Wow. Greater than this "engineer" failure?
You are very well correct. Indications are is that the designers were hesitant to carve and then seal capture drain basin “grooves” in the foundation rock. In addition, the bedrock would have to have been sealed to resist/prevent water penetration into the bedrock until it reached the catch drain basin grooves.
Stagnation Pressure Failures of spillways weren’t well documented in the day. Only after 2 dams failed did this issue become a high consideration. However, Oroville was already completed. Then the issue became a discussion on if the anchoring system + crack/seam maintenance repairs would suffice. If not, the cost would be very painful to tear up and replace this (now proven) fatal design.
Engineering judgement in compromises or analysis has led to failures of great magnitude. In the case of a dam, with the destruction and damage it would incur to the State of California, businesses, agriculture, citizens, and even the federal government in bailing it out, the Engineering judgement MUST be such there are very high safety factors and redundancies.
What is worse, competent engineers knew the warning signs and should have raised the alarms years back. Instead, we are witnessing one of the greatest engineering failures in history. No excuses.
btw- good engineers are in all lines of work. I’ve known engineers that were just as good if not better in analysis of designs in cross engineering fields. In fact, a top Weyerhaeuser research PhD who was fearless. He had his degree in mechanical engineering, but was able to apply his skillset in many other fields. He also relied on talking to knowledgeable people to get their input. A fantastic person. Working with classified scientists & engineers, they too rely on sharing expertise. There needs to be more “grey beards” to pass on these characteristics to all so that the wealth of skill, drive, responsibility, and knowledge is given to those that are willing to grow and learn.
I will comment about the characteristics of various engineers who one might consider “good” due to their through application of disciplines. Often that analysis does not take into account their full performance ability.
I have worked with, supervised, employed, built from designs, used for forensic analysis, purchased peer reviews from, and otherwise utilized a large variety of engineers in almost 50 years of construction. Some of the best forensic engineers or peer review engineers, cannot be trusted to complete a design project.
What makes them strong on the task given can make them where they can’t meet a deadline, ever finish the documentation, understand the limitations of field construction, interface as part of a team or otherwise get a design done in a reasonable period of time.
Likewise, I have seen design engineers that design aspects of a project that would be great projects but the owner buys the initial design and then uses government inspectors and engineers and by cutting to original designer out of that administrative process misses the chance for field correction of misunderstandings or a faulty detail being corrected in ink rather than dollars.
Owners set the buying environment for the project. Concept, Budget, design, purchase, administration and deadlines are all set by the Owner. Owners allow a weak facet of that project flow to go off course.
Several new pertinent pics today.
https://pixel-ca-dwr.photoshelter.com/galleries/C0000OxvlgXg3yfg/G00003YCcmDTx48Y/Oroville-Spillway-Incident
Also,
Oroville Dam: Photos taken weeks before spillway broke show something wrong
PUBLISHED: March 11, 2017 at 5:14 am | UPDATED: March 11, 2017 at 5:19 am
Oroville – Something was wrong with the Oroville Dam spillway weeks before the Department of Water Resources noticed a hole in the concrete.
Two photos taken by photographers from this newspaper show discoloration and possible damage to the concrete of the spillway at the spot where a gaping hole opened Feb. 7. Those pictures were taken Jan. 13 and Jan. 27.
When asked for a response to the photos, California Natural Resources Agency deputy secretary for communication Nancy Vogel wrote in an email to this newspaper, “Oroville dam was frequently inspected by multiple state and federal agencies. Reports of those inspections did not reveal any major causes for concern. DWR will soon name a panel of independent experts to investigate the cause of the main spillway failure and ascertain if such a failure could occur again. We hope that what we learn about the cause of this incident and how to prevent it elsewhere will help dam owners around the world.”
She did not ask to view the photos.
So why didn’t the water agency see what the pictures show?
The answer may have to do with inspections of the dam and spillway.
Before Feb. 7, the last inspection on the entire spillway structure by DWR was Feb. 3, 2015. Despite claims the department performed inspections twice per year, the spillway had not been fully inspected with operations and maintenance workers on the concrete in just over two years, according to a DWR spokeswoman, before a worker noticed the concrete breaking up on his way to work this Feb. 7.
After the February 2015 inspection, there were inspections of the dam by the DWR in July 2015 and August 2016, but those didn’t involve workers walking on the spillway getting a close look.
“During annual inspections, the Oroville Dam, and its appurtenances, have been repeatedly found safe for continued use, which includes the emergency spillway,” Vogel wrote.
The reason for the lack of complete spillway inspections is, presumably, safety.
“DWR (operations and maintenance) could not inspect the flood control spillway by walking it immediately before and after the spillway was used in March 2016, because the lake elevation was too high — there was water behind the radial arm gates at the top of the flood control spillway,” Vogel wrote. “Typical DWR safety protocol does not allow people to walk in the spillway when water is against the radial gates on the lake side.”
Nearly a year ago, on March 24, 2016, the flood control gates at the top of the spillway opened for the first time in five years.
The spillway was not fully inspected by DWR before or after that event. It took nearly five months before the department checked the dam structure in August 2016, and only a visual check was performed on the concrete spillway.
The Federal Energy Regulatory Commission inspected the dam May 25-26, 2016, and found nothing wrong at that time. But because DWR’s July 2015 review was a joint inspection with FERC and the July 2015 DWR review did not fully inspect the spillway, it’s unclear whether the commission’s annual 2016 inspection fully reviewed the spillway.
A five-year review board also didn’t find anything wrong.
“The most recent 2014 Oroville Dam federal and state board of independent experts concluded that there was no reason to expect either spillway to fail under operation,” wrote Maggie Macias of the Department of Water Resources public affairs office.
Two years after that board met, water was released for the first time in five years. Three years after the board met, the spillway broke and the structure was ruined. It has been more than a month, and the cost is estimated to be $4.7 million per day, or about $150 million to date.
Early rough estimates by DWR acting Director Bill Croyle put the cost to either fix the existing spillway or build a new one are between $100 million and $200 million.
Wow. Greater than this "engineer" failure?
I can’t help but wonder about the sheer vastness of scale of this project dealing with such incredible masses of water and dynamic force.
At the time, was there anything comparable to this project meant to artificially contain such force and scale of dynamic-water force?
One wonders if part of the problem may have been possible miscalculation of the incredible, tremendous force of water at full load on this enormous spillway.