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THE STEEPEST RIVER?

I’ve been playing with a theory lately, and I can’t seem to disprove it. I’m starting to think that it just might be true. My hypothesis is that the Kaweah is the steepest river in the United States.

Now, I’ll be the first to warn you that you should always be skeptical of claims that something topographical is the ultimate example of its category. Such claims are often exaggerations or tricks of definition.

A good example locally is the claim that Kings Canyon is the deepest canyon in North America. There are lots of problems with this assertion, including little things like the Grand Canyon of Arizona, Hells Canyon, and the huge Copper Canyon in Chihuahua, Mexico. For that matter, defining just how deep a canyon is can be tricky as well. Sometimes it’s not easy to figure out just what constitutes a canyon’s rim.

But what about my Kaweah River proposal? How does one define the “steepness” of a river? The definition I am trying out defines a river’s steepness in terms of how far it descends and how many miles it takes to make that descent. Allow me to give these definitions a try. You can judge the results.

Only a handful of river systems in the United States have descents approaching or even exceeding 10,000 feet. Most of these begin somewhere in the Rocky Mountains. Falling into this category are many of the major rivers of the American West including the Rio Grande, the Colorado, the Platte and Arkansas, and farther north, the headwaters of the Missouri and Columbia.

But, without exception, these rivers that begin in the middle of North America are long. The Colorado, for example, is officially defined as being about 1,450 miles in length and the Arkansas, even though it is headed to a different ocean, is about the same. The Missouri is even longer. It takes the river over 2,300 miles to makes its way from Bower’s Spring, Montana (altitude 9,030 feet) to its confluence with the Mississippi at St. Louis.

The Snake is a good example of the rivers that flow westward from the northern Rockies. Beginning on the 10,000-foot-high Two Ocean Plateau near Yellowstone National Park, the river flows not quite 1,100 miles to its merger with the Columbia.

No rivers in the Pacific Northwest or Alaska have such huge drops. The high mountains there, peaks like Rainier and Mt. Baker and the huge mountains in southern and Central Alaska, are glacier-covered down to relatively low altitudes. This means that the rivers that begin in these areas can’ start very high.

That leaves the Sierra Nevada of California. Here, a number of rivers do start at very high altitudes. You probably can name some of them. They include, in addition to the Kaweah, the Kern, Kings, San Joaquin, Merced, Tuolumne, and Stanislaus.

But here’s the key point: All these other Sierra Nevada rivers are two to three times as long as the Kaweah. The Tuolumne, for example, flows for 150 miles, and the Kings takes about 125 to make it from the crest of the Sierra Nevada to the Tulare Lake Basin. The Kaweah drops as far in only half that distance.

So, if you are now ready, here’s my claim: The biggest (by flow) and longest branch of the Kaweah is the Middle Fork. The two most significant sources of the Middle Fork are Lone Pine Creek (which starts at Lion Lake, elevation 11,005), and Cliff Creek, which starts at Columbine Lake (elevation 10,970). From these points of origin, it takes the Kaweah about 40 miles to flow to Terminus Dam (base altitude about 500 feet) or about 75 miles to reach the Tulare Lake Basin (altitude about 100 feet). This makes it twenty times steeper than the Colorado.

And that’s my argument. If you know of another river that drops 10,000 feet in less than a hundred miles, let me know. Until then, our Kaweah seems to hold the title.

© Wm. Tweed