Paradise Dam failing on multiple structural levels
PARADISE Dam isn't just failing on one structural level, but several.
Sources have told the NewsMail you could have heard a pin drop as the room of community leaders on the newly-formed Paradise Dam community reference group fell silent, as the magnitude of the dam's structural problems dawned on them during the group's first meeting last week.
The Paradise Dam spillway is to be lowered by five metres, with the dam's capacity to be reduced to, and maintained at 42 per cent until safety repairs are completed.
Despite the region being in drought, an estimated 105,000 megalitres must be released from the dam.
"Rumours have bounded around the Dam - they have for years - that there's either a problem with the dam wall itself, or there's a problem with the skirting at the front, or there's a problem with the rock that it sits on," one source said.
"What we found the other night is that it's basically all three."
The source said another issue was highlighted by Sunwater's tests on the dam.
A bonding agent used to join and marry the layers of roller compacted concrete that make up the bulk of the dam wall, had failed.
"From their core samples, it would lead them to indicate that the bonding agent has failed from construction," the source said.
A second source confirmed this was consistent with their understanding.
An October community update release from Sunwater said "under normal and current forecast weather conditions, Paradise Dam is safe".
However, it went on to state that in the unlikely event of the community experiencing another one-in-200-year event like 2013, "the dam spillway (wall) may not perform to dam industry standards".
The source said this effectively meant it could fail if a major weather event happened before the spill level was lowered.
The source said it had taken so long for information to become available following the 2011 and 2013 floods because the engineers liked to be thorough, and didn't want to ring alarm bells that didn't need to be rung.
"In 2011 they found some issues and were in a process of validating, checking, rechecking and resampling and all that sort of stuff when 2013 hit.
"What that does is invalidates all the information you got from 2011 and you have to redo it all again because things change.
"You've now got a second event; your numbers are now different."
The source said the reason the dam hadn't seen a major failure before now was because there were other things holding it all together, like the reinforced concrete holding it up.
Sunwater was unable to answer specific questions sent by the NewsMail yesterday as to the exact nature of the structural failures, passing the query on to Minister for Natural Resources Anthony Lynham.
"As I have said previously, the dam is safe today and tomorrow, but Sunwater's advice is that action needed to be taken immediately to ensure community safety," Mr Lynham said.
"The recent highly-technical report is currently being reviewed by one of the world's few experts in this area.
"As the Premier said on Monday in the Wide Bay, these reports will be released when they are completed.
"This will give the people of Bundaberg and wider Burnett community full information, first-hand."
Mr Lynham said he expected the community would get this information by the end of the year.
Meanwhile, Bundaberg Chamber of Commerce president Tim Sayre has raised concerns about the region's water security in the future.
"While the Chamber understands the priority is life then livelihood, we are concerned about water availability for any future investments," he said.