This was investigated in 2004 and 2005
The enormous Glen Canyon Dam was completed in 1964 in northern Arizona. At the time, it was very unpopular for having flooded many thousands of beautiful natural canyons and structures for roughly two hundred miles upstream along the Colorado River in creating the enormous Lake Powell Reservoir for this dam.
The Glen Canyon Dam was built during a world-wide flurry to harness hydroelectric power in the 1960s and 1970s, when a large number of very large dams were constructed.
A terrible oversight was made regarding the design and construction of the Glen Canyon Dam. It seems astounding that no one seemed to have ever considered the Physics and Engineering of safe construction practice.
This subject was first investigated in 2004 and 2005. This presentation was first placed on the Internet in January 2012.
It turns out that much of the Southwest has topography which is rather soft and very porous sandstones. Nearly all is sedimentary rock.
There seems to have been an ASSUMPTION made that pouring millions of tons of concrete into a 700-foot-tall block would simply be so heavy that it would be permanent. That is NOT the case. In fact, many school children could do the calculation regarding the dead weight of hundreds of millions of tons of Reservoir water pressing against one side of the Dam. Yes, the curved shape of the Dam was correct in enabling the structure of the Dam to withstand that constant pressure and force.
However, no one seemed to have ever considered how to ATTACH the structure of the dam to the surrounding natural layers of sandstone!
In May 2005, I had a nice conversation with the Chief Engineer at the Dam. I had specifically brought up to him that the naturally porous Navajo sandstone must certainly allow some amount of seepage of water through the sandstone rock, AROUND the dam, through the natural sedimentary layers surrounding the Dam. I had actually expected the original Design of the Dam to have somehow limited that flow, so I had expected him to only refer to a mere trickle of water seeping through the rocks.
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I immediately responded with my concern that such rapid erosion would certainly cause such flows to grow faster and faster, eroding more and more of the nearby soft sandstones. I expressed the concern that at some point, so much of the nearby attachment rock would be eroded away that the Dam would no longer be attached to anything. I asked if there was a danger of the entire Dam coming loose and catastrophically falling over. (my comments of May 2005 are paraphrased here as I do not remember my exact wording.)
He stood silently. No response was necessary. We both had a good understanding of the situation.
I asked if he had gone out into the field to try to monitor such leaking and flows, and he said that he had done so a number of times. I was not able to be in the area for long enough to go on such a hike with him, but I certainly wish I had had the time available.
We both knew that any water (in the reservoir) which is at a depth of 700 feet has an internal water pressure of around 350 PSI (by standard scientific formulas). Even strong iron water pipes can sometimes burst if exposed to such high water pressure. So there can be no doubt that the cracks in the sedimentary rocks near Glen Canyon Dam are exposed to extremely high water pressure which tries to seep through even tiny cracks in order to get past the Dam. Winter freezing-thawing causes such water paths to become wider, and after a constant exposure for forty years of such extreme pressure, it is not surprising that he described those things to me.
It seemed clear to me that he really had no one else to talk to about such a subject. It is likely that very few Employees of the Dam would have understood about such a subject, and Page Arizona is a very remote and small community. That city only came into existence for the construction of that Dam, and clearly no one there would want to hear anyone say anything bad about the center of their Universe.
He and I spent the next several minutes exploring various ideas regarding the possibility of somehow sealing the existing leaks. We agreed that trying to inject concrete would likely have minimal success due to the constant 350 PSI water pressure (which would likely simply immediately wash away any concrete particles). We agreed that trying to line the entire nearby area of the Reservoir would involve many square miles of area which was all very deep underwater. Again, any sort of membrane seems likely to immediately get sucked in and through the flow passageways. He had clearly thought about such subjects for a long time, but between us, we had no ideas which seemed credible.
