Dams and Sedimentation

1
Dams and Sedimentation

• Siu Lan Zhang
• Senior Project
• MPS 402
• December 9, 1998

2
Dams and Sedimentation

• Dams
• Sedimentation
• Three gorges dam
• plan

3
Dams

• Definition
• Structure of dams
• Design of dams

4
Structure of Dams

• Bottom outlet
• Spillway
• Overflow gate

5
Three Design of Dams

• Earthfill dams
• Gravity dams
• Arch dams

6
Sedimentation

• What is sediment?
• The problem of sediment
• Controlling
• Modeling

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Sediment Controlling

• Reduce sediment inflow
• Sediment removal
• Provide large storage volume

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Modeling

• Mathematical modeling
• Physical modeling

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Mathematical Modeling

• Simplifications and assumptions
• Field data
• Input parameters

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Simplifications and Assumptions

• Predominance of the length of the reservoir over
  the other two dimension
• Difference in the rate of change of water levels
  and bed levels
• Imperfect knowledge of sediment transport
• Very irregular reservoir topography

11
Field Data

• Survey of the reservoir topography
• Water level observations and measurement
• Water discharge measurements
• Sediment investigations

12
Input Parameters

• Physical parameters
• Operational parameters

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Three Gorges Dam
14
Plan