NSW FIVE METRES AHEAD AS NOISE EXPERTS GO HAMMER AND TONGS

By Andrew Herington

Day 7 was turned over to an active debate on noise levels with stark differences being highlighted.  Not only are the standards that apply in NSW tougher than those in Victoria but there will be different standards applied at each end of the tunnel.

The “assessment criteria” used in NSW are generally 5 dBa lower than the equivalent standards for Victoria. There are different specific levels set for day and night and higher levels are permitted adjacent to existing freeways rather than new ones. These are design objectives and not mandatory limits as in Victoria.

The LMA expert Peter Fearnside testified that “as a rule of thumb” there is a 1 dBa reduction in noise levels for each 1 metre increase in height of the noise barrier. Thus where 2.5 metre noise barriers are proposed in the CIS they would need to be 7.5 metres high to meet the NSW assessment criteria.

Along Alexandra Pde, where noise barriers of 4.5 metres are recommended along the north side – the height would have to be raised to 9.5 metres to reach the NSW standard, which would be impractical.

The proximity of the Debney Park flats (35 metres) to the proposed Part B viaduct came under close scrutiny with debate about where the noise should be measured –inside, outside or at ground level (which is where the LMA prefer to do it).

In the afternoon, discussion turned to vibration with more rules of thumb about the level which would cause ripples in a glass of water and the level at which one would be “rocked to sleep”. The need for strengthened requirements covering blasting which may be needed under Carlton was discussed and the option of voluntary relocation in the period that the activity was going underway.

Again it was said that vibration would be “immeasurable” at the boundary of the zoo (at least to a human). Further work was called for but the who or how this would be done was not made clear. Animals affected by vibration find it hard to settle. Elephants and rare cats were mentioned as two potentially vibration sensitive species The LMA expert suggested that Mr Ed would be useful to get direct feedback on animal impacts

Regenerated noise from the tunneling would be audible at the surface over 35dBa and at lower levels in quiet rooms.

Next witness , Peter Nadebaum addressed the issue of contaminated soils listing an alarming range of issues that had been identified or could be encountered during  tunneling – carcinogenic compounds beneath the gasworks, leachate from the cemetery, asbestos from wartime housing in Royal Park, naturally occurring arsenic, acid sulphate soils and all many of things in the old West Melbourne tip.

His was possibly the LMA’s most forthcoming witness, acknowleded the issues, responded to the various issues raised by other submissions and suggested ways to tighten the requirements for the project, the need for more research and suggested a full Contamination Management Plan was needed before work could proceed.

If only the rest of the LMA expert witnesses had been so forthcoming.  The Assessment Committee has now heard too frequently the words that Clayton Utz had helpfully provided to all LMA witnesses in their “expert witness template”. (Document 48)

“There is nothing in those submissions that has caused me to depart from the findings and opinions expressed in my Technical report. The issues raised have been fully addressed in the technical report.

However his testimony all fell apart under cross examination where he admitted he hadn’t visited the sites, was mistaken which end of the tunnel the spoil was coming from and had to take more than half a dozen questions on notice. He admitted he was relying on advice given his by the GHD team that prepared the CIS.

In order to get through the LMA’s witnesses the Committee sat until 6 pm for the second day in a row. Groundwater expert had some pretty maps and explained the paleo-channels (old rivers) running beneath Carlton that would potentially dam up against the tunnel structure.

Tomorrow will see two milestones -the end of the LMA evidence and the number of tabled documents will pass 100