Soil testing and a Marine Ecology study have been
undertaken and a Review of Environmental Factors prepared to fully understand
the river in the vicinity of the dredging. These documents produced a number of processes contractors need to
undertake to minimise environmental impacts during the dredging.
This includes the use
of markers to indicate no-go zones plus silt booms and silt curtains to
minimise dispersal of silt into the river.
The dredging itself employs a ‘clam shell’ excavator
which creates much less disturbance to the river bed. The excavator being used is new and designed to minimise noise.
The bed of the Woronora River is owned by NSW
Department of Planning Industry and Environment - Crown Lands, and general
dredging are other works are undertaken by them. Council has a dredging policy under which dredging is only undertaken for safety or
critical navigation, under which this project is classified.
The spoil is being taken to a disposal at sea site
authorised by Australian Federal government approximately 10 km off the coast
of Sydney Harbour. Stringent environmental testing was required and undertaken
to achieve the permit to allow this to occur.