RegGuheert
Well-known member
Officials are evacuating below the Oroville dam because the first use of the emergency spillway in the life of the dam (it is over 50 years old) has lead to excessive erosion and the possibility of imminent failure.
188,000 residents were evacuated overnight. Fortunately, the level of the lake has been reduced below the lip of the emergency spillway. Officials are hoping to drop the level of the lake by 50 feet in order to prepare for the weather coming later this week.RegGuheert said:Officials are evacuating below the Oroville dam because the first use of the emergency spillway in the life of the dam (it is over 50 years old) has lead to excessive erosion and the possibility of imminent failure.
It seems CA needs to hire civil engineers who can tell the difference between a catastrophically-damaged spillway and one which will work as designed.The Sacramento Bee said:“There wasn’t any evidence that anything more needed to be done,” said Dossey, “repairs were smooth and looked like they were good and secure.”
RegGuheert said:It appears that the civil engineers responsible for maintenance at the Oroville Dam were not able to properly identify the catastrophic condition of the main spillway when they inspected/repaired problems with it in 2013:It seems CA needs to hire civil engineers who can tell the difference between a catastrophically-damaged spillway and one which will work as designed.The Sacramento Bee said:“There wasn’t any evidence that anything more needed to be done,” said Dossey, “repairs were smooth and looked like they were good and secure.”
lorenfb said:RegGuheert said:It appears that the civil engineers responsible for maintenance at the Oroville Dam were not able to properly identify the catastrophic condition of the main spillway when they inspected/repaired problems with it in 2013:It seems CA needs to hire civil engineers who can tell the difference between a catastrophically-damaged spillway and one which will work as designed.The Sacramento Bee said:“There wasn’t any evidence that anything more needed to be done,” said Dossey, “repairs were smooth and looked like they were good and secure.”
And you'd have thought that this state, given the periodic droughts, would've provisioned for a rainy season
like this year, e.g. all that wasted water. Bring on the future CA droughts and water rationing! But again, can CA
really expect more from whom it elects.
downeykp said:People in CA have been trying to expand the reservoir system for years, but no one wanted to pay for it. There are many proposals including raising some dams like Shasta, but again money always seems to get in the way. .
Actually, not an extraordinarily wet winter, yet.downeykp said:... How does one plan for biblical floods? These rains are unprecedented...
The real tragedy is that billions (?) of dollars of economic losses could probably have been avoided by some fairly cheap engineering, planning, and maintenance.="downeykp"...People in CA have been trying to expand the reservoir system for years, but no one wanted to pay for it. There are many proposals including raising some dams like Shasta...
Interesting! When and where did this happen?Marktm said:Had an analogous failure in Texas in a major CORP OF ENGINEER'S lake. The overflow spillway was severely eroded and formed a new mini Grand Canyon for miles! This exposed really nice archaeological structures - the state is making money with tours in the canyon. Man is no match for catastrophic natural events.
edatoakrun said:Best news coverage is from the Sac Bee..
An emergency spillway design that failed within hours of its first use?
http://www.sacbee.com/latest-news/article132528514.htmlEngineers have known for decades that Oroville’s backup spillway was unreliable
...In 2003 through 2005, three environmental groups – Friends of the River, the South Yuba Citizens League and the Sierra Club – urged the federal government to require the lining of the auxiliary spillway as part of the dam’s licensing process.
“At present, the ungated spillway at Oroville Dam consists of a spillway lip only – and utilizes a hillside as the project spillway,” the groups wrote in 2003 to the Federal Energy Regulatory Commission. “Utilizing such a spillway has the potential to cause severe damage to the downstream hillside, project facilities and downstream environments located in the path of the flood release.”
Despite such concerns, FERC ultimately decided not to require lining of the spillway, as the San Jose Mercury News reported Sunday. A senior engineer told his manager that it would take a “rare event” to utilize the emergency spillway and that using it “would not affect reservoir control or endanger the dam.”
Late last week, engineers discovered a gaping hole in the concrete of Oroville’s main spillway, following heavy releases from the reservoir. To stem the damage, they reduced flows going down the spillway, allowing the reservoir level to rise and spill over the auxiliary spillway for the first time in the dam’s 48-year history.
The result was severe erosion at the base of the spillway, along with “severe damage to the downstream hillside” – just as the three environmental groups had predicted...
Oroville provides water to the State Water Contractors, which includes the powerful Metropolitan Water District of Southern California, as well as water districts in Silicon Valley and Kern County. Documents from 2006 show that lawyers for the State Water Contractors downplayed the risk of the unlined spillway, and argued that relicensing was the wrong forum to address such issues...
philip said:downeykp said:People in CA have been trying to expand the reservoir system for years, but no one wanted to pay for it. There are many proposals including raising some dams like Shasta, but again money always seems to get in the way. .
