No edit summary
No edit summary
Line 29: Line 29:
* In the second method, a trailing suction hopper dredger removes sediment from the surface of the sea floor. The dredger is pulled along the sea floor like a vacuum cleaner and leaves behind a furrow between 2 and 4 m wide and up to 0.5 m deep.  
* In the second method, a trailing suction hopper dredger removes sediment from the surface of the sea floor. The dredger is pulled along the sea floor like a vacuum cleaner and leaves behind a furrow between 2 and 4 m wide and up to 0.5 m deep.  


Source:  
Source: BFN, German Federal Agency for Nature Conservation
https://www.bfn.de/en/activities/marine-nature-conservation/pressures-on-the-marine-environment/sand-and-gravel-extraction.html


===MSP Challenge 2050:===
===MSP Challenge 2050:===

Revision as of 14:20, 13 April 2018

Sand & Gravel Extraction
Layer Info
Category Shipping
Editable Yes
Data source Estimations & data fragments
Types

Description:

Methods of extraction

Typical purposes of sand or gravel extraction can be to obtain useful material (for e.g. heightening beaches, or in building or infrastructure development), and/or to deepen the sea in a particular area (e.g. a fairway to allow large cargo or tanker vessels with deeper drafts to enter a port).

There are two main methods of extracting sand and gravel:

  • In stationary extraction, an anchored cutter suction dredger excavates huge pits in the sea floor with depths of normally about 10 m and diameters of between 10 and 50 m.
  • In the second method, a trailing suction hopper dredger removes sediment from the surface of the sea floor. The dredger is pulled along the sea floor like a vacuum cleaner and leaves behind a furrow between 2 and 4 m wide and up to 0.5 m deep.

Source: BFN, German Federal Agency for Nature Conservation

MSP Challenge 2050:

Sand & gravel extraction areas are polygons, i.e., geometric shapes that you can draw in, edit or remove when making a plan.

Sand & gravel extraction areas create the following pressures on the ecosystem:

  • Bottom disturbance
  • Noise

IN THIS TAB EXTENDED CONTENT IS PLACED

This page was last edited on 13 April 2018, at 14:20. Content is available under GPLv3 unless otherwise noted.