[BigBobber]

My model does not require vast amounts of water to be released over a short period, as yours does.

In my model, God created the world over billions of years, so untold numbers of Grand Canyons have been formed and obliterated through the eons. There is nothing in my model that requires lots of Grand Canyons all over at any point in time. Yours does because you only allow a compressed timespan for geologic processes to work.

Now can you address the other two points in my first post?

[Gargantua]

In my model, untold numbers of Grand Canyons have been formed and obliterated through the millenia as a result of The Flood and both prior and subsequent plate-tectonic activity.

The most obvious one that remains today happens to be the one that formed well above what then became sea level. The ones that formed below what became sea level were covered by the receding waters of The Flood, and they are all over the 75% of the planet now covered by water.

Next?