Definitions of Environmental Change
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Alteration of tidal propagation
a change in tidal propagation can affect levels of high and low water, the extent to which saline water penetrates up estuaries, mixing and drainage of estuaries and embayments etc. Causes may include new structures, dredging, reclamation etc.
Change in hydrodynamics
a shift in the current water movements. May include localised or widespread changes, ranging from small eddies or water movements to shifts in the main flow. Such changes can result from construction in the intertidal/subtidal, dredging, reclamation, habitat creation etc.
Change in sediment transport
a shift in the existing movement of sediment. May lead to changes such as erosion and/or deposition, differences in the movement of various sized sediment particles etc. Potential causes include those that affect the hydrodynamics, construction where areas of lower or increased water speed result and hence increased/decreased potential for deposition/erosion, dredging which may increase deposition or increase erosion, installation of structures which trap sediment or focus energy in areas leading to scouring etc.
Emissions to air
non-noise emissions to air generally relate to exhausts, gases, dust or particles etc. Activities that can are associated with emissions to air include shipping, construction plant, movement and storage of cargo etc.
Generation of ship waves
vessels moving generate ship waves, which are a function of the size of vessel and the speed of movement.
Generation of wind waves
wind blowing over the water will lead to the generation of wind waes, the size of which is dependant on a number of factors including the fetch or the amount of water across which the wind can blow to generate waves. Altering the available fetch or the shelter afforded to a waterbody could therefore affect the generation of wind waves. Activates that could lead to such changes can include construction of tall buildings, reclamation, harbour walls etc.
Habitat loss
relates to the direct loss of an existing habitat, such as through dredging, where the existing bed level is removed, or when a new structure is placed on top of an existing habitat, such as when a new breakwater is constructed.
Increase in total suspended solids
release of sediment into the water column either directly by disturbance or following an alteration in erosion, can lead to an increase in sediment in the water column, with potential effects such as changes to light penetration, smothering as the sediment settles out, effects on fish/shellfish etc. Sources of suspended solids include discharges, dredging, construction, vessel movements, anchoring etc.
Introduction of non-native species
the main sources of non-native species are ballast water and ships hulls. As ships move between ports, encrusting species can grow on the hull, potentially releasing eggs or larvae into ports in different areas. Water taken on for ballast can contain numerous species in different life scages, with the potential to colonise new port areas when ballast water is discharged. The introduction of such species can have issues connected to disease or disruption/alteration in the existing ecology.
Light Pollution
an increase or decrease in ambient light levels, which may be intermittent, regular or permanent. A decrease in light levels can result from shading, for example due to the presence of new structures (mobile and fixed). An increase in light levels is generally associated with an increase or new requirement for lighting, both on board ships and dockside, with the increase generally relevant for part of the day only.
Noise and vibration above water
an increase in ambient noise levels or vibration in the air. Significant increases in ambient noise levels are generally associated with construction and/or operation. Specific activities connected to increased noise and/or vibration include piling, construction, construction plant, shipping, demolition etc.
Noise and vibration below water
an increase in ambient noise levels or vibration in the water. Significant increases in ambient noise levels are generally associated with construction and/or operation. Specific activities connected to increased noise and/or vibration include piling, construction, construction plant, shipping, demolition, dredging etc.
Physical Disturbance
physical disturbance changes relate to an existing habitat or species being physically disturbed, moved or relocated from its current location. Examples may include disturbance during construction, anchoring, dredging etc.
Physical Presence
the introduction, on a temporary to long term basis of a new structure. May range from moving ‘structures’ such as vessels, to small or large fixed installations.
Release of microbial /bacterial contaminants
a number of microscopic organisms are associated with certain activities, in particular with sewage or faecal contamination (human or other species, such as birds or livestodk). The main source of anthropogenic microbial or bacterial contaminants is primary from discharges or secondary release when contaminated sediments are disturbed for example during dredging or construction activities.
Release of organic carbon and nutrients
the main sources of organic carbon and nutrients are from discharges, disturbed sediments, spillages etc.
Release of toxic contaminants
toxic contaminants can be released through discharges, leachate from structures or vessels, spillages, disturbed sediments etc.
Sediment deposition
a change in sediment deposition can occur either as a result of a change in the sediment dynamics or following an increase in suspended sediment.
