Very interesting video, and lots of great photos and diagrams. Thanks for sharing!! The most interesting of all are the great closeups of the White Canyon area before the dam and today. It really mirrors a separate recent thread on this site about what happened to Fort Moqui, because this video illustrates that discussion perfectly. It's hard to imagine 150 feet of silt and mud built up anywhere, but there it is in photos, and yes, that blob of silt deposition (the "delta") is slowly moving downstream, and will continue to do so. Pretty amazing to see the power of a river, and such a huge evolution over a short period of time.
Now there is the separate question of what to do (if anything) moving forward. You have to start with the fact is that Glen Canyon Dam is there, and has been for decades. Changing the status quo is always an iffy proposition with lots of unintended consequences, something as true today as it was in 1963. There were great reasons for the dam, and although those reasons are still there, many other factors are now in play that were never seriously considered, or even imagined, in part related to the pace of the filling of the canyon from the head, and in part related to changing environmental values, at least among a good portion of the populous. When the dam was built, USBR estimated it would take 700 years to fill Lake Powell with sediment, and that may turn out to be accurate. Of course, none of us will be alive then, so that means it's far beyond the threshold of political or generational thought, which is why it's unlikely that the dam will be going anywhere anytime soon if ever. But in the great span of time, Glen Canyon will eventually become a massive mudflat at more or less 3700 feet with a meandering river across the top that carves through a wide swath of mud, alternating meanders with small waterfalls where the strata is tougher, behind which will be perched pools. Imagine the entire lake looking something like the kind of scene you see today from White Canyon to Hite, with North Wash perched like a mini-lake behind a silt dam, and walls of silt and mud lining the shores. That will be Glen Canyon in a thousand years and beyond, with the dam itself forming a huge manmade (and spectacular) waterfall.
This is not a judgment on my part, just a hydrologic fact, and that will be the long-term outcome of Glen Canyon. Maybe in a thousand years there will no longer be any need for water storage or power from the dam, but the point will be moot anyway, because there will no longer be either whether or not we need it at that time. As sure as the sun rises, the reservoir storage capacity will continue to decline. It already has--as originally designed, Lake Powell could hold 27 maf, but today, because of sedimentation, we're down to a little over 24 maf, or about 10% of the original capacity taken up by silt in about 58 years. That's an amazing and humbling thought. It's also basically consistent with USBR's prediction of 700 years, because if you extrapolate that rate of capacity loss over time as a constant (might be a bad assumption), you end up will full siltation happening in about 600 years more or less.
And yet, the lake is here to enjoy and use and benefit from right now, and will be here in one form or another for generations. But the truth is that Lake Powell is just a fleeting moment in the long arc of time. As our human needs change, and other ways to find water and power emerge, or if population patterns shift, the immediate need for those aspects of Lake Powell might diminish or even go altogether. We're not there yet, but it's foreseeable. But it's the modern recreational aspect that will be lost for good if the lake goes away. Good or bad? A debatable topic. Bad for most of us on this forum who like to fish or swim or boat. But I can make a solid argument in the other direction too. Maybe that discussion is far down the river, so to speak, but it's out there in the future somewhere.
For me personally, the existence of Lake Powell has always been the most fascinating meeting of human engineering and the natural world. It's rare to be able to measure the benefits and consequences of that kind of meeting in real time, but here we have it. I'm conflicted. Like all (most?) of you, I love going to Lake Powell. It's an endless source of interest and fascination for me. It's a place I know very well, as do most on this forum. And we've all seen it change a lot over time, for better or worse it's hard to say. Now I'm not Katie Lee--I didn't live and breathe and smell and hear and see Glen Canyon before the dam, so I don't have the same visceral emotional connection to a place that disappeared that she did. I can't feel the same sadness as she did. But I sure do understand it...
Thanks again for sharing that video--great food for thought!
One more thought, they are only comparing the last 60 years, I wonder what it looked like 120, 180, and 240 years ago? This land scape is always changing In the Grand Canyon.
