Originally Posted by kerry

I think some basic knowledge of river hydrology would have helped them in those situations. The bank was steep because it was on the outside of the river current where the river always cuts away the bank steeply. If the had toppled a tree into the river upstream and redirected the current away from that outside bank, the river would not have been cutting away at it so steeply and probably would have been depositing debris in the eddy behind the tree. The current in the middle of the river would then have been a little faster but the sides would have been much easier to deal with.