2016 SoE Marine Chapter - Pressures - Dumped wastes

Brief description

The Marine chapter of the 2016 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "Pressures on the marine environment associated with dumped wastes". The full Expert Assessment, including figures and tables (where provided), is attached to this record. Where available, the Data Stream(s) used to generate this Expert Assessment are accessible through the "On-line Resources" section of this record.

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DESCRIPTION OF THE PRESSURE
Dredging associated with the development or maintenance of port facilities around the coast of Australia is a necessary and unavoidable activity, vital to the continuity of the Australian economy. Disposal of dredged material is mostly commonly by placement on the sea floor in specially designated areas. By volume this is by far the largest pressure on the marine environment due to “dumped waste” and over the period from 2011 to 2016 totalled in the region of 90 million cubic meters of sediment (Ports Australia 2014, 2015). The areas selected as disposal sites and the nature of disposed dredged material at sea are highly regulated to minimise the risk of marine organisms being exposed to toxic materials and that the sites chosen are the most likely to be minimally affected by the application of additional sediment (Ports Australia 2014). Pressures arising from this practice include direct burial of biota as well as less direct impacts arising from resuspension of sediments placed on the sea floor. While the footprint of disposal sites is relatively small on the scale of Australia’s continental shelf, the area affected by remobilised material is potentially larger and less well known (McCook et al 2015).

The amount of dredged material disposed of at sea in the 5 year period up to 2016 has increased markedly over that reported up to 2011 (Fig. 1). This is mainly due to two large port developments in north-western Australia’s Pilbara region (Gorgon and Wheatstone). Generally there appears to have been a strong upward trend in volumes in the Pilbara over the past decade and two new project approvals have been granted for a further 34 million cubic meters at Anketell Port and 42 million cubic meters at Port Hedland of dredging and disposal in the region. Given the decline in resource development experienced since 2014, this trend may abate in the short term.

DATA STREAM(S) USED IN EXPERT ASSESSMENT
Data used in assessment cover the entire continental coastal zone of Australia, and include all major ports. See "On-line resources" section of this record for links to specific data products.

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2016 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details]

• 2016 •
Assessment grade: Good
Assessment trend: Stable
Confidence grade: Adequate high quality evidence and high level of consensus
Confidence trend: Adequate high quality evidence and high level of consensus
Comparability: Grade and trends are somewhat comparable to the 2011 assessment
• 2011 •
Assessment grade: Very good
Assessment trend: Stable
Confidence grade: Limited evidence or limited consensus
Confidence trend: Limited evidence or limited consensus

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CHANGES SINCE 2011 SOE ASSESSMENT
At sea dumping was not included in the 2011 SOE assessment as a separate section, where it is barely mentioned.

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Statement: QUALITY OF DATA USED IN THE ASSESSMENT
The data comes from industry sources through reports which explicitly state that they are not fully comprehensive but are likely to cover the vast majority of activity. That being said, data for at least one project was not included (Wheatstone) which would have made a major difference to overall trends, while another (Gorgon) was only included in part, with only 8 of an estimated 40M m3 being reported.

Notes

Purpose
To describe the pressures on the marine environment associated with dumped wastes for use in the Marine chapter of the 2016 State of the Environment report.