The following information comes from “Your Guide to the Grand Canyon” by Tom Vail.
Many people are taught that the Grand Canyon was carved out by the Colorado River that runs through it. Could a river create such a large canyon? Uniformitarianism scientists agree so. But how could this have been formed in light of Noah’s Flood? Recall the article “Where did the flood waters go?” Was it formed by a little bit of water over a long period of time, or a lot of water over a short length of time? There are two theories that explain how the Grand Canyon was formed relatively quickly:
Theory 1: After the flood, there were two or three very large lakes that formed north and east of the Kaibab Plateau (through which the canyon is carved). As the lakes continued to fill, they finally overflowed and breached their natural dams, carving through the loose sediments in the Plateau, and thus creating the canyon.
Theory 2: There was massive sheet erosion during the flood’s recession (after the 150 days of water covering the earth). As the waters receded off of the land, they channelized as more land was exposed. It was during this process that the waters moved westward and carved through the loose sediments, creating the canyon.
More information about the Grand Canyon can be found at: http://www.answersingenesis.org/articles/cfl/grand-canyon
Watch the following video to witness the awesome power of water. But first, click on this link to understand more about the video. This sheds light on how the Grand Canyon could have been formed.