The Port waterways (Port River and Barker Inlet Estuary) support
a highly productive and biologically diverse aquatic ecosystem.
The waterways have economic value as a nursery for commercial
fish species such as King George whiting. Other human uses of
the estuary, such as recreation, transport and industry, bring
economic benefit to the state but may also threaten the health
of the estuary. There are 9 monitoring sites in the Port Waterways,
including Inner Harbor, North Arm, Barker Inlet and Outer Harbor.
>> Map
The Port waterways are currently suffering from serious nutrient
pollution. The major sources of nutrients are the Bolivar wastewater
treatment plant (WWTP) and the Penrice soda ash plant at Osborne.
The excessive nutrient levels in the Port waterways have lead
to frequent algal blooms and the abundant growth of nuisance macroalgae
such as Ulva (sea lettuce). The algal blooms cause noticeable
water discoloration, reduce water clarity and sometimes
include species that are toxic. Ulva and other macroalgae
form floating rafts that block cooling water intakes, smother
mangrove pneumatophores and accumulate along the shoreline in
large stands that decompose, producing unpleasant odours. >>
More
>> Photos of the Port
waterways
The water
quality indicators that are used to describe water quality
condition in the Port waterways are nutrients, heavy metals, bacteria
and turbidity.
The results represent nine different sampling sites, which are
shown on the map of the Port River.
The water quality at these sites is quite variable because each
site is influenced by local pollutant sources as well as factors
such as water flow and depth.
Water quality classification for April to September 2006
|
Indicator
|
|
|
|
|
|
Poor
|
NA
|
Good
|
|
|
Poor
|
NA
|
NA
|
|
|
Good
|
NA
|
NA
|
| Soluble Phosphorus |
Moderate
|
NA
|
NA
|
|
|
Good
|
NA
|
NA
|
|
|
Good
|
Good
|
NA
|
|
|
Poor
|
NA
|
NA
|
|
|
Poor
|
NA
|
Good
|
|
|
NA
|
Good
|
Good
|
Notes NA = not applicable
The water quality monitoring results for this period were generally
consistent with, or lower than, previous seasonal results for
this site. Further monitoring is required to determine whether
the slightly lower nutrient concentrations may be an early indication
of a trend, or may be a response to the drought.
Ammonia, oxidised nitrogen and chlorophyll (a) were classified
as poor and soluble phosphorus was elevated at most sites. This
is probably due to industrial discharges into the river (such
as those from Penrice Soda Products and Bolivar Wastewater Treatment
Plant), historical contamination from the now-closed Port Adelaide
Wastewater Treatment Plant and the large number of stormwater
drains that discharge into the Port waterways.
Heavy metals were classified as poor (copper and zinc), which
are most likely due to urban runoff containing heavy metals washing
off roads and galvanised iron roofs into the marine environments
during rain events. In July 2006, a new method for analysing heavy
metals was introduced which can detect metals at much lower concentrations
than before. It is now possible to confidently compare concentrations
to National Water Quality Guidelines.
Turbidity has decreased from the high levels recorded in the
previous monitoring period (which were due to dredging over the
summer 2005-06 in the Port River channel to enable passage of
large ships).
>> Archived results