Near the end of our conversation, I suggested to him to try to get a system installed that is commonly used near Earthquake zones to try to determine earth motions (Geodimeters). I suggested a laser-based monitor to constantly precisely locate the exact position of several points near the top of the Dam (as measured from observation sensors on the opposite (west) side of the canyon). Geodimeters can constantly monitor distances and locations within a fraction of a millimeter, which is important regarding earthquake fault zones for monitoring earth movements toward future earthquakes. I wanted to use such technology of Geodimeters to constantly monitor a system to always know how far the top of the Glen Canyon Dam might have moved. Since we basically were conceding that there seemed no Technological way where the attachment of the Dam can be ensured, and that it WILL come loose and fall over, I felt that the people and cities downstream deserved as much warning as possible.
Geodimeters can detect even a fraction of a millimeter of movement in either side of an earthquake fault, and Researchers constantly monitor such motions at many locations along many Faults in California. I just proposed using this well-established technology to constantly monitor the exact position of different locations along the top of the Glen Canyon Dam. I wanted to install such Geodimeters on the west side of the local canyon walls which face the front side of the Glen Canyon Dam, and to affix Retroreflectors near the top of that front surface of the Dam. That technology uses Interference of the optical waves to detect even a half-wavelength change of the length of the light path, so it is amazingly sensitive to monitoring locations. If such Geodimeters had been installed in 2005 when I had brought up the idea to him, we would already have eight years of graphs of motion by now (2013). If any location at the top of the Dam had moved even one millimeter westward so far, we would know. Or if the entire top of the Dam had moved westward. This might give data regarding whether one side or both of the Dam's attachment to the sandstone bedrock had changed over time. My fear is that we might by 2013 be seeing even 100 millimeters (four inches) of westward movement of the entire top of the Dam. That would be terrifying confirmation that the stability of the Dam was in question. Even though the Dam was installed with an awareness of the weakness of Navajo Sandstone, where they created unusually large abutments between the Dam and the bedrock, it might be that the Dam is now taking even a good deal of bedrock with it in its slow westward movement. Not just the bare Dam might be tilting toward catastrophe, but it might be taking thousands or even millions of tons of that Sandstone with it.
IF, however, less than one millimeter of movement had occurred in these eight years, as is certainly true for most of the major Dams around the world, there would be little to worry about and I would shut up. But since no Geodimeters were installed at Glen Canyon Dam, it does not appear that we have any data regarding WHETHER the Glen Canyon Dam has moved or tilted at all. That seems immensely foolish! To deny people downstream any possible knowledge of any concerns about the potential for them all to be drowned.
The seepage of large amounts of water THROUGH the Navajo Sandstone over the past fifty years is a natural action, which is unavoidable. The very high pressure of the water leaking out of the Lake Powell Reservoir makes this occur even faster. The fact that such Sandstone erodes by such action makes it also unavoidable that such water seepage pathways constantly erode out to allow even faster and more water to pass through. That accelerates the erosion rate even more. It is unavoidable that these natural actions have been occurring for the entire fifty year existence of the Glen Canyon Dam. The only unanswered questions are HOW FAST the erosion has been and is occurring and HOW TILTED the Dam has become during these fifty years. The fact that the seepage pathways keep getting larger means that the erosion constantly becomes faster, and with winter freezing-thawing of water within those erosion pathways, I suspect that the evidence might already be terrifying.
Once the Glen Canyon Dam releases all the water in the 185 mile long Lake Powell Reservoir, all that water will immediately roar down the Colorado River. Rough estimates suggest that a trillion tons of water will suddenly be released to roar downstream. Phantom Ranch at the bottom of the Grand Canyon and about sixty miles downstream, would and will clearly get a tsunami-type flood of possibly more than 200 feet deep, once the Glen Canyon Dam comes loose and falls over and essentially no longer exists. Even the Hoover Dam which is hundreds of miles further downstream would and will certainly be over-topped by possibly a 50-foot-high tsunami-type wave. The number of people who would immediately be washed away and die, along much of the Colorado River, might be extreme.
