Inland Waters
Page 167
Typical pollutants collected by stormwater in urban and commercial/industrial
land uses include sediments, heavy metals, pesticides and nutrients. The two
most recent investigations into quality of stormwater in catchments are via
the
AMLR NRM Board's water monitoring network that monitors stormwater run-off
in 'real time' to help Councils and the Board determine where new stormwater
harvesting projects would be best developed to reduce stormwater discharge to
the Gulf St Vincent. The monitoring program measures water quality and
quantity, to provide a comprehensive picture of stormwater across the NRM
region. The network comprises thirty sites across the region which record water
volume and flow rates and monitors salinity, turbidity and suspended solids, and
nutrients. T
he EPA Water Quality Improvement Program for the Port River and
Barker Inlet is also another valuable program that is well acknowledged.
Within the Council area, pollutants found to be at high concentrations are the
nutrients and heavy metals, an important source being Council’s significant
industrial and commercial sectors and their accompanying transport networks.
There are a wide range of heavy metals found in water including copper (Cu),
lead (Pb), zinc (Zn) and other potential contaminants such as nitrogen oxides
(NOx), phosphates, salinity and total organic material. In water, most metals are
attached to particulate matter and usually end up in floor sediments - and are a
potential contaminant to biota, especially if remobilised into the water. In animal
tissues these metals can increase via bioaccumulation (continue to increase in
tissues throughout the life of an organism) and biomagnification (increase up
the food chain).
Motor vehicles, high traffic areas and industrial precincts are major sources of
heavy metals. Car brakes, tyres and exhaust emissions provide the bulk of the
catchments’ heavy metal load, and activities on industrial sites
.
Wetland Gross Pollutant Traps
The quality of the stormwater entering the wetlands varies with each catchment.
Gross Pollutant Traps (GPTs) intercept litter and large organic debris at the
entry to the wetlands.
