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Dredging Lower Fraser
Dredging in the Lower Fraser River

The shipping channel in the South Arm of the Lower Fraser River between Delta and Richmond is maintained by the Port of Vancouver. This includes regular maintenance dredging.
 
However, the secondary channels have been neglected by both Provincial and Federal Governments. As 20 million tons of sediment flow down the river each year, some of that sediment accumulates in the channels creating shallow waterways and sandbars.
 
There is currently no maintenance plan in place to ensure safe navigation in the secondary channels.  Water, in British Columbia is owned by the Crown and water leases are assigned by the Ministry of Water Lands and Resource Stewardship in consultation with First Nations.
 
The Province of BC benefit economically from the Fraser River through commerce,  industry, water leases, property tax on water leases and permits. However, the businesses and people that support the Province through the Fraser River are ignored.

Dredging Facts

What is dredging?

Dredging involves the removal of fine gravel and silt materials from a riverbed, coastline, reservoir, or other body of water. ​

History of Dredging
Archeological evidence suggests dredging dates back to the Mesopotamians and ancient Egyptians. These civilizations had large river-based communities that used a rudimentary irrigation tool called a shadoof or shaduf. The shadoof sus
opends a long pole with a bucket or basket on the end from a frame. Inhabitants would lower the bucket into water, lift it and place it in another water source or on land. 

Benefits of Dredging
  • Dredging helps to increase water flow and transport capacity in a river. 

  • Used to restore/maintain water depth to ensure safe Navigation of Marine Vessels.

  • Dredging is also used to address a broad range of maritime infrastructure needs – with economic, social and environmental implications.

  • Dredging deepens ports and access channels to accommodate global waterborne freight transport of goods.

  • Dredging also removes silt buildup and then transports these materials to onshore locations where they are used to replenish eroded marshes and rebuild coastlines for protection of low-lying areas against storm surge.

  • Modern dredging vessels and technologies can collect and transport large quantities of sand to improve and expand existing ports, and to build land reclamations, which form platforms for offshore airports, residential and commercial areas.

       https://www.iadc-dredging.com

Concerns with Dredging
The primary concern raised with regards to dredging is that of Environmental consequences. Dredging can alter or damage wildlife habitat if it is not performed with respect to the area and species within that specific area. 

Dredging in the Modern Era

Renowned Renaissance artist and inventor Leonardo da Vinci drew a design for a type of drag dredger around the 16th century. A few hundred years later, the Industrial Revolution began and marked noteworthy advancements in dredging techniques, including the beginning of motorized dredging.

 

The invention of the steam engine in the 18th and 19th centuries led to the use of motorized steamboats. This new technology made dredging easier and far more effective than at any other time in dredging history. From there, dredging took off and was pivotal in land development and building and expanding ports and canals. 

In the early 20th century, dredging was also crucial for land reclamation, or constructing new land in the sea.

 

For example, in 1932 the Dutch government drained the Zuiderzee, a shallow part of the North Sea bordering the Netherlands. Cutting this off from the North Sea made it possible to reclaim the shallow wetlands and led to the creation of the Flevopolderin, an island polder and one of its surrounding lakes, the IJsselmeer. 

History Of Dredging (Geoform International)

Dredge Material as a Resource

 

Many people all over the world think of dredged material as dirty, unwanted soil – something that is unclean. This is by and large erroneous. Dredged material is predominantly a clean, usable product; in many cases akin to the soil in one’s garden, in which vegetables are grown

Dredge Material as a Resource PDF

 

Sturgeon Bank Restoration Project

Methods of Dredging

There are several methods of dredging used, including hydraulic dredging, mechanical dredging, and environmental dredging. Hydraulic dredging involves using water to loosen and transport sediment, while mechanical dredging uses machinery to physically remove sediment. Environmental dredging is a specialized method used to remove contaminated sediment from waterways. Each method has its own advantages and disadvantages, and the choice of method depends on the specific of the project.

Mechanical Dredging

In essence, mechanical dredging is the act of using a dredge that digs materials from an extraction site. Most often, there is a stationary, bucket-oriented machine that scoops the desired materials before transporting them to the sorting area.

Clamshell Dredge

Clamshell Dredge

Hydraulic Dredging

Hydraulic dredging is centred around the concept of transferring dredged materials from the dig site to a processing location for sifting and sorting. It involves creating a slurry—a fluid mixture comprising elements like rock, dirt, and gravel—which is then transported to a sorting facility.

Water Injection Dredging

The injection of water separates and mobilises these particles so they can be washed away in the lower third of the water column. The 'density current' travels downriver on an outgoing tide and disperses through natural processes, usually wave action.

Cutter Suction Dredge

Hydraulic Suction Dredge

Water Injection Dredge

Water Injection Dredge (WID)
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