Water Doesn't Run Uphill

Selected from Chapter 2 of the book "Grand Canyon Today and all its yesterdays" William Sloane Associates, New York, 1958.

One does not need to be trained to ask geological questions to be struck by the fact that this is not the way rivers swift enough to cut deep channels are accustomed to run. Swift rivers run straight; sluggish ones meander. Looking at the course taken by the now swift San Juan, one is likely to be reminded of some slow-moving brook lazing its way across a nearly flat meadow and running so feebly that the slightest impediments turn it aside as it follows the path of least resistance here and there across the flat surface. If such a meadow brook cut deeply enough, it would make its own "gooseneck" canyon. But of course it doesn't and it couldn't. It is not swift enough to cut much, and if it were swift, it would flow over the almost invisible little obstructions which now turn it this way and that. In fact, it meanders so irresolutely that it may vary its channel from time to time, leveling the meadow still further. But it will never cut a deep channel.

Obviously the San Juan at the Goosenecks must have been sometime a meandering stream. As a matter of fact, the Goosenecks form what geologists call "an entrenched meander." But what, one wonders, can have happened to turn this feeble little current into a torrent large enough and swift enough to cut through hundreds of feet of solid rock and yet not make the straight channel to be expected of a swift river?

Probably, one will think first of the possibility that the earth, in one of her periodic convulsions, suddenly raised or tilted the flat surface across which the stream meandered, thus making it swifter and for some other reason more abundant. But that won't do. Tilt the meadow with its brook, and the stream will simply leap over the sinuosities of its low banks to take a shorter cut from high ground to low. Under those conditions it might cut a channel but it would not be the channel of its old meander.

There is, however, an obvious explanation of the anomaly. The land must have risen, but risen so slowly that the stream was never dumped out of its channel; so slowly, indeed, that it deepened this channel as fast or faster than the land rose and thus preserved the same course it had taken when it was too feeble to do more than obey the demands of every minor variation in level.

Yet the existence of the Goose-necks and the Canyon for which no credible explanation not involving millions of years is discoverable is just one of the many kinds of things which gradually forced upon the human mind the intellectual conviction that the mountains, plains, and rivers among which man passes his brief life are old beyond his power to grasp, and make demands on his imagination that it can hardly compass.

Was Grand Canyon formed in precisely the same way as its small brother, the Goosenecks? Though many nineteenthcentury geologists thought so, it is now generally believed that the explanation is not quite so simple. The Colorado also winds back and forth, but its meanderings are probably, in part at least, the result of rock structures encountered during its downward progress. It is not, in other words, merely the entrenchment of early meanders. But the essential fact that remains is this: The Colorado, like the San Juan, once flowed across flat country which lay at approximately the level of the present stream bed. It had climbed no mountains to get there; resisted no impulse to run steeply the shortest way downhill; and its height above sea level was not greater than it is now. The river, though it cut through rock now forming the rim, was never "up there."

Slowly, however, the earth began to rise under the river never fast enough to dump it out of its channel, never so fast that it could not cut downward more rapidly than the earth rose. At the same time, the Colorado was becoming a mightier river. When the Rocky Mountains first rose, they had brought down more water and made or increased western rivers. Later, as each of the successive ice ages ended, melting snow and ice brought flooding waters and with them the sand and pebbles and stones with which the river cuts downward not so much like the knife with which it is commonly compared, as like a file or a cutting disk well supplied with abrasive. Moreover, as geologists are fond of pointing out, the process was not like pushing a knife into a cake, but like raising the cake slowly upward against an immobile knife.

No one knows why the earth rises, falls, and sometimes buckles or breaks in its alarming way. But it has done just that many times in the past and is doing it now. A year or two ago one of the Galápagos Islands rose with such unusual sudden-ness that what had been a bay became a shore. The Himalayas are believed to be still in the making, and Mount Everest is said to be rising. Parts of the California coast are also rising; other parts of the United States sinking. Whether or not the rocks of the Canyon walls and floor are still moving upward, no one knows, though earthquakes in the region suggest that they may be, and there is plenty of cutting power still left in the Colorado. In recent times it has carried as much as 27,000,000 tons of sand and silt past Bright Angel Point in one day and probably averages more than half a million another reminder that "human aid" couldn't approximate its work.

Mountains are still a great deal more massive than skyscrapers. The most awesome force that man-induced atomic fission has ever released is puny by comparison with that unleashed in a hurricane, to say nothing of that which lifted the Rockies and the Alps. If, as park naturalists often point out, the Empire State Building had been built on the river, its summit would be just barely visible from the rim as it peeped above the inner gorge some four thousand feet below. That the Colorado dug out what our bulldozers could not is even more vividly suggested by a comparison with the work done on the Panama Canal. That, I suppose, represents man's greatest attempt to rival nature as an earth mover. It involved the stupendous task of moving something like 450,000,000 cubic yards of dirt and stone. But the Colorado moves about 170,000,000 cubic yards per year or more than a Panama Canal-full every three years. And it has been working at various rates, of course for several millions of years. ☐☐☐