Theories for the Formation of Grand Canyon Sidebar 3
The Breached Dam Theory
The Breached Dam Theory states that there was an enormous lake covering over 30,000 square miles of Utah, Arizona, and parts of Colorado and New Mexico (See Figure 6). The proposed area for this lake is the Colorado Plateau—an uplifted basin surrounded by mountains. Due to the collapse of a natural dam (the Kaibab Upwarp), the lake drained catastrophically and etched out the Grand Canyon. Figure 6
(See Figure 7) The theory says that it happened in two stages—first a lake in Arizona breached the Kaibab Upwarp and formed the gully through which the Colorado River runs (See Figure 8). Later, another large lake in southeastern Utah breached its dam and caused massive erosion and established connection with the upper Colorado River basin (See Figure 9). | | | | | | Figure 7
| | | | | | Figure 8
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Figure 9
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Examples of Breached Dams:
There are several known examples of massive erosion caused by the breaching of a dam. For example, the Teton Dam broke in Idaho in 1976 and the water caused the erosion of 20 feet of bedrock. Another example is the natural glacial dam that broke in Idaho which had restrained Montana's Lake Missoula. As the lake water rushed over Washington, it scoured out the Channeled Scablands, including the Grand Coulee - a trench 50 miles long with steep walls up to 900 feet high. A third example of the erosive effects of catastrophic floodwaters is from Mt. St. Helens. When a debris dam was broken, water and mud eroded several canyons, up to 140 feet deep. Evidences for the Breached Dam Theory:
There are four types of evidence for a breached dam east of the Grand Canyon. First, there is evidence for an ancient lake. There is evidence in the rock layers (thin laminae, and fresh water fossils) that the Colorado Plateau was covered by water in several places. The most substantial evidence is for Hopi Lake in eastern Arizona, east of the Kaibab Upwarp. A lake could not exist there now because of the Grand Canyon, but it is generally accepted that there was once a great lake there. The second type of evidence for the Breached Dam theory is the presence of "underfit" rivers that course through Grand Canyon and valleys upstream of the Canyon. A river is called underfit because the valley or canyon through which it flows would have taken far more water velocity and volume to carve. Underfit rivers are evidence of greater water flow in the past. Figure 10
 | The third type of evidence for a breached dam is in relict landforms. There is geological evidence of great volumes of water flow in the Grand Canyon and in eastern Arizona. When water drains out of a lake, the water that has been trapped in the mud layers below the lake seeps out. The oozing of the water causes structural collapses in predictable formations (amphitheater-shaped) (See Figure 10). There are many side canyons in the Grand Canyon that have an amphitheater shape, rather than a V-shape, and these side canyons could be explained by water seepage as massive amounts of water rushed through. Further evidence that the Canyon was formed by a catastrophic event in the past (rather than by gradual erosion) is that the cliffs appear to be stable—with relatively few boulders from landslides. Also, the desert varnish, which accumulates gradually, coats layers like the Redwall Limestone indicating that the cliffs have been stable for some time. If the Canyon were being eroded as uniformitarians suggest, there should be evidence of cliff instability. Instead, the Grand Canyon gives evidence of stable cliffs that were eroded in a great catastrophe. |
The fourth type of evidence for catastrophic erosion (breached dam) is found in the Colorado River delta in the Gulf of California. The rock layers show no evidence of a river delta until the Pliocene layer, and the Pliocene rocks have characteristics of rapid deposition. The rock layers that record the history of the Colorado River delta seem to give evidence for a sudden and rapid formation of the Colorado River which quickly deposited thick strata. The Breached Dam Theory can be modified to fit a Young-Earth Creationists model of Grand Canyon formation. According to the Flood model proposed by Austin and others, "Late in the Flood, and in the immediate post-Flood, the Kaibab Upwarp was formed. This Upwarp blocked the drainages of the Colorado Plateau. In the post-Flood period, possibly hundreds of years after the Flood, enough water had built up in these lakes, that dam failure could occur." (Austin, 1994) References
Austin, S.A. 1994. "How was the Grand Canyon Formed?" in The Grand Canyon: Monument to the Flood Institute for Creation Research, Santee. p. 83-110.
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