The Ports Corporation of Queensland (PCQ) will be undertaking
capital dredging at Port of Hay Point to increase water depth for
ships departing the port.
An Environmental Impact Statement (EIS) has been completed for
the project in accordance with approved Terms of Reference (ToR)
and the requirements of Commonwealth and state approval agencies.
All development approvals have now been obtained for the project
and dredging was approved to commence on 1 May 2006.
The project
The capital dredging works will include:
- A ship manoeuvring apron immediately adjacent to and parallel
to the existing terminals. The apron will be 500m wide and dredged
to achieve a minimum declared depth of -14.9m (Lowest Astronomical
Tide).
- A departure path from apron to sea. The path width will be 500m
wide for the first 500m then taper to a width of 300m over the next
three km. There will be a transition zone between the apron and
path. The remainder of the path will be 300m wide and continue
until a minimum natural depth of -14.9m is achieved. The total path
length is approximately 9.5km.
The project includes the installation of up to six beacons
to mark the departure path for shipping.
Clean dredged material for both the capital and maintenance
works will be disposed at sea at a new disposal ground further
seaward and in deeper waters than the current disposal ground.
Dredging program
Dredging
commenced in May 2006.
The dredging is undertaken by a large trailing suction
hopper dredger, the WD Fairway. Its
35,000 cubic metre capacity enabled the works to be
completed in the shortest time possible. The WD Fairway also
employs innovative features designed to minimise environmental
impact from the turbid waters generated during dredging.
Environmental management measures
As part of the EIS, a number of measures were proposed to manage
and monitor potential impacts. These measures were included in an
Environment Management Plan (EMP), which has been approved by the
Great Barrier Reef Marine Park Authority. The measures are to be
implemented as part of the capital dredging program.
The EMP details:
- Management actions - to be implemented to minimise
the potential of an impact occurring.
- Performance indicators - against which the implementation
of the management actions can be measured.
- Monitoring programs - detailing the process of measuring actual
performance.
- Reporting - requirements to enable agencies and the
community to receive information about the implementation of the
EMP.
- Corrective actions - to be implemented should a
performance indicator not be achieved.
Implementation of the EMP is a condition of all approvals for
the project.
Environmental monitoring
The EMP includes implementation of several detailed studies to
monitor particular impacts of concern and to provide an indication
of the longer-term impacts associated with the project and recovery
of impacted areas.
Model Validation Study
The Port of Hay Point Modelling Study, prepared as part of the EIS,
was an important element in determining potential impacts
associated with the dredging works. The results of the modelling
study were used to quantify potential impacts and assist
in the development of management measures.
As part of the environmental monitoring the modelling study was
validated with actual water quality data collected during the first
month of dredging. It is expected these results will confirm the
predicted outcomes of the model and provide important information
for determining impacts associated with future maintenance dredging
at the Port.
Seagrass Monitoring Program
A detailed seagrass
monitoring program was developed by the Department of Primary
Industries and Fisheries. The study will provide direct information
on the impact of the dredging works on seagrass and algae and will
monitor recovery.
Surveys started in late 2006 and continued to the end
of 2007 to enable a clear indication of the longer-term impacts on
the recovery of seagrass and algae within the affected area.
Coral Condition Monitoring Program
Coral condition monitoring at Round Top Island and Victor
Islet was used to identify potential changes in the reef
communities. Two control sites were monitored to enable
scientists to differentiate between natural changes in condition
and those which may be associated with the dredging.
Baseline survey of the monitoring sites was undertaken
regularly for the first two months of dredging and with
a final coral condition report planned after dredging is
completed.
Water Quality Monitoring Program
Water quality
monitoring is via remote monitoring devices to be located at Round
Top Island, Victor Islet, areas of seagrass beds and two control
sites. The devices are monitored via telemetry, which can be
accessed 24 hours a day and provide ongoing data in the analysis of
survey findings from other monitoring programs.