Shipping channel and berth maintenance works
- Published: Friday, 08 April 2022 08:06
CentrePort is undertaking maintenance to ensure sufficient depths for shipping at some of its wharves, and improvements to shipping channel safety on behalf of the Harbour Master (a downloadable version of this story can be found here)
The Dutch Dredging company vessel Albatros, seen in Wellington Harbour last year, returns to clear build-ups of sand in front of the Aotea Quay, and the Thorndon Container, Seaview and Burnham wharves.
The Albatros will be working in areas immediately in front of the wharves, known as ‘berth pockets’. The Harbour Master reminds recreational vessels to maintain a minimum 100m distance from the Albatros during operations.
Shipping movements and propeller wash create mounds of sand which needs to be removed to maintain necessary depths for safe and efficient movement of vessels.
The wharves all play vital roles for CentrePort and importers/exporters. Aotea Quay facilitates the movement of bulk cargoes such as logs and vehicles. Thorndon Wharf, home to CentrePort’s two large ship-to-shore cranes allows the movement of shipping containers. Seaview is where fuel for the lower North Island is offloaded, while all Wellington Airport’s aviation fuel goes through Burnham Wharf.
In addition, the Albatros will be doing work on behalf of the Harbour Master/Greater Wellington Regional Council (GWRC). It will be removing sand mounds at Falcon Shoals - an area of water between Seatoun and Eastbourne.
The removal of material at this site will enable greater separation of the inwards and outwards shipping channels, enhancing safety. This is acting on recommendations in a joint review by GWRC and CentrePort of navigation safety of the Wellington Harbour entrance conducted last year.
All the material removed by the Albatros will be deposited at a site off Thorndon Container Wharf. The site has been used previously for deposits and is done safely and without disrupting the environment.
Greater Wellington Regional Council has granted resource consent for the project covering areas such as care for the environment, maintenance of health and safety, and engagement with Te Whanganui a Tara iwi.
With over 7,000 commercial shipping movements per annum (including inter-island ferries, container vessels, fuel tankers, bulk cargo vessels), Wellington is the busiest shipping harbour in New Zealand.
The work covering the berth pocket clearance and shipping lane work is schedule for two weeks, beginning April 11.
Why is the berth pocket maintenance necessary?
Sand caused by propeller wash and shipping movements build up in areas in front of wharves (known as berth pockets). A minimum depth is required to safely allow for vessels to berth, and to be loaded and unloaded.
Why is material being removed from the Falcon Shoals? Commercial shipping has designated inwards and outwards lanes. A review in 2021 conducted by maritime consultancy South Maritime Solutions on behalf of GWRC and CentrePort ( ‘Review of Navigation Safety Wellington Harbour Entrance’) recommended a greater separation of the outward western lane from the inward eastern lane. The removal of mounds of sand which currently have to be sailed around, will allow for that greater separation. The shipping lane adjustments will have no impact on areas used for recreational boating/ water activities.
How will the material be removed and where will it go?
The vessel Albatros operated by the company Dutch Dredging will do the work. A pipe is lowered to the targeted areas and the sand is sucked up onto the vessel. The vessel will make a series of trips to an area off Thorndon Container Wharf to deposit the material. This area was used for depositing material following the 2016 Kaikoura earthquake and last year’s channel maintenance work and meets environmental consenting requirements.
How long will the work take?
The work is scheduled to be completed within two weeks. The berth pocket maintenance at the four wharfs will take approximately a week and the Falcon Shoals work approximately four days. The Albatros hours of operation will be between 6am and 6pm.
Will it cause any disruption to commercial shipping/recreational use of the harbour?
There will be no disruption. CentrePort and the Harbour Master will keep harbour users informed of the work. The sound levels will be no greater than usual commercial shipping activity.
What about the environment?
The project has been granted resource consent by the Greater Wellington Regional Council. This includes managing operations to protect the marine environment.
The Albatros undertaking channel maintenance work in Wellington Habour 2021
Aotea Quay and Thorndon Container Wharf areas for berth pocket maintenance (approximate depiction only – not exact coordinates)
Seaview Wharf area for berth pocket maintenance (approximate depiction only – not exact coordinates)
Burnham Wharf area for berth pocket maintenance (approximate depiction only – not exact coordinates)
Falcon Shoals area (approximate depiction only – not exact coordinates)