Once flow is confined in a channel, the erosional power of a stream is related to its slope and discharge. When the flow of water is sufficiently strong, it can dislodge particles from the channel and lift them into the moving water In this manner, the force of running water swiftly erodes poorly consolidated the bed and sides of a stream channel on occasion, materials on banks of the channel may be undercut, dumping even more loose debris into the water to be carried downstream.