Nope, 2.7 billion was approved for water projects, and raising Shasta dam was one of the proposed projects.
Apparently raising this dam would cause too much of an impact to endangered Salmon and the U.S. Fish and Wildlife Service did not like the mitigation that was proposed.
downeykp said:lorenfb said:RegGuheert said:It appears that the civil engineers responsible for maintenance at the Oroville Dam were not able to properly identify the catastrophic condition of the main spillway when they inspected/repaired problems with it in 2013:It seems CA needs to hire civil engineers who can tell the difference between a catastrophically-damaged spillway and one which will work as designed.
And you'd have thought that this state, given the periodic droughts, would've provisioned for a rainy season
like this year, e.g. all that wasted water. Bring on the future CA droughts and water rationing! But again, can CA
really expect more from whom it elects.
Oh and your perfect. How does one plan for biblical floods? These rains are unprecedented. People in CA have been trying to expand the reservoir system for years, but no one wanted to pay for it. There are many proposals including raising some dams like Shasta, but again money always seems to get in the way.
The Governator did nothing to make this situation better and from your comment above he was on your team.
Aquifers are getting lower and lower in the area. It will be interesting as an outside observer to watch the decline when the aquifers run dry. Places like Phoenix cannot sustain to support as many people as live there in the long range.LTLFTcomposite said:I seem to recall a book called Cadillac Desert that described how the southwest came to support a much larger population than it ever should have had the lands been left in their natural state without all these water projects.
You had to read a book to figure that out?LTLFTcomposite said:I seem to recall a book called Cadillac Desert that described how the southwest came to support a much larger population than it ever should have had the lands been left in their natural state without all these water projects.
Just wait, CA has been undergoing a water crisis for years but the full impact of climate change is still ramping up. Phoenix, Las Vegas, and LA all sip on the Colorado River. Where does that river come from? If you ask residents of those states it comes from the magic water place. In fact, the Colorado River comes from the snowpack on the Rocky Mountains in Colorado. The snowpack is less and less every year, it's just a matter of time until the first snow-free summer happens at Rocky Mountain National Park's Trail Ridge Road. Let's see Las Vegas and Phoenix survive when the Colorado River goes dry for half the year (predicted to happen in as soon as 50 years).Durandal said:Aquifers are getting lower and lower in the area. It will be interesting as an outside observer to watch the decline when the aquifers run dry. Places like Phoenix cannot sustain to support as many people as live there in the long range.
LTLFTcomposite said:I seem to recall a book called Cadillac Desert that described how the southwest came to support a much larger population than it ever should have had the lands been left in their natural state without all these water projects.
VitaminJ said:You had to read a book to figure that out?
Just wait, CA has been undergoing a water crisis for years but the full impact of climate change is still ramping up. Phoenix, Las Vegas, and LA all sip on the Colorado River. Where does that river come from? If you ask residents of those states it comes from the magic water place. In fact, the Colorado River comes from the snowpack on the Rocky Mountains in Colorado. The snowpack is less and less every year, it's just a matter of time until the first snow-free summer happens at Rocky Mountain National Park's Trail Ridge Road. Let's see Las Vegas and Phoenix survive when the Colorado River goes dry for half the year (predicted to happen in as soon as 50 years).[/quote]VitaminJ said:Aquifers are getting lower and lower in the area. It will be interesting as an outside observer to watch the decline when the aquifers run dry. Places like Phoenix cannot sustain to support as many people as live there in the long range.
What do you mean 162% of normal? Are you talking about the snowpack? If so you probably mean it's 162% of median. In February it used to be 180-200% of median snowpack and 160% would be common in May and sometimes even through July.LTLFTcomposite said:No, but I thought others might consider it for their reading lists, particularly since it appears many in CA seem to think that an ever-expanding population is a top priority.
Maybe after the 162% of normal melts off. Seriously there is enough money in CA they'll get as much water as they want one way or the other.
In the West, much of our water infrastructure is old. Oroville Dam, north of Sacramento, was completed in 1968, nearly a half a century ago. Other major components of our water system are generations older, and maintenance has not been a priority. The damage to Oroville Dam, where the primary spillway developed a giant gash and the emergency spillway threatened to erode, illustrates the hazard of relying on aging infrastructure to protect us from extreme weather.
But age and upkeep are not the only problems. Our water system was designed and built in an old climate, one in which extremely warm years were less common and snowpack was more reliable. Here in the West, we use the same dams and reservoirs for both water storage and flood control, so during the wet season, reservoir managers continuously balance the dual pressures of storing as much water as possible for the dry summer and releasing sufficient water to create room for the next storm.
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