And so I felt there should be a constant monitoring of the POSITION of the top of the Glen Canyon Dam. Conceding that it WILL collapse is one thing. Trying to give everyone in the water path the greatest possible period for escape is entirely another. In the weeks and days just before the Glen Canyon Dam comes loose and falls over, the rate of movement monitored by such Geodimeters will begin to rapidly increase. Everyone will then have at least some days or weeks to try to abandon dangerous areas to survive. Even people in boats on Lake Powell deserve to know the coming danger.
The Engineer I talked to in May 2005 said that he would CONSIDER bringing up such an idea to the Board which manages that Dam. But he pointed out that there was an immense amount of politics everywhere. He worried that simply MENTIONING such an idea might trigger such a public uproar that the political consequences would be great. He doubted that they would ever even seriously consider installing such a monitor, because of political implications and consequences of the resulting publicity.
And it was clear to me that he realized that he would immediately be fired, just for MENTIONING such a politically undesirable subject.
I believe I then made some reference to an ostrich having its head in the sand! I remember that he smiled at that.
It is apparently considered more expedient to DENY that serious problems may or might exist, and only then have to try to describe ignorance AFTER some disaster had already occurred. Our conversation then moved to Hurricane Katrina and New Orleans. I mentioned to him that I happened to have been one of the many people who had made phone calls and written letters to Authorities in Louisiana to express earlier concerns regarding the safety of New Orleans, averaging seven feet BELOW sea level, was totally dependent on around 117 miles of levees and dams, many of which were (and still are) simply earthen dams. But BEFORE Katrina, absolutely no one was interested! Virtually no Mayor or Governor or Police Chief or University Researcher would ever even respond to any of my communications on such concerns.
I believe he then added: A lot like the situation now here at Glen Canyon Dam.
I then asked him if he had noticed any slowing of the seepage water flows, but he said that he had not noticed any reduction, but that he tended no longer to go out to look at those flows, because it was too depressing to see. I can understand that! If there is a situation where nothing useful can be done, and that you don't even dare mention any problem, it must be immensely frustrating.
But he said that the US Congress demands for electricity production clearly requires that he release MORE water now (in May 2005) because the shallower depth of the Reservoir contained less Potential Energy per cubic meter of water, made him hope that the Reservoir might continue to drain lower and lower as a result. He then smiled again as he said that by the time Washington politicians realized the consequences of their absolute demands for electricity, they may have essentially emptied out the Lake Powell Reservoir, and thereby made the Glen Canyon Dam a lot safer!
We both laughed as we knew that was NOT going to happen!
SOOO! Since at least May 2005, many flows of water have been growing through the sandstones near the Glen Canyon Dam, flowing fast because of the 350 PSI water pressure of the Reservoir driving them, but also growing larger and faster as the water pathways erode out to become larger and straighter flows. It IS unavoidable!
COULD anything be done? Probably not. But maybe! Imagine if a Reporter or an Internet Blogger took a movie camera on a hike around the nearby cliffs near the Glen Canyon Dam, to record the many leaks which exist. If such a video was put on You-Tube or in a Newspaper or TV News Investigation, maybe someone might eventually actually CARE. But it still seems that nothing can actually be done to save that Dam from a catastrophic failure. It is all extremely frustrating to know the Physics and Engineering of such situations, where no one seems willing to listen! Of course, until AFTER it happens!
THEN, hundreds of 'experts' will be on National TV News griping about why no one had ever realized this before. Maybe they might THEN print out this web page!
I held off uploading this web page for fear of getting that nice Engineer fired, where still no one would do anything to save all the lives when that Dam comes loose and catastrophically fails.
Construction continued from February 1972 through September 1975. The Reservoir began filling on Oct 3, 1975. The Teton Dam collapsed and catastrophically failed on June 5, 1976, after only eight months! The failure occurred because of water erosion, and eleven people died. History records rarely seem to mention that Dam or its catastrophic failure.
The Glen Canyon Dam is far taller and it holds back phenomenal amounts of water in the enormous Lake Powell Reservoir, and when it fails, the consequences will be far worse.
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C Johnson, Theoretical Physicist, Physics Degree from Univ of Chicago