The river trip starts at the Glen Canyon Dam. Glen Canyon was first considered as a dam site in the 1920s, but Hoover Dam, downstream of the Grand Canyon in Black Canyon, was built instead. A few decades later, it was decided that additional reservoirs were necessary to support the growing population. Glen Canyon Dam--built between 1956 and 1966--holds back the Colorado River, flooding upper Glen Canyon to form Lake Powell, the second largest man-made reservoir in the country (after Lake Mead, formed by Hoover Dam).
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| The dam is 710 ft (221 m) tall. To reach our launch site, at the base of the dam, we were driven through a two mile tunnel that was built before the dam construction began. |
Glen Canyon Dam is highly controversial for many reasons. The construction of this and other dams along the Colorado River has altered the river dramatically. But while some effects, such as the Colorado rarely reaching the sea, seem highly problematic, there are also benefits, such as irrigation for crucial agricultural areas and the 4.5 billion kilowatt hours generated annually by the Glen Canyon Dam alone. And then there are the mixed effects, such as the ecology of the river and canyon.
For example, the Colorado was so named because of its red color, due to the sediments it carried. It was these sediments that made the Colorado River so effective at carving canyons through the landscape: the sediment-laden water acted like abrasive sandpaper. Combined with seasonal flooding, this prevented any stable beaches or vegetation from forming in the canyon. The creation of the dam has held back the silt, turning the water blue-green, and limited variation in flow rates. This has led to problems for some species, such as endemic fish species that were adapted to the pre-dam Colorado River, and advantages for others, such as all those that rely on the narrow beaches, grasses, and trees that now line the river. I suppose that's all to say, "It's complicated".
Now back to the trip, and of course the photos. Still within sight of the dam, we saw ospreys (Pandion haliaetus). The first was in its nest, head barely visible.
The second was flying. It soon landed on a pole, on the opposite bank from the nest, where it stayed for quite a while. I only noticed later, looking at the photos we took, that it was carrying a fish!
We saw several great blue herons (Ardea herodia) along the way, wading in the water, flying along the river, and perched above us, looking down.
All of this greenery is a good example of what would be tumbled away by an undammed river. You can also see some slight turbulence in the water here.
Take a look at the canyon walls below. See those two huge gouges that look a little bit like eyes? Those were caused by giant boulders carried along by the Colorado cutting into the surrounding rock.
Most of the trip was filled with gorgeous views like this one. I struggled to limit the number of photos I included here, but like the Grand Canyon, every angle and perspective was interesting and different.
Another great blue heron.
Although many stretches of the canyon walls are smoother, this section was rather columnar.
These arch-like features in the walls are very common. They are areas where the rock face has collapsed, leaving crumbled pieces at the bottom and this interestingly shaped depression in the wall above.
One of the highlights of the river trip was so-called Petroglyph Beach, where we had the chance to wade or swim in the river. The water downstream of Glen Canyon dam is extremely cold, because the water released through the dam comes from the bottom of Lake Powell. It is 47 degrees Fahrenheit (8.3° C) when released and warms only about one degree per 20 miles. But it feels good (briefly) on a hot day.
The other attraction of Petroglyph Beach is, unsurprisingly, the petroglyphs. Most are zoomorphic and have been etched into the dark rock varnish.
Rock varnish is the dark layer on the surface of the rock, composed mostly of silica, and formed by exposure to the arid environment.
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While the petroglyphs were etched by humans, the river has etched its own figures into the canyon walls. We enjoyed pointing out ones that looked like something recognizable, much like is often done with clouds. This one looked like some sort of mythical creature to me (maybe part hedgehog?).
Here are some more views of the canyon itself, as we floated slowly down river.
I am always so impressed with how plants can grow in the seemingly most inhospitable circumstances.
On the south side of the river is the Navajo Nation. Fun fact: although Arizona does not observe daylight saving time, both Utah and the Navajo Nation do, making automatic time settings on phones rather unreliable in this area. The Navajo Nation is roamed by mustangs, feral (not wild) horses that are descended from domesticated horses that were introduced to the Americas by the Spanish.
