Years ago I canoed down Putah Creek, putting in at the bridge (as I recall), and taking out in Solano Lake. It was fine--we saw a bunch of wood ducks and assorted other wildlife including a mink. Fine, that is, until we floated around a bend and found an enormous fallen tree lying across the creek. The canoes dumped, and four folks including me found ourselves trapped by the current against all those branches and flotsam. Somehow I was able to push myself away from the tree far enough to find slack water and make my way to the shore, as did my three companions (including a nine-year old). One of the canoes was wrecked, the other pretty badly dented (aluminum). I'm not suggesting that it's impossible (we did make it to Solano Lake), but I will never float Putah again and for that matter I won't float any moving water anywhere without a thorough recon first. That I am alive today is entirely a matter of luck.