WHAT IS DREDGING

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WHAT IS DREDGING?
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DEFINITION

• Dredging is the removal of bottom sediments from
  streams, rivers, lakes, coastal waters, and
  oceans, and the resulting dredged material is
  then transported by ship, barge, or pipeline to a
  designated disposal site on land or in the water
  where it is discharged.

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US PORTS WATERWAYS
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CLAMSHELL
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ENVIRONMENTAL BUCKET (Courtesy CableArm)
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HOPPER DREDGE
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HOPPER DREDGE (LIBERTY ISLAND, COURTESY OF GLDD)
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Hopper Dredge
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OPEN WATER PLACEMENT
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CUTTER SUCTION DREDGE
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Advancing with fixed spuds (Courtesy of P. deJong)
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Booster Pump, Unloader, Spider Barge
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PIPELINE DREDGES AND TRANSPORT

• Typical pipeline diameters range from 15 to 92 cm
  (6 to 36 in)
• Pipes are commonly constructed with steel or a
  composite material such as polypropylene
• Pipelines may be submerged, floating, or placed
  on the shore.
• Floating pipelines may be supported by pontoons
  or flotation material.
• Length of the pipelines varies from short
  distances such as several hundred feet to several
  miles.

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DREDGED MATERIAL PLACEMENT

• Open Water Placement
• Confined Disposal Facility (CDF)
• Beneficial Use

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CONCEPTIAL CONFINED DISPOSAL FACILITY
(CROSS-SECTION) (Courtesy of M. Palermo)
AREA FOR FINE-GRAINED DREDGED MATERIAL STORAGE
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CONCEPTIAL CONFINED DISPOSAL FACILITY (PLAN VIEW)
(Courtesy of M. Palermo)
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ISLAND CDF
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BENEFICIAL USES

• USACE (1987) describes ten broad categories of
  beneficial uses of dredged materials
• Habitat restoration (e.g. wetlands, islands for
  birds and waterfowl)
• Beach renourishment
• Aquaculture
• Parks and recreation
• Agriculture, forestry, and horticulture
• Land reclamation and landfill cover
• Shoreline stabilization and erosion control (e.g.
  fills, submerged berms, etc.)
• Industrial use (e.g. port development, airports,
  residential development, etc.)
• Material transfer (fill, dikes, levees, parking
  lots, highways, etc.)
• Multiple purposes

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BOLIVAR SALTMARSH TEXAS DREDGED MATERIAL ISLAND
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Beach Nourishment (Courtesy of Adam Kiecke)
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INDUSTRIAL / COMMERCIAL FILLS