Dodging Mudbergs, Boating Through Terra Incognita - Tracking Sediment Changes On Lake Powell
On a scorching July afternoon, Mike DeHoff steered his small metal motorboat down what one could argue is the weirdest stretch of the Colorado River in all of its 1,450 miles: the delta of Lake Powell. DeHoff’s boat floated on roiling water supercharged with sediment, the same color as an iced latte. Craggy, gnarled mud formations rose up from the river channel. Rapids made of mud, which change their contours by the hour, tossed the boat from side to side. “I mean, look at this,” DeHoff said. “It's like boating through what you think Mordor would look like.”
Winds whipped up dirt and fine sand from giant, dried-out mud flats, spilling more sediment back into the river. Whole slabs of mud cleaved themselves clean off, like a calving glacier. One attempt to climb up the sediment-caked canyon walls by this reporter and his photographer nearly triggered a dirt avalanche big enough to bury a person. In the delta, the river’s water appeared so thick with sediment that it threatened to turn back into mud at any moment.
The launch point for this trip, an access area called North Wash, near Hite, Utah, is so steep and unstable that rafting outfitters have to use complex winch and pulley systems just to get boats out of the river. It can’t really be called a boat ramp with a straight face, DeHoff said. The chaos created by a receding reservoir caused the Colorado River to jump its channel, and begin carving away at the ramp. Lake Powell’s delta is the place where the flowing Colorado River meets the stillwater reservoir. And it moves, depending on the year. The river’s flow and the reservoir’s elevation dictate where they meet. It is a “no man’s land,” as DeHoff called it, between the whitewater rapids of Cataract Canyon and the motorboater’s paradise of Lake Powell.
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The next day, the boats rolled into Lake Powell and veered up into one of its many side canyons. Years ago, when the reservoir was full, a boat could continue up for miles into this narrow canyon. Now the low level forces boaters off at a narrow sand bar and requires a hike up to see any natural wonders that await. This canyon featured a forest of formerly underwater cottonwoods, flooded during the reservoir’s initial rise in the late 1960s and preserved in place at its bottom. They now stand darkened and dead among vibrantly green regrowing vegetation. A shallow flowing creek full of tadpoles winds its way through the canyon. Willows line its banks and play host to an insect symphony. “Oh, man, that smell,” said Eric Balken, as he led a group up the canyon, inhaling deeply. “The willows smell so alive.” Balken runs the Glen Canyon Institute, which advocates draining Lake Powell and moving what’s left of its waters downstream. DeHoff and Lefebvre’s Returning Rapids is a project underneath the Institute’s umbrella. Balken pointed out a high water mark from the reservoir stained on the redrock one hundred feet or more above our heads. “There are a lot of big changes coming to the Colorado River,” he said. “And this is one that's a good change. To see this canyon come back is really special.”
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https://www.kunc.org/environment/2022-08-04/a-mud-caked-terra-incognita-emerges-in-glen-canyon-as-lake-powell-declines-to-historic-low
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