How was Grand Canyon formed—a lot of water over a little time, or a little water over a lot of time?

In the evolutionary worldview, the Grand Canyon formed slowly as the Colorado River wore the rocks away. But if that’s the case, where’s the thousand cubic miles of debris at the river delta? And why are the cliffs so sheer and stable? And why does the Canyon look like it hasn’t changed since it was formed?

Well, because the Canyon didn’t form over millions of years! It was catastrophically carved out when huge lakes left behind by the waters of the global flood burst their dams. The Canyon is a remnant of the aftermath of the flood!