Storm King Dam bill at $2m
IN A one-in-2000-year flood event, Stanthorpe's Storm King Dam could “overturn” and the cost of stabilising it now will cost the community almost $2 million.
However, this year's flood was a one-in-75-year event and engineering director Peter See has questioned the state Department of Resource Management's (DERM's) insistence of council stabilising it before October this year.
At this week's engineering services committee meeting, council reluctantly moved a motion to advertise for expressions of interest for the $1,987,000 upgrade work on the dam.
“I'm probably stating the obvious but apart from saying rude words, we don't have a lot of options, do we?” Cr Peter Blundell said.
“We've all got something stuck in our throat,” Cr Ross Bartley agreed.
“But that's how it is.”
Mr See later explained that the reluctance to carry out the work was because it had a “sense of ridiculousness” as there was very little chance of such a mega-event destabilising the dam.
He said DERM had moved the goalposts recently in terms of dam safety standards.
Though the department has agreed to finance 40% of the repair work, council has asked for an extension on the deadline and has received no response.
Mr See said there was no way council could do the work before October and it was more likely to be done at the beginning of April next year, in the dry season.
To fix the dam, contractors will need to drill through the dam wall into the rock underneath then use anchors.
Steel cable will be sunk into the rock and it will be grouted with cement and the tension will hold the dam solid on to the rock.
Connolly Dam also has been earmarked for improvement works, but engineers have not looked at what needs to be done there.
Mr See said the issues were slightly different as Connolly Dam was rock facing, while Storm King was made of concrete.
“We're a little bit behind with it,” Mr See said.
“But, like Storm King, the issues will only arise in a mega-event.”
Mr See said recent flooding had had little effect on Warwick's drinking water.
Yesterday, reports in other media said there were long-term concerns about the standard of water in Wivenhoe Dam since flooding led to increased silt levels.
“There is a bit of turbidity because of suspended dirt due to the floods but we have treatment processes set up to deal with that,” Mr See said, adding that most of Warwick's drinking water came from Leslie Dam and about only one-seventh from Connolly Dam.
There are major concerns in Stanthorpe's Quart Pot Creek with huge increases of silt in the water, particularly near houses, and local MP Lawrence Springborg has written to council to express his concerns.
It should not affect water quality but did pose a serious threat if there was another flood event.
Cr Ross Bartley said it was a “huge” issue.
“We seriously need to sort it out,” Cr Cameron Gow added.
However, clearing the creek was the responsibility of the local river trust and not council.
Mr See said this issue was not as much of a problem in the northern part of the region in the Condamine and tributaries as it was in Granite country, where traditionally there was more sand and gravel.
Council moved a resolution to liaise with the Stanthorpe River Trust to try to solve the Quart Pot Creek issue.
Leslie Dam operators SunWater this week said the dam had been inspected by experts since the January flood and was structurally sound.
- It would take a one-in-2000-year event to topple Storm King Dam
- January's flood was a one-in-75-year event