123
Over 2.5 km
2
of actual acid sulfate soils are present in the Gillman area. Release of acid and metal ions
into the environment can cause major habitat degradation and loss of biodiversity (SACPB, 2003). The
Coastal Acid Sulfate Soils Program (CASSP) was established to define the ASS problem at Gillman, to
prevent it from increasing and investigate remedial actions to reduce the impact these soils are having on
the environment (Thomas et al, 2003).
7.4.
Groundwater
The Study Area falls within the boundaries of 2 prescribed wells areas which guide the management and
use of groundwater resources; the Northern Adelaide Plains Prescribed Wells Area (PWA) which covers
a small portion of the Western Region, in the north-eastern part of the City of PAE and the Central
Adelaide Plains PWA which applies to the rest of the Region. A new Water Allocation Plan (WAP) is
currently being prepared that will include both of these PWAs (AMLR NRMB, 2011).
The
Groundwater Status Report
(DfW, 2011) reports the condition of the Central Adelaide Plains PWA as
showing ‘Adverse trends indicating low risk to the resource in the medium term’. Key threats to the
groundwater resource in the region include increasing demand, reduced recharge resulting from reduced
rainfall and runoff, and increasing salinity.
Figure 7.3
shows the licensed and stock and domestic (unlicensed) extraction bores in the Region, and
the boundaries of the Prescribed Wells Areas. There is a concentration of shallow wells on Lefevre
Peninsula, assumed to be used for stock and domestic purposes. The map shows 106 licensed extraction
bores (in 2010) with a total allocated volume of 5224ML. In addition, there are 67 license applications for
a total of 5,433ML, suggesting an increase in demand for groundwater in the region.
7.5.
Impacts upon Natural Resources from Climate Change
The potential impacts of climate change on the natural resources of the Study Area are summarised in
the
Table 7.4
below (adapted from AMLR, 2007).
Table 7.4: Potential Climate Change Impacts on Natural Resources
Natural Resource
Potential Impact
Surface water resources
Direct reduction in rainfall, runoff and infiltration
Increasing water demand with warming, drying
Groundwater resources
Direct reduction in rainfall, runoff and infiltration
Terrestrial biodiversity
Increase in hot, dry conditions
Most local biodiversity is highly adapted to variable, hot, dry conditions but
bioclimatic envelopes could change significantly
Freshwater biodiversity
Most catchments are short and highly dependent on regular rainfall
Many freshwater ecological systems are already extremely marginal
Salinity, pollution and turbidity levels will all increase, with reductions in average
flows
Coastal systems
Projected sea-level rise
Tidal, estuarine and dune coastal systems are highly dependent on sea-level,
tidal range and flooding regime
