Tag Archives: Dam

$20m (AUD) to fix Canberra’s Scrivener Dam

Up to $20 million will be spent repairing Canberra’s Scrivener Dam after a safety audit uncovered corrosion problems.

The annual safety audit of the dam three weeks ago found corroded bolts in the flap gates of the dam wall which are opened during flooding to regulate the level of Lake Burley Griffin.

It recommended 120 anchor bolts be replaced within one to two years.

“The engineering work involves replacing every bolt, on every hinge, on every gate,” said National Capital Authority (NCA) chief executive Gary Rake.

“Each of the five flap gates will, in turn, be removed and replaced by a temporary floating gate while the bolts are changed.”

Most of the bolts are encased in steel structure or concrete and are difficult to access.

The work will also include redesigning the anchor bolt system to reduce corrosion and improve accessibility.

It is expected to cost between $15 million and $20 million (AUD), and will take up to 18 months to complete.

Mr Rake says the lake level is also being lowered to the same level reached in February 2003 during drought conditions.

“Lake Burley Griffin was lowered 200 millimetres last Friday evening in anticipation of increased water inflows,” he said.

“We will lower the lake by another 300mm. Lowering the lake to this level will assist us in managing risks associated with both the day-to-day operation of the dam and the completion of these engineering works.

“We expect that the lake will remain at this lower level throughout the work.

“There may be occasions when the lake needs to be lowered even further. Lake users will be given advance notice of expected changes in the lake level whenever possible.”

Mr Rake says the dam remains safe and fully functional.

“Undertaking these works will not interfere with the regular operation of the dam. We have been advised by independent engineers that Scrivener Dam remains safe and fully functional,” he said.

“All risks associated with these works and the day-to-day operation of the dam are being appropriately managed.”

SOURCE: http://www.abc.net.au/news/2011-12-01/scrivener-dam-repair-bill/3706644 

Corrosion under the Lincoln Street Bridge is prompting the City of Wichita to begin building a new bridge

Lincoln Bridge Closing Disrupts Local Fishermen

“I know they’ve got to do their job but it’s going to affect a lot of the good fishing down through there,” said Kenneth Snell, with a fishing rod in one hand, ready to fish south of the Lincoln Street Bridge.

Fishermen along the Arkansas River were not looking forward to finding new spots to make a catch.

“This is the best spot. The heads are taking it down from us but we could wait. We don’t have no other choice,” said Snell.

The 40-year-old bridge is located above a dam that has been wearing down the support and steel. City engineers said patching up the problems would be too costly.

“Even though the existing bridge could be repaired, we’ve done an economical analysis and found that it was more economical to construct a new bridge and then move the current dam out from underneath,” said Jim Armour, city engineer for the City of Wichita.

The new dam will be moved about 200 feet downstream from its current location. Engineers said the new dam will help stabilize river levels upstream.

“Although this won’t completely eliminate any flooding upstream, it’ll reduce the occasions of that,” said Armour.

Starting Monday, engineers will lower river levels. This is something engineers said will be helpful in the long-run.

“The citizens will see a lot more stability in the river level upstream once the new dam is completed,” said Armour. “I think this bridge will have a service life of 50 to a hundred years.”

Although fishermen didn’t like the move, they said they’re looking forward to a new bridge.

“Whenever they do get through it, I know it’ll look nice,” said Snell.

The Lincoln Street Bridge will be closed to pedestrians and motorists starting Monday. Traffic will be detoured using Harry Street, McClean Boulevard, and both Main and Market Streets.

The project is expected to be complete by the fall of 2012.

SOURCE: http://www.kake.com/news/headlines/Lincoln_Bridge_Closing_Disrupts_Local_Fishermen_123719869.html