Eden Breakwater Wharf extension - frequently asked questions


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Why is dredging being undertaken?

Dredging works are required to create a minimum clear depth of 10.5 m for large cruise ships to be able to berth in Eden once the wharf extension is complete. The dredging works contract also includes installation of scour protection to protect the existing and the new wharf from the turbulence created by cruise ship propulsion systems.

Who will be undertaking the dredging?

The dredging contract has been awarded to Heron Construction Company Ltd, an experienced operator in Australia and New Zealand.

When will dredging start?

The dredging is scheduled to commence in September 2017 and will take up to 15 weeks to complete, weather permitting. Dredging and offshore disposal activities will be undertaken 24 hours per day, seven days per week, with noise and water quality monitoring in place to ensure compliance with the project’s permits and approvals.

What is the location of the dredging?

Dredging will be undertaken in the Port of Eden; Snug Cove/Twofold Bay.

How much material will be removed?

Up to 231,500 m3 of material will be removed to create the berthing pocket and approach channel. The majority of the dredge material is sand, with a minor percentage of rock and silt.

What will happen to the material after it has been dredged?

The material dredged out of the port will be disposed of at a dedicated offshore disposal site, which is situated approximately six nautical miles east of Twofold Bay, in approximately 60 m deep water. The disposal location was used previously by the naval wharf dredging program and is regulated by the Commonwealth Government under the Environmental Protection (Sea Dumping) Act 1981.

What equipment will be used?

Heron will use a backhoe dredge, the ‘Machiavelli’. The dredge will excavate the material and place it into the accompanying split hopper barges that are towed by tugs from Pacific Tug. When each barge is at capacity, the tug will tow it to the offshore disposal site. Two hopper barges will operate on a rotational basis (one being filled, while one is being emptied).

Will the Breakwater Wharf be closed during dredging?

The Breakwater Wharf officially closed to the public and port users on 12 August 2017, though some access was provided during a transitional period to allow some fishermen and port users access. The wharf will be reopened when the project is completed in mid-2019. The mooring and main jetties can still be used by the public. More information is available from the Port of Authority of New South Wales

Will boats still be able to enter the Port of Eden?

A public notice to mariners was issued on 14 July 2017 that advised vessel operators to exercise caution when navigating in the vicinity and not to attempt berthing alongside the Breakwater Wharf. Further information is available from the Port of Authority of New South Wales

Vessel operators should also note there is a 50 m exclusion zone around the dredge.

Will cruise ships visit Eden during construction?

Cruise ships will continue to visit Eden during construction, with their tenders using the T-jetty adjacent to the Breakwater Wharf.

Who approved the dredging works?

Development consent has been provided by the NSW Department of Planning & Environment and an Environment Protection Licence was issued by the NSW Environmental Protection Authority. The Port of Eden Harbour Master has also authorised the works. All dredging and disposal of dredge material will be undertaken in accordance with the National Assessment Guidelines for Dredging 2009, Environment Protection and Biodiversity Conservation Act 1999, Environmental Protection (Sea Dumping) Act 1981, Australian and New Zealand Guidelines for Fresh and Marine Water Quality (ANZECC/ARMCANZ 2000), and State Legislation.

What happens after dredging is finished?

Once dredging and scour protection works are complete, works on the marine structures will commence which will include:

  • extending the existing wharf by approximately 95 m
  • installing three mooring dolphins and two berthing dolphins
  • installing onshore mooring bollards on the existing wharf
  • upgrading existing services such as lighting, power and potable water and emergency fire-fighting water
  • installing navigation aids.

It is expected that these works will commence in early 2018.

Managing construction noise

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What is noise?

Noise is defined as an ‘unwanted sound’. Everybody perceives noise differently, and everyone has a different tolerance level for noise.

What noise will be generated during the dredging?

During dredging, the dredge will produce noise similar to the sound of an engine running. Modifications have been made to the dredge to reduce noise levels specifically for this project. This involves:

  • lining the engine bay with high-quality sound absorbing materials
  • sealing the engine bay and fan areas along joints and gaps
  • inserting noise-reducing materials into the covers of mufflers
  • covering the area above the engine bay with rubber
  • placing noise-absorbent and sound-deflecting materials around the fans, external handrails and centre section of the backhoe body.

