This document includes the river width, it says there are too many variables.

https://www.nature.com/articles/s41598-019-44347-4

https://link.springer.com/article/10.1007/s11629-014-3265-0

here's a cool reference:

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL082027

Did you know that a given type of rock gives mountains with all the same slope angles, i.e. there are mountains with ravines averaging 23 or 14 or 33 or 50% for the same mountain group, and screes inclines are rarely an irregular mix.