In rivers with a current do not float with your body on the down river side of the canoe. By staying upstream you can avoid being pinned against an obstruction. Surprisingly, even a light current flow could cause you to be pinned if you are between an immovable object and your canoe is in a tidal flow. Stay away from strainers and sweepers. Sweepers are low-hanging branches which touch the water in a current.
Strainers are trees and parts of trees or posts which are submerged and subject to strong currents.
If you are swept by the flow against an obstruction lean your body toward the obstruction instead of pushing away. Pushing invites the flow to come in over the side rather quickly, since water moves irresistibly and is constant. Trash Bags - clean up after yourself, and remember to leave our fragile environment as beautiful and healthy as it was before you arrived.