To dispose of dredged material, tugs tow barges to a disposal site located approximately six nautical miles offshore. The noise produced will be similar to that of the tug boats currently operating in the Port of Eden.

During the fabrication of scour protection, there will be some noise from the fabrication works and from truck deliveries. This will take place during normal construction hours, which are from 7.00 am to 6.00 pm Monday to Friday and from 8.00 am to 1.00 pm Saturdays. The use of horns and alarms on vehicles at the Breakwater Wharf will be minimised.

What noise will be generated during construction of the marine structures?

During construction of the marine structures noise will be generated from:

  • construction vehicle movements
  • loading, unloading, moving equipment and construction materials
  • excavating
  • piling
  • drilling pile rock sockets
  • pre-cast and in situ concreting works
  • saw cutting and breaking concrete.

The noise will be temporary and will change as the work progresses.

Before the commencement of the marine structures, the successful tenderer will be required to prepare a construction environmental management plan (CEMP). The CEMP will detail the mitigation measures to be put in place to manage construction noise.

What legislation covers noise?

Our management of construction noise is guided by the following key documents:

  • the project’s state significant infrastructure approval, which details the conditions under which the project must operate, including management of construction noise
  • Environmental Planning & Assessment Act 1979
  • Protection of the Environment Operations Act 1997
  • AS 2436-1981 ‘Guide to Noise Control on Construction, Maintenance and Demolition sites’
  • Interim construction noise guideline.

In addition, the environmental impact assessment for the project addressed the requirements of the above. Where the requirements could not be met, additional mitigation measures were developed to reduce noise impacts.

How will noise levels be assessed and monitored?

Noise is assessed by averaging the quietest and loudest (actual and/or predicted) measured noise levels, with consideration to how the human ear perceives sound.

Three noise monitors (sound loggers) have been installed at various locations around Snug Cove, which enable project staff to remotely monitor noise levels 24 hours per day. In addition, a noise specialist will be present periodically throughout the project to measure noise levels at various residential and commercial locations in Eden.

Why is noise monitoring being done?

We recognise construction noise can be a major annoyance, especially for residents and businesses. We are committed to mitigating and limiting the impact of construction noise wherever possible.

Noise monitoring is also a requirement of the project’s state significant infrastructure approval.

Water quality

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Why does water quality need to be monitored?

To allow cruise ships to berth at the new Breakwater Wharf, up to 231,500 cubic metres of material must be dredged from the seabed in Snug Cove and Twofold Bay. During dredging, sediments are disturbed and can become suspended in the water, which can impact the living conditions of native marine flora and fauna.

Turbidity is a measure of the cloudiness of water and will be used to determine water quality during the project. Turbidity measures the amount of tiny particles, such as silt and clay, organic matter and microscopic plants and animals suspended or floating in the water.

The water quality in Snug Cove and Twofold Bay will be monitored to ensure dredging the seabed does not have an adverse impact native marine flora and fauna.

Sediments can also contain naturally occurring contaminants such as nitrogen, phosphorous and mercury. Previous testing of the sediments has shown that the levels of contaminants in Snug Cove and Twofold Bay are not above limiting thresholds.

Will specific habitats be monitored during construction?

Water quality will be monitored near the following habitats:

  • the seagrasses within Cattle Bay
  • rocky reef habitats near Shelly’s Beach
  • the Eden mussel aquaculture farm adjacent to Cocora Beach.

How will water quality levels be monitored?

Purpose-built water quality monitoring instruments mounted on buoys will measure turbidity. The buoys have been installed in Snug Cove and Twofold Bay. Sensors continually monitor water quality and the buoys transmit the data to an online monitoring system.

Continuous monitoring of turbidity acts as an early-warning system and allows the dredging contractor to take actions to ensure water quality is not significantly degraded during operations.

How long will water quality be monitored?

Water quality will be monitored for the duration of dredging activities.

Will there be any impact on seafood in Snug Cover and Twofold Bay?

We don’t expect fish, mussels and other marine species in Snug Cove and Twofold Bay to be affected by dredging activities. The mussel farm will continue to undertake water-quality and product sampling when harvesting mussels, as required by the NSW Food Authority and in accordance with statutory requirements.

What legislation and guidelines cover water quality?

