So the insurance company is going to cover errosion by mother nature? I'd throw my 210 down in there and hurl all that up on the bank in a day. 1200yards wouldn't take long. I'd leave all stumps possible, no need to rip out a tree thats holding the bank in the first place. Looks already like rip rap size rocks and sand. Just pile all the small stuff up and then line the bottom of the bank with the larger rocks to hold it. As long and you make the channel straight and the way it should it will be fine. Although I'm going by a picture it sounds like your making it harder than it is but thats just me.