x2 on the water depth. I have had our bx7510 in water about a foot deep or so with chains on the front tires. There was a clay bottom and there would be no way I would have gotten out if I didn't have the chains on. That being said, a rocky/gravel bottom should be fine. Don't go charging into a deep spot and REALLY TAKE YOUR TIME, after all, your on a tractor and not a boat. The other point I would make is try not to get into a situation that you can't get out of. As in sliding in between two trees or only being able to back into a deep pool of water.
If the banks are really steep why don't you just pull the tractor up to the edge and throw the junk into the bucket instead of a wheel barrow? Atleast it will be easier to move around!