Coast & Estuaries
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Modelling of water quality processes in the estuary has allowed the EPA to
calculate the reductions in nutrient discharges from Penrice and SA Water
(Bolivar Wastewater Treatment Plant) that are needed to improve the water
quality to meet regulatory standards and community expectations.
The necessary reductions are substantial and may be costly to implement, but
is envisaged to return very significant social, environmental and economic
benefits to the region.
The WQIP was reviewed in 2008. The review included monitoring (and public
reporting) of the progress of nutrient reductions and improvements in water
quality of the waterways
.
Adelaide Coastal Water Study (ACWS)
Currently, nitrogen loads to Adelaide’s coastal waters primarily come from three
main sources: wastewater treatment plants (WWTPs), the Penrice Soda
Holdings discharge into the Port River and stormwater from a large section of
metropolitan Adelaide’s catchments.
The total 2008 nitrogen load was 1,796 tonnes, a reduction of nearly 25% from
the 2003 load of 2,357 tonnes/year. Since the information gathering work for the
ACWS was completed in 2003, some improvements have already been made in
treatment and industrial process that have resulted in improved water quality.
However, significant improvements are still required to achieve the
recommended targets set in the ACWS and to see an improvement in water
quality that creates the conditions where seagrass can return closer to shore.
Reducing nutrient loads
Recommendation 2 of the ACWS indicates that a reduction in nitrogen loads to
around 600 tonnes per year (a 75% reduction from the 2003 value of 2,400
tonnes/year), is needed to halt current seagrass loss and create the conditions
which support seagrass recovery.
Issues and opportunities
•
Council to advocate for the State Government’s implementation of a key
action in the State Wetland Strategy - that is, to prepare management
plans for wetlands of natural significance - specifically in relation to the
Barker Inlet /St Kilda wetlands (as shown in figure 54).
