Coast & Estuaries
Page 217
Dredging of the Port Adelaide River
Work has been completed on deepening the channel at Outer Harbor from 12.2
metres to 14.2 metres to accommodate large Panamax ships as part of the
ongoing Flinders Ports development. Several other one-off or regular
maintenance dredging occurs at various sites along the River. Dredging has
potential significant environmental consequences on benthic (living on or in
sediments of the sea floor) flora and fauna and the re-distribution of exotic
marine species.
The long term effect of dredging activities is not well documented. Further
research is required to investigate the impacts of dredging and recovery rates in
specific locations and in various conditions.
Shipping
The management of the Port and the Shipping Channel is undertaken via
Flinders Ports. Flinders Ports runs the seven South Australian Ports, which
includes Adelaide, Port Giles, Klein Point, Wallaroo, Port Pirie, and Thevenard.
Of these ports, Port Adelaide is the largest. Flinders Ports has berthing at two
locations at Inner Harbor and Outer Harbor.
The major threat to water quality from shipping is the risk of an oil spill and the
potential impact of the oil, and dispersants used to treat the spill, on marine and
estuarine waters. The two major oil spills in the region both resulted from
activities associated with the former Port Stanvac oil refinery.
With the closure of the refinery, fuel is now transported to facilities in Port
Adelaide and this has increased the risks in that area. In 2004–05, 103 vessels
unloaded over 2 million tonnes of petroleum product at Port Adelaide (Flinders
Port, 2010). The significantly increasing number of new fuel storage terminals
and fuel wharf transfer facilities on the Lefevre Peninsula also increases the
potential for fuel spills to the River or estuary in the future.
Discharge of bilge water from shipping can also impact on water quality, but
usually in a localised area. However, discharge of ballast water, hulls or anchor
ropes from these vessels in the port is a major factor in the spread of marine
pests. Tributyl tin (TBT), which was used for many years to control growths on
hulls on vessels, has been detected in sediments in the Port River. TBT is toxic
to marine organisms, particularly shellfish.
Pressure indicator:
Introduced marine species identified in the Port Adelaide
area
