1 Dredging Phases 4 phases –excavation –lifting –transportation –disposal Guide 4: Machines,...
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1 Dredging Phases • 4 phases – excavation – lifting – transportation – disposal Guide 4: Machines, Methods and Mitigation; Chapter 2: Phases of a Dredging Project;
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Transcript of 1 Dredging Phases 4 phases –excavation –lifting –transportation –disposal Guide 4: Machines,...
1
Dredging Phases
• 4 phases– excavation– lifting– transportation– disposal
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 15
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 15
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Dredging Phases
• Excavation of the in-situ material by– cutter head– draghead– cutting edge of a bucket
• Main environmental aspects– Increase of suspended sediments– Mixing of soil layers– Dilution (in case of hydraulic dredging)
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 15
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 15
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Dredging Phases
• Raising the material– mechanically backhoe, dipper, bucket ladder
dredger– hydraulically cutter suction, trailing suction
hopper, disc bottom, auger and sweep dredgers
• Main environmental aspects– Release of suspended sediments– Loose and mobile spill layers– Density of material– Overflow during loading of hopper or barges
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 16
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 16
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Dredging Phases• Horizontal transport by
– hydraulic pipeline
– hopper dredgers
– barges
– also: trucks or conveyor belts
• Main environmental aspects– safety– dilution
– spillage– noise and air pollution
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 16
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 16
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Dredging Phases
• Placement or further treatment– reclamation of a site– beach nourishment– wetland creation– relocation on land, in a pit or at sea (underwater)
• Main environmental aspects– Occupation of space and surface– Dispersion of the deposited material– Noise and air pollution– Groundwater quality
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 17
Guide 4: Machines, Methods and Mitigation;
Chapter 2: Phases of a Dredging Project;
Page 17
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Environmental Dredging• Often with normal equipment• Sometimes with adapted procedures• When required, with special tools
• Always resulting in lower output, higher costGuide 4: Machines, Methods and Mitigation
Chapter 3: Dredging Equipment
Page 19
Guide 4: Machines, Methods and Mitigation
Chapter 3: Dredging Equipment
Page 19
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Suction Dredger (SD)
Guide 4: Machines, Methods and Mitigation
Chapter 3: Dredging Equipment
Page 19
Guide 4: Machines, Methods and Mitigation
Chapter 3: Dredging Equipment
Page 19
