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Acid sulfate soils
: - Potential acid sulfate soils (ASS) are widespread in the coastal
environments of the Western Adelaide region. Sulphide formation has occurred in some areas
due to drainage and other disturbances associated with infrastructure development, resulting in
the production of acid that may contaminate surface waters and groundwater. Elevated sea and
groundwater levels, coupled with informed development practices, may reduce the risk of
activating new areas of ASS. However any new permanent or prolonged inundation of formerly
dry land with potential ASS, could result in their sulphide and acid generation.
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Beach amenity and width:
Coastal climate change may adversely affect coastal landscapes
through loss of dunes, movement of sand and longer duration of inundation of the beach. This
may, in turn, affect beach access, use, aesthetics and value. Projected increases in summer
storminess (e.g. frequency) and swell generation (CSIRO, 2003) may also affect beach amenity.
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Ecological changes:
Sea water inundation and coastal recession and secondary impacts (e.g.
activation of ASS, further salinisation of aquifers) may affect coastal habitats and ecosystems.
No observed ecological changes have been identified for the purpose of this study, however this
should be examined in more detail during Stage 2. Rising water temperatures (at an average of
0.11°C/ decade between 1950 and 2005; CSIRO, 2006) may affect some ecological processes
and could increases in the risk of algal blooms in vulnerable areas.
Many coastal environments within the Study Area are intensively managed to minimise the effect of
coastal hazards (e.g. beach erosion from storms, storm surge inundation). Existing coastal management
measures (e.g. beach nourishment, maintenance of sea walls) and those that are developed in response
to experienced impacts of climate change and as a result of existing coastal management strategies and
policies would be expected to mitigate at least some of the potential impacts described above.
5.4.
Summary
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Global mean sea level is projected to increase by between 18 and 140cm by 2100, with 83cm
projected under a high greenhouse gas emissions scenario. Land subsidence in the Study Area
could exacerbate the impacts of sea level rise on coastal flooding.
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Under a high sea level rise scenario for 2100, storm tides could reach areas that are currently
2.4m above mean sea level. Damage resulting from such floods is estimated to exceed $180
million (compared with $26-28 million currently).
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Exposure of the Study Area to inundation resulting from projected sea level rise has been
modelled for various timescales and scenarios. These analyses show that residential and other
buildings in these areas could be exposed to periodic coastal flooding events, resulting from storm
tides and sea level rise.
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Coastal recession, the landward retreat of a coastline, presents a significant risk to infrastructure,
