Following our further inquiries in relation to the polystyrene debris that everyone has been endeavouring to clean up from pontoons that escaped during the February floods, we received the following information in italics from the Officer of the Minister for Transport and Main Roads and the Department of Transport and Main Roads (TMR).

We shall also post up a summary from the Polystyrene Roundtable hosted by Noosa Council where DES, MSQ and community representatives were in attendance, once we receive the minutes.

Noosa is one of a number of correspondents currently exploring this issue following the recent floods, which washed many pontoons composed at least partly of polystyrene (EPS) down the waterways of South East Queensland.

Approximately 130 pontoons containing polystyrene have been recovered by Maritime Safety Queensland (MSQ), with approximately 100 of these damaged to an extent they require disposal.  Most of these wrecked pontoons are private domestic pontoons.

The Department of Environment and Science (DES) has raised concerns with TMR at officer level and communication from Mr Jamie Merrick, Director-General (DES), may be forthcoming.

Regulatory framework for private pontoons

  • TMR does not regulate the manufacture, design, or installation of private and commercial pontoons. Development approvals for private pontoons are generally assessed by local government.

Use of EPS in pontoons

  • EPS is typically used as floatation material in pontoons due to attributes including:
    • very low density and good compressive strength
    • can easily be cut to shape
    • low water absorption to volume ratio – very important if the outer protective membrane ever leaks
    • readily available and low cost.
  • It may be difficult to find alternative fill-materials with the same attributes.
  • TMR-owned pontoons utilise EPS with robust outer protection and have flood restraints to prevent movement from site in significant events.
  • More robust outer membranes (such as concrete, steel and aluminium to provide greater impact/puncture resistance) may be a solution however, this risks greater consequential damage to structures from impacts and is likely to be cost prohibitive to the average domestic pontoon owner.

Potential actions by TMR

  • The Australian Standard for design of maritime structures (AS4997) is currently under review by Standards Australia and TMR is expected to have opportunity to provide comment when community consultation occurs later this year.
  • TMR (via Maritime Safety Queensland – MSQ) has initiated discussions with the Marina Industries Association and Boating Industry Association to investigate viable alternatives to EPS and to consider different pontoon design options.
  • MSQ has established an intergovernmental working group to collaborate, share experience, frameworks, policy, and process relating to floating pontoons and structures in Queensland Waterways to mitigate the vulnerability of these structures to future weather events.