. Cohesive strenght and compressive strenght are correlated and "harder" rocks are more difficult to erode. For example erosion caused by breaching of the lava dams in the Grand Canyon eroded away nearly all of the basalt from the lavas without significantly eroded the stronger Vishnu Schists and Zorastor Granites. To use erosion of soft mud and ash that has no cohesive strength as an analogy for erosion of solid rock makes no sense.
So it was not turbulent but somehow eventually carved a canyon thousands of feet deep in rock with sufficient compressive strength to support cliffs thousand of feet high. How did that work?
So tell us what sea water chemistry resulted in a flood depositing the very pure Mississippian Redwall limestones in a layer 400-800 feet thick atop all the underlaying layers and how is it that the only macro fossils in the Redwalls are Mississippian? Or don't you think the Redwall is a flood deposit? Perhaps you could tell us exactly which layers are flood deposits and which aren't.
Geologic Formations of Utah: Redwall Formation
This sure doesn't sound like something deposited by a global flood to me.