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Cavitation
by John D. Morris, Ph.D. *

One glance at Grand Canyon evokes wonder at the extensive erosion that occurred—but the canyon is only the final whisper of a grand-scale event. The massive erosion episode leveled off and gouged out the Colorado Plateau, covering much of Arizona, Utah, New Mexico, and Colorado. The present-day Colorado River hardly seems capable. Something of a much larger scale accomplished this!

Creationists assign most sedimentary rocks to the great Flood of Noah’s day, which then eroded as the Flood ended and the waters rushed off the rising continents. Seeming problems arise in attributing all this erosion to the short time period assumed for the Flood and the centuries following. What could have accomplished this?

Cavitation, a process well-studied by engineers and geologists today, is known to be quite capable of eroding huge volumes of rock and concrete quickly. As water moves at a high velocity over a rough surface, vacuum bubbles form and implode with such a great force that they fracture the adjacent rock, thereby accelerating erosion. The U.S. Army Corps of Engineers reckons that cavitation was the culprit that eroded enormous thicknesses of reinforced concrete and the surrounding rock under a spillway draining Glen Canyon Dam in 1983, just upriver from Grand Canyon.

The dam had been constructed to protect the Colorado River and Grand Canyon below from intermittent water floods. But spring runoff was threatening to overtop the dam and send enormous volumes of water downstream, possibly inflicting much damage to the dam and inhabitants below. To minimize the damage, the overflow spillways were opened, draining the excess water in a controlled fashion. Soon, clear lake water gushed from the tunnels as if from a giant hose.

On June 15, 1983, after four days of release, the lake level continued to rise, and flow through the spillway increased. All appeared to be going well, but seismographs sensed that something more substantial was happening underground. Suddenly, the exiting water turned muddy red—the color of the underlying rock—and huge chunks of rock and concrete were thrown out.

Before they could close the spillway, water flowing at a rapid velocity had eaten through the spillway’s thick reinforced concrete casing and opened a huge chasm in the rock beneath. Within minutes, a cavern 32 by 40 by 150 feet had been excavated. Cavitation had eaten through the three-foot-thick, steel-reinforced concrete lining of the tunnel and into the underlying rock. It is possible that cavitation was pulverizing concrete, steel, and sandstone at a rate in excess of 1,000 cubic feet per minute during the peak period of erosion. Sixty-three thousand cubic feet of concrete was required to fill this enormous hole.

Never again can we doubt that dynamic moving waters are capable of doing extensive geologic work in a hurry, even under “normal” conditions. We are still left to ponder the effects of the much more intense great Flood, which would have produced erosion on an even grander scale with waters flowing at much greater sustained volumes and velocities.1

Reference

Austin, S., ed. 1994. Grand Canyon: Monument to Catastrophe. Santee, CA: Institute for Creation Research.

* Dr. Morris is President of the Institute for Creation Research.

Image credit: Glen Canyon Dam Failure. U.S. Bureau of Reclamation

Cite this article: Morris, J. 2012. Cavitation. Acts & Facts. 41 (8): 16.