THE Gladstone Ports Corporation ignored its approved plans and external advice when it failed to build a rock covering over the geotextile fabric which tore on a bund wall in Gladstone harbour, confidential government documents have revealed.
An independent engineer who examined the failure of the Fisherman's Landing bund wall for the Federal Government's review has revealed the failure to build a rock covering was the key problem that led to sediment leaking through and under the bund in 2011 and 2012.
The failures on the wall were one of the key problems on the controversial Western basin dredging project and associated works, which coincided with a fish disease outbreak in the harbour.
And while the review panel members, led by CSIRO scientist Dr Andrew Johnson, had other expertise, no specific engineering expertise was originally proposed in the review's terms of reference.
It was not until Engineers Australia publicly complained about the lack of such expertise on the panel that it sought coastal engineer Dr Peter Cummings' independent advice.
Dr Cummings' confidential report to the panel has revealed that in the final construction of the bund wall, the port ignored its own EIS designs and advice from consultants to complete the rock covering over the geotextile fabric to prevent it failing.
His report, obtained under Freedom of Information laws, shows that while the consultant's advice was "recognized good industry advice"; "the as-built wall does not appear to have followed (it)".
"The design as built did not meet industry best practice and/or recognized industry standards," his report reads.
While the port's inquiry submission said it received other advice from contractors that laying the geotextile on the surface would have the "same filtration effect" as laying it under the original rock covering proposed, Dr Cummings said such advice was a "departure from normal practice".
"The use of an unrestrained exposed geotextile filter on the internal wall of the bund is not accepted practice because the geotextile is susceptible to disruption by hydraulic pressure and wave action," his report states.
Dr Cummings said that while the approved plans and external advice originally stipulated the use of the rock covering; "something happened at the very end and I don't know what it is and the review panel didn't know what it was".
"If you like it was at the nuts and bolts level that something happened and the rock covering for the geotextile was not applied," Dr Cummings said.
The actual geotextile fabric used on the bund wall has also been questioned by engineers who worked on the project, who have argued the fabric used was not sufficient to prevent damage and leaks.
But Dr Cummings said he believed that irrespective of what specific geotextile was used in the project, the failure to cover and weigh down the fabric properly was the "key problem".
But despite the failures in building the bund wall, Dr Cummings said the remediation works taken almost 12 months after the bund wall was confirmed to be leaking was "industry best practice".
Dr Cummings also said that during his inquiries, the Department of Environment refused to allow him to meet with the port to examine the issues in more detail, rather than relying on the port's submission to the inquiry and regulatory documents.
"It would've been preferable if I could have spoken to them, I probably would've found out a bit more," he said.
"I was really examining documents provided to me by the department and I had one or two other documents I obtained myself.
"The people actually on the inquiry did interview them but because I wasn't an official panel member, they said no."
The Federal Environment Department did not respond to questions regarding Dr Cummings' original report or the failure to allow him to meet with the port directly during the review.
A spokeswoman for Gladstone Ports Corporation refused to answer questions.