civil Engineering

Discipline

Civil Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• experimental study
• reservoir sedimentation
• reservoir
• turbidity current
• turbidity currents venting
• venting
• suspended sediment concentration
• suspended sediment
• sediment deposition
• plunging point
• sediment management technique
• sediment
• density current
• reservoir operation
• sedimentation management
• sediment routing
• pass-through sediment routing
• pass-through technique
• experimental work

Abstract

Reservoirs are one of the most important components of our hydraulic systems around the world, and the effectiveness of their performance is threatened by sediment deposition within the impoundment. To achieve long-term sustainable performance of reservoirs, and to reach effective sediment management techniques, it is necessary to understand the characteristics of sediment and how it behaves before, during and after the turbid inflow plunges and flows along the bottom of the storage pool. For this study, a series of experiments were conducted on a laboratory flume to analyze the behavior of turbidity currents while using the pass-through sediment management technique of venting. The main focus was to explore and develop a better understanding of the streamwise flow velocity and suspended sediment concentration vertical profiles, and the deposition patterns while the turbidity currents are vented. For this, two sediment management conditions or scenarios were recreated: the Turbidity Currents Venting scenario, where sediment-laden underflow was intended to be released through the low-level outlets of the scaled dam; and the Normal Reservoir Operation scenario, where the bottom outlets were closed and the discharge flowed over the dam. This was considered the control scenario. The efficiency of the turbidity currents venting technique varies for each case depending on the geometry, and sedimentological and hydrological characteristics. Those characteristics were set constant for all the experimental runs performed on this study. The flow velocities of the turbidity currents generated by the experimental design did not have the capacity to maintain all the inflowing sediment in suspension. Therefore, significant deposition occurred along the bed, reducing the suspended sediment concentration of the turbidity currents reaching the dam. Even though venting did not eliminate the sediment deposition completely, the results show that the useful life of the storage pool was extended when applying the turbidity currents venting technique. This supports the theory where the application of this technique is expected to reduce the sediment deposition inside the storage pool.

Graduation Semester

2016-05

Type of Resource

text

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http://hdl.handle.net/2142/90810

Copyright and License Information

Copyright 2016 Marielys Ramos-Villanueva

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