Siltation rate changes (heavy)

Siltation (or sedimentation) is the settling out or deposit of silt or sediments suspended in the water column to the sea bed. Changes relate to those over natural siltation and those above 5 cm (less than this depth is covered by different pressure), or where a high level of deposition is continuous (e.g. fish farming). Siltation of this level can completely smother species and habitats, particularly sessile organisms. Impacts are mainly from hypoxia, inability to feed or photosynthesise and potentially death unless tolerance species or species that can re-emerge.

Benchmark: 
Heavy deposition of more than 5cm and up to 30cm of fine material added to the habitat in a single discrete event or continuous deposition of fine material.
Examples: 
Activities associated with this pressure type include fin fish aquaculture, land claim, navigation dredging, aggregate extraction, cable and pipeline laying, drill cuttings, various construction activities and waste disposal.
Notes: 
Excludes shellfish culture (shell/seaweed debris captured under 'intro of other substances'). <5cm cover siltation changes (light) covered by separate pressure.

Faroe Shetland Channel

The tables in this section reflect the output of the workshop (October 2019) when the pressures from human activities were assessed for the period 2014 to 2018 for the region. The summary text below the tables elaborates on some of the points that were made at the workshop.
This pressure assessment uses the FeAST classification which includes two abrasion pressures: surface abrasion & sub-surface abrasion. Some expert groups combined these as a single pressure "surface & sub-surface abrasion" whilst others focussed on using surface abrasion alone, hence there is a slight difference in handling for some regions.
The ranking of the pressures in terms of impact is a relative exercise within each region, and is not a statement of their absolute impact. Detailed comparison between regions on the basis of these relative pressure assessments is therefore not advisable.

Main pressures identified

Faroe Shetland Channel

Clyde

The tables in this section reflect the output of the workshop (October 2019) when the pressures from human activities were assessed for the period 2014 to 2018 for the region. The summary text below the tables elaborates on some of the points that were made at the workshop.
This pressure assessment uses the FeAST classification which includes two abrasion pressures: surface abrasion & sub-surface abrasion. Some expert groups combined these as a single pressure "surface & sub-surface abrasion" whilst others focussed on using surface abrasion alone, hence there is a slight difference in handling for some regions.
The ranking of the pressures in terms of impact is a relative exercise within each region, and is not a statement of their absolute impact. Detailed comparison between regions on the basis of these relative pressure assessments is therefore not advisable.

Main pressures identified

Clyde