If the turkeys can get to the creek bank on the otherside, I would set up decoys on the bank on your side of the creek and setup. If the birds see the decoys from their side of the creek, I bet they will fly across! Hey what the heck you have got nothing to lose but eveything to gain. I actually saw a video were a guy did this. Big Tom flew right cross the small river and He blasted him as soon as he landed.