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Disposal of dredged material

Ports of Auckland was granted a marine dumping consent EEZ400011 on 27 June 2019 for a period of 35 years. The consent will expire on 27 June 2054.

​​ ​​​​​​​​​​​​​​​​​​​​​The permit, granted by the Environmental Protection Authority (EPA) pursuant to sections 62(1)(a) of the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012 (EEZ Act), authorises the disposal of capital and maintenance dredged material at the Cuvier Disposal Site (CDS) 27 nautical miles east of Cuvier Island.

The CDS is one of five disposal sites around New Zealand designated for the disposal of, amongst other things, dredged material. The CDS is beyond the Hauraki Gulf but within New Zealand's Exclusive Economic Zone. The location of the disposal site in relation to Auckland and the Coromandel can be seen on this map.

The marine dumping consent authorises the disposal of a maximum of two million cubic metres of dredged material from capital dredging and 1.75 million cubic metres of maintenance dredging at the CDS over the term of this consent. The permit restricts disposal activities to no more than 50,000 cubic metres of dredged material from maintenance dredging, nor more than 400,000 cubic metres of dredged material from capital dredging, in any consecutive 12-month period.

POAL's application and supporting impact assessment can be found here.

EPA's decision report can be found here.​

Why does Ports of Auckland need to dredge?

The increasing demand for imported goods in Auckland is leading to the need for larger container ships. Larger ships mean imports can be brought to Auckland more cost effectively and with fewer carbon emissions per tonne of imports.

To ensure Aucklanders​ can get the imports they want and need, Ports of Auckland needs to deepen the shipping channel, some berths and berth approaches so larger ships can get to port safely. We have applied to Auckland Council for consent to do this.

Ports of Auckland currently has two permits, issued by Auckland Council, authorising the removal of any natural sediment build-up from the seabed in order to maintain the notified depths at within the port, the port approaches and in th​e Waitematā Navigation Channel.  Under these consents, Ports of Auckland carries out a programme of regular maintenance dredging and removes around 50,000m3 of built up material annually.

Ports of Auckland dredging is undertaken using a barge mounted excavator filling a bottom opening barge, either self-propelled or towed, as shown above.  When full, the barge will be towed to the CDS and the dredged material dumped via the bottom opening of the barge.

Requirements of the Marine Dumping Consent

The new marine dumping consent requires that POAL comply with a number of consent conditions.

1. The method of dredging and disposal - The consent authorises the disposal of material dredged by barge mounted mechanical excavators and disp​​osed of using only a bottom-opening barge at the disposal site.

2. The location for disposal – the dumping of approved dredge material is authorised within a circle of 200 metres radius centred on position 36°28′S 176°17′E.

3. Volume of material to be disposed – POAL is authorised to dispose of a maximum of two million cubic metres of dredged material from capital dredging at the CDS over the term of this consent. The permit also restricts disposal activities to no more than 50,000 ​​cubic metres (m3) of dredged material from maintenance dredging, nor more than 4​00,000 m3 of dredged material from capital dredging, at the CDS in any consecutive 12 month period.

4. The quality of the material to be disposed of at the site - The permit requires a comprehensive process of sediment sampling, testing, assessment and approval to confirm that all material is clean and safe to be disposed of at the site.  This assessment process includes contaminant concentrations and biosecurity risks. This process is outlined in the diagram here​.  It requires POAL to prepare and submit a sampling plan for each area to undergo capital dredging or every 3 to 5 years for areas undergoing maintenance dredging.  These sampling plans must be approved before any sampling can be undertaken and the results compiled and approved by EPA before any disposal at the CDS can take place.  The dumping consent also sets out the procedure that must be used to characterise the quality of sediment of a source site and the contaminant levels that are considered suitable for marine disposal.

The first of these sampling plans, covering stage 1 of the capital dredging proposed for the Waitematā Navigation Channel, the Fergusson North Berth and approaches was submitted to EPA for review and approval in August 2019.  POAL is currently working through a number of information requests from EPA.  It is hoped the sampling plan will be approved in November 2019 and the sampling undertaken in January / February 2020.

Ports of Auckland will ensure that all submitted and approved sampling plans will be publically available through this website, along with all summary reports that analyse the results of each approved sampling plan and EPA's approvals and notifications.

5. Reporting – The consent requires POAL to submit a range of weekly, monthly and annual reports to EPA when dumping is occurring.  These reports include confirmation of:

    • ​Source site (dredging)
    • Dumping operations (quantities, locations, timings)
    • Marine mammal sightings

Each reports will be published on this website as it is submitted to the EPA.

6. Pre Dumping Seabed Survey – Ports of Auckland is required to undertake a video survey of the seabed to the north of the disposal site to identify if any rare or vulnerable ecosystems, or habitats of threatened species, are present. Should any rare or vulnerable ecosystems, or habitats of threatened species, be identified in the first survey, it must be repeated, as near as possible along the same transects, three years from the commencement of this marine dumping consent, at the completion of the capital dredging, and then at least every ten years thereafter for the duration of this consent.  The results of all these surveys will be available through this website.​

​When will Ports of Auckland start dumping at the Cuvier Disposal Site?

Ports of Auckland are not planning to exercise this consent and dispose of dredged material at the Cuvier Disposal Site until at least 2021.

Ports of Auckland recently lodged an application for consent to undertake capital dredging of the Waitematā Navigation Channel and the Fergusson North Berth and its approaches with Auckland Council.  This consent is expected to be granted in 2020 and capital dredging will commence in 2021.​​​​