Dam wall damage unavoidable, says excavator
THE crisis unfolding at the Bolzan Quarry dam is repeated time and again, on a smaller scale, after prolonged drought weakened the structure of private dams across the Southern Downs.
Warwick excavator Steve Windle said it's a common issue facing his customers.
"There's quite a few dams around here now that have lost the middle of their dam walls," Mr Windle said.
"It's been so dry that the dam walls aren't compacted anymore, which means it's easier for them to move around.
"It takes a little while for the earth to soak up the seal again, which is your main issue when water comes down in such a hurry."
Mr Windle spoke to the Daily News as he prepared for a job on Yangan Rd this afternoon, where he would have to "dig out the middle and recompact it again."
"The worst thing is, with the weather the way it has been, there's really nothing you can do about it," he said.
Certain precautions could be taken, however, to avoid total collapse.
"Sometimes they don't make the dam wall wide enough to account for a lot of water coming into it in a hurry," he said.
"I like to make mine so wide you can drive a car around the top of it, so if there's any water running over it won't weaken and wash away. That's a common issue at the moment.
"You've also got to make sure you've got your levels right for your bywash, so the water can get around the corner without having to go over the wall."
The dam wall at Talgai doesn't appear as though it will fail completely in Mr Windle's opinion.
"There's enough water coming out of the middle there to take the pressure off it," he said.
"I think the authorities are just being cautious."