Relevant legislation and standards governing the management of water quality are:

  • National Assessment Guidelines for Dredging 2009
  • Australian and New Zealand Guidelines for Fresh and Marine Water Quality
  • NSW Water Quality Guidelines
  • NSW Water Quality Objectives
  • National Water Quality Management Strategy
  • Protection of the Environmental Operations Act 1997
  • Protection of the Seas (Prevention of Pollution from Ships) Act 1983.

The project’s environment protection licence and its state significant infrastructure approval detail the conditions under which the project must operate, including the management of water quality.

In addition, the environmental impact assessment for the project addressed the requirements of the above.

Will there be a noticeable discolouration of the water during dredging?

There will be discolouration of the water around the dredge and at the offshore disposal site caused by the materials being excavated from the seabed. This is not harmful and will not impact marine life, recreational and commercial fishing, and people swimming at nearby Corcora Beach and Shelly Beach.

Marine mammal and turtle management

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What marine mammals are found in Snug Cove/Twofold Bay?

The following types of mammals often come into Snug Cove/Twofold Bay:

  • humpback, southern right, orca, sperm and minke whales
  • bottlenose and common dolphins and seals.

When does whale migration take place?

Whale migration takes place annually from July to December. In winter, whales migrate north to warmer waters and return south between August and December.

Will the project impact whale migration?

As Twofold Bay is traditionally a fishing area, and Snug Cove is an active port, there is already moderate to high shipping traffic in the area. According to assessments made during the environmental impact statement phase of the project, there should be no significant impact on whales or their migration by the additional vessels being used during the project.

Because whales are a protected species under state and Commonwealth legislation, additional conditions and management controls have been put in place for the duration of the project to ensure there is no negative impact on the animals.

What types of marine animals are specifically protected?

The following marine animals are protected under state and Commonwealth legislation:

  • whales
  • marine turtles
  • dolphins.

These animals are specifically protected by the project’s permits and licences and will be monitored during the project.

What controls will be in place to ensure marine animals will not be impacted during construction?

The project’s environment protection and biodiversity conservation referral and its sea dumping permit specifically address whales and dolphins and require adherence to certain conditions to ensure impacts to protected species are minimised.

A project-specific aquatic ecology management plan and a marine ecology monitoring program have also been developed and will be in effect for the duration of the project.

The following project controls will be in place to manage dredging and spoil disposal activities around marine mammals and turtles:

  • All vessels associated with dredging and construction will travel at a speed of 6 knots or less within the port limits, on the way to, or at the disposal ground. Vessels will also minimise noise and avoid any sudden changes in direction. The slow movements will allow animals adequate time to avoid vessels.
  • Vessels must maintain a 300 m exclusion zone with all whales on the way to and from and within the disposal ground.
  • Where marine mammals and turtles are sighted within the 300 m exclusion zone, dumping activities will not commence until 20 minutes after the last sighting. Alternatively, the vessel may move to another area of the disposal site to maintain the minimum distance of 300 m.

In addition:

  • Marine animal observers will be on board all marine vessels.
  • All personnel will be educated on the requirements via site inductions and toolbox talks.
  • There will be regular information exchanges with local residents, commercial fishers and whale watch cruises on known marine animal activity.

The following project controls will be in place during construction of the wharf:

  • Marine animal observers will visually monitor for whales for a minimum of 30 minutes before the commencement of piling.
  • If no whales have been spotted within the observation zone (which is between 1.5 m and 2.2 m) after 30 minutes, piling will commence with a gradual increase in piling impact of no more than 50% of full impact energy for 10 minutes. If no whales have been sighted, full impact piling will then commence.
  • If visibility is poor and marine animal observers are unable to clearly identify objects to the full observation zone distance, a vessel or aircraft search must be conducted until visibility has improved.
  • If any whales are spotted, piling will cease for a minimum of one hour after the last sighting.

Will there be monitoring of marine mammals and turtles?

The construction contractors are required to produce weekly and monthly environmental reports. Part of this reporting involves keeping sighting logs of whales, dolphins and marine turtles.

What legislation covers protecting marine animals?

Relevant legislation covering the protection of marine animals are:

  • Protection of the Environment Operations Act 1997
  • Environment Protection and Biodiversity Conservation Act 1999
  • NSW Fisheries Management Act 1994
  • Threatened Species Conservation Act